Yedoma. Part 1. Annals of geocryological research in the XIX-XX centuries

IntroductionIn accordance with the definition of Yu.K.Vasilchuk ^[1]: edoma is a highly acidic (containing more than 50-90% of ice), as a rule, rich in organic material (containing more than 1-2% of organic matter), silty and powdery sandy loam and fine sandy loam Late Pleistocene deposits; in intermountain basins and on slopes edoma strata, can be saturated with soil and crushed stone, and in the valleys and deltas of rivers, edom strata may contain gravel and pebbles.

The age of the edom strata varies from 11.7 to 50 caliber. thousand years and older. Edom deposits contain powerful (up to 15-20 meters high and more and 1-3.5 m wide), often multi-tiered, syngenetic re-vein ice. Edom deposits exposed by outcrops, as a rule, emit a specific smell of "old stable" due to decomposing organic matter. In the foreign literature, the term "yedoma" has been adopted, denoting not a geomorphological or stratigraphic element, but a special type of sildist deposits with syngenetic re-vein ice, common in the north of Siberia^[2].

Distribution of edom thicknessesEdom strata are widely distributed within the cryolithozone of northern Asia and North America (Fig. 1). The most famous areas of northern Asia (Siberia), where diverse and age-diverse types of edoma are widely represented, are the Kolyma and Yano-Indigir lowlands, as well as the Novosibirsk Islands and the valley of the Lena River and its tributaries.

Extensive arrays of edom were found in the Leno-Anabar, Anabar-Khatanga regions (north of the Krasnoyarsk Territory and Yakutia), in the Magadan region, as well as fragments of edom were found on the Taimyr and Yamal peninsulas. Small arrays of edom are also found in more southern regions of Siberia – for example, in the valley of the Aldan River, in southern Yakutia – south of 57 ° s.w. – in the valley of the Olekma River and its tributaries, and even south of 55 ° s.w. – in the upper reaches of the PP. Oud, Biryusa, Gutara.Fig. 1. Distribution of edoma in the north of the Russian cryolithozone.

From J.Strauss et al.^[3] with additions for Yamal and Gydan peninsula by Yu.K. Vasilchuk

In North America, edoma is widely found in Alaska, Yukon and in some areas of Canada that did not experience the cover glaciation in the late Pleistocene.

Edoma in Siberia and North America occurs on an area of about 450,000 ^km2, including about 90,000 ^km2 in Alaska^[3], and contains up to 130 gigatons of organic carbon^[4]. Edoma is vulnerable to climate change and fluctuations due to its high ice content and silty composition. Thermokarst and thermal erosion of these ice-rich deposits pose a serious danger to the environment and socio-economic systems, which in some cases may require expensive relocation of various infrastructure facilities^[5]. The growth of interest in the study of edoma in recent decades is associated with the unique preservation of paleoclimatic, paleogeographic and paleogeocryological information preserved in its original form ^[6,7], and with a high content of frozen organic matter, the release of which during thawing leads to changes in biogeochemical processes and greenhouse gas emissions^[4] and to the destruction of the ozone layer.

The analysis of the granulometric composition of edom deposits of Siberia and Alaska performed by L. Schirrmeister and co-authors^[8] in more than 770 samples from 23 edom massifs showed that sandy loam-loamy soils noticeably predominate over clay and sandy soils (Fig. 2). This is especially noticeable in the sections of the Edom Duvan Yar; Kytalyk on the Berelek River (the basin of the river Indigirka); in the thickness exposed by the Batagai megaproval and in the outcrops of Tabaga and Yukechi in Central Yakutia. And in general, the Arctic and Alaska are dominated by edoms composed of clay soils.

Fig. 2. Granulometric composition of edom deposits of Siberia and Alaska in 23 edom massifs. According to (Schirrmeister et al.^[8]): 4 – Volt Creek Tunnel; 3 – Seward Peninsula (Ketlack River); 1 – Colville (northern slope of De Long); 2 – Itkillik; 12-16 – Novosibirsk Islands; 17 – Bolshoy Lyakhovsky Island; 18 – Oygossky Yar; 11 – Buor Khaya Peninsula; 10 – in Muostakh; 9 – Bykovsky Peninsula; 8 – in Kurungnakh; 6-7 – Ebe-Sise and Hardang Islands; 5 - Mammoth Fang Cape; 19 – Duvanny Yar; 20 – Kytalyk (Berelekh River); 21 – Batagai megapolis; 22-23 – Tabaga and YukechiHistory of the study of edom strata

Since the beginning of the XIX century, numerous hypotheses of the origin of edoma have been developed, and for a long time the underground ice in edoma was considered buried by snow, lake or glacial ice^{[9, 10]}. G.Galvitz^[11] and A.I.Popov^[12] developed a provision on the syngenetic accumulation of permafrost strata. A.I.Popov^{[12, 13, 14]} proposed the hypothesis of alluvial sedimentation, accompanied by the formation of large syngenetic re-vein ice.

Other hypotheses of the origin of edoma suggest Aeolian^[15,16], slope ^[1,17,18,19], heterogeneous ^[7,20] or polygenetic ^[21] origin of edoma. T.N. Zhestkova et al.^[21] proposed the term "equifinality", suggesting that similar results can be achieved by different processes and under different initial conditions. The leading factors in the formation of edom are a cold climate and prolonged long-term sedimentation and almost synchronous freezing.

          The first information about the presence of fossil ice deposits in permafrost deposits of northern Siberia was obtained in the 30s of the XVIII century from participants of the largest scientific and geographical enterprise of the XVIII century, which later became known as the Great Northern Expedition, lieutenants of the Russian fleet of the Swede P. Lassinius and X. Lapteva. During 1733-1743, this expedition conducted mapping of the northern and eastern coasts of Russia from the White Sea to the Sea of Okhotsk, reached the western shores of North America and made geographical discoveries in the Arctic^[22]. X. Laptev writes: "Cape S. Ignatius (the place about which X. writes Laptev corresponds to the current cape Krestovsky). The shores are steep, rocky, near which the alluvial forest has a lot to offer. In the fields, the earth is meaty and there is moss on it. A 2 ^1/2-foot-long mammoth horn was dug out of the ground here. At this cape, the mountain has been made of ice for a long time... "^[22].

        One of the first descriptions of the edom strata was made on the territory of Alaska by the famous Russian navigator of German origin from Estonia, O.E. von Kotzebue, who, together with his companion, also a Baltic German, J.F.G. von Eschscholz, studied in 1816 in the cliffs of the coast of Alaska deposits of underground (most likely re-vein – edom) ice, expressed the idea ^[23] that they should be attributed to buried snowfields or clusters of firn – metamorphosed, packed snow: "August 8. We spent an unpleasant night in the midst of a storm and rain; as the morning did not portend better weather, I decided to return to the ship, but we had barely sailed half the way when a violent storm from SO began; a strong leak opened in the longboat, and we used all our efforts to reach the place we had left again shortly before that. We were soaked through, and finding here, as everywhere else in these countries, a large amount of driftwood, I ordered a fire to be lit; we dried our clothes and cooked soup. It seems that fate has sent this storm to give us an opportunity to make a remarkable discovery here, which we owe to Dr. Eschscholz. Although we walked a lot during the first halt, we did not notice that we were walking on icy mountains.The Doctor, having now taken a longer walk, was surprised to see that one part of the shore had collapsed and it consisted of pure ice.

Having learned about this, we, having stocked up with shovels and peshny, went to explore this diva; soon we came to a place where the coast rises almost 100 feet steeply above the sea, and then, rising obliquely, stretches into the distance. We saw here masses of the purest ice 100 feet high, which were covered with a layer overgrown with moss and grass. The place that collapsed is now subject to the influence of air and sunlight. A lot of mammoth bones and fangs (among which I found one of the most beautiful), protruding on the surface of the melting ice, serves as indisputable proof that this ice is primordial.

The layer covering these mountains is no more than half a foot thick and consists of clay mixed with sand and earth. The ice melts little by little under this layer, so that it rolls down, continuing to nourish the most pleasant greenery there. One can foresee that after many years this mountain will disappear altogether, and a green valley will take its place (apparently, this is almost the first case of the discovery of fossil ice. No wonder he caused such surprise.). Based on reliable observation, we determined the latitude of the spit 66°15'36" s.w."^[24]. Two years after the publication of O.E. von Kotzebue, the Russian Admiralty published the work of A.E. Figurin^[25], which reported on the widespread occurrence of large deposits of underground ice and described in detail the conditions of its occurrence in the frozen shores of the Laptev Sea and the rivers flowing into it. According to A.E. Figurin, ice bodies in the permafrost column originated in "ancient times" and continue to occur in frost-breaking cracks as a result of penetration of surface and soil water into them.

M. M. Gedenstrom during a three - year expedition to the Novosibirsk Islands in 1809-1811 identified two types of occurrence of underground ice: 1) horizontal layers and 2) vertical veins. There he formulated for the first time the question of the origin of ice layers. M. M. Gedenstrom ^{[26, pp. 119-120]} wrote: "The composition of the land near the Arctic Sea is an incomprehensible mystery of nature. Steep banks of streams and lakes, several fathoms high, are made up of layers of earth and solid ice. The ice layers mostly also lie horizontally, as well as the earthen ones. The latter always cover the former. The ice veins crossing them sometimes perpendicularly are of the newest origin, from the rupture of a whole mass by snow water. How could the alternating layers of ice and earth be formed in a horizontal position? All kinds of layers come from a gradual, undisturbed precipitation; but how can one imagine a mass of water, frozen by time, covering again with the same thickness of the earth, and so on.".I.Lopatin^[27] described masses of underground ice in the sediments of the river terraces of the Yenisei Arctic and attributed them to veins formed in frost-breaking cracks from water penetrating into them from above.

The conjection-vein hypothesis of the origin of underground ice deposits was developed in 1886-1895 by A.A.Bunge, who studied re-vein ice in the Lena Delta^[28,29] and on the island of B. Lyakhovsky^[30,31]. However, E. Tol ^[9,32], who described the outcrops of underground ice in the lower reaches of the Yana River, on the Lyakhovsky and Novosibirsk Islands attributed these ices to the remnants of the continental glaciation – burials of firn ice, although the signs of re-vein ice in the outcrops were very obvious (Fig. 3).

Fig. 3. Sketches of the underground ice of the Novosibirsk Islands, made by E. Tolem from photographs by A. Bunge (from the book by E.Tolya^[9])

     The re-vein ice arrays first described by O. von Kotzebue and I.F. von Eschscholz on the northern shore of the Seward Peninsula were studied in detail by L. Quackenbush^[33], who worked here as part of mammoth expeditions in 1907-1908. The outlets of powerful ice were discovered by L. Kvakenbush for many kilometers along the southern shore of the Eschscholz Bay.

      L.Quackenbush^[33] described in detail 14 locations of ice in the Historical Cliff alone, and although he describes the ice encountered more often as glacial, he writes about one of the fragments of outcrops: a wide wedge-shaped mass of ice submerged in silt was noticed on the Buckland River ^{[33, p. 102]}, i.e. describes a typical ice vein, and in two photographs, they undoubtedly captured edom cuts, in one the field of baijerakhs speaks about it ^{[33, Fig. 2 on tab XXI]}, and on the second, in addition to Baijerach, typical Pleistocene re-vein ice is captured ^{[33, Fig. 2, on tab XX]}.

    During the same period, C. Gilmore worked as part of the mammoth expedition of 1907 in Yukon and Alaska^[34]. For example, he cites a photograph in the Palisades area on the Yukon of a cliff typical of edom thicknesses ^{[34, Fig. 2 on page 18]}, about which he writes: The cliff area... from one hundred fifty to two hundred feet (i.e. from 45 to 60 m) in height and firmly frozen, consist mainly of very fine silt of a greenish-gray color.... Their almost perpendicular outcrops are constantly being washed away by a rapid current, causing large masses of soil to split off, which occurs repeatedly with a stunning sound and a subsequent splash when they fall down into the water. During our two days here, the rumble often sounded so that we were amazed by the sharpness of the sound^{[34, p. 18]}. Also, C. Gilmore^[34] describes numerous ice outcrops in outcrops in the Palisades, Old Crow, etc. areas. He compares the sites of mammoth finds with the discovery of a mammoth skeleton on the Berezovka River in Siberia in 1901 ^{[34, p. 20]}.

The idea of syngenetic accumulation of frozen rocks arose in the late 19th-early 20th centuries independently from I. Lopatin, R. Abolin, Nekipelov and E. de K. Leffingwell.

      R.I. Abolin^[35] explained the formation of permafrost strata by the growth of peat cover and the accumulation of precipitation in the valleys: “If we now take into account that there is a constant accumulation of fresh organic matter on the surface of the swamp, causing a new and new increase in the surface, then it is natural that the horizon of extreme summer thawing will also be from year to year year to rise. At the same time, the corresponding ice layers and nests will move from annual formations to the category of fossil rock ice. Ice layers in the mineral soil will persist for a longer time only if new layers of sediment are deposited on the surface, which will also increase the horizon of the ultimate thawing of the soil. Similarly, ice rods that fill cracks are able to persist indefinitely for a long time only if they are covered with a layer of some kind of bad heat conductor. The conservation conditions in the latter case are more favorable only in the sense that cracks, for example, formed in winter from frost, often already enter the horizon of permanently frozen soil and, as we saw earlier, usually expand under the sod layer. The latter in such cases, especially if it is strongly peaty and is in a constantly wet state, is a good defender of the ice formation hidden under it against the melting effect of sunlight. If, as is usually the case in reality, the peat character of the covering sod layer gradually increases and the accumulation of organic matter continues continuously, then here we have all the data to ensure that such an ice vein passes as an equal member to the number of modern sediments” ^{[35, pp. 101-102]}.

The process of burial of sediments burying frozen layers, geologist Nekipelov explains as follows: “…It seems to me that the permafrost gradually increased from the bottom up, when filling river valleys and mountain slopes with loose material. It could happen like this: during the winter, the soil froze so much that it did not have time to thaw in a short summer period, and its lower horizons remained frozen for the next year.

At the same time, the soil continued to grow from above, being covered partly with new alluvial material, partly with vegetable humus and, thus, the lower frozen layer becomes even more protected from thawing, and the second layer froze over it the following winter and also, which did not have time to thaw over the summer, remained in conditions of permanent permafrost. Such an increase in permafrost should occur all the time while the accumulation of material continues ...” (“Geological description of the terrain in the area of the railway from Kerak station to Chaldonka station, compiled by geologist Nekipelov” – cit. in Lviv ^{[36, p. 628]}.

One of the earliest studies of re-vein ice in the southern part of the cryolithozone was carried out by A.V. Lvov in his fundamental work on Transbaikalia^[36]: “In winter during severe frosts, especially with a small amount of snow, the earth cracks to a greater depth, which contributes to the freezing of deeper soil horizons. Middendorf, Meisel, Wrangel and other travelers in the Yakut region drew attention to these phenomena at the time, linking the very origin of permafrost with such deep cracks in the soil. Such cracks are observed in Transbaikalia and in the areas of the Trans-Amur railway; when measuring some cracks on the Perevalnaya (in the “dirty recess”) and near the Zubarevo station, their depth reached from 3 to 6.8 meters or more. If water gets into such cracks in the spring when the snow melts, then the latter, freezing, forms ice veins that fill the former cracks”^{[36, p. 90]}.

E. de K. Leffingwell^[37,38] in the period from 1906 to 1914 spent nine summer seasons and six winter seasons on the Arctic coast of Alaska, making 31 trips by dog sled or small boats. E. de K. Leffingwell is perhaps the first researcher of re-vein massifs and, including edom strata, which you can call it a professional geocryologist. He created the first accurate map of a large part of the Arctic coast of Alaska. E. de K. Leffingwell concluded that the formation of ice veins occurs in open frost-breaking cracks, which are filled with water formed as a result of melting snow, while: "the growth of ice in frost-breaking cracks occurs from year to year except for years with mild climatic conditions, when there is no the need for stress relief by cracks by opening them"^{[37, p. 642]}. The maximum length of the ice veins observed by him was about 3 meters, however, given the width of the veins, E. de K. Leffingwell assumed that the veins were wedged at a depth of 2-3 times greater. He concluded that as the growing vein of ice becomes larger and more wedge-shaped, pressure begins to influence its edges. This causes the vein to rise up. If the uplift occurs, the ice will also lift the overlying layers of soil, as a result of which it may be at the level of the polygon surface or even higher. E. de K. Leffingwell pointed out ^{[37, p. 647]} that usually fine ground material covered with turf or peat formed by sphagnum moss lies above the ice. If the thickness of this coating increases, the sole of the seasonally thawed layer also shifts to the surface, which allows the ice wedge to grow upwards (i.e. described the process of syngenesis in the development of veins). E. de K. Leffingwell investigated the most powerful veins, probably in edom deposits, in the coastal outcrop of the Noatak River ^{[37, pp. 205-206]}.

Very precise remarks on the structure and conditions of formation of vein ice in the valley of theYany is cited by hydrographer P.K. Khmyznikov, who explored the valley in 1927-28. “In the structure of the middle terrace, soil ice occupies no less important place than in the composition of the upper one...Of the forms, the most typical is the shape of a horn placed vertically with an upward extension”p^{[39, p. 44]}. About the modern formation of veins, P.K.Khmyznikov reports: “The formation of such ice veins, apparently, is happening at the present time. The cracking of the soil noted by previous researchers in Verkhoyansk in the coldest time also occurs here, forming an initially narrow crack, further expanded by freezing of water flowing into it in spring and summer. In Verkhoyansk, this process, due to the dryness of the air and the absence of excess soil water, does not give channels wider than 0.25–0.5 m, and the high summer temperature melts the ice formed in them during the winter. His conclusion about the peculiarities of the distribution of veins along the valley of the Yana River is very interesting: “Parts of the seabed emerging from the water to the daytime surface, modified by the processes of overgrowth and deposition of wind sediments, are subject to dislocations of frost-breaking cracks. Further, the above-mentioned sequential freezing is the formation of ice masses in the predominant form of the vein. Hence it is clear that the longer the area of the soil is above the surface of the water, the more ice it carries.

The modern formation of soil ice is probably characteristic of other deltas of the Yakut rivers. So, in the Lena Delta there are islands identical in height to the Yanskaya middle terrace, including ice formations. For example, the islands of Dashka, Cherny and others from the archipelago at the mouth of the Bykovskaya Channel of the Lena Delta reveal narrow ice outlets, which should also be classified as vein forms”p^{[39, pp. 45-46]}.

P.K. Khmyznikov also observed older vein ice in sections of high terraces in the middle reaches of the Yana and in the lower reaches from the foothills of the Kundyulung ridge to the mouth of the river and described baijarakhi on the shores of Lake.Vasilevsky, near the village. Cossack.

Later in the middle of the 20th century in the works of H.Galvitz, E.M. Katasonov and A.I. Popov formulated the idea of syngenetic formation of powerful re-vein ice in edom strata.

One of the outstanding researchers who made a major contribution to the study of Edoma is the Austrian geologist G.Galvitz^[11]. Being an expert on Jurassic rocks, back in the mid-30s, G. Galvitz described the layers of wedges-pseudomorphoses, in quaternary deposits on the territory of a former glass factory north of the Trophy in the city of Halle, federal state of Saxony-Anhalt, Germany^[39]. In particular, in this work he came to the conclusion that the loess profile can be divided into an older and a younger loess. Older and younger generations of permafrost cracks are associated with this loess, which indicates a significant improvement in climatic conditions in the interstadial. This point of view is confirmed by tree pollen found in the humus horizon of the interstadial. Older frost-breaking cracks have certain differences in size and shape compared to younger ones, which is apparently related to the climate^[39].

Based on these field studies, as well as acquaintance with the works of G.Steche and V. Zergel^[40] on Pleistocene pseudomorphoses and soil wedges and E. de K. Leffingwell^[37,38] on the ice veins of Alaska, G. Galvitz formulated several prerequisites: "When E. de K. Leffingwell after his research... for the first time he reported on the wedge-shaped growth of underground ice in frost-breaking cracks, in geological circles this publication received little attention. The ground structures that could indicate such fossil ice wedges were still barely known. This was the reason that the first descriptions of clay wedges ... were not given in connection with ice wedges."

G.Galvitz^{[11, p. 5]} notes that the phonography of F.Frekha^[41], which shows all the peculiarity of the ice wedges of Siberia, has not received an explanation and further attention. The merit of G.Kharasovitz^[42] in his study of bauxites in upper Hesse is that he first explained wedge-shaped loess inclusions as ice wedges. Then P.Kesseler^[43] recognized traces of Pleistocene ice wedges in sandy cracks in the clays of the Rabutzer basin and Thuringian deposits. V. Zergel^[40] studied in detail numerous subsequent finds in Thuringia and assessed Pleistocene ice wedges as paleoclimatic. Further, G. Galvitz states that in the last 15 years, the material of observations of fossil ice wedges has been multiplied by numerous geologists in different parts of Germany and neighboring countries, as a result, researchers were better informed about the nature of ground (ice) wedges from fossil finds than from observations of modern ice wedges in subarctic and Arctic regions, excluding works by E. de K. Leffingwell^[37,38].G. Galvitz ^[11] comes to the conclusion that all the various forms of ice wedges can be divided into:

"1. Epigenetic ice wedges.

These wedges are formed in the already accumulated rock.

a). Their fossil forms are filled with fine-grained material: epigenetic undisturbed ice wedges.

b). Their fossil forms have deformed walls due to host rocks: epigenetic broken ice wedges.

2. Syngenetic ice wedges.These ice wedges grow in accumulating sediments as the surface rises:

a) syngenetic undisturbed

b) syngenetic disturbed ice wedges dominated by coarse-grained sediments.

It is often not easy to distinguish syngenetic ice wedges from epigenetic ones, since the assessment of this issue retains an important form. The thinner the sediment, especially of the same grain composition, the sooner its epigenetic origin can be assumed, if this is not the case, its syngenetic nature can be assumed ^{[11, p. 19]}.

It is important that G. Galvitz, who has never seen ice veins, very accurately showed the cyclicity in the development of veins during syngenetic freezing, with a single change in the rate of accumulation of deposits (a) and with a constant increase in height (Fig. 4).

Fig. 4. Cyclical formation of ice wedges during syngenetic freezing, with a single change in the rate of accumulation of deposits (a) and with a constant increase in height (b). From Galvitz^{[11, p. 12]}

    A comprehensive geological and geographical justification of the vein origin of these ices was given in 1949 by A.I. Popov, who, in the words of E.M. Katasonov ^[44,45]: "we can say that A.E. Figurin and A.A. Bunge restored common sense in this matter."

    The beginning of the 50s of the XX century was the time of the beginning of a professional comprehensive study of edom strata, almost simultaneously in North America and in Eurasia.

Studies of edom strata in the second half of the XX century . The 50s of the XX century.

The publications of A.I.Popov^[12,13], E.M. Katasonov^[45,46], B.N. Dostovalov^[47], P.A. Shumsky ^[48,49], B.I.Vtyurin^[50] aroused great interest among the entire permafrost community and already in the first half of the 50s, dozens of people went to the areas of re-vein ice distribution permafrost detachments, in almost each of which specialists worked, among the most important scientific tasks of which was the study of ice veins. A.I. Popov, who studied vein ice in the northern Taimyr in 1949, came to the conclusion about the syngenetic formation of ice veins simultaneously with the accumulation of precipitation in the floodplains of Arctic rivers. In further works, A.I.Popov provided evidence of the syngenetic vein origin of the main masses of fossil ice in northern Siberia^[12,13].     

In North America, powerful re-vein ice has been studied on the coast of Alaska^[51,52,53]. Undoubtedly, T. Peve's innovative contribution was the introduction of radiocarbon dating into the practice of permafrost research, less than 5 years after this method was invented by W. Libby in 1946. T.Peve^[53] in 1951-52 selected samples of macroorganics from ice, wood and sandy loam deposits containing ice veins in a 40-meter section of Edoma Willow Creek. A sample of wood taken by him in 1951 2.5 m below the surface of late Pleistocene sediments was dated to the age of 23300 ± 1000 years (W-435), and wood samples taken in 1952 at the base of the Late Pleistocene formation and near its middle ^[15] were deposited 23 thousand years (L-157A) and 30 thousand years ago (L-163J), the age of the wood at the base of the ice vein is 24400 ± 650 years (I-2116). T.Peve in his dissertation ^[53] and in the article ^[54] showed that frozen edom silts in the valleys of the Yukon-Tanana upland in the Fairbanks region of central Alaska demonstrate a complex history formation, erosion, freezing and thawing over the last 20 thousand years^[53]. A thin layer of organic silt with a radiocarbon age of more than 20 thousand years was deposited on gold-bearing gravel in the bottoms of valleys. Then, according to T. Peve, this territory was covered by a powerful loess cover. Fossils of radiocarbon age from 12 to 16 thousand years are found in these loess, which also contain buried trees, mammalian bones and several partial carcasses of extinct mammals.

R.F.In his dissertation^[53] and in articles^[51,55,56], Black considered the structural features of re-vein ice near Barrow, Alaska. His findings confirmed the hypothesis of compression of E. to K. Leffingwell in the development of vein ice. All ice veins are characterized by many bands of air bubbles and inclusions of organic material, as well as silt, sand and gravel, which in most wedges form a noticeable layering, sub-parallel to the sides of the veins. Some bands intersect inside the ice veins. Most air bubbles and inclusions are stretched vertically regardless of the orientation of the strip in which they are located. The movement inside the wedges is determined by grain recrystallization, tension cracks, shear planes, displaced bands of air bubbles and inclusions.     

A.I. Popov, who studied vein ice in the northern Taimyr in 1949, came to the conclusion about the syngenetic formation of ice veins simultaneously with the accumulation of precipitation in the floodplains of Arctic rivers. In further works, A.I.Popov provided evidence of the syngenetic vein origin of the main masses of fossil ice in northern Siberia^[12,13]. A. I. Popov in 1952 published one of his most important works devoted to frost-breaking cracks and the problem of fossil ice^[13] which he observed during work on the Taimyr, in connection with the excavations of the mammoth.

  Observations of fossil ice in the Northern Taimyr, made by A.I.Popov together with E. P. Shusherina, showed that there are two types of ice in this area. generation: 1) wedge-shaped-lattice, fractured and 2) snow-covered, firnized. A. I. Popov has found that the ice of the first generation fully corresponds to the type of fractured wedge-shaped fossil ice. A powerful ice vein has been studied in detail, which was drilled to its very base. Then a deep and wide pit was dug here, which gave an idea of the configuration of the wedge, the structure of the ice and the structure of the rocks surrounding the wedge. The depth of the wedge was about 6 m, its width in the upper part was about 2.5 m. E.P. Shusherina, who took an active part in general observations on the occurrence and distribution of fossil ice in the Northern Taimyr, also systematically investigated the structure of ice in the field, determined its bulk weight, determined the amount of mineral impurities and studied their distribution by depth in ice wedges. In Moscow, according to ice samples taken by E. P. Shusherina, its chemical composition and the composition of diatoms were determined. Images of the ice structure in polarized light were taken using ice monoliths delivered to Moscow in a naturally frozen state. The characteristic vertical banding of ice in the wedges has been interpreted as the result of annual cracking, followed by the flow of turbid water into the cracks from above. A.I. Popov^[13] concludes that those researchers are certainly right who say that the proliferation of ice wedges occurs due to the annual deep cracking in winter of the entire frozen polygonal system and filling the cracks in spring during high water A.I. Popov^[13] notes that in the section such ice massifs, being exposed by a river or sea, especially along the stretch of long ice wedges, often create the impression of reservoir deposits, which sometimes mislead researchers. In his opinion, the main accumulation of wedge–shaped ice occurs, apparently, during the period when the surface of the terrace is experiencing a floodplain stage, i.e. when this surface is periodically covered with hollow waters, the developing polygonal relief and the growth of wedge-shaped ice are mutually conditioned phenomena confined to modern accumulative terraces, i.e. floodplains, which are currently covered with water in high water. With the cessation of the floodplain regime and the accumulation of precipitation, the growth of ice stops and they, together with the polygonal relief, become relict. A.I. Popov concludes^[13]: the main accumulations of fossil ice in our north and northeast are fractured, wedge-shaped lattice; they were formed and are being formed in the floodplains of the alluvial plains, in the harsh climate of the Arctic and the Subarctic with little snow in winter. Their development in these conditions is determined by the development of the floodplains themselves, which depends both on climatic and largely on tectonic causes.

      In 1952, the work of B.N.Dostovalov^[47] was published on the physical conditions for the formation of frost-breaking cracks and the development of re-vein ice in loose rocks. B.N. Dostovalov^[47] came to some concrete conclusions regarding the physical causes of the tetragonal network of cracks, as well as the conditions and mechanism of crack development. B. N. Dostovalov^[47], came to some concrete conclusions regarding the physical causes of the tetragonal network of cracks, as well as the conditions and mechanism of crack development. Dostovalov suggested that the problem mathematically solving the physical essence of crack formation was not only not solved by him, but also not set, it is so mathematically complex. B.N. Dostovalov^[47] proposed a method for approximate determination of the age of fractured ice: a). In the area of Lake Abalakh (central Yakutia), a vein of ice with a width of about three meters, extending deep, was discovered in a 10.5 m deep hole. Wells in the same area have shown the capacity, apparently, of the same age ice up to 18 m. Assuming a cracking depth of 5 m = 500 cm and an average thickness of an elementary vein of 0.5 cm, the number of annual cycles according to B.N.Dostovalov is 2160. Thus, with these data, the period of time during which this vein developed is not less, but rather more than 2160 years. b). Ice with vertical striping in the form of wedges and veins with a height of 30-40 m and a width of about 15 m are observed on the Novosibirsk Islands. Assuming an average depth of an elementary vein of 5 m and its average width of 1 cm, the number of annual cycles is 12,000^[47]. B.N. Dostovalov hoped that studies of the structures of fractured ice would lead to more accurate definitions of the depths and thicknesses of elementary veins, which, in turn, would undoubtedly clarify the age of fractured ice^[47].

      At the same time, an article by P.A. Shumsky was published ^[48]. It establishes the conditions and the form of occurrence of fossil ice in the form of a lattice of vertical veins, develops a criterion for the visual determination of re-vein ice, the ability to distinguish it from other types of underground ice, this criterion consists in the vertical layering created by layers of soil or air bubbles, which according to P. A. Shumsky^[48] is sufficient proof of belonging ice to the re-core type. However, it is useful to note that in 1952 P.A. Shumsky still doubted the syngenetic nature of a number of powerful ice veins. He wrote ^[48]: "As can be seen from the above description, there is no data in the structure of the veins studied by us that would allow us to talk about their growth simultaneously with the accumulation of precipitation in the floodplain. Such syngenetic growth, obviously, should have affected the presence of parts of elementary veins nearby, at the same level – layers formed at different depths below the surface and therefore having different power, crystal size, crystallographic orientation, degree of development of optical anomalies, etc., etc. There are no signs of such a displacement of the tops of the layers it was not detected in the vertical direction. Apparently, the growth of veins of fossil ice occurred from top to bottom with the unchanged position of the earth's surface, that is, after the deposition of the entire thickness of precipitation. Consequently, with such an epigenetic type of growth, the veins are apparently able to penetrate to a depth of 20-25 m, at which the lower ends of the veins were observed in drilling wells and outcrops in the area of the Leno-Amginsky interfluve. This, of course, does not mean that in other conditions, for example, with intensive freezing of the sediment column simultaneously with their accumulation, the development of ice veins does not occur syngenetically, during the accumulation of precipitation in the floodplain, so that the growth of veins in the vertical direction would be limited only by the thickness of this sediment column, as G.Galvitz suggests ..., A. I. Popov... and B. N. Dostovalov. Future studies in the Primorsky Lowland of northern Yakutia should establish whether the exceptionally strong development of fossil ice in this area is due to syngenetic or epigenetic growth of repeated ice veins."P.A. Shumsky reports that in 1950, the Institute of Permafrost Studies of the USSR Academy of Sciences organized extensive field studies aimed at solving the problem of underground ice in central Yakutia.

A geophysical detachment was sent to the Leno-Amginsky interfluve, in which P.A. Shumsky, with the participation of a student-intern B. I. Vtyurin (later a professor of cryolithology), studied the conditions of occurrence and structure of ice bodies in pits, the composition, texture and structure of ice, and R. I. Korkina conducted geophysical work. The work on structural and textural research, which began somewhat earlier than the geophysical ones, very soon led to the conclusion that the underground ice, which was taken by previous researchers as firn (and P.A. Shumsky also thought so at first), are vein-like, formed in frost-breaking cracks in the soil. The basis for such a conclusion in the field, according to the study of ice with a magnifying glass and polaroids, was definitely the primary nature of the vertical "banding" or "fracturing" of fossil ice, as the supporters of the firn and buried glacial hypotheses called the stratification. The ice layers in the investigated pit of the 1940 expedition in Abalakh lay in the form of a narrow, slightly expanding fan: vertically in the middle, and on the sides with a drop inwards of no more than 75 ^o. As P.A. Shumsky and B.I. Vtyurin concluded, the ice body opened by the pit to a depth of 10.5 m could not be anything other than a vertical vein ^[48].     

In the publication of 1953, the most important for the development of Edoma research, A.I. Popov^[12] develops previously obtained conclusions, continuing to polemize with E.V. Tolem and A.A. Bunge, whose versions do not explain the conditions for the formation of powerful fractured polygonal ice, emphasizing that only the facies composition of sediments reaching high power and accompanying ice, it serves as an indication of the simultaneous accumulation of these two components. He claims that the already mentioned crumpling, bending of the layers of floodplain sediments near contact with ice is very indicative. If wedges or veins of fractured ice were growing from top to bottom, in the already deposited sediment thickness, as A.A. Bunge suggested, penetrating deeper and expanding more and more in the upper part, we would have to observe the greatest crumpling, bending of layers in the upper horizons of the thickness, since here their compression must inevitably be greatest. With depth, the degree of bending of the layers should gradually decrease. However, in reality, something else is observed. With depth, there is a change in the degree of bending of the layers near the contact with the ice, which can be traced several tens of meters vertically. Usually, a gradual or more or less abrupt change from very strongly curved layers to almost horizontal is traced vertically downwards, strongly curved layers are again observed even lower, and then again weakly curved, almost perpendicular to the plane formed by ice. At the same time, it turns out that the plane of contact between ice and soil is not smooth at all, but also curved in accordance with changes in the degree of bending of the layers. Such a picture in the arrangement of the layers at the ice contact clearly indicates that each of these layers was deposited already in the presence of ice nearby and only then deformed, but to varying degrees depending on the intensity of the impact of ice on it. 3The intensity of the impact of ice on the ground changed with the layering of sediments, and this could only happen if ice was also growing at the same time. A.I. Popov^[12] emphasizes that a very important and, apparently, completely irrefutable proof of the described process is sometimes the observed change in the facies composition of sediments in the horizontal direction – from the middle of the "earthen" pillars to their periphery. It consists in the fact that the ice veins are gradually wedged with highly enriched" plant residues, fastened with roots of grasses, and peat lenses representing the deposits of swampy intra-polygonal depressions. Near the iciest veins, they pass into thin layers, relatively depleted of plant residues. Such peat lenses are arranged in several tiers one above the other and are found at different depths in the "earthen" pillars between the ice veins. In the vertical direction, they are interspersed with mineral layers significantly less enriched with plant residues. There is no doubt that each peat lens marks the position of an intra-polygonal swamp once located on the surface of the floodplain terrace, overlapped by precipitation, as they accumulate.Popov formulates two important conclusions: 1). Recognizing the powerful fossil ice of Siberia as fractured-polygonal, and not firn or glacier, the most significant argument in favor of the former cover glaciation of the plains of Siberia disappears and 2). The recognition of the fractured-polygonal origin of the main masses of fossil ice also entails the denial of significant climate fluctuations for a long time in the Quaternary period, the different size of wedges and veins of ice in the deposits of terraces of different ages indicates not so much the climatic differences under which both were formed, as the time during which the terrace, i.e. its surface was in a floodplain state, as well as about the regime of precipitation accumulation.

A.I.Popov^{[12, 13]} and E.M.Katasonov^[45] brilliantly demonstrated the example of the Muskhain ice complex in the lower reaches of the river.I believe that even very powerful deposits of underground ice can form syngenetically. These works marked the beginning of a very rapid development of views on the origin of edom re-vein ice. E.M. Katasonov was the first in the early 50s of the XX century to cryolithologically investigate the Muskhai edoma (Fig. 5) notes that "The Muskhai section...it differs from the other two typical sections in its completeness. In it you can observe the bedrock, riverbed, ancient and floodplain deposits. The section has a peculiar rhythmic structure... Below we will give a full description of this outcrop, which, by the richness of the rocks represented in it and by the nature of the structure of the latter due to the presence of ice in them, can be called a natural museum"^{[46, p. 74]}. Fig. 5. Edom Mus-Hai.

Photo by E.M.Katasonov

    E.M. Katasonov ^[45,46] summed up his studies of the Muskhain edoma: "The facies varieties we have identified, as follows from the analysis of the lithological column... they are arranged in a certain order, repeated in the context of the Musi-Hai, which is why its rhythmic structure is connected. It is difficult to say whether such a regular alternation of facies in time is due to uneven tectonic movements (subsidences), displacement of the riverbed of the Great or periodic changes in its hydrological regime. Apparently, all these reasons took place and overlapped with each other.  Another feature of the Mus-Hai cut... The two lower horizons and the facies composing them are the most seasoned in the expanse of the Mus-Hai outcrop, which, apparently, is due to the influence of the old man that existed here before on the morphology of the floodplain during the accumulation of the first and second horizons. On the contrary, the third and fourth floodplain horizons are much less sustained in space. The formations of heavily waterlogged polygons developed in the middle part of the outcrop in the western direction (the western circus) sometimes turn into the wet meadow facies (the fifth, sixth and seventh horizons); in the eastern direction, on the contrary, they are replaced by the subfaction of flat low-waterlogged polygons. These facies transitions are observed only in the Mus-Hai outcrop. Outside of it, the picture changes completely...The third feature of the Mus-Hai section is its extremely large iciness. The ice veins here reach such a size that they make up at least half of the entire thickness by volume...   In addition to the development of large ice veins, the Musi-Hai outcrop is also characterized by exceptionally strong iciness of the frozen rocks themselves due to texture-forming ice ..., which reflect the conditions of accumulation and freezing of precipitation and at the same time are directly related to vein ice. They are an important link between ice veins and their host rocks. In this case, this relationship between the amount of texture-forming ice (i.e., the iciness of the rocks themselves), the growth of ice veins and the peculiarities of the development of facies here is most pronounced in the context of the Musi-Hai. The features of the Mus-Hai section noted here are obviously due to the same reason. As an assumption, we can assume that this reason lies in the inheritance of the old regime in time. In other words, the existence of a large old man on the site of the Mushai in the past affected all subsequent stages of sedimentation, influenced the appearance of the facies that formed and replaced each other ... ^{[46, pp. 97-99]}. N.A.Grave, A.I.Efimov and P.A.Solovyov in Central Yakutia collected interesting material about the composition and structure of fossil ice, significantly clarified the limits of their distribution.

  N.N.Romanovsky^[57,58], who studied Bolshoy Lyakhovsky Island, confirmed earlier conclusions that there are completely no glacial deposits on the island.

   The powerful ice thickness is not buried glaciers, but alluvial deposits with re-vein ice. In this regard, it is extremely difficult to compare with areas where traces of glaciation are noted. All the sediments of the island are represented by continental facies, with the exception of the horizon of gray sandy loams with an indistinct wavy stratification lying at the base of the section. According to N.N.Romanovsky^[57], they belong to lagoon-type formations.The 60s of the XX century.

In the next decade, the study of edoma continued both in Yakutia and in Chukotka, and even in Western Siberia (although at first the West Siberian housing complexes were not classified as edoma).

 River. Nurma-Yakha, Yamal Peninsula. G.I. Dubikov^[59,40] studied the re-vein ice in Western Siberia, and on the basis of this he gave some considerations on the climate of the late Pleistocene. In the valley of the Nurma-Yakha River in the thickness of the second terrace, G.I. Dubikov^[59] described powerful buried re-vein ice. Their apparent height reaches 8 m. The width of the ice wedges is 3-4 m at the top, 1.5-2.0 m at the bottom; the distances between them are 5-6 m. His calculation showed that the total height of the ice bodies should be about 12 m. In some cases, small veins of ice of higher-order generations are observed (width 0.5-1.5 m, apparent height 1.0-1.5 m), the formation of which is associated with further cracking of large polygons. Such veins break the rock into blocks of 1.5-2.0 m in size. The ice wedges are covered with a layer (1.5-3 m) of undisturbed gray, slightly calcified loam with unclear horizontal layering. Deposits containing ice wedges are represented at the top by dark gray heavy loam with a large number of horizontal and oblique layers of ice from 3 to 10 cm thick. Between the thick ice slivers, the rock has a thin-mesh cryogenic texture. The high height of the ice veins, the high iciness of the horizon of the enclosing loams, the alternation in the vertical section of bundles of undisturbed horizontal layers with bundles of layers bent to varying degrees - all this indicates, according to G.I. Dubikov ^[59], the synchronicity of the growth of ice wedges and sedimentation, which is possible only in a very harsh climate. Only at the end of the formation of the alluvial deposits of the second terrace, there was probably a slight warming. It caused the cessation of ice accumulation, but was insufficient to cause the pulling out of previously formed ice wedges. A clear pattern is established in the distribution of ancient re-vein syngenetic ice. Firstly, fossil syngenetic veins are developed in the northern part of the lowland. In the southern zone, isolated finds of this kind of partially excavated veins at great depth are possible. Secondly, with the advance to the east, where the climate is more continental, the number of syngenetic ice and ice-ground veins in the alluvium of the terraces decreases, and the boundary of their distribution moves to the north. Thirdly, in the north of the Gydan Peninsula, lake-marsh deposits are especially widely developed, the accumulation of which was accompanied by simultaneous freezing and vein ice formation. On the Yamal Peninsula, similar deposits, according to the conclusion of G.I. Dubikov^[60], occur sporadically in the central part. B.I.Vtyurin^[61] summarized observations on the cryogenic structure of Quaternary sediments and re-vein ice on the territory of the Anadyr lowland.

Re-vein ice with a well-defined vertical layering was found even in coarse-grained elluvium on the slope of the remnant of indigenous basalt rocks in the valley of the Anadyr River. However, this is the only case in all the years of B.I. Vtyurin's work (he has also not found such information in the literature). The width of the observed vein on the top was 0.75 m, its vertical length was about 2.5 m. The vein wedged two large basalt blocks and was covered from above with a 1.5–meter layer of multi-grained deluvium. In the section of the second terrace in the middle reaches of the Kanchalan River, he recorded that the vertical extension of the ice veins is probably more than 20 m. The dimensions of the lower parts of the veins remaining from pulling out are even larger: the width on top is about 1 m, and in depth they go under the river's edge. Large syngenetic ice veins up to 3 m wide were observed on one of the sections of the 10-meter (first) terrace of the Anadyr River. Their vertical extension could not be established, since they are opened to a depth of only 3 m ^[61]. B.I.Vtyurin notes that re-vein ice is also well developed in deluvial-solifluction deposits. As a rule, these are veins with a surface width of 0.5–0.7 m and a vertical length of 2-3 m. The upper 0.3–0.5 m veins are usually syngenetic. Larger ice veins were observed on the slope of the hill, composed of bedrock, in the area of the village. Anadyr. In the upper part of the slope, where deluvial-solifluction deposits are represented by frozen unsorted loam with crushed stone of layered-mesh cryogenic texture, the width of the ice veins on top is 1 m or more, up to a maximum of 2 m. Vertical layering is weakly expressed. There are a lot of gas inclusions and few solid impurities (about 0.2% of the rock weight). In the lower part of the slope, there are fewer impurities of coarse-grained material in the loam and its rolling is large. In general, the breed is more icy. Ice veins are more common. The width of the veins on top often exceeds 1 m, the maximum is up to 3 m. One of the workings for 20 m revealed four ice veins with a width of more than 1 m on top. Unlike the veins of the upper part of the slope, the ice texture here is pronounced vertically layered. It is formed by numerous inclusions of soil in the form of vertical layers 2-5 mm thick. Sometimes xenoliths of soil with a length of 20-40 cm and a width of 5-10 cm can be observed in the ice . In addition, gravel, pebbles and crushed stone particles are found in the ice^[61]. Sh. Sh.

Hasanov^[62,63] characterized the underground ice of the Chukchi Peninsula. In the course of his research, he studied more than 400 outlets of re-vein ice. Two- and three-tiered ice veins are often found in the sediments of the lower parts of the slopes in areas of low-mountain relief. To the south and southeast of the old bottom of the lake. A small remnant of a river terrace up to 350 m wide can be traced along the lower part of the slope of the Scallop ridge . The absolute marks of the terrace surface increase from 8 to 12 m. Deep thermokarst hollows are formed by syngenetic ice veins. The vertical length of the syngenetic vein here is more than 7 m, and its maximum width is about 4 m. There are quite a lot of xenoliths of the host rock in the lower part of the vein. The heads of elementary veins come out on tortuous lateral contacts, which is a sign of syngenetic vein ^[63]. A large group of examined Sh.Sh.The Gasanov vein is located within the slope of the Scallop ridge, where deluvial-solifluction detached loams and sandy loams with rolled pebbles and small boulders are developed. By the bottom of the slope , the thickness of the sediment layer reaches 8-9 m . According to Sh.Sh.Gasanova^[63] the most interesting of the considered group of re-vein ice is a vein located in the lower part of the slope on the border with the river terrace. The ice vein has a two-tiered structure and consists of two veins nested one into the other, differing in size, structure and origin. The width on top of the lower vein is more than 3 m, the vertical length of the lower vein is more than 8 m, and the corresponding dimensions of the upper vein are 1.8 and 5 m. The heads of elementary veins in the lower ice vein go to the lateral contacts, and in the upper vein to the upper contact, which indicates the syngenetic origin of the lower vein and the epigenetic origin of the upper vein ^[63].Cape Barrow in Alaska.

       The first attempt at radiocarbon dating of the vein array was made by J. Brown in the section at Cape Barrow in Alaska^[64]. One of the re-vein ice arrays lay at a depth of 3 m. The age of the overlying sediments with sediment residues and lemming pellets was determined at about 14 thousand years, by which time the cessation of the growth of re-vein ice was attributed.

      Seward Peninsula.Despite the fact that the first North American edom strata were studied in this region by O.von Kotzebue and I.F. von Eschscholz^[23,24], and then by L.Quackenbush^[33], they were subsequently studied rarely and rather schematically, nevertheless, D.Hopkins^[65] obtained data on the wide distribution within the peninsula of silnoldist edom strata with powerful systems of ice veins.The 70s of the XX century.

Approximately 20 years after the pioneering work of E.M. Katasonov, in the context of the Muskhain edoma, K.A.Kondratieva and co–authors ^[66] identified and described 7 floodplain horizons - naturally constructed cycles of two or three lithological differences that differ little from each other, represented by sandy loam dusty from light to heavy brownish-gray differences. The age limits of the accumulation of the Muskhain ice complex were determined by radiocarbon dating from a depth of 2.0 m 11500 ± 210 years (MAG-137), from a depth of 5.0 m 15500 ± 50 years (GIN- 500)^[66], also radiocarbon date 23360 ± 720 years (MAG-175) was obtained from a depth of 15.5 m ^[66] . The mammoth bone from the Muskhain strata was dated by the author using the AMS method in the Arizona Radiocarbon Laboratory ^[67] - about 35 thousand years (35400 ± 2000, AA – 27373), and earlier this bone was dated by L.D.Sulerzhitsky – 34600 ± 470 years (GIN-8711). It is possible, with a high degree of confidence, to assume that the dates were obtained from well-preserved organic matter and are quite reliable, and the Muskhain Edom was formed from 35-40 to 11 thousand years ago.Several works very significant for the study of edoma were published by T.N. Kaplina and co-authors ^[68-71].

These are works in which the climatic model of the epoch of accumulation of the edom formation ^[68] and the rate of accumulation of edom strata of the Primorsky lowland of Yakutia ^[69] are considered. Two publications are devoted to the results of work on the reference sections of the Kolymo-Indigir region: the Sypny Yar on the Indigirka^[70] and the Duvan Yar on the Kolyma^[71].     

 Sypny yar. The cryogenic structure, conditions of formation and age of the constrictive Rash Yar on Indigirka were described by T.N. Kaplina and A.V. Sher ^[70]. Here , for a long distance , a predominantly sandy layer of alluvial sediments with a thickness of about 50 m is exposed . The Sypny yar is located on the right bank of the Indigirka River, in a steep bend, 25-40 km upstream from the mouth of the Shangina River and reveals a powerful layer of sediments that perform the tectonic depression of the Shanginsky Valley. The absolute surface marks here gradually decrease from south to north, towards p, Shangina from 80 to 50 m. The length of the yar along the river is about 15 km . The ledges of the main surface facing the shore have a height of 48-52 m above the river. At the top of the bend of the Indigirka River there is a 1200 m long cliff, which in June-July 1925 (in high water) was a sheer wall with continuous collapse of large blocks of thawed and sometimes frozen rock. The downstream part of the yar is uncovered for 2 km, it forms a slope with a steepness of up to 50-55, well accessible to study almost the entire height, except for the lower 4-5 m above the beach, covered with scree. The thickness of the Rash Yar as a whole is characterized by the absence of large accumulations of bones of various animals. This circumstance reflects the constrictive type of accumulation of the thickness, the absence of intensive washing of sediments, which usually leads to a secondary concentration of bone residues. A low-power layer of peat in thin-layered sands, torn by pseudomorphoses along ice veins, is also described at a height of 5 m above the edge of p, Indigirka. T.N. Kaplina emphasizes that the presence of two tiers of ice veins, at least one tier of pseudomorphoses in the lower pack of sediments with wood residues allows us to confidently say that the processes of the formation of polygonal vein ice occurred not only after completion, but also during its accumulation. Moreover, despite the fact that the ice veins were buried under the sands and, consequently, experienced at least temporary flooding, they did not pull out. Ice veins in sandy loam-loamy bundles have different sizes, and there is a connection between both vertical and horizontal sizes with the capacity of the bundles. The most powerful ice veins were found at a height of 14-18 m above the river, where the width of the veins along the top was 2.5 m. The sizes of polygons on average are 7-9 m, but it should be noted that there are often thickenings of the grid up to 3-4 m, although in these cases the veins themselves are smaller. Of particular interest, according to T.N. Kaplina and A.V. Sher, is the relationship of sandy loam-loamy sediments, sands and ice veins. With a sharp change from bottom to top along the section (when laying) channel sands on siltstone sandy loam (light loam), the upper surface of the ice veins usually has a smooth horizontal section. With gradual transitions (through a gradual change of sandy loam-loam composition to sandy or through the layering of silted and fine-grained sands), small sprouts often remain in ice veins, sometimes several nested tiers of ice veins can be seen in sections, which indicates the dynamism, variability of their growth conditions, probably a fairly rapid accumulation of stratified on top of each other packs of alluvium. All the veins studied by us had a high degree of soil contamination - many vertical strips consisting of fine sand or dust. Most of the ice veins lying in sandy loams and silted sands, starting from a height (from the lower end) of 0.7-1 m, have characteristic signs of syngenesis on the side contacts – the stepwise and soldering of ice "belts" to the shoulders of the veins, as well as the exits of elementary ice veins to the side contacts. However, in the same sediments, the smaller veins were clearly epigenetic. The latter in powerful bundles of sandy loam-loamy composition usually lie in several tiers. Along with ice cores, small ice-ground veins were found in sections - up to 0.3 m wide, with a vertical length of up to 1.5 m. Such veins are found in silted sands, but they are often confined to fine-grained sands, i.e. they grew in the lower part of the near-shore shoal. They are distinguished by especially often rebuilt lattices. Such systems as a whole are synchronous to the host precipitation. At one time, Yu.A. Lavrushin outlined two types of sections of the constrictive alluvium, in which the placement of ice veins can be tiered. In the first case, the tiering is due to clear changes in lithology, in the second – climatic fluctuations. T.N. Kaplina concludes that the Bulk Yar is a striking example of the first type of strata.^[70]

V. I. Solomatin, based on studies of edom re-vein ice in the deltas of the Yana and Omoloi rivers and the Muostakh Island, concluded that sedimentation of edom strata occurred under conditions of colossal waterlogging of the territory in shallow basins migrating along the surface of the alluvial lake plain, similar to shallow thermokarst lakes of the Alas on the plakorny, such as the Yano-Omoloi interfluve, areas and lakes internal floodplains and deltas, similar to those currently observed in river valleys and deltas.^[72]  According to the structure of the contacts, V. I. Solomatin^[72] identified two main types of veins — with the presence of deformations of the host deposits and without them. In the structure of the layers bent at the contacts, there are no traces of significant dynamic loads corresponding to the scale of deformations; bending began with the freezing of rocks and developed after it; violations did not go beyond the area of plastic deformations, ice layers did not experience violations of cleavage, rupture, etc. According to the observations of V. I. Solomatin^[72], segregation processes of ice formation are intensively developing at the lateral contacts of veins. His study of the texture and structure of segregation slots parallel to the lateral contacts of the veins gave grounds for the conclusion that the slots are formed already in frozen rock. ^[72] V. I. Solomatin managed to trace the gradual transition of segregational slots into vein ice, which explains the border of veins by segregation processes.^[72] An important feature of the textures of vein ice, according to V. I. Solomatin's observations, is that inclusions in the ice correspond to the host deposits at this level and change vertically with the change of rock lithology. This fact, firstly, casts doubt on the significant extrusion of ice, and, secondly, proves that the inclusions did not fall into the vein ice from above, together with water pouring from the surface into the cracks, but were brought from the host deposits and fixed at the level where they had previously been in the rock, without moving in, the vein vertically. according to V. I. Solomatin^[72], such a feature of textures can serve as a confirmation of the flow of water from the host sediments to the contacts during segregation processes, and the soil particles turned out to be included in the ice veins. Structural analysis has shown that vein ice consists of successively increasing vertical layers.^[72]In 1975, N.N. Romanovsky defended his doctoral dissertation^[73] on the materials of the study of polygonal-vein structures, and in 1977 published these data in a monograph^[74].

       In the sections: on the mechanism of growth of syngenetic re-vein ice and signs of syngenetic development of re-vein ice, N.N. Romanovsky emphasizes that in wide parts of growing ice veins, especially in the powerful ice veins of the ancient alluvial complex of the northern regions of Yakutia, many features characteristic of small developing veins are lost. The ice slots of the intra-polygonal blocks lose their connection with the veins, are torn away from them, and the sharp serration along the contact of the ice veins disappears. Signs of syngenesis N.N. Romanovsky^{[74, pp. 124-128]} proposed to divide into four groups – signs related to: a) with the structure of the ice veins themselves, i.e. their textural features and morphology; b) with the relationship of ice veins and migration-segregation ice slots in the host sediments; c) with permafrost-facies features of rocks containing ice veins, which are due to the nature of sedimentation and formation of cryotextures in polygonal microrelief conditions, as well as changes, conditions of frost - breaking cracking; d) with the inclusion of the ground parts of polygonal-vein formations located in the STS above the ice veins in the frozen thickness. N.N. Romanovsky also published a paper on the peculiarities of the formation of re-vein ice and the development of polygonal vein ice in a special issue of the journal Periglacial Bulletin "Periglacial phenomena and paleogeography of the Pleistocene"^[75]. Walt Creek on the Chatanika River.

 In a 15-meter outcrop on the banks of the Chatanika River, 2 km downstream from the bridge on the Elliott Highway over the Chatanika River, 40 km north of Fairbanks in the northwest, T.Pev^[15] described the outcrop of deposits of the Goldstream formation containing powerful syngenetic ice veins. A layer of volcanic ash with a thickness of 1 to 10 mm is marked in the sediments. The radiocarbon date of 14,760 ± 850 years (GX-0250) was obtained from a gopher mink 4 m below the ash layer. The date 14 510 ± 450 years (W-2703) was obtained from gopher coprolites from silt 1 m above the ash layer. Thus, the ashes are dated to about 14 thousand years. and the ice veins in the sediments of the Goldstream formation date back to the very end of the Late Pleistocene.In 1967, Peve selected samples of macroorganics from ice, wood and sandy loam deposits containing ice veins in a 40-meter section of the Willow Creek Edoma. In the laboratory of the University of Arizona, several dates with an age of more than 25 thousand years were obtained by 14 ^{S. T.Pev believes that a more detailed dating could give the age of the veins between 25 and 30 thousand years, since the wood samples selected in the early 50s were dated between 23 and 30 thousand years. years ago (L-163J), the age of the wood at the base of the ice vein is 24400±650 years (I-2116).[15]}The 80s of the XX century.

 The first radiocarbon-dated isotope-oxygen diagram.

       On December 17, 1982, during the defense of his PhD thesis, the author^[76] presented for the first time a radiocarbon-dated isotope-oxygen diagram of the Seyakhin edom strata on the eastern coast of Yamal, which was published in DAN in mid-1984^[77]. These works marked the beginning of a new stage in the study of edom strata - obtaining reasonable quantitative characteristics of winter paleotemperatures of the time of formation of edom re-vein ice. These works and a number of other publications have established the widespread occurrence of deposits of a special genetic type: deposits of a polygonal-vein organo-mineral complex, intensively formed 30-22 thousand years ago, which are important for paleogeographic and stratigraphic constructions. In August 1984, these materials were reported at the 29th session of the International Geological Congress in Moscow. The term edoma in relation to the Seyakhinskaya thickness was first used by V.F. Bolikhovsky^[78], who visited this section a few years later.

     Vorontsovsky Yar. In 1975-1976, the TIG DVNC detachment carried out a study of one of the most famous outcrops of Edoma - Vorontsovsky Yar^[79]. The section is located on the right bank of the Indigirka River, near the mouth of the Bolshaya Ercha River, at the Vorontsovo hydrometeorological post, at a distance of about 250 km from the shores of the Arctic Ocean. The Vorontsovsky Yar area is located in the zone of the hypo-Arctic taiga. Sedimentary deposits with a thickness of 50 m , lying between absolute heights of 91 and 41 m , were studied . Vorontsovsky Yar is an active thermokar, which arose as a result of the descent of the waters of a small thermokarst lake into the Indigirka River through the edom bridge and the formation of a canyon-like breakthrough valley in it. The actual edoma loams and sandy loams are dusty, gray and dark gray in color, horizontally layered with fossil soils, containing continuous re-vein ice. The distance between the re-core ice is 8-12 m, the width of the veins in the roof is about 1.2 m. At a depth of 40-41 m, the edom soil is represented by wavy-layered powdery fine-grained sands. A notable feature of the Vorontsov edoma is the inclined position of many re-vein ice and ground cores of polygons. The maximum deviation of their long axes from the vertical is 20 °. The apparent thickness of the edoma in the outcrop is about 41 m, and the total is slightly more than 50 m. 68 large ice veins were found in the thermokarst ledge of Vorontsov Yar with a length of 650 m in the summer of 1975. According to the characteristic features of the occurrence and structure of re-vein ice belong to the syngenetic type. They were formed in the conditions of active formation of permafrost rocks in parallel with the accumulation of the material of the host rocks. The unevenness of the sedimentation rate is reflected in the morphology of the pancreas. Thus, during the period of formation of fossil soils, when the rate of sedimentation was minimal, there was a relative growth of re-vein ice in width. The maximum width of re-vein ice (up to 4-6 m) is several times greater than their usual width in the section. The growth of re-vein ice in breadth with slowing sedimentation was accompanied by crumpling of the host rocks, as can be seen from the raised edges of parallel-layered cryotextures at the contact of re-vein ice and the host soil. Syngenetic re-vein ice belongs mainly to the conjugation type; the proportion of sublimation material in it is small. There are few air bubbles in the PLL of the Vorontsov Yar compared to the PLL of the Musikhai section, studied by B.I. Vtyurin on the Yan River. Small spherical bubbles with a diameter of 1 mm or less prevail. Zones of bubble condensation tend to layers with solid impurities. Such a character of gas bubbles indicates their purely aquatic origin. The conclusion about the Late Pleistocene age of the edom deposits of the Vorontsov Yar, made from the fossil theriofauna, is confirmed by the final radiocarbon dating of wood from the Vorontsov fossil soil at a depth of 29.6 m - 37,000 ± 1100 years (GIN-1675). The date > 37,000 years was obtained from the same soil for wood (MSU-535). Another date was obtained from the remains of herbaceous plants from a rodent nest found in the former seasonally thawed horizon under the oldest fossil soil, at a depth of 35 m. It is > 41,000 years old (GIN-1674). The upper 40 m of the edom thickness (up to the absolute mark of 101 m) accumulated over 37,000 years at an average rate of 1.1 mm per year. Isotope-oxygen analysis was performed by S.A. Gorbarenko and V.I. Kiselev using an upgraded MI-13-09 mass spectrometer^[80]. Low values of ?18 O in ^edom are associated by B.I. Vtyurin and V.F. Bolikhovsky^[79] with colder climatic conditions compared to modern times.

       Several important works for the study of edoma during this period were published by T.N. Kaplina and co-authors ^[81-85]. These are articles in which the reference sections of the edom strata on the Allaiha River (lower reaches of the Indigirka) are studied^[81], the Molotkovsky Stone (Maly Anyuy River) ^[82], the sandy edoma in the Tuostakh depression ^[83], and a generalizing work on the history of frozen strata of Northern Yakutia ^[84]. In 1987, at the Institute of Permafrost Science SB RAS in Yakutsk, T.N. Kaplina defended a very important doctoral thesis for the development of ideas about edoma dissertation on the topic: "Regularities of the development of cryolithogenesis in the Late Cenozoic on the accumulative plains of Northeast Asia"^[85].

       Allaiha River. The outcrops on the Allaiha River were studied in 1975 by T. N. Kaplina and A.V. Sher^[81]. The main studies were carried out on outcrops 4.5–4.8 km above the mouth of the Achchagy-Allaiha channel, and 2.2-2.7 km above its mouth. In sections of the left bank of the Achchagy-Allaiha channel, two strata are distinguished. The lower one, with a thickness of about 20 m, is composed of weakly icy dense loams with seasoned layers of peat. The upper one, with a thickness of up to 25 m, is sandy loam and loam with powerful polygonal-vein ice^[81]. Buried polygonal-vein ice is present in individual bundles of alluvial sediments. Two tiers of ice veins were found in the native section of the Achchagy-Allaiha channel. The lower one is described in a layer of loam at a height of 5.5 to 9 m (below the veins do not end, but are covered with scree). In this context, it is interesting not only the fact of the preservation of ice veins, but also the syngenetic nature of their contacts with the host rocks – the presence of ice slots ("belts") in the rock and their soldering to the shoulders of ice veins. In the range from 6 to 15 m above the edge, the re-vein ice has a relatively small size: 1.5-3.0 m vertically with a width of 0.5-1.0 m. Their presence, according to T.N. Kaplina, indicates that during the accumulation of alluvium, local thawing of frozen rocks was carried out with the extraction of small ice veins. Sections of lake sediments are often crowned with peat bogs with a thickness of 0.3 to 1.5 m, but 20 km above the mouth of the Achchagy-Allaiha channel, Yu. A. Lavrushin described a section of lake and lake-marsh sediments with a capacity of about 10 m. For the most part, peat bogs lie in "slabs", limited in extent by several meters. With the general unity consisting in the presence of powerful polygonal-vein ice, the sediments of the edom formation experience some changes along the section and along the strike. In the most complete section located above the mouth of the Achchagy-Allaiha channel, the suite is divided into two bundles. The lower pack of the Edom formation lies here at an altitude of 20 to 23 m and, apparently, performs an erosive lowering in the roof of the Achchagy formation. At its base lie gray-brown loam, a distinctive feature of which is the extremely high iciness of rocks in the blocks between the ice veins. Ataxite cryotextures predominate here; there is a rhythmic vertical alternation of layers with greater and lesser iciness, measured in several centimeters, that is, the structure of the pack is typical for syngenetically frozen precipitation. For a short distance in the pack, changes can be traced: in one wall of the circus, loams have an unclear horizontal layering and are saturated with grass roots; in the opposite wall in the pack, traces of washouts are visible and the layers overlap each other obliquely, with a cut. Here the rocks contain many pieces of allochthonous peat, in places turf with grass that has retained its green color. There are also many mammalian bones buried here with remnants of soft tissues, some of them in articulation (bison vertebrae). These signs indicate a rapid (to catastrophic) accumulation of streaming. The data obtained by T. N. Kaplina and A.V. Sher ^[81] from the section of loose sediments on the Allaiha River, in their opinion, show that this section captured several stages of the evolution of the natural environment in the Pleistocene. Thus, the accumulation of the visible part of the Allaikhov formation section began in a forest-tundra environment that existed in a continental rather dry climate and the development of permafrost rocks. The deposits of the Achchagy formation corresponding to this phase record intensive, though not continuous, thawing of permafrost rocks. This thawing gave a peculiar appearance to the lower thickness, due to the low iciness of its precipitation and the predominance of epigenetic cryogenic textures. The lower pack of the edom suite begins to form even in fairly mild conditions, but in the process of its accumulation, the severity and dryness of the climate rapidly increases and vegetation changes from forest tundra to shrubby tundra and tundrasteps. The similarity of the paleoclimatic characteristics of the upper lower strata and in this part of the section allowed T.N. Kaplina to assume that the same phase of warming and climate mitigation was recorded here. Higher up in the section of the edom formation, there is a further change in conditions towards a typical cryoxerotic situation and the formation of the coldest and driest variant of the tundrasteps. The upper part of the visible section of the Edom suite apparently captured the beginning of a new phase of climate mitigation.^[81]

  The Tuostakh depression is located within the Yano-Adychansk erosion-denudation plateau, in the area of rare-coniferous larch forests in the lower reaches of the Adych River (right tributary of the Yana). The absolute marks of the bottom of the depression rise from north to south from 300 to 800 m . The modern channels of the river Adycha and its tributaries are located at 145-135 m . A well–defined element of the valleys in the depression is a terrace about 70 m high above the rivers, composed mainly of sand. Its section was studied by T.N. Kaplina and co-authors ^[83] on the right bank of the river. Adycha in the outcrops of Hoton-Khaya (1 km above the village of Betenkes) and Ulakhan-Sular (7.5 km below the village of Betenkes). The most interesting two horizons of the Ulakhan-Sular section are the lens of gray sands, which are gradually enriched up the section with layers of silted sands and autochthonous peat. Along the sole of the lens are the stumps of coniferous trees, buried in the lifetime position. The preservation of the wood is very good, the fragments and stumps have a very "fresh" look. In the lower part of the lens there is an abundance of small wood, including branches of shrubs. The most interesting feature of this pack is the presence of a system of polygonal-vein ice in it. The distance between the ice veins is 10-12 m, their width on top does not exceed 0.5 m. The ice veins are epigenetic in relation to the sediments containing them and grew at a time when the daytime surface corresponded to the buried soil noted above. The sediments of this pack, according to the conclusion of T.N. Kaplina^[83], accumulated in the floodplain (possibly old) hollow. The buried soil indicates a certain break in sedimentation, however, this break was hardly long, but a period of several hundred years was sufficient for the growth of the ice veins described above.^[83] The river composing the main part of the Ulakhan-Sular section is composed mainly of gray and yellow-gray fine sands and seems monotonous, but in it T.N. Kaplina identified ^[83] layers differing in lithological features. In the roof of this pack, pseudomorphoses are noted along fairly large ice veins – up to 4 m vertically and up to 2 m wide. The pseudomorphoses are made with sand with pieces of peat, probably trapped in them as a result of the activity of the stream, since there is no peat in the sediments that contain and directly overlap the pseudomorphoses. Pseudomorphoses fix a break in sedimentation. The presence of three systems (tiers) of ice veins in the section of the Ulakhan-Sular formation indicates that the formation, starting from a height of 12 m, accumulated during the existence of permafrost rocks. The average annual temperatures of the frozen strata were no higher than -3 – -5 ° C, since ice veins grew in the sands of near-shore shoals and often flooded hollows. Moreover, during the accumulation of the formation, the existence of frozen rocks was continuous, and even under the riverbed, which deposited a sandy layer, there were no through taliks. This circumstance, according to the conclusion of T.N. Kaplina, also testifies to the severe geotemperature regime of the era of accumulation of the Ulakhan-Sular formation.^[83]Descriptions of edom outcrops located on large islands of the Novosibirsk archipelago allowed S.V. Tomirdiaro^[16] to single out a single region of the remnants of the loess-ice plain:

         a) fr.

Stolbovoy: steep banks formed, stacked with ice... Along the entire cliff of ice, earthen inclusions are traced in the form of windows. The latter have a triangular shape and a tiered arrangement... The height of the coastal slopes, where such ice is exposed, reaches 20-25 m, and the baijarakhs on them are arranged in several rows, and the higher ones are located in the lower tier. This description, according to S.V. Tomirdiaro^[16], fully corresponds to the appearance of the studied in detail edoma Oygossky Yar. the name of which is assigned to the shelf type edom. b) fr.

New Siberia. Thermoterrace is formed on the shores of the island with the outcrops of powerful fossil ice (Fig. 7) due to exceeding the rate of retreat and thawing of the ice column (the impact of meteorological agents) over the rate of retreat of the underlying low-ice strata eroded by the sea. The same phenomenon is observed on the outcrop of the Oygos Yar. The development of the shelf type on the island of Edoma is evidenced by an exceptionally thin ground layer on a powerful ice column. An important parameter determining the thickness of this edoma, which lies on the underlying low-ice sediments, is the height of the internal ice ledges of the thermoterrace, it usually does not exceed 8 m in the central part of the terraces.

    c) O. Bol. Lyakhovsky: E. V. Toll ^[95], describing powerful outcrops of ice and host soils on Bol Island. Lyakhovsky was firmly convinced that these were fossil glaciers. According to S.V. Tomirdiaro^[16], the photograph taken by N. N. Romanovsky is the most convincing documentary evidence of the presence of an offshore type on the island of Edoma. It shows almost vertical sections of "earth pillars" in thick ice and a very thin ground cover on ice bodies. Characteristic incoherent bundles of search cryogenic layering (thick-shelled full-layered cryotexture) are clearly distinguishable. The cryogenic layers placed on the head of each underlying bundle are cut off by the sole of the overlying bundle. Bundles with thick-shelled cryotexture can be traced to the very top of the edoma, without being replaced by a solid tier of loess rock with micro-shelled cryotexture.

According to his descriptions, thick-shelled layered cryotextures are also developed on the sections of the Edoma of the Oygos Yar studied by S.V. Tomirdiaro^[16] in the upper part of the stratum up to the very cover layer of seasonal thawing.   

d) fr. Boiler room. Quaternary deposits are developed on the western coast of the island. The upper limit of the ice is at an altitude of 15-16 m above sea level. The sea is washed away by an ice cliff with veins, its thickness is not less than 16 m ... when the ice melts, the baijarakhs are 6-7 m high. This description, according to the conclusion of S.V. Tomirdiaro^[16], indicates the development of an offshore type on the island of Edoma.

    e) O. Faddeevsky: as we move towards the watershed, the tracts of drained tetragonal bogs are successively replaced by Baijarakh and, finally, by the final member of the evolutionary series, reduced Baijarakh. As it was established by S.V. Tomirdiaro^[16] during an aerial survey of the island, not a baijarakh, but a blocky-bumpy microrelief is developed on the watersheds not disturbed by erosion, which indicates a shelf-type edoma.

   In 1979, in the eastern wing of the outcrop of the Oyagossky Yar S.V. Tomirdiaro, samples of organic matter that lay in situ in blocks of loess rocks with micro-shlir and thick-shlir cryotexture were first selected. These were heavily blocked soils, in places with thin layers of peat, which were fixed on the outcrop in the form of peculiar "hummocks". According to them, the following dates were obtained: more than 35,000 years (MAG– 551) – a sample from the underlying terrace 8 m above sea level; more than 41,000 years (MAG– 545) – a sample from a thin (0.2 m) peat interlayer, taken at an altitude of 18 m above sea level; 37,700 ± 200 (MAG– 543) – a sample from a similar peat layer (0.2 m), taken at an altitude of 26 m above sea level; 34,200 ± 200 (MAG– 544) – a sample from a peat layer (0.2 m), taken at an altitude of 30 m above sea level. These datings allowed us to think that the sediments of the Edom formation in the Oyagos Yar section were formed during the Karginsky interval and, apparently, during the Zyryan interval preceding it. But according to S.V. Tomirdiar's position, such a conclusion cannot be accepted, because, firstly, it contradicts the main features of the cryogenic structure and composition of the edoma strata, and secondly, a new radiocarbon dating of more than 46,360 years (LU-1219A) was obtained from samples from the Oyagossky Yar (depth of 5 m). Considering the above, S.V. Tomirdiaro concluded that the studied sediments of the Oygos Yar edom complex were formed in the Zyryan time.Baltylakh stream.

         One of the southernmost locations of alluvial-proluvial deposits with powerful re-vein ice in the Russian cryolithozone was found on the right bank of the Olekma River in the interfluve of the pp. Imangra and Honey. Here (56°47 s.w., 121° 02 v.d.) the stream. Baltylakh (right tributary of the Imangrakan River) on the starboard side, 0.5 km from the mouth, washes away a terraced surface (terraso-uval) with a height of 7-8 m. In a steep bend of the stream for about 50 m in an almost vertical wall with a height of 7-8 m, O.G.Boyarsky, A.B.Chizhov, N.I.Chizhova and others ^[86] observed two layers differing in composition and character of stratification of rocks and morphology of re-vein ice. The upper part of the section is represented by dark brown peat, poorly- and medium-decomposed, with a thickness of 0.5–0.8 m. Below lies fine and fine sand, dusty, torn off in the upper part, in the lower part with lenses and layers of medium– and coarse-grained sand with soil. The thickness of the layer varies from 1.5 to 2.5 m. In the lower part of this layer, the moisture content increases to 20-25%. The cryogenic texture is predominantly frequent thin-lenticular (the thickness of the slots is from 2 to 10 mm), thin-mesh in sections, with ice nests up to 0.5 cm. In the right part of the outcrop, re-vein ice is observed with a width of 0.35–0.4 m in the upper part. The lower ends of the veins penetrate into the underlying sediments, their vertical length is 2-4 m. Here, directly under the thawing layer (from a depth of 0.5 m), an ice sprout 2-3 cm wide was observed, wedged into the “head" of the vein, lying at a depth of 0.65 m. The high content of tritium (64 TE) in the ice sample from the vein from a depth of 0.8 m, according to N.I.Chizhova and A.B.Chizhov^[86], suggests that the growth of re-vein ice is currently occurring. In the section of the lower layer, re-vein ices of two tiers are observed (Fig. 6), the lower one – most likely of late Pleistocene age – of the edom type. The width of the re-vein ice in the upper part is from 2 m to 3.4 m. The vein heads lie at a depth of 1.8–3.0 m. The visible vertical length of the veins (up to the water edge) is 5.0–6.5 m, their width at the level of the cut is 0.5–1.0 m. Deposits containing large re–vein ice are dusty thin and small the sands are interlayers of mixed-grained sand, with inclusions of a large amount of gravel (up to 20-30%). Rubble appears in the lower part of the incision.Fig. 6. Probably the southernmost find of the Edom strata is alluvial-proluvial deposits with powerful re-vein ice on the right bank of the Olekma River in the interfluve of the pp.

Imangra and Honey. Here (56°47 s.w., 121° 02 v.d.) in the valley of the stream. Baltylakh (right tributary of the Imangrakan river) on the starboard side, 0.5 km from the mouth. Photo by O. Boyarsky

Sometimes polygons formed by modern veins coincide in plan with the polygonality of Late Pleistocene veins, and then modern veins can be embedded with tails in late Pleistocene veins. About the movement on the stream. Baltylakh is most likely the southernmost find of a typically Edomian strata, although late Pleistocene veins at these latitudes and even further south were previously encountered ^[87,88]. A.G.Kostyaev describes the outcrop of late Pleistocene alluvium on the river.Tynda ^[88]. In the sediments of the second above - floodplain terrace of p . Tyndy in the area of Tyndy (55 ^o 08 s.w., 124 v.d.) in the east of Transbaikalia, already in the Amur region, during the construction of the railway station, probably late Pleistocene re-vein ice with a vertical length from 4.9 to 6.0 m. Veins lie at different depths (1.0 and 7.8 m), which indicates the presence of two or more horizons with re-vein ice^[88]. In the excavation for the railway station, an orthogonal, sometimes trapezoidal system of ice veins was observed in the sediments of the floodplain facies. Their first generation forms a lattice with a diameter of 4 m, the width of the veins varies from 0.25–0.4 to 1-1.35 m. The second generation of veins forms polygons about 1 m in size, the width of veins (ice or ice-ground) is 5-10 cm, sometimes only 1.5–2 cm. Within one generation, the greater the width of the veins, the more dispersed and humusified the host rock. On contact with large ice bodies, the latter is usually enriched with plant residues (felt). The ice of most veins is characterized by a clear vertical banding, at the top along the sides the rock layers are slightly raised. According to the conclusion of A.G.Kostyaev, the upper parts of the veins are syncreogenic. There is a thinning and wedging of ice veins horizontally, namely in the direction of the areas of occurrence of washed yellow or brown sands. The vertical thickness of the veins, judging by fragmentary drilling data, was 6 and 4.9 m. The occurrence of ice at different depths indicates the presence of two or more horizons of veins, which is also characteristic of the II and I terraces in the basin of the Olekma river ^[87].

 Edom strata in the lower reaches of the Kolyma

The author and colleagues performed isotope-geochronological studies of reference sections of the edom strata of Cape Verde^[89], Plakhinsky Yar^[90] and Duvan Yar^[91] in the lower reaches of the Kolyma, Bykovskaya Edoma in the Lena Delta^[90], Kularskaya Edoma and edom strata of Chukotka on the island of Ayon^[92] and in the valley of the Main River^[92]. These studies made it possible to obtain isotope-temperature dependence and to construct paleotemperature maps for the development of edoma in the key stages of the Late Pleistocene, which were first presented in Kaunas in 1989 at the 3rd All-Union Symposium "Isotopes in the Hydrosphere"^[93]

     The data obtained by the author^[89] in the process of studying the structure of the section of the Late Pleistocene organo-mineral strata, which includes a representative (both vertically and in terms of the volume of ice as a whole) polygonal-vein complex on the right bank of the Kolyma River, in its lower reaches, give grounds for very definite conclusions about climatic changes in the late Pleistocene, at least during the formation of the studied strata. The height of the outcrop exposed by the temporary watercourse is more than 30 m, but the lower 3 m were covered with scree during the observation period. The incision is clearly divided into two parts. The upper, less icy part – in the range of 0-10 m is composed of a homogeneous, almost non-layered dark gray heavy sandy loam, strongly dusty. In the more ice-saturated lower part, in the range of 10-27 m, three bundles of dark gray sandy loam with a capacity of 1.8, 3.3, 3.4 m, saturated with organic matter, represented by roots and twigs of small shrubs, stems of grasses and mosses, separated by layers of sandy loam without vegetation residues, the thickness of which is 3.3 and 3.6 m. The most important feature of the structure of the section is the presence of a complex of syngenetic re—vein ice. There are powerful veins that dissect the entire thickness of the sediments, their apparent height is more than 26 m. Samples were taken from the thickness containing the re-vein ice and directly from the veins, in which the content of stable oxygen isotopes was determined and palynological, hydrochemical and radiocarbon analyses were carried out. To determine the content of the heavy oxygen isotope, 26 samples were taken from two nearby veins, in the depth range of 1-27 m. As a result, a diagram of the distribution of oxygen isotopes by depth has been obtained, on which 4 contrasting segments are distinguished — isotope-oxygen zones. The time of formation of veins is very reliably determined by radiocarbon dating of the deposits containing the veins, more precisely, their organic component — allochthonous detritus. The sample from a depth of 23.7 m was dated at 37,600 ± 800 years (GIN-3576), from a depth of 16.4 m - 27,900 ± 1200 years (GIN-3575), from a depth of 12.0 m - 28,600 ± 1500 years (GIN-3574). Dates close to these are given in ^[94]. For strongly torn layers of edoma, opened 8 m above the river on the right bank of the Kolyma, in the area of the village. Chersky, A.V. Lozhkin ^[94] obtained dates of 35.2, 28.2 and 27.2 thousand years. This indicates the reliability of these definitions and allows us to assume that the formation of veins occurred in the range of 40-16 (18?) thousand years ago (the upper limit is indicated taking into account the fact that the "heads" of veins lie more than 10 m above the deposits dated at 28 thousand years). This gave the basis for the authors to estimate severe climatic conditions for the entire specified interval, and for the period for which the isotope-oxygen diagram was obtained – 37-16 (18?) thousand years ago, we can confidently speak of significantly more severe climatic conditions than modern ones: winter temperatures were 5-15 °C lower than modern ones.^[89] The blown Yar. From syngenetic re-vein ice lying in the organo-mineral thickness, the authors ^[91] conducted a detailed testing for the analysis of the isotopic composition of oxygen.

  62 samples were taken vertically and more than 30 horizontally (across the stretch of veins on three levels). Isotope-oxygen diagrams were compiled based on measurements from samples arranged vertically, and data from samples of horizontal sections were used for control. The range between the extreme values of ?18 O ^{in the Late Pleistocene veins of the Duvan Yar was 4.0%,, with the maximum value of ?18} O ^{-28.7% and the minimum -32.7%. On the isotope diagrams, the authors have identified isotope-oxygen zones with a step of 2%. Comparing with the values of ?18} O ^{in modern syngenetic veins (averaging -26%), these zones can be characterized as follows: in the range from -28 to -30% – moderately light (UL); from -30 to -32% – light (L) and below -32.4%, very light (OL). Interpolating radiocarbon dating from synchronous veins of the host strata, it can be concluded that the isotopic diagram of the middle fragment of the outcrop covers a time interval from 40 to 20 thousand years ago and its lower part is synchronous with the upper part of the diagram compiled for the lower fragment of the outcrop dated 45-30 thousand years ago. The average values of ?18} O ^{of winter precipitation in the studied area were about -26.7%, which is very close to the value of ?18} O ^{in modern syngenetic veins, and in the water of the Kolyma River -20.4% (in September). In small reservoirs, the values of ?18} O ^{range from -20% to -5%. Thus, the data obtained by us on syngenetic veins of the Duvan Yar, along with paleoclimatic information, reflect changes in the contribution of various waters to the formation of veins. The authors concluded[91] that the paleofrost assessment of the obtained materials using the previously proposed method of interpretation of isotope-oxygen data[6] and the above limitations suggests that the geocryological situation of the entire period of formation of ice veins in the organo-mineral complex of the Duvan Yar was significantly harsher than modern (soil temperatures were at least than 4-10 °C lower than modern ones), and although paleoclimatic fluctuations undoubtedly occurred, they practically did not affect the mode of vein formation [91].}

       Plakhinsky Yar. Here the veins have a vertical length of about 14 m, they are usually narrow (1– 1.5 m wide), located at a distance of 3-4 m from each other, have a ribbon shape ^[90]. The sandy loams containing them include a relatively small amount of organic material, which managed to date the time of the beginning of the formation of veins – about 30-27 thousand years ago. The completion of the accumulation of the strata, most likely, occurred no later than 15-16 thousand years ago. The formation of the housing complex took place in rather harsh conditions. This is indicated by the data of spore-pollen analysis from the host strata and from the veins themselves. In both cases, with sporadic occurrence of tree pollen, the pollen of the group of shrubs and grasses is noticeably predominant, its content in almost all samples exceeds 75% of the total composition of the spectra. The severe mode of formation of veins is convincingly evidenced by their isotope-oxygen composition (19 samples were analyzed). The values of ?18 ^O in edom veins range from -34.7 to -29.9% (here, on the floodplain, the sprout of the syngenetic vein is characterized by the values of ?18 ^O from -27.0 to – 25.3%). Extremely low concentrations of heavy oxygen isotopes (below -33%), indicating the most severe winters of the vein formation period, are noted in the lower half of the diagram and in its uppermost part, which approximately corresponds to the time periods 30-25 and 15-17 thousand years ago (the dated sample from the middle part of the section was selected by N. Kudryavtseva). The values of ?18 ^O above -31.0on the segment of the diagram separating them indicate a less severe geocryological situation^[90]

      Bykovsky Peninsula, near the permafrost station. The author^[90] in the context of the 20-25-meter terrace of the Bykovsky peninsula in the edom thick noted that re-vein ice is very difficult to lie. Here, in the outcrop, a thickness is revealed, consisting of rhythmically alternating layers of sand with gravel and pebbles, sandy loam, often with an abundance of organic matter (in the form of detritus and peat hummocks), clay. In total, up to 3-4 such layered bundles are noted in the section, they, as a rule, correspond to the number of tiers of ice veins, since the heads of veins are most often confined to the horizons of detached sandy loams, and their "tails" go out into the underlying gravelly sands. In some cases, the overlying veins enter the veins of the lower horizon and form a single multi-tiered ice wedge. The presence of well-rounded gravel most likely indicates the alluvial genesis of the main part of the strata. In the thickness of the modern floodplain (laida bay), an identical structure of the section is noted, and there also the heads of syngenetic veins are confined to the torn-off soils in the upper part of the section, and the tails go out into the underlying sands with gravel. The time of formation of ice veins and sediment strata composing the terrace is fairly reliably dated by a series of radiocarbon dates, which indicate that the beginning of the formation of the described strata occurred about 40 thousand years ago, and the completion of syngenetic accumulation of veins occurred, judging by previously published dates, no later than 28-30 thousand years ago. The values of ?18 ^O of the main mass of edom veins (49 samples were analyzed) vary from -34.9 to -29.8%. The upper Holocene ice wedge, saturated with air bubbles and having a white color contrasting with the gray ice of Edoma, is characterized by values of ?18 ^O from -28.7 to -263% (in the modern sprout of the syngenetic vein on the laide of the Buor-Hai lip, ?18 ^O = -24.2%). The isotope diagram clearly highlights the period of the most severe winter climatic conditions (more than 10° C colder than modern ones) about 40-38 thousand years ago, the stage 36-34 thousand years ago was much harsher than modern, then the winters softened, in the intervals of 38-36 and 33-30 thousand years ago, the winters were harsher than modern "only" by 5-6 °S.^[90]

 Native strata of Chukotka     

  Ione. In the edom thickness of the island of Aion (on the west coast), lying in the range of absolute heights from +5 to +30 m, the author recorded ^[92] well-defined three layers of organic matter in the intervals from +8 to +10 m; from +19 to +21 m; from +29 to + 30 m. The layers of organic matter were dated by radiocarbon: the lower one – at an altitude of +8 and +9 m, dates were obtained from the accumulation of roots and grasses about 28 thousand years ago; the upper one - at an altitude of +30 m - more than 10 thousand years ago. From this section, a detailed characterization of the isotope-oxygen composition of re-vein ice and textural ice from the soils containing them was obtained. Note that part of the heads of ice veins opened in the section lies at the level of horizons saturated with organic matter. In the body of veins dissecting the entire thickness of sandy loam, clearly defined shoulders are marked at the same levels, which makes one think that the most powerful veins consist of three wedges nested into each other. In the isotope profile constructed from vein ice, the specified cyclicity can also be distinguished. This cyclicity is manifested against the background of the general trend of weighting the isotopic composition of ice veins (68 definitions) from the bottom up as they rejuvenate, the values of ?18 ^O increase from -34.0 to -28.7%. The character of the isotopic curve along the veins is cyclic: in the intervals from +6 to +9 m and from +12 to +15 m, the values of ?18 ^O tend to decrease, and in the intervals from +5 to +6 m, from +9 to +12 m and from 15 to +24 m they they increase and the ice becomes isotopically positive.        A characteristic feature of the complex is a relatively uniform vertical distribution of oxygen isotopes in textural ices (9 definitions) from the rocks containing the veins, in which the values of ?18 ^O range from -31.2 to -29.0. The proximity of the values of ?18 ^O in different types of ice indicates that the facies conditions of the time of accumulation and freezing of deposits and the cycles of vein formation were close to each other. It must be assumed that sandy loam deposits accumulated in the estuary of the big river and froze almost immediately, and when passing into high floodplain conditions, powerful re-vein ice began to form here. The predominantly subaerial growth of veins and the atmospheric origin of the water that fed them is also confirmed by the analysis of the mineralization of ice veins: the dry residue ranges from 36 to 108 mg/l (65 mg/l is the average according to 40 definitions), bicarbonates (44%) and sodium sulfates (17%) predominate. This situation was repeated at least 3 times in the studied area. The author calculated using the previously published formula ^[6] that the average winter temperatures, judging by the variations in the values of ?18 ^O in certain periods of the formation of veins, were 5-8 °C colder than modern ones, and on average were only 2-4 °C colder (obviously affected by the softening influence of the nearby ocean) and ranged from -33 to -28°C, average January temperatures from -53 to -45°C.^[92]

              Mein. In the valley of the Main River, the author ^[92] characterized in the most detail the section of the edom thickness of the Ice Cliff, composed of sandy loams (desalinated), cyclically overlapping with organic-saturated horizons. The number of cycles is different, depending on the power of the opened thickness of the edoma. With the largest autopsy – over 50 m – there are six of them, about 30 m – five, at the time of the examination by the author, the thickness was 22-25 m. No more than three horizons of organic matter were clearly distinguished. In the stage of study on the Ice Cliff preceding our research, A.N. Kotov and V.K.Ryabchun^[95] obtained a series of ^10-14 S-dates without inversions from 42,000 ± 1300 years (MAG-801) to 19,500 ± 500 years (MAG-815).

       In the isotope-oxygen composition of the re-vein ice of the Ice cliff outcrop, the cyclicity of the distribution of values ?18 ^O along the vertical is clearly distinguished. Varying in general from – 28.8 to – 26.2%, the values of ?18 ^O show a pronounced tendency to increase in the intervals from +26 to +29 m, from +38 to +42 m, from +46 to +48 m. Even more pronounced are the segments with a noticeable decrease in heavy oxygen isotopes released in the range from +29 to +38 m, from +42 to 46 m. Judging by these fluctuations, we can confidently speak about the cyclical formation of the isotopic composition of ice veins formed from 40 to 20 thousand years ago. This cyclicity was associated with periodic climate changes and with the cryocyclic nature of the formation of re-vein ice, the active growth of which occurred during periods of drainage of areas of re-vein ice formation, synchronously with the accumulation of interlayers enriched with peat and remnants of shrub vegetation. During periods of accumulation of purely mineral deposits – strongly desalinated alluvial sandy loams – the growth of veins sharply slowed down or stopped altogether.

     A.A. Archangelov et al.^[96] and M.A. Konyakhin^[97] investigated the cryostratigraphy and isotopic composition of the edom strata of the Duvan Yar, Cape Chukochy, and the Beautiful outcrop on the Mal River. Anyu as an indicator of the conditions of their formation and genesis. In the dissertation work of M.A. Konyakhin ^[97], the provision on paleotemperature control of the isotopic composition of re-vein ice is formulated, which consists in the fact that: a). The values of ?18 ^O of atmospheric precipitation correlate well with the temperature of the surface layer of air; b). The values of ?18 ^O of surface waters of the Kolyma Lowland reflect the magnitude of ?18 ^O of atmospheric precipitation, but unlike them, the values of ?18 O of surface waters are more stable. The isotopic composition of the half-ice water of rivers and lakes is determined by the values of ? ¹⁸ O of thawed snow water. In the vicinity of the village . Chersky the difference between them does not exceed 2-3%; c). The water filling the frost-breaking cracks is fed mainly by thawed snow water; d). The rapid freezing of water in a frost-breaking crack leads to the fact that the isotopic composition of the elementary vein and the water from which it was formed practically do not differ from each other; e). There is a good correlation between the change in the isotopic composition of modern re-vein ice and the average winter surface air temperatures. M.A. Konyakhin^[97] calculated that a change in the average winter air temperature (within the Kolyma lowland) by 1 ° C leads to a change in the values of ?18 ^O of re-vein ice by 1.25%. According to approximate calculations by M.A. Konyakhin ^[97], during the cold snap epochs, the average winter air temperature decreased by 2-5 °C compared to modern values at the end of the Middle Pleistocene, by 5-8 °C in the Zyryan epoch, by 4-7 °C in the Sartan epoch. During periods of climate warming, the average winter air temperature was 1-2 °C colder than modern values at the end of the Kazantsev epoch. M.A. Konyakhin ^[97] suggested that the depression of the sea by 750-800 km in the Zyryan and Sartan eras led to a decrease of 2-4 °C. A good correlation of modern average winter and January temperatures allowed M.A. Konyakhin^[87] to assume that the minimum values of the average January temperatures of the time of accumulation of edom thicknesses decreased to -42 – -50 °C.  Taktoyaktak Peninsula.

      J. Ross McKay^[98] for the first time generalized data on oxygen isotope variations in permafrost rocks of the Taktoyaktak peninsula. The data on edom veins in the work are single - on Hooper Island, organic matter from the active layer lying directly on the hypsithermal unconformity (from the thawing layer) was dated at 8765 ± 230 years (SgX–4352). A sample of ice from a Pleistocene ice vein, the top of which was cut off by this disagreement, gave a value of ?18 ^O equal to -32.3%, which is much lighter than that of modern vein ice. For the ice of a modern ice vein, p-ov Taktoyaktak J.Ross McKie gives the values of ?18 ^O from -22 to -26. Despite the small amount of data on Edom, the work of J.Ross McKie^[98] played an important role in isotopic studies of edoma, as she demonstrated additional new possibilities in its study.McLeod Point. R.F. Black^[99] described three levels of Late Pleistocene and Holocene ice veins, in the McLeod area, 120 km southeast of Barrow, in northern Alaska in a 7.2 m high cliff.

      A system of actively growing, large near-surface ice veins (in the upper horizon) has been uncovered in the cliff, overlapping the cut ends of two buried, superimposed systems of inactive ice veins in the sediments of the two lower horizons. Four radiocarbon samples from the base of the upper peat bog between large near-surface veins date the beginning of the formation of veins in concave polygonal bogs approximately 12 thousand radiocarbon years ago. Two dates > 33,200 and > 40,000 years ago, obtained from the lower horizon of organic matter, which separates the deposits of the two lower horizons, indicates the ancient age of the oldest system of ice veins. R. Black explained the origin of the tiering in this system of re-vein ice not climatic, but sedimentation reasons ^[99].

            Fox permafrost tunnel. About from Fairbanks, to the east of the Goldstream Valley, CREEL employees dug a 110 m long tunnel during 1963-1966. In 1969, a 61 m long inclined underground excavation was carried out from the main tunnel near the entrance to the underlying gravel about 6 m below the bottom of the tunnel. A detailed study of Late Pleistocene edom deposits uncovered in the Fox Permafrost tunnel was carried out by T.D. Hamilton, J.L.Craig and P.V.Sellman^[100]. The Fox Permafrost Tunnel represents undisturbed outcrops of ice-saturated sandy loams and loams that overlap gravel and bedrock. Large ice veins are found both in the upper and lower horizons of sandy loam deposits. The veins in the lower horizon have vertical dimensions of 3-4 m and a width of 2-4 m in the upper part . 33 radiocarbon dates were obtained from the Fox Permafrost tunnel. Nine younger dates, approximately between 38,500 and 30,000 years ago, record a period of rapid accumulation of native sandy loam deposits, accompanied by the growth of ice veins. Most of the interval between 33 and 30 thousand years ago must have been a period of slowing down the accumulation of loess and the formation of surface turf, the growth of ice veins and the later cutting of some of them. The dates of the seven samples taken near the entrance to the tunnel are in the range from 11300 to 14280 years. The five youngest dates were obtained from proluvial clastic deposits that formed in the marginal part of the valley, are between approximately 12.5 and 11 thousand years old.^[100] Ipikpuk River.

On the Ipikpuk River, in Alaska, in the outcrop of a terrace with re-vein ice, R.Nelson and co-authors^[101] obtained a number of radiocarbon dating from 8.8 to more than 49 thousand years. The age determined from monolithic samples (13.3-30.3 thousand years) and from individual identified plant remains (9-9.5 thousand years) turned out to be different from the same samples. Apparently, most of the organic material was re-deposited, although it had excellent preservation. This confirms the conclusion that it is possible to detect redeposited organic matter in subaqueous sediments under conditions of permafrost development.^[101]

      The Titaluk River. The reliability of radiocarbon dating was successfully supported by thermoluminescent dating, U/Th dating and other methods. L.D. Carter ^[102] was able to date the formation of ice veins on the Titaluk River in Alaska from 35 to 27 thousand years ago. The results of parallel radiocarbon and thermoluminescent dating were very close. For the upper 25-meter fragment of the coastal outcrop, three radiocarbon dates were obtained: 31.2; 29.5 and 35.3 thousand years and three thermoluminescent dates: 27.9; 27.4 and 27.3 thousand years.

The 90s of the XX century.

Isotope–temperature dependence and paleotemperature maps for the development of edoma in the key stages of the Late Pleistocene. Materials of the author's report in Kaunas in 1989^[93] were continued in the form of publications in Russian and English in a special issue of the journal Water Resources ^[103] and in the proceedings of the International Conference on Permafrost Studies in Beijing,^[104] and were also defended ^[105] in the form of a doctoral dissertation on October 29, 1991 at the Institute of Permafrost Studies SB AS USSR. A new understanding of the geotemperature evolution of the frozen strata of the cryolithozone of Northern Eurasia over the past 40 thousand years is the main result of the research conducted by the author.^[105] The study of more than 50 sections of late Quaternary syncryogenic strata in the north of Eurasia from Yamal to Chukotka by complex conjugate geocryological analysis, in which isotopic methods play an important role, made it possible to perform interregional cryostratigraphic correlations and paleogeocryological reconstructions. Approximate quantitative paleotemperature characteristics make it possible to more definitely represent the conditions for the development of edom syncreogenic strata in the late Quaternary. The final stage of the late Pleistocene – the period of 40-10 thousand years ago – is distinguished by the author as a single cryochron with very severe winters, within which the oscillations of air temperatures and frozen strata were insignificant.^[105] The formation of the cyclic nature of the properties and structure of syncreogenic strata often occurred autonomously, even with relative climate stability. Methodological and theoretical developments are based on the analysis of extensive geocryological data. The geocryological field study of sections of syncreogenic frozen strata performed by the author throughout the studied space of the cryolithozone of northern Eurasia was carried out in a single key. This study includes, along with the methods adopted in the coupled paleogeographic analysis (palynological, micro– and macrofaunistic, geochemical, radiocarbon), permafrost–facies analysis and a new research method – isotope–oxygen analysis of macro– and mesotextureforming ice. The use of the isotope–oxygen method makes it possible to move from qualitative estimates to approximate quantitative reconstructions of the dynamics of frozen strata in the past. Indirect data on paleotemperature conditions were obtained using cryolithological, cryohydrochemical, botanical, micro– and macrofaunistic methods; direct – approximate (numerical) paleotemperature characteristics were obtained for summer conditions using the palynological method, and for winter – isotope–oxygen; – age binding of the obtained paleogeotemperature data was carried out (approximately) for syncreogenic strata. To increase the reliability of age definitions, an assessment was made of the synchronicity of the accumulation of sediments and organic material buried in the thickness, which often turns out to be re-deposited, which required the use of mass radiocarbon dating. Paleogeocryological indicators of air and rock temperatures have been found and investigated, which make it possible to obtain approximate quantitative indicators characterizing changes in geotemperature conditions in time and space. The main method of reconstruction is the comparison of isotopic data on late quaternary syncreogenic strata with modern analogues and the search for correlations of changes in the content of heavy oxygen in underground ice and temperatures of air and frozen rocks.^[105] The study of reference sections of late Pleistocene and Holocene syncryogenic strata within various regions of the north of the Eurasian cryolithozone by the method of conjugate isotope–paleogeocryological analysis made it possible to clarify the features of their structure and composition and create a new base of paleogeocryological data complementing previously known, as well as for the first time to obtain approximate quantitative characteristics of changes in paleotemperature of frozen strata for the last 40 thousand years. The main features of the isotope–oxygen composition of underground ice in syncreogenic permafrost strata formed in the final 40 thousand years of Late Quaternary time have been established: a). The trend of distribution of oxygen–18 in veins of various ages in the north of Eurasia was determined: – in late Pleistocene re–vein ice, the trend of changes in ?18 O was similar to the modern one: ?18 O decreases with moving from west to east by 8-10%, from -19 to -25% in West Siberian vein systems to -30, -35% in the North Yakut, and then increases again by 2-3%: to -28, -33% in the north of Chukotka and by 6-8%, to -23, -29% in the east of Chukotka.^[105] These data indicate that the nature of air transport in most of the Eurasian Subarctic at the end of the Late Pleistocene was similar to the modern one, western air mass transport prevailed. The influence of the Atlantic (over the entire area from Yamal to northern Yakutia) was significant, although somewhat weaker than the modern one. In the easternmost regions (Chukotka), the influence of Pacific air masses was noticeably less than the modern one. Here, especially in winter, the anticyclonal continental regime prevailed; – in Holocene re–vein ice, the same distribution trend of ?18 ^O remained – a decrease of 6-8% to the east: from -14, -20% in West Siberian vein systems to -23, -28% in North Yakut, however, significantly more positive became values of ?18 ^O in Chukchi veins: up to -15, -21%. The distribution of ?18 ^O values in modern vein sprouts and in snow cover is very close to this (for averaged values over the winter). For the first time, isotope–oxygen diagrams were compiled for late quaternary edom veins, which show the change of ?18 O and 18 O (the difference from modern values) with absolute age for the last 40 thousand years. A new scenario of the evolution of air temperature and frozen strata in the upper horizons of the cryolithosphere in the late Quaternary has been developed based on data obtained using conjugate isotope–paleogeocryological analysis: – mass data of palynological (more than 2000), radiocarbon (about 400) and isotope–oxygen determinations (more than 1500) served as the basis for compiling a new scale of paleoclimatic changes in the north of Eurasia for the last 40 thousand years: 2 stages are distinguished – Late Pleistocene Cryochron and Holocene. During the formation of Edoma 40-10 thousand years ago, the average winter air temperatures in the north of Eurasia were 6-8 °C lower than modern ones (and reached -22, -33 °C), and the average January temperatures were 8 – I2 °C lower than modern ones (up to -33,-49 °C)^[106]. New cryolithological aspects of the formation of syncreogenic strata and re–vein ice in them in the north of Eurasia in the last 40 thousand years have been established and their role as stratigraphic and paleogeographic indicators has been emphasized: a new idea has been developed about the macrocyclic mechanism of the formation of powerful syncreogenic re–vein ice, about the cyclic development of syngenetic frozen rocks) in the edom strata of the Late Pleistocene. The formation of ice veins is confined mainly to the time of accumulation of layers of subaerial deposits in overlapping subaqual–subaerial strata of different genesis: alluvial, lacustrine, deluvial, etc., and in the subaqual phase it slowed down or stopped. This led to the formation of longline veins – cryocyclites ^[105].

It is established that the coastal plains of the Subarctic, within which undeformed Pleistocene re–vein ice is distributed in the syncreogenic strata of the ice complex, were not overlapped by cover glaciations both during the formation of veins and subsequently. Paleogeotemperature and paleoclimatic maps have been compiled for different chronocreases of the Late Pleistocene and Holocene, which for the first time show the change in time and space of approximate numerical values of average winter and Average January air temperatures, the sum of temperatures of winter and summer seasons and average annual temperatures of permafrost rocks ^[103-105].

These materials were published by the author in the form of a 2-volume monograph^[6]. In it, the paleogeographic and paleotemperature conditions of the formation of edom strata are considered in detail, and, in addition to the data contained in the doctoral dissertation in Chapter 9, the features of the dynamics of global isotope exchange in air transport in the eastern sector of the northern hemisphere in late Quaternary time, i.e. during the formation of edom are considered in detail ^{[6, pp. 346-353]}.

Summing up the consideration of the reference sections of Edoma and their isotopic characteristics, the author came to the following conclusions ^{[6, pp. 286-287]}:

   "1). The strata of the ice complex of the Late Pleistocene are heterogeneous in terms of their sedimentation.

   2). Fragments of various facies and even different genetic types of sediments can be combined (and are combined) in modern, at first glance, single edom arrays.

   3). The age of the Edom strata in the vast majority of cases is late Pleistocene (from 40 to 10 thousand years), however, the edom deposits of different areas are not synchronous and even within geomorphologically uniform massifs there are heterochronous fragments of edom.

   4). The spectrum of facies in which edom strata with powerful syngenetic veins were formed could be wider than the modern one: veins were formed in various facies of valley - river, slope, lake, swamp and even (rarely) coastal-marine complexes. Veins could also develop in subaqual (including, though rarely, in areas of the coastal-marine littoral) conditions.

  5). One of the main reasons for the active growth of veins in the late Pleistocene was noticeably colder than modern winters and, in general, a more severe geocryological situation.

    Summarizing in general the material presented in this part^[6], the author noted:

   1). Reference sections of Late Pleistocene syncreogenic ice strata within various regions of the cryolithozone of northern Eurasia have been studied by the method of conjugate isotope-paleogeocryological analysis. Thus, a new factual basis was created, which made it possible for the first time to obtain direct approximate characteristics of paleotempepatures of frozen strata for the last 40 thousand years.

    2). The latitudinal trend of oxygen-18 distribution in veins of various ages in the north of Eurasia has been determined.

    In Late Pleistocene re-vein ice, the value of ?18 ^O decreases as it moves from west to east: from – 19-=-25% in West Siberian vein systems from -30 to -35% in North Yakut, and then increases again to -28 – -33% in the north of Chukotka and to -23 – -29% on east of Chukotka. These data indicate that the nature of air transport in most of the Eurasian Subarctic was similar to the modern one, western air mass transport prevailed. The influence of the Atlantic was significant, although somewhat weaker. In the easternmost regions, the influence of Pacific air masses was noticeably less than the modern one. Here, especially in winter, the anticyclonal continental regime prevailed,    3).

Paleotemperature conditions for the development of syncreogenic permafrost strata and features of the formation of underground ice at the end of the Late Pleistocene were determined. A new scale of paleoclimatic changes in the north of Eurasia for the last 40 thousand years has been compiled. In contrast to the accepted schemes of V. A. Zubakov, N. V. Kind and others, paleoclimate oscillations are given in approximate numerical form using mass data of radiocarbon and isohope-oxygen determinations.

    4). The existing views have been revised, according to which the final stage of the late Pleistocene was extremely severe – 20-10 thousand years ago. Based on isotope-hydrogen data, it is shown that the climate 40-10 thousand years ago was relatively homogeneous, the natural conditions were somewhat more severe in the time intervals 40-38 and 30-25 thousand years ago. During these periods, the average winter air temperatures in most areas of the cryolithozone were 6-8 °C lower than modern, the average annual temperatures were 1-5 °C lower than modern, the average annual rock temperatures in some areas during these periods were 5-9 ° C lower than modern, in the remaining time periods of the Late Pleistocene (cryochron – 40-10 thousand years ago) The paleoclimatic and paleogeocryological situation was also harsher than modern ones. Temperatures of permafrost rocks ranged in the north of Western Siberia from -10 to -15 ° C, in the north of Yakutia from -18 to -21 ° C, in Central Yakutia from -16 ° to -18 ° C, in the north of Chukotka from -15 to -19 ° C.

    5). The importance of local facies changes in the formation of the structure and composition of syncreogenic strata is demonstrated. The idea of the macrocyclic mechanism of the process of formation of powerful syncreogenic re-vein ice in the strata of the ice complex of the late Pleistocene, which led to the formation of longline veins – cryocyclites, is developed; the formation of ice veins is timed to the time of accumulation of interlayers of subaerial deposits in overlapping subaqual-subaerial ice strata of different genesis: alluvial, lacustrine, deluvial, etc. Techniques for studying the genetic nature of the ice complex thickness and the frequency of vein formation cycles are proposed based on comparing the nature of isotope-oxygen diagrams in re-vein ice and in textural ice from the sediments containing them.

    6). It is proved that all the coastal plains of the Subarctic, within which undeformed Pleistocene re-vein ice is widespread, were not overlapped by cover glaciations, both during the formation of veins and subsequently"^{[6, pp. 286-287]}.

      In the final chapter of the monograph, the author summarizes ^{[6, pp. 346-353]}: "In solving the problem of the evolution of global isotope exchange associated with the dynamics of air transport in the north of Eurasia, isotopic studies of frozen strata can play a constructive role. At the same time, the results of isotope studies now refute rather than confirm many existing paleoclimatic and paleogeographic constructions for the north of Eurasia. First of all, this concerns the problem of cover glaciation. Once again, we recall that according to the prevailing paleoglaciological paradigm, significant changes in the area and volume of glaciers of the Northern hemisphere have occurred over the past 40-50 thousand years. According to some estimates, in the Late Jurassic era, the area of the cover glaciers was even maximum, although now the point of view about the insignificant spread of glaciers during this period is increasingly prevailing,

    In the Holocene, the cover glaciers, as is known, almost completely disappeared (it seems to the author that it should be recognized that the climatic conditions of Wurm were very cold, this caused a low moisture content in the air and prevented the proliferation of glacial covers). In addition, the prevailing views are that the volumes of the cover glaciation varied greatly in the late Wurm and within the time interval 40-10 thousand years ago. The minimum size of this glaciation reached in interstadial epochs, such as, for example, Karginsky (Bryansk, Denekamp and other regional synonyms) time. The author's research has demonstrated the unreality of such a paleoglaciological model. This is primarily indicated by the long-standing steady trend of the isotopic composition relief from west to east from the Atlantic to the North Yakut plains. The stability of the values of ?18 ^O in atmospheric precipitation, reconstructed by the author from syngenetic ice veins formed from 40 to 10 thousand years ago, practically excludes the possibility of noticeable rearrangements in the atmosphere and hydrosphere during this period, and the appearance or destruction of large glacial covers should have had a decisive effect on the dynamics of the isotopic composition of continental precipitation. Thus, the stable stability of the isotopic composition in syngenetic re-vein ice formed 40-10 thousand years ago over a large area of the Eurasian cryolithozone from Yamal to Chukotka allows us to speak with great confidence about the stability of atmospheric circulation during this entire time and about the unreality of paleoglaciological reconstructions involving a change in the volume of glaciers in the eastern sector of the Northern Hemisphere during this period. And even more inexplicable for such paleoglaciological constructions is the preservation of the isotopic trend in atmospheric precipitation during the transition from the Late Pleistocene cryochron to the Holocene. Preservation of the same difference of 8-10%, by which the Yamalo-Gydan veins differ from the North Yakut ones. What is noted in vein systems dating from the Late Pleistocene cryochron, in Holocene and in modern veins, certainly indicates the stability of the direction of global air transport in the northern regions of Eurasia during this time. And the fact that, in general, the isotopic background in the Holocene was different than in the late Pleistocene, testifies, as it seems to the author, only to different temperature conditions, first of all, to the more severe winters inherent in the epoch of the Late Pleistocene cryochron, compared with the Holocene and modernity.

      An equally important issue is the problem of the dynamics of moisture redistribution in winter in the north of Eurasia. Once again, let's pay attention to the data ... according to which in the north of Eurasia about 80% of snow is formed from Atlantic moisture and only about 20% – from the Pacific. The role of moisture brought from the Arctic in winter is negligible, although the Arctic anticyclone undoubtedly affects the temperature conditions more noticeably. It seems quite logical to assume that in the epoch of the Late Pleistocene cryochron, the introduction of moisture from the Arctic was even less significant due to some increase in ice cover due to cooling. I must say that isotopic studies on the ice veins of Northern Eurasia confirm this. The influence of the Atlantic is clearly recorded for modern, Holocene and Late Pleistocene veins from Yamal to Aion Island (a little east of the Kolyma Valley, and the influence of the Pacific Ocean affects mainly in a narrow strip – mainly Chukotka and the Magadan region....

    As already mentioned, there are now many contradictory facts "for" and "against" the development of vast plain glacial covers in the era of Wurm in Eurasia. This paradigm is opposed, first of all, for the regions of the Asian cryolithozone, the widespread development of late Pleistocene syncryogenic strata with powerful undeformed re-vein ice, and for the European region, the former distribution of permafrost rocks is indicated by direct indicators of frozen strata – pseudomorphoses found at many points. Moreover, they were also found in those areas that were traditionally considered to be covered by glaciers in the late Wurm....

      As is known, the predominant western transport of air masses and the atmosphere is determined by the temperature horizontal heterogeneity (the temperature difference between the tropics and the poles) and the deflecting action of the Earth's rotation around its axis. At the same time, winds are observed at high levels, as a rule, only in the western direction, and in the surface layer they are regulated, in addition, by the specific location of high and low pressure areas.

        During the Late Pleistocene cryochron, perhaps the most important differences from modern ones should still be considered the existence of glaciation in North America, glaciation (mainly in winter) The North Atlantic and extensive glaciation of the mountainous regions of the Alps and Scandinavia (which also overlooked the adjacent plains). This led to the formation of a high pressure area that existed almost year-round in these regions. Most likely, this extensive anticyclone was deeper in winter. The direction of the moisture-saturated Atlantic air masses shifted under its influence to the north in the area of the Aleutian Islands, from where they acquired a predominantly western direction, and when they reached the northern regions of Eastern Europe, they shifted to the south (the strengthening of the northwestern component of air transport here was also determined by the Western European-North Atlantic anticyclone). An important regulator of the winter movement of air masses was also the Siberian anticyclone, which, undoubtedly, was also deeper, and its center shifted somewhat to the north. The interaction of these two large anticyclones and the existence of a slightly lower pressure area in the south of Western Siberia led to the fact that the north-western and northern air mass transport prevailed on the western outskirts of Western Siberia, and on its eastern outskirts (and, accordingly, on the western periphery of Central Siberia) – the southern and south-western transport. This led to a noticeable increase in the amount of precipitation (snow) in the south of Western Siberia (although even further south over Kazakhstan the amount of precipitation was low). In the north of Western Siberia, the possibility of an increase in precipitation during this period is problematic. And further to the east, in the north of Yakutia, where the western transfer of air masses also persisted, the amount of snow decreased noticeably (and was probably even less than at present).

    As already mentioned, Northern and Central Yakutia during the cryochron era experienced a strong influence of the deep Siberian anticyclone in winter. The interaction of the same anticyclone on its eastern periphery with the North Pacific cyclone led to intensive frontogenesis with heavy precipitation in Chukotka and Kamchatka with the predominance of southwestern air mass transport.

   In the summer, the situation changed radically. The Siberian anticyclone was destroyed in the summer, but the Western European - North Atlantic one most likely persisted, due to the slightly decreasing area of glaciation of the Alps and Scandinavia, although the summer destruction of the ice cover of the North Atlantic led to the displacement of the center of this anticyclone on the territory of Europe. Precipitation (rains) increased along the western edge of this anticyclone (possibly capturing England and Ireland), and the temperature, in general, decreased. The blocking influence of the Western European anticyclone was manifested primarily in the following. that it was dry and cold in the central part of Western Europe and in Scandinavia, and in Eastern Europe it was also cold, although not so dry. Further to the east, the circular activity in the cryochron was most likely similar to the modern one (there is reason to believe that the blocking effect of anticyclones provoked by the slightly increased glaciation of the Verkhoyanye was insignificant), i.e., in the middle and upper troposphere, the western transport of air masses prevailed, and in the lower troposphere there was frequent formation of mobile cyclones and anticyclones (under under the influence of the baroclnine instability of the western transfer), shifting to the east. In the process of isotope research, a number of controversial points were revealed, which the author also seems to point out.

When interpreting the isotope-oxygen data, the author had to ignore the sublimation processes, the activity of which could be different in areas with varying degrees of continentality: a slight evaporation of snow in winter was in a humid marine climate and, obviously, more noticeable in a sharply continental one.

This aspect was not considered in the work also because the degree of continentality in the vast majority of the coastal regions of Northern Eurasia, on the basis of the study of which the global reconstruction was compiled, is approximately the same.  Although a more significant drainage of Northern Yakutia at the end of the Wurm should not be underestimated.

Making the necessary amendments to paleostructures, as well as taking into account the continental effect for the central and southern regions of Eastern Siberia is one of the important tasks to be solved. It is impossible not to point out that the work does not contain data on the vast expanses of Central Siberia. This is mainly explained by the fact that the mentioned region is mainly a mountainous territory, and here it was difficult to take into account the distorting effect of high-altitude zonality at the present stage of the study. The issue of isolating isotopic zones probably needs further elaboration, since although the scale proposed by the author (where zones are distinguished after 2%) allows for interregional correlations, but the existing experience of repeated isotope analyses (when the results differed by more than 1%) and the establishment of noticeable (1 – 1.5%) fluctuations in The isotopic composition of samples from the same horizon makes it critical to classify ice that differs by 2% to different isotopic zones, but we emphasize once again that this is the first attempt to establish quantitative criteria for isotopic zoning and, in addition, classifications of this kind always carry an element of arbitrariness and voluntarism.

   Probably in the future, there will still be a study of the rigor of using modern dependencies between the values of ?18 ^O in veins and air temperature for ancient objects (or a search for correction regional coefficients), although now there is not enough data for such a revision"^{[6, pp. 346-353]}.

     Later, V.I. Solomatin^[106] wrote about the generalizing works of the author: "It seems to us that the most promising direction of paleotemperature reconstruction is associated with the analysis of the isotope-oxygen composition of ice veins. For the first time such a study was carried out by Yu.K. Vasilchuk^[93]... As a result of the research, the author came to the conclusion that the average winter air temperatures in the era of accumulation of the ice complex of Northern Yakutia were 15 ° C colder than modern ones. It is difficult to overestimate the significance of this work, since it actually opens up a new promising direction of underground ice research, which has its own method and allows obtaining the most important results that cannot be obtained in any other way"^{[106, p. 236]}.

      In the mid-90s, A.Yu. Derevyagin and A.B. Chizhov began performing together with G.-V. Hubberten, K. Siegert, etc. a joint Russian-German project to study the isotopic composition of the edom re-vein of the lake district.Labaz ^[107] and Cape Sablera ^[108] on Taimyr.     

Significantly colder than the modern paleoclimatic conditions of the time of accumulation of edoma on the lake. The laboratory indicates the isotopic composition of the deposits of the ice complex. According to the research of A.B. Chizhov et al.^[107] the deposits of the ice complex on the lake.The labas lie on clays and boulder loams of the time of the Zyryansk glaciation. Their age, based on the dating of plant detritus from, was 43.9 thousand years. The deposits include syngenetic re-vein ice up to 10 m thick. The average winter temperatures during the formation of these ices were about 7 °C colder than modern ones. Judging by the isotopic composition, the values of ?18 ^O vary from -30.7 to -29.4, and the values of ?2 H vary from -233.6 to -230.6, the average winter temperatures during the formation of these ices, recalculated by the formulas of Yu.Vasilchuk^[6] were about 7 °C colder than modern ones. Modern re-vein ice is heavier here, ?18 ^O varies from -25.5 to -23.0, and ?2 H from -194.4 to -143.6.^[107]

    Field work has established that the Late Pleistocene and Holocene deposits of a 30-meter-high terrace, 30 m high at Cape Sablera, contain three tiers of powerful re-vein ice. Almost inversion-free series of dates have been obtained from the sediments of Cape Sabler containing ice veins. One series of dates from 28.5 to 13.5-14 thousand cal. years ago it was obtained by L.D. Sulerzhitsky^[109] for deposits in the depth range of 1-17 m; later, 13 dates from 35.1 to 11.8 thousand cal. years ago, they were obtained for deposits at depths from 3 to 25 m^[99]. According to the dating, edom deposits at Cape Sablera were formed between 35 and 13-12 thousand cal. years ago.

      The values of ?18 ^O in the ice veins dated from 34.5 to 30.9 thousand cal. years ago, ranged from -31.5 to -28.3%; in veins dated between 22 and 14 thousand cal. years ago, the values of ?18 ^O varied from -29.5 to -24.3 %. The heavier isotopic composition is characteristic of modern Holocene ice vein sprouts, where the range of variation in the values of ?18 ^O is -20.6%, -20.1%, and the range of variation in the values of ?2 H is -158, -153%, respectively.^[108] Conducted by A.Yu.Derevyagin et al.^[108] based on the obtained isotopic data, paleotemperature calculations using known formulas ^[6] show a clearly pronounced tendency to winter warming since the end of the Karginsky time, when the average winter temperatures were about 6-7 °C lower than modern ones. The results of detailed testing of Late Pleistocene veins suggest the presence of a trend towards a decrease in average winter temperatures at the end of the Kargian time from about -28°C to -31°C and their increase during the Sartan time from -28 -29°C to -25°C, which is only 1.6°C lower than the average temperature of modern winters ^[108].

     The first direct AMS radiocarbon dating of microinclusions of organic material extracted directly from edom re-vein ice. In early September 1999, at a conference on accelerator mass spectrometry in Vienna, Yu.K. Vasilchuk and colleagues^[110] reported on the results of the world's first practically direct determination of the age of edom re-vein ice. Age determinations were made on the basis of AMS radiocarbon dating of microinclusions of organic matter extracted from the veins of the Seyakhinskaya edoma^[110]. It was possible to determine the age of Late Pleistocene syngenetic ice veins in two different ways. Initially, a number of radiocarbon dating of peat from the host sediments was obtained, which showed that 11 m of syngenetically frozen sediments accumulated at the base of the section, from 30 to 22 thousand years ago ^[77], approximately within 7.5-8 thousand years. The ice veins were dated by microinclusions and alkaline extraction from all organic matter contained in the ice. For the two upper samples, the alkaline extract turned out to be older. This can most likely be explained by the contamination of the ice veins with ancient fine organic dust. On the contrary, the AMS dating of the alkaline extract and microorganics in the lower sample are almost identical: the re-vein ices opened at the base of the section began to form about 21 thousand years ago, and the AMS dating from the upper part of the 11 m puff, lying at the base of the section, showed that the puff completed its accumulation 14.7 thousand years ago^[110]. For the first time, it was possible to confirm the vertical age stratification of re-vein ice formed by successive penetration of meltwater through frost-breaking cracks geologically simultaneously with the accumulation of precipitation on the surface. These data were published a year later in DAN^[111], EPSL^[112] and NIM^[113].

      Sections of edom thicknesses saturated with crushed stone in the upper reaches of the Kolyma River. Powerful syngenetic re-vein ices are usually found in edom strata in river valleys, on the coasts of seas and lakes, in mountainous and foothill areas they have been studied much less - powerful Late Pleistocene syngenetic veins were found^[19] in the Phoenix and Duck edom sections and sandy loam sediments saturated with gravel, pebbles, gravel in the basins of the Verkhnekolymsky highlands, within the river valleys of the Eastern Sayan, Olenek-Anabar formation plateau.

Southwest of the mouth of the river.Duck, upstream of the Kolyma, a few kilometers from the town of Sinegorye, 25 km south of the village.Yasny (62 ^o 15' s.w., 150 ^o 45' v.d.) is located the Phoenix gold mine, where in the middle mountains, in the valley of the small stream Yasny, flowing into the Kolyma on the right, on the slope at an absolute height of 412-434 m, lies a late Pleistocene polygonal-vein complex, expressed in relief in the form of a hollow-sloping terrace. Sandy loam-gravelly deposits with a thickness of about 1 m are opened in the lower part of the section.^[19]

Above, with a clear contact separating them from the lower strata, lies a 15-16-meter thick layer with large (5-15 cm) crushed stone, saturated with texture–forming ice - up to 50-60% of the total volume of the rock.

A system of powerful two-tiered syngenetic re-vein ice dissects the entire thickness. The height of the ice veins of the lower tier is about 9-10 m, the ice in the lower part is yellow-gray. The ice veins of the upper tier are composed of transparent, rarely light gray vertically striped ice. The width of the veins of both tiers is 1.2–1.5 m, they expand slightly upwards. In the lower part of the outcrop, peat with roots, branches and fragments of larch trunks is found in the gravelly sandy loam thickness.

      The values of ?18 ^O in the Late Pleistocene syngenetic vein in the upper part of the Phoenix mine range from -30.4 to -32.6%. The definitions of ?18 ^O in the lower part of the polygonal-vein complex gave values from -25.7 to -27.7. Near the sole of the Duck section, the values of ?18 ^O were also relatively high: from -24.9 to -29.3. AMS dating of microorganics from the upper part of the upper tier vein at the Phoenix mine 11000 ± 80 years (SNU02-143), indicated the completion of the formation of veins in the Phoenix section about 11 thousand years ago, radiocarbon dating of peat and wood taken at an altitude of 332.8–334.9 m in sandy loam-gravelly soils containing ice veins at the Utinoye mine showed that re-vein ice began to form from 32.1 to 42.1 thousand years ago. The average January temperatures for most of the time of the formation of veins were lower than the current 7-9 ° C and amounted to -46 ... -48 ° C. Currently, the temperatures here are -24... -27°C and -37... -40°C.^[19]

       Cyclicity of edom deposits and re-vein ice. Yu.K. Vasilchuk^[114] proposed a new structural model for the formation of powerful syngenetic re-vein ice. The model is based on the meso- and macrocyclic mechanism of formation of syngenetic veins. The logical essence of the proposed model is that the process of syngenetic formation of powerful ice veins is not considered within the framework of the accepted paradigm – as a process of continuous ice formation, but in a slightly different interpretation as a pulsating – cyclic process.The main difference between this model and the existing models of cyclic development of veins is not the climatic triggering mechanism of the identified cyclicity (i.e. cyclicity manifests itself regardless of the climatic rhythms of warming or cooling). According to this model, the main determinant mechanism was the repeated repeated change of the suberal and subaqual nature of sedimentation on the surface of the polygonal massif.^[114] The subaqual regime refers to a small water capacity on the surface of a polygonal massif, it rarely exceeds 1-1.5 m (otherwise, the veins lying below could have thawed even in the harsh conditions of the late Pleistocene). It is usually assumed that syngenetic ice veins form only under conditions of slow continuous sedimentation accompanied by repeated frost-breaking cracking. However, we believe that such a situation is quite rare and this type of sedimentation has been manifested sporadically over the past 50 thousand years, more often subaqual sedimentation has been replaced by subaerial conditions for the growth of re-vein ice. The change of the subaerial regime by the subaquatic one may be associated with the formation of small thermokarst lakes formed as a result of partial pulling out of veins, as well as with the damming of small rivers, flooding of floodplains, lowering of the coasts of seas, bays and lips, the formation of dams or extensive sores, etc.^[114]Yu.K. Vasilchuk^[114] identified three types of cyclicity in syngenetic deposits with re-vein ice, including in Edom: micro-, meso and macrocyclicity, reflected in the cyclicity of the structure of sections and the location of syngenetic re-vein ice.

        Microcyclicity is associated with the interannual frequency of changes in the depth of the active layer and the accumulation of a thin layer on the surface, the duration of microcycles is calculated from the first years to hundreds of years.

The vertical scale of microcycles is centimeters – tens of centimeters.

Mesocyclicity is associated with a pulsating change in the level of the reservoir, along the shores of which, or on the shallows of which veins are forming. The duration of mesocycles is usually calculated from many hundreds to the first thousands of years. The vertical scale of mesocycles is the first meters.

Macrocyclicity is associated with a radical restructuring of the sedimentation regime or less often (mainly in the south of the area of re-vein ice) with large climatic oscillations. The duration of macrocycles is usually calculated in many tens- and sometimes hundreds of thousands of years.^[114] The vertical scale of macrocycles can reach tens of meters. The Edoma or Late Pleistocene polygonal-vein complex is generally a macrocyclite, and the Holocene polygonal-vein complex is probably also an independent macrocyclite.

D.V. Mikhalev, in his PhD thesis^[115], analyzed variations in the isotope-oxygen composition of texture-forming ice in edom sections: Kolyma lowland - "Duvanny Yar", "Cape Chukochy", "Krestovka", "Beautiful", "Alyoshkinskaya Zaimka". This analysis showed that the texture-forming ice of the syncreogenic Pleistocene strata of the Kolyma Lowland is characterized by a significantly lower content of heavy isotopes ¹⁸ 0 compared to the ice deposits of the modern active layer. The low content of heavy oxygen isotopes in the tested ice reflects the harsh paleoclimatic environment of the period of formation of the "ice complex". However, D.V. Mikhalev made an assumption that during the period of syngenetic accumulation of edom strata, climatic conditions were not unchanged, and the climatic fluctuations that occurred manifested themselves in the partial degradation of permafrost strata (formation of sediment horizons of the ancient alasny complex "Duvannoy Yar", as well as in the accumulation of sediment packs with an increased content of heavy oxygen isotopes in the ice (sediment horizons in the thickness of the "Duvan Yar", the "Molotkov" layers at the base of the section are "Beautiful".  M.A. Konyakhin, D.V. Mikhalev and V.I. Solomatin summarized the data of two dissertations ^[93,115] - in the form of a textbook.

^[116]      

Herschel Island in the Beaufort Sea. The two-tiered re-vein complex was found by V. Pollard within the upper 10-15 m of frozen fine sediments. Ice veins account for up to 60% of the ice in the frozen sediments of the upper 10 meters at one of the sites in the Tethys Bay, where 31 veins were uncovered in a 150-meter outcrop ^[117]. Re-vein ice is often characterized by a gradual change in structure and texture from the center of the vein, where, as V. Pollard believes, younger ice is located to the sides of the wedges (where older ice is found). The polygonal-vein complex of Herschel Island has a distinct cyclicity, complicated by the extrusion of an older edom relic vein of the early cycle, in the process of formation, a younger vein of the late cycle Edoma in the valley of Last Chance Creek.

  On the Klondike, underground ice is found in the form of very widespread ice wedges in Late Pleistocene Edom strata^[118]. The ice veins of the lower tier lying at the base of the section are dated by radiocarbon, their age ranges from 40 to 45 thousand years: 14 From the date 45500 ± 580 years (BGS-2019) and 40060 ± 280 years (BGS-2018) were obtained from rhizomes collected directly above gravel and wood from cryoturbated facies, respectively. The range of values of ?18 ^O determined for samples from these veins: from -28.3 to -26.3, and the range of values of ?2 H was from -225 to -209^[119]. Conclusion

In the XIX century, the first observations of edom strata in the Russian and North American Arctic were made. In the XX century, edoma research reached a new level: the basic principles of the mechanism of accumulation of edoma strata were formulated, the different genesis of edoma was shown, radiocarbon dating was obtained, which made it possible to definitely judge the age of edoma, a study of stable oxygen and deuterium isotopes was initiated, which gave the basis to reconstruct the winter paleotemperatures of the formation of re-vein ice in edoma.