Ion geochemistry of massive ice at Yamal Peninsula: Bovanenkovo, Erkutayakha and Mordyyakha

Vasil'chuk Yurii Kirillovich ORCID: 0000-0001-5847-5568 Doctor of Geology and Mineralogy Professor, Lomonosov Moscow State University, Faculty of Geography, Department of Landscape Geochemistry and Soil Geography 119991, Russia, Moscow, Leninskie Gory str., 1, office 2009 vasilch_geo@mail.ru Other publications by this author

Introduction

The chemical composition of ice layers is most often fresh or ultra-fresh, which is equally inherent in glaciers (and buried glacial ice) and in-ground underground ice. There are also fresh formations lying in saline rocks, and rarely saline ice in saline rocks, so the chemical composition can only be an auxiliary indicator of the nature of ice deposits.^[8]

One of the important criteria for assessing the nature of stratified ice deposits is the fact that the largest massifs are confined to lowland territories that were influenced by marine transgressions in the Late Pleistocene. These are Yugorsky, Yamal, Gydan, Taimyr, Chukotka, Novosibirsk Islands, north Yukon, Delta R.Mackenzie, islands of the Canadian Arctic Archipelago. Formation deposits are very rare in the north, in the central part and in the south of Yakutia, within the Magadan region, in Alaska (off the coast), in Mongolia, China, etc.

The analysis of a large array of data on the mineralization of underground ice in different areas of the cryolithozone of Russia allowed the author to develop the following classification: ultra–fresh ice with a mineralization (mg/l) of less than 50, fresh – 50-200, desalinated – 200-400, slightly salted – 400-1000, medium–salted - 1000-5000, highly saline - more than 5000 mg/L.^[3]

The purpose of the article is to determine the qualitative and quantitative ionic composition of the studied three stratified ice deposits in the central and southern parts of Yamal: a) Bovanenkovo, on the shore of Lake.Hanikosito; b) in the upper reaches of the Mordyakha River and c) in the Yerkutayakha River valley, compare it with the ionic composition of the known Yamal formation ice (Bovanenkovo, Kharasaway, Mare Sale, Neito, Yuribey, Sabetta) and associated territories (Gyda, Tanama, Ust-Port, Ice Mountain) and on the basis of this identify the genetic similarity of the studied deposits with the formation ice, the nature of which is more definite.

Fig. 1. Map of the location of the studied formation ice in the Yamal Peninsula:

1-2 – continuous distribution of permafrost rocks from the surface (northern zone), 1 – low–temperature syngenetic permafrost rocks underlain by epigenetic (tundra subzone), 2 – high–temperature permafrost rocks - mainly epigenetic (forest-tundra subzone); 3 - massively insular and insular from the surface distribution of permafrost rocks (north taiga subzone); 4 – the boundaries of permafrost zones and subzones; 5 – the location of the studied formation ice: Bo - Bovanenkovo, Mo - in the upper reaches of the Mordyakha river, Er - in the valley of the Yerkutayakha river

Methods

For samples from formation ice, a method was used to measure the mass concentration of Ca2+, Mg ²⁺, Na⁺, K⁺, NH ₄^{+ cations} in samples of drinking, mineral, natural and wastewater water by ion chromatography FR.1.31.2005.01738, the range of detectable concentrations is 0.10-20.00 mg/dm ³, and for the determination of anions, a method was used for measuring the mass concentration of Cl^-, SO ₄ ^2-,NO 3_{- in samples of drinking, mineral, natural and wastewater by ion chromatography FR.1.31.2005.01724, the range of detectable concentrations is 0.10-20.00 mg/dm} ³ and the method of performing measurements of the mass concentration of ions in samples of natural, drinking and wastewater by ion chromatography HDPE F 14.1:2:4. 132-98, The range of determined concentrations of cations is 0.10-150.00 mg/^dm3. Measuring instruments: ion chromatograph "Steyer", detection limit for chloride ion 0.02 mg/l.

The isotopic composition of oxygen and hydrogen in vein ice was determined in the Laboratory of Stable Isotopes of the Faculty of Geography of Lomonosov Moscow State University using a Delta-V Plus mass spectrometer using the gaz-bench complex. International standards V-SMOW, GRESP, and SLAP were used for calibration of measurements. The error of the definitions was ± 1 % for δ ² N and ±0.4 % for δ ¹⁸ O. The values of δ18 ^O and δ2 H are expressed in ppm relative to VSMOW.

We have an assumption, which has not yet been sufficiently confirmed experimentally, that Late Pleistocene underground ice may contain an admixture of hydrogen of post-sedimentation origin. It is known that usually Late Pleistocene deposits with a high content of organic matter have a very specific hydrogen sulfide odor that distinguishes them from Holocene ones. This is most likely the result of the release of trapped hydrogen sulfide bubbles during thawing of frozen strata and ice. Perhaps the form of hydrogen sulfide in underground ice is not quite common, and even hydrogen sulfide is not released immediately from melts of Late Pleistocene ice. When repeated measurement of the isotopic composition of the same samples of Late Pleistocene ices by balancing on a mass spectrometer using a gas bench for measurements of values of δ18 ^O, the reproducibility of the results was almost ideal, while the results of measuring the values of δ2 H differed in individual samples (as a rule, these are 1-3 samples out of 100) on a few ppm. Repeated measurements in the same series of samples of the SMOW-V and GISP standards revealed ideal convergence for the values of δ2 H. Also, in these repeated measurements, good convergence and repeatability of the results were found for the values of Δ2H ^of other types of ice or waters of a similar phenomenon. Therefore, when interpreting the data, we preferred the distribution of δ18 ^O in the formation ice.

Results

Formation deposits near the village. Bovanenkovo. The territory in the vicinity of the village. Bovanenkovo belongs to the areas with the highest concentration of formation ice on Earth, along with the lower reaches of the Mackenzie River. Heterogeneous autochthonous and allochthonous stratified deposits near the village of Bovanenkovo with a capacity from the first meters to several tens of meters, extending in horizontal directions for hundreds of meters (sometimes more than a kilometer) are found in wells and in many natural outcrops of the Bovanenkovsky GKM. Ice layers are often uncovered near gas production facilities. Formation ice is more often traced under the remnants of the third and second terraces (with absolute marks from 15-20 to 40 m), as well as within the floodplain.^{[5,7,15,16,20,22,30,31]} Even under the Seyakha riverbed, stratified ice with a thickness of 7 to 9 m was noted.

Fig. 2. Powerful formation ice on the territory of the Bovanenkovsky GKM. Photo by D. Yu.Nekrasova

To date, it has been possible to analyze data from about 3 thousand wells with a depth of 10 to 100 m drilled within the territory of the Bovanenkovsky GKM on the interfluve of the Naduyakha and Nguriyakha rivers, of which 260 formation ice has been uncovered.^[5,31] The bulk of the ice deposits are located in Late Pleistocene rocks of coastal-marine genesis, less often in alluvial, slope or lake-marsh sediments. The formation ice is overlain by either clayey marine and coastal marine sediments, or loamy deluvial sediments.

The former form the plinths of terraces and are covered on top with a layer of younger Late Pleistocene sandy-loamy sediments.

The latter cover the slopes of the terraces with a cloak with a capacity of 1-6 m. Sometimes the formation deposits are overlain by younger Holocene lake-marsh deposits.

Formation ice, most often, have the form of lenses of different thicknesses, wedging along the strike. Drilling of hundreds of wells that have opened up the ice shows that the roof of the ice deposits is located both directly at the bottom of the seasonally thawed layer at absolute elevations of 25-30 m, and at depths of more than 50 m from the daytime surface. The sole of these deposits was found at depths from 1 to 57 m.

Variations of stable isotopes of oxygen and hydrogen. The isotopic oxygen composition (δ18 ^O values) of the samples taken from the formation ice varies from -12.49 to -22.95. The values of δ2 H range from -91.7 to -177.1. The deuterium excess (d _exc) varies from 3.4 to 10.6%.

Previously published works^[5,20,30] showed that the values of δ18 ^O in the formation ice of the Bovanenkovskoye field vary from -11.23 to -25.2. According to 142 definitions conducted by V.I. Solomatin and M.A. Konyakhin, more than 60% of the values of δ18 ^O fall into a relatively narrow range from -16 to -20.

The values of δ18 ^O in whitish bubbly ice range from -18.4 to -22.4% (on average equal to -20.4%), in “crystal” ice δ18 ^O varies from -17.4 to -25.4% (on average -22.7%), in ice ground δ18 ^O is -12.5%.

Yu.K.Vasilchuk^[5] also obtained a very homogeneous isotope profile from the formation ice exposed at a depth of 28 to 32 m in the 34-P well, where the values of δ18 ^O varied from -16.95 to -18.29, and the values of δ2 H ranged from -131.7 to -146.

The same homogeneous isotope profiles were obtained for layers 1 and 3, where the variations of δ18 ^{O values} did not exceed 1%, and the variations of δ2 H were less than 4%.

In the 34-P well, in the depth range from 28.5 to 32.4 m, the isotopic composition of the formation ice is quite homogeneous. The values of δ18 ^O vary from -16.95 to -18.89%, δ2 H – from -131.7 to -146.0% (thus, the range of variations of δ18 ^O is 1.94%, and δ2 H is 14.3%).

According to the average absolute values, this ice is the most isotopically heavy compared to other stratified deposits studied here. The average value of δ18 ^O is -18.1%, the average value of δ2 H = -140.6%.

The isotope-oxygen and deuterium curves have the same configuration, which most likely indicates the equilibrium conditions of fractionation during formation of formation ice.

In reservoir No. 1, the isotopic values in the six-meter ice formation are very homogeneous and vary in δ18 ^{O values} from -21.55 to -22.74, and in δ2 H from -163.1 to -171.3. Thus, the range of variations in the values of δ18 ^O was 1.19%, and δ2 ^{H was 8.2}%. The average value of δ18 ^O was -22.14%, and the average value of δ2 H is -167.14%.

The nature of the isotope curves indicates that these minor changes in the content of stable isotopes occur synchronously for the values δ18 ^O and for δ2 H.

In reservoir No. 3, the isotopic values in the two–meter thick ice are very homogeneous: the values of δ18 ^O vary from -22.4 to -23.13, and δ2 H - from -173.1 to -177.1 (i.e., changes in the values of δ18 ^O do not exceed 1%, and changes in δ2 H do not exceed 5%). The average value of δ18 ^O is -22.78%, the average value of δ2 H is -175.2%. The change in the deuterium content also occurs according to the change in the stable oxygen content.^[5]

At the same time, reservoir No. 4 was found in one of the outcrops, the content of stable isotopes in which varies very significantly and is about 10% in magnitude δ18 ^O, and about 80% in magnitude δ2 H.

In the upper ice sample from a depth of 0.2 m, maximum isotopic values were noted (δ18 ^O = -12.49%; δ2 H = -91.7%), and minimum values were recorded at depths of 0.9 and 1.9 m (δ18 ^O less than -22%; δ2 H less than -169%). If we do not take into account the upper sample with abnormally heavy values, then the value of δ18 ^O in the depth range of 0.3-2.8 m varies from -16.85 to -22.75, and δ2 H – from -129.6 to -171.9. Thus, the range of variations in the values of δ18 ^O is 5.9%, and in δ2 H it reaches 42.3%. The average value of δ18 ^O is -19.13%, the average value of δ2 H is -146.3%.^[5]

Such significant variations, as shown earlier by Yu.K.Vasilchuk^[3], with a high degree of reliability indicate ice release during freezing of water-saturated soils in a closed system (lenses of syngenetic segregation ice at the mouth of the Gyda River were characterized by extremely large variations in the values of δ18 ^O from -16 to -34%).

The nature of the distribution of stable isotopes in formation 4 suggests the initial formation of isotopically heavier ice in the uppermost and lowest parts of the formation, where the values of Δ2H ^are higher (-130%), and the subsequent formation of the central part of the formation, where the values of Δ2H ^are noticeably lower (-140%).

Formation ice in the valley of theSeyakha (Muddy) on the shore of Lake.Hanikosito, near the village. Bovanenkovo.

The structure and isotopic composition of the Bovanenkovo ice deposit, on the shore of Lake.Hanikosito. The outcrop of stratum ice in the northern part of Lake Hanikosito (point L) has been studied on the territory of the Bovanenkovsky NGKM. The outcrop of the formation ice is revealed in the sides of the thermocircle along its perimeter (Fig. 5, 6). The top of the thermocircle is located 130 m from the shore of the lake. The visible part of the outcrop is about 30 m wide and 6 m high.^[15]

In the section at the top, they are opened:

0-12 cm – detached brown light loam with inclusions of sphagnum mosses.

12-20 cm is a grayish-brown medium loam with a pronounced angular-granular structure.

20-85 cm – glued bluish medium loam

85-200 cm – gray and brown ice crater (Table 1.)

200-600 cm – layer ice.

J. Vasilchuk and I.Shorkunov performed horizontal sampling at a depth of 3 m every 5-10 cm, and vertical sampling to a depth of 6 m.^[15]

Fig. 3. Formation ice on the territory of the Bovanenkovsky GKM, on the shore of Lake.Hanikosito. Photo by J. Y. Vasilchuk

Table 1. Description of the deposits of the upper part of the strata containing Late Pleistocene formation ice in the area of Bovanenkovsky NGKM, on the shore of Lake.Hanikosito. From^[15]

On the formation ice in the valley of the river .Seyakha (Muddy) on the shore of Lake.Hanikosito obtained fairly high values of δ18 ^O, ranging from -17.9 to -20.5 and δ2 N, ranging from -137.5 to -150.2. Even higher values of the isotopic composition were obtained from the ice layer covering the formation: the values of δ18 ^O from -12.6 to -14 and the values of δ2 H from -97.5 to -105.1.^[15]

Fig. 4. Sampling from the formation ice on the territory of the Bovanenkovsky GKM, on the shore of Lake.Hanikosito. Photo by J. Y. Vasilchuk

Ionic composition of stratified underground ice near the village Bovanenkovo. In the ionic composition of the Bovanenkovo formation ice, on the shore of Lake.Hanikosito is noticeably dominated by Na+ cations, reaching 38.95 mg/l in cloudy ice with large inclusions of loam and K⁺ up to 21.76 mg/l in highly bubbly transparent ice with large crystals (Table 2).

The average concentration of chlorine anions in the Bovanenkovo ice formation, on the shore of Lake.Hanikosito is 3.13 mg/l, and the spread in different parts of the deposit is from 1.73 to 27.02 mg/l. The average concentration of sulfates is 1 mg/l, and the spread in different parts of the deposit is from 0.22 to 4.1 mg/l.

The determination of the chemical composition of the formation ice in the Bovanenkovsky NGCM area showed that Na⁺, Ca ²⁺ and HCO ₃^{- predominate in the composition of ions}. The concentration of sodium varies from 1.6 to 9.4 mg/l, in some samples reaching values of 12.7-16.8 mg/l, calcium – from 6.9 to 11.2 mg/l, the concentration of bicarbonates varies from 13.4 to 25.5 mg/l. The total mineralization of ice varies from 9.7 to 70.4 mg/l, averaging 33 mg/l. Ice containing loam inclusions is usually characterized by the highest values of predominant ions and mineralization, in an ice sample with large loam inclusions, the content of Na⁺, Ca ²⁺ and HCO ₃ was 39, 34.5 and 62 mg/l, respectively, and mineralization reached 168 mg/l.^[15] The ratio of Cl-/SO4 ^2- in most ice samples was 2-4, in three samples it reached values up to 100, the ratio of Cl-/SO4 ^2- above 20-40 was noted in brackish-water subsurface taliks of the rivers of the Ob Bay basin and in the salty waters of the creeps of Central Yamal.^[12]

Fig. 5. Ionic composition of the Bovanenkovo underground ice formation in the valley of theSeyakha (Muddy) on the shore of Lake.Hanikosito

Stratified ice deposits in the upper reaches of the Mordyakh river

The structure and isotopic composition of the ice deposit in the upper reaches of the Mordyakh river. A heterogeneous stratified ice deposit with a paragenetic combination of an autochthonous segregation ice layer (Fig. 6, a) and an autochthonous injection formation ice (Fig. 6, b) with syngenetic re-vein ice in the upper reaches of the Mordyakha River was investigated by us in August 2011. Here, a deposit with a thickness of more than 4 m with normal horizontal layering laterally turns into vertically layered ice and is dissected by powerful 4-5-meter syngenetic re-vein ice (Fig. 6, 7). This is a very rare combination of stratified and syngenetic re-vein ice in a single section. Previously, such combinations were rare on the territory of the Russian cryolithozone.

In August 2011, Yu.K. Vasilchuk and N.A. Budantseva described a new stratified ice deposit (Fig. 6) located in the upper reaches of the Mordyakha River in central Yamal, at absolute elevations of 66-70 m^[11]

Here, an ice deposit with a thickness of more than 4 m with normal horizontal layering laterally turns into vertically layered ice (see Fig. 7).

The heterogeneous ice deposit is dissected by powerful 4-5-meter syngenetic re-vein ice (see Fig. 7, a). Ice veins are composed of vertically layered yellowish-gray ice

The ice layers are opened in the left part of the outcrop at an angle of 65-75°. In the central part of the outcrop, the ice is relatively clean, and the layering is visible due to layers of ice of different colors. The width of these interlayers is from 1-3 to 10-15 cm.

To the left, this ice gradually turns into an ice crater also obliquely vertically oriented. The ground layers are represented by gray sandy loam. Closer to the periphery of the deposit, to the left, the amount of soil increases, and about 10 m from the central ice part, the reservoir ends and the host deposits here are gray sand.

To the right of the central part, where obliquely vertically layered ice is fixed, there is a slightly later tab in the upper part, represented by horizontally layered ice. The width of this tab is about 10-12 m, the height is 2.5–3 m.

The distributions of the values of δ18 ^O and δ2 H fully correspond to the heterogeneous origin of the strata.^[11]

The isotopic composition of the ice and the obliquely vertically oriented ice ground located in the left part of the outcrop shows very slight isotopic variations: the change in the values of δ18 ^O in the ice is about 1%, from -22.4 to -23.3%, which indicates the segregational nature of ice formation in an open system.^[11]

Fig. 6. Heterogeneous stratified ice deposit: paragenesis of vertically layered (a) and horizontally layered (b) intra-soil injection-segregation formation ice, as well as Pleistocene re-vein ice dissecting them in the thickness of the Kazantsev deposits in the upper reaches of the Mordyakha River, Central Yamal (according to Yu.K.Vasilchuk^[7,11]): 1 – segregated horizontal and subhorizontal layered ice and ice crunch; 2 – injection vertically layered ice and ice crunch; 3 – overlapping loam; 4 – oplyvina; 5 – re-core ice

Fig. 7. Formation ice in the upper reaches of the Mordyakha river GKM: vertically layered (a) and horizontally layered (b). Photo by N.A. Budantseva (a) and Yu.K. Vasilchuk (b)

Ionic composition of stratified underground ice in the upper reaches of the Mordyakh River. The ionic composition of the formation ice in the upper reaches of the Mordyakha River is noticeably dominated by Na⁺ cations, reaching 68.51 mg/l in the ice ground and 6.1 mg/l in crystal and glassy ice with a small number of sandy loam inclusions (Table 3).

The average concentration of chlorine anions in the formation ice deposit in the upper reaches of the Mordyakha River varies markedly in different types of ice and amounts to 2.27 mg/l in crystal and glassy ice with a small number of vertical inclusions of sandy loam, and the spread in different parts of the deposit ranges from 1.12 to 6.76 mg/l. The average concentration of sulfates in crystal and glassy ice is 2.36 mg/l, and the spread in different parts of the deposit is from 1.22 to 4.1 mg/l.

The average concentration of chlorine anions in the ice ground is 7.0 mg/l, and the spread in different parts of the deposit is from 2.50 to 15.96. The average concentration of sulfates in the ice ground is 9.76 mg/l, and the spread in different parts of the deposit is from 3.03 to 20.27 mg/l.

Table 3. Ionic composition of stratified and re-vein underground ice in the upper reaches of the Mordyakha River

Stratified ice deposits in the valley of the Yerkutayakha river

The structure and isotopic composition of ice deposits in the valley of the Yerkutayakha river. A heterogeneous stratified ice deposit^[6] with a paragenetic combination of an autochthonous segregational ice formation and autochthonous injection formation ice on the left bank was investigated by us in July 2010 in the Southern Yamal, in the Yarolabkhana tract, near junction 10 on 222 km of the Ob-Bovanenkovo railway, 4 km below the railway bridge. This is the southernmost location of the formation ice studied in Yamal. In an outcrop with a height of 18-20 m, composed mainly of layered sands, ice of two types is opened: in the central part, a rod of deformed ice of a vertical direction is opened, and on contact with it on both sides there is a dislocated layered stratified deposit (Fig. 8, 9).

The outcrop of stratum ice studied by Yu.K. Vasilchuk and N.A. Budantseva is located in Southern Yamal, on the left bank of the Yerkutayakh River (68 ^o 1'18" s.w., 68 ^o 51'39" vd.).^[7.10] This is the southernmost of the locations of stratum ice studied in Yamal.

In an outcrop with a height of 15-18 m, a dislocated stratum deposit with a total length of about 100 m is opened, which is mainly occupied by layered sands. The ice deposit was most fully uncovered in the circus.

In the central part of the circus, the reservoir lies directly under the layer of seasonal thawing, it is sharply lifted up and cut off, most likely, by postgenetic subaqueous thawing. In the apical part of the circus, the deposit is blocked by Holocene lake-marsh sediments with a capacity of about 1 m.

On both sides of the central part of the deposit, the ice layers fall steeply obliquely (see Figures 8 and 9) and after 15 m the roof of the ice deposit turns out to be at a depth of 8 m.

The ice inside the deposit is characterized by significantly different cryotexture. It is mainly ice of four types: 1) the ice is pure matte white, with a large number of gas xenogenic inclusions; 2) the ice is “crystal” transparent, sometimes with soil inclusions; 3) the ice is gray with a steel sheen, layered, the layering is parallel to the slope of the upper surface of the ice deposit; 4) the ice is gray blocky, lies in the form of tiles.

In the general composition of the deposit, we^[10] identified the central dislocated part – a rod with vertically and subvertically overlying layers of ice (the ice here is crystal and dirty gray with a large number of mineral inclusions) and two peripheral parts stacked with horizontally layered ice (the ice here is predominantly gray with a steel sheen, layered, matte white and gray blocky). The horizontal layering of these two parts of the deposit changes to an inclined one at the contact with the central rod. Such contact indicates the effect of the ice of the central rod on the occurrence of horizontally layered ice.

From east to west, layered ice with a total length of more than 100 m steeply falls and after 15 m the roof of this ice deposit turns out to be at a depth of more than 8 m. The ice is layered, the layering is parallel to the slope of the upper surface of the ice deposit.

The structure of the ice complex on the Yerkutayakha River and the study of spore-pollen residues in the ice, which demonstrated almost exclusively tundra pollen and spores, allowed a more definite answer to the question of the genetic affiliation of the studied deposit. In the apical part of the deposit, the ice is injectable, and in the distal parts on both sides of the central injection, the ice is segregated (Fig. 10), i.e. the ice deposit is heterogeneous autochthonous, formed by a combination of segregation and injection formation ice.^[7,10]

Fig. 8. Heterogeneous stratified ice deposit: paragenesis of segregation and injection ice layers in the thickness of the Kazantsev deposits in the valley of the Yerkutayakh River in the south of Yamal (according to Yu.K.Vasilchuk et al.^[10]):

1 – segregational horizontal and subhorizontal layered ice; 2 - injection vertically layered ice; 3 – Holocene lake–marsh loams and sandy loams with peat; 4 - sands containing an ice deposit; 5 – oplyvina

For isotopic and hydrochemical determinations, 33 samples of formation ice from different fragments of the outcrop and from ice of different types were selected.

Variations of stable isotopes of oxygen and deuterium in the deposits are significant: in pure, matte, white ice, the values of δ18 ^O vary from -19.64 to -20.54, and the values of δ2 H range from -152.4 to -156.9, in “crystal” transparent ice, the values of δ18 ^O vary from -19.24 to -20.24, and δ ² H is from -149.6 to -160.7.^[10]

In gray, transparent ice with a steel cast, the values of δ18 O vary from -19.44 to -21.33, and the values of d2H from -150.3 to -163.8, and in gray block ice and dirty gray, the values of δ18 O are more negative and they range from -22.13 to -23.42, and the values of ^{δ 2} H from -165.5% to -172.7%.

Estimating the entire range of variability δ18 ^O (about 4%) and δ2 H (about 20%), we can talk about relatively small fluctuations in the isotopic composition, therefore, the source water for ice of all types was the same or similar in isotopic composition.^[10]

In addition, the isotopic differences practically did not exceed the usual isotopic difference resulting from fractionation during freezing of free water.

A relatively small range of variations in the isotopic composition speaks more in favor of the intra-soil nature of the deposits, although significant differences in the texture of the ice make it seem that the deformed and vertically layered ice in the central part of the deposit is more likely to have an injectable nature.

Differences were also revealed in the degree of rolling of quartz particles – in the ice of the stock they are uncoated, and in the horizontally layered peripheral ice, the rolling of quartz particles is good.

This indicates different sources of water supply for feeding the vertically layered ice of the central stem and the horizontally layered peripheral ice.

Fig. 9. Formation ice in the valley of the Yerkutayakha river Photo by Yu.K. Vasilchuk

Fig. 10. The structure of the formation ice in the valley of the Yerkutayakha river Photo by Yu.K. Vasilchuk

Ionic composition of stratified underground ice in the valley of the Yerkutayakha river. Approximately equal amounts of Na⁺ cations, reaching 3.64 mg/l, K⁺ and Mg ²⁺ up to 2.71 and 2.56 mg/l in dirty gray ice with a large number of mineral inclusions, are observed in the ionic composition of the formation ice in the Yerkutayakha River valley (Table 4). NO ₃^{- and sulfates dominate among the cations} (SO ₄ ^2-) to 5.61 and 6.35 mg/l, respectively.

The average concentration of chlorine anions in the formation ice deposit in the valley of the Yerkutayakha River varies in different types of ice and amounts to: 0.76 mg/l in crystal and milky-white ice, 1.46 mg/l in gray ice with a large number of inclusions, and 1.48 mg/l in vertically layered ice of the central stem.

Table 4. Ionic composition of stratified underground ice located on the left bank of the Yerkutayakha River, southern Yamal, in July 2010 (point 10–YuV–Yerk)

A joint analysis of the distribution of ionic composition, stable isotopes, and spore-pollen residues in a reservoir on the Yerkutayakha River allows us to conclude that this is an intragrund (autochthonous) heterogeneous reservoir.^[7,10]

Discussion

The distribution of salts in the underground formation ice of Western Siberia is very different. This is due to the varying degree of "contamination" of the ice formation by mineral inclusions, as well as to the different mechanism of formation of deposits and the different nature of the water - the resource that fed the ice layers.

Holocene formation ice near the village. Sabetta. There are stratified ice in the thickness of the lida, they have different thickness and depth of occurrence. As a rule, reservoir deposits are confined to sandy deposits and only in one case the formation ice is covered with a low-power sandy loam horizon. The formation deposits have a tiered arrangement in depth, so four wells have opened the formation ice of three tiers ^[33]: ice lenses with a thickness of about 1 m or slightly less lie at depths of 2, 4 and 8 m from the surface. The ice formation of the lower tier may have a length of more than 50 m. One of the wells uncovered an upper-tier reservoir with a capacity of about 3 m (it lies at depths from 2 to 5 m from the surface).^[12]

Holocene formation ice in the thickness of the first terrace can be very long – more than 50 m and powerful – more than 2 m. Interestingly, in these cases, the layers have a continuation in the thickness of the laida. In some cases, the formation deposits of the upper tiers are permeated with re-vein ice.

The ice mineralization of the studied deposits varies markedly: from 13.5 mg/l to 81.9 mg/l.^[12] Chlorides predominate in white and brown non-porous ice.

Table 4. Geochemical composition of Holocene stratified ice deposits near the village Sabetta in the north-east of the Yamal peninsula

Ultra-fresh brown vertically layered ice (mineralization 40.64 mg/l) is characterized by a chloride-sulfate-magnesium composition; ice is slightly alkaline (pH – 7.9), lies in the sandy column. The content of carbonates in it is 29.14%-eq, which can be correlated with the gradual freezing of the host sands. The ratio of Cl^-/SO ₄ ^2- in it is 0.96.^[12] In terms of chemical composition, this ice is closest to the chemical composition of the waters of the Gulf of Ob, given by S.M.Fotiev.^[27] The ratio of Cl-/SO ₄ ^2- in the Gulf of Ob is 0.84, i.e. there are slightly more sulfate ions in the ice, which is natural when a sandy water-saturated reservoir freezes.^[19]

Brown non-porous ultrapressure ice (81.9 mg/l) has a sodium chloride composition and a weakly alkaline pH, the ratio of Cl^-/SO ₄ ² is 9.77. According to this ratio, as well as the content of anions and cations, the values of the average composition of fresh formation ice in Yamal are close to this ice.^[27] We also note that the water of the Kara Sea also has similar meanings. Another sample of brown non-layered ice (229.28 mg/l) is also characterized by a sodium chloride composition and a neutral pH, but the ratio of Cl^-/ SO ₄ ^2- in it is significantly higher – 68.91, which is due to the very low content of sulfate ions, which is often noted in cryopags, especially under riverbeds. The authors did not find any direct analogues among fresh or brackish underground ice to this sample of brown non-layered ice. The values of the Cl^-/SO ₄ ^{2 ratio closest to brown ice}, as well as the composition of both anions and cations, are characteristic of the subsurface taliks of the rivers of the Ob Bay basin – 27.67 and for the average composition of brackish formation ice in Yamal – 26.39.^[27]

White ice is the freshest of all studied in sections of wells at the mouth of the river.Sabettayaha. Its mineralization is 10.92-13.52 mg/l. Although the ice is ultra-fresh, it has a magnesium chloride and calcium chloride composition, the pH is slightly alkaline (8.00-8.01). The ratio of Cl^-/SO ₄ ^2- is in the range of 3.29-4.95. A similar chemical composition was noted for the average composition of the texture-forming ice of Yamal^[27], as well as for the river waters^[29] of Yamal, the values of the ratio Cl-/SO ₄ ^2–, respectively, – 4.30 for texture-forming ice - 4.67 for the river waters of the Kara Sea river basin.

The peculiarities of the chemical composition of underground formation ice of various types at the mouth of the Sabetta River demonstrate the formation of underground ice due to the supply of groundwater, lake, swamp and atmospheric waters. Analysis of cryohydrochemical features of formation ice at the mouth of the river.Sabetta suggests that vertically layered brown ice was formed during the freezing of sands saturated with the waters of the Gulf of Ob; brown non-layered ice could have formed as a result of freezing of the waters of the lake talik, the origin of white ultra-fresh ice can also be associated with lake and river waters.^[12,32]

Formation ice in the lower reaches of the Yamal Juribey. The ice layers opening up in the lower reaches of the Yuribey River in Western Yamal were studied by Yu.K.Vasilchuk in 1987 in the section of the remnant of the Kazantsev plain in the lower reaches of the Yuribey.^[3] It lies here in the thickness of dark gray loam. Their cryogenic texture in the ice contact zone is medium- and coarse-grained, medium-sized. At a depth of 15 m, a powerful ice body opens up in a wide, more than 20 m, semicircular circus. The structure of the ice body is complex. In the axial part of the formation there is a trapezoidal ice core with a width of 3 m in the lower part and 2.5 m in the upper part. On contact with this core, an ice crater is observed, consisting ofIt consists of layers of ice with a thickness of up to 0.5 m and loam with a thickness of 0.2–0.3 m, and the slope of the layers of ice soil repeats the direction of the lateral surface of the core. The angle of inclination of the layers is 40°.

The ice layer was probably formed as a result of repeated injections of water and suspension, followed by its segregation into ice and soil.

The analysis of the water extract from the loamy soil containing the ice layer and the soil interlayers in the ice layer thickness showed the identity of their composition. The total amount of water-soluble salts in the host sediments varies from 0.09 to 0.3%, in the soil layers – about 0.3%. In both cases, there is a predominance of sulfates (up to 1.8 mg-eq) and chlorine (up to 1.4 mg-eq) and a subordinate value of hydrocarbonates (up to 0.2 mg-eq). Sodium ions (up to 3.5 mg-eq) dominate sharply among the cations, and the content of calcium ions (no more than 0.1 mg-eq) and magnesium (up to 0.14 mg-eq) is extremely low. Thus, the host sediments and soil layers in the ice are characterized by weak chloride-sulfate-sodium salinity, which allows us to assume precipitation in a shallow slightly saline marine basin.

In the chemical composition of water from the ice of the central core, there is a slight predominance of the bicarbonate ion (up to 1.1 mg-eq) and a lower content of chlorine and sulfate ions (up to 0.3-0.8 mg-eq). Among the cations, the sodium ion is sharply predominant (up to 1.7 mg-eq), while the content of calcium and magnesium ions is no more than 0.1 mg-eq. It follows from the above data that the ionic composition of ice differs from the composition of the aqueous extract of the host rock and soil layers in the ice, although there is an analogy of their cationic groups.

Data from the analysis of foraminifera (analyst G. N. Nedesheva) were also used to study the genesis of the host sediments. It was found that the section reflects two stages of sedimentation. The lower part of the section (depth range 19-21 m) was formed in a shallow basin with low salinity and temperatures not exceeding 2 °, as evidenced by the depleted complex of Boreal-Arctic foraminifera forms. The dominant species are Elphidium subclavatum, Cassidulina subacuta, Cassandra teretis. Above the no section, foraminifera occur sporadically (Elphidium subclavatum, Cussidulina subacuta), the content of sodium and chloride ions decreases from hundredths to thousandths of a percent, which indicates the formation of the stratum under conditions of increasing cooling and decreasing salinity.

The freezing of the sediments composing the massif in the lower reaches of the Yuribey began, judging by the presence of a syngenetic ice vein in the sands of the Kazantsev formation, overlapping the Middle Quaternary loams, at the beginning of the Upper Quaternary time. Loam was frozen epigenetically. After the freezing front reached the aquifer, it partially froze; at the same time, the intra-stratum pressure in the formation increased significantly. The freezing of the soil caused the occurrence of deformations in the loamy thickness, the appearance of cracks in them. The violation of the continuity of the roof over the aquifer freezing horizon led to an intense release of water under high pressure upwards. The structural features of the overlapping loams led to the fact that in the upper part of the section, pressure waters penetrated into the strata through contact between the slab-like individuals, forming an ice block with a vertically layered thick-sheeted cryotexture. After unloading as a result of the discharge of water, the internal pressure drops. In the future, freezing covered the underlying aquifers, as a result of which repeated injections occurred, which were embedded in the already deformed upper part of the section and froze in the form of a rod. Judging by the heterogeneity of the structure of the layers, the structure, the color of the ice and the composition of spores and pollen, such injections occurred repeatedly.^[23]

Formation ice in the middle reaches of the Yamal Juribey. In 1977, in the middle course of this river along the right bank within the Khoi upland, a more well-exposed complex array of frozen strata containing subvertical layers (rods) of ice was studied^[3] (Fig. 11).

In this massif, dislocated layered brown and ochre-yellow sands with a total thickness of up to 10 m have been uncovered in the upper part of the outcrop. Below them, along the steeply falling (close to the subvertical) contact, dark gray heavy loams with a thickness of 10-11 m are located. In the upper part they are slightly sanded, have a massive cryogenic texture, which is replaced by a layered one in the lower part. There are two "layers" of ice in these loams. The first of them has an apparent size of 2.5 x 4 m. It lies subvertically (in Fig. 11 it is on the left and has a lighter color), its lower end is covered with scree. At its contact with the enclosing loams of the upper layer, a layer of fine-grained, thin-layered sand of dark gray color is observed; the thickness of the interlayer is 0.1 m.

Fig. 11. Exposure of ice layers of buried sedimentation (left) and injection (right) genesis in the middle reaches of the Yuribey (Yamal). Photo by A. I. Spirkin

The layering of loamy rocks directly in contact with this formation is horizontal, without traces of deformation and crumpling, oriented according to the direction of the long axis of the formation. At some distance from it, the loams are strongly dislocated, crumpled into an anticlinal fold (see Fig. 11). There are two types of ice texture in the formation. The upper part of the 2 m thick formation consists of white ice with a large number of air bubbles, the lower part is made of transparent ice. The second "layer" of ice is opened 5 m upstream (to the right of the first one) and 0.6–0.8 m below the first one. In shape, in the exposed section, it resembles a pear. The layers of the host rock above it are strongly deformed, especially in the apical part, where discontinuous disturbances are observed. The cryotexture of the very highly saturated host rock around this "formation" is reticulated, and the vertical slots are more pronounced than the horizontal ones. This indicates that this is a "layer" of injection genesis, and it was formed much later than the first layer.

But if the upper layer of sedimentary (sedimentation) ice, then why does it currently lie not horizontally, but subvertically? What forces gave him this unnatural position for the sedimentation layer?

According to V.T. Trofimov and Yu.K. Vasilchuk^[23], the complex structure of this massif was obtained later by sedimentation of the ice layer and freezing of the loamy sediments containing it. The creation of such a specific structure is associated with the introduction of masses of water and suspension from the underlying strata during their epigenetic freezing in the upper Quaternary. Their injection, the center of which was located near one of the ends of the buried ice formation, caused a strong "reversal" of the formation and its host rocks and the creation of a complex "fold", clearly visible in Fig. 11.

The mineralization of formation ice in the middle reaches of the Yamal Juribey ranges from 20 to 300 mg/l. Thus, even within the same massif, formation ice of very different genesis can often occur, at first glance, seemingly incompatible, since injectable ice is usually considered an indicator of epigenetic freezing of strata, and buried ice is considered syngenesis.

Formation ice near Marre Sale. The dislocated stratified ice deposits of injection genesis in the Marre-Sale area were studied by I.D.Streletskaya and co-authors ^[25,26] and E.A.Slagoda and co-authors.^[24] The formation ice in the Marre-Sale area lies mainly in the lower parts of coastal ledges up to 20-30 m high and is confined to dislocated deposits of marine and coastal-marine genesis.^[26]. The apparent thickness of these deposits reaches 20 m, their composition is dominated by clays and loams with layers of sand and sandy loam.

The interlayers of gray-yellow and brown sands and sandy loams stand out sharply against the background of dark gray clays and emphasize the dislocation of the strata. The thickness of sandy and sandy loam interlayers usually does not exceed 0.5-1.0 m, and their share is slightly more than 12% of the total capacity of the surveyed sections.

Formation ice was found in the range from 5.5 to 4.5 m above sea level. The conducted geochemical testing of sections, both free of and containing formation ice, showed that the sediments are saline. The composition of water-soluble salts in sediments is predominantly sodium chloride, the degree of salinity usually increases down the section, reaching 0.9% in clays, 0.2% in sands and sandy loams. In sections containing formation ice, the amount of water-soluble salts decreases as they approach the deposit.

The formation ice in the section is fresh (the total mineralization varies from 39.0 to 67.0 mg/l) and differs in ion ratio from the pore solution of overlapping and underlying sandy-clay deposits. There are no sulfates in the melts of the formation ice and significantly more hydrocarbonates. Unlike precipitation, ice contains more magnesium and less calcium and sodium. The mineralization of the ice melts sampled in different parts of the deposit varies: the minimum value is noted in the center of the deposit (39 mg/l), and it increases towards the upper and lower contacts (67 and 54 mg/l, respectively). The content of chlorine and magnesium ions increases from the center of the deposit to the contacts. Most likely, the salts got into the desalinated groundwater before the freezing of the strata from saline sands, which played the role of an aquifer, and from eroded clays. The degree of salinity of the sands at the lower ice contact is several times higher than in the sands overlying the deposit, the mineralization of the pore solution increases here to 2362.4 mg/l. This is probably due to the fact that some of the salts were pressed down during freezing.^[26]

E.A.Slagoda and co-authors^[24] revealed a clear difference between the lower deposit, which lies in accordance with the host marine clays, and other types of ice. The ice of the lower deposit is characterized by relatively increased mineralization values (up to 350 mg/l) due to sodium chlorides (more than 50% of the total salts), a reduced content of calcium and magnesium bicarbonates (less than 10%). An ice sample from one of the clearings is characterized by a typical ratio of basic ions for seawater: (rNa ⁺ + rK⁺)/rCl^– and rMg ²⁺/rCl^–, equal to 0.9 and 0.2, respectively. The chemical analysis of ice samples from the upper deposit is characterized by a bicarbonate sodium-calcium composition, which is typical for fresh leaching waters. The upper parts of ice laccoliths in sandy sediments are less mineralized compared to the lower horizontal sections of the deposit in icy loams, in which soil inclusions and ice-ground interlayers are widespread. With the increase in mineralization in the ice of the horizontal sections of the upper deposit, the predominance of sodium bicarbonates was noted in comparison with the sum of calcium and magnesium bicarbonates, which N.P. Anisimova noted as a characteristic feature for freezing closed taliks in sandy sediments. The maximum mineralization was detected in lenticular inclusions of transparent ice with large air bubbles, a high content of sodium chlorides was noted here (up to 70% of the total salts with an average content of 20-40%.^[24]

The formation ice of the upper deposit in the Marre-Sale area, which lies in the deposits of the taberal complex and syncreogenic lacustrine-alluvial deposits, according to A.N. Butakov^[1,2] has a mineralization from 33 to 274 mg/^dm3 with an average value of 94 mg/^dm3, bicarbonate-chloride, bicarbonate, calcium-magnesium-sodium and sodium composition. The formation ice of the lower deposit has a mineralization from 23 to 455 mg/^dm3 with an average value of 155 mg/^dm3, bicarbonate-chloride and chloride, calcium-magnesium-sodium, calcium-sodium and sodium composition.

S.M. Fotiev analyzed the data on the chemical composition of Bovanenkovo formation ice, given in the works of Yu.B. Badu, V.V. Baulin, Yu.K. Vasilchuk, G.I. Dubikov, M.M. Koreisha, L.N. Kritsuk, M.O. Leibman, I.D. Streletskaya, N.A. Shpolyanskaya, etc. and he showed the dependence of the chemical composition of the formation ice on their mineralization. The ionic composition of ice with a mineralization from 10 to 300 mg/l is usually dominated by HCO ₃^{- ions}, and bicarbonates in the salt composition. This ice composition was formed with the active participation of lake waters. The ionic composition of ice with a mineralization from 300 to 1000 mg/l and especially from 1000 to 10,000 mg / l is dominated by Cl^– and Na⁺ ions, and in the salt composition – sea salts or chlorides.^[13] Such an ice composition was formed with the active participation of either seawater or cryometamorphosed seawater. S.M. Fotiev suggested that seawater penetrated the ice layer. They changed the primary bicarbonate composition of ice to chloride and increased its negligible mineralization to 300-1000 mg/l or more.

Formation ice in the area of the village. Harasaway. A formation deposit that opens up in the outcrop of the second terrace near the village. The Harasaway, with a vertical capacity of more than 1.5-2 m, has been repeatedly described and tested in detail, so it is interesting to compare the results of hydrochemical testing.^[4,16,21,28] Chemical analysis of the ice from the second terrace shows that all the ice is fresh, much less often slightly saline, their mineralization ranges from 40 to 700 mg/l, and the ionic composition varies in area and depth. The ratio between the various anions does not remain constant: according to the predominant anion, ices can belong either to the bicarbonate, sulfate, or chloride class; according to the leading cation, they all combine into the sodium group. The ice of monolithic ice blocks is characterized by lower mineralization compared to the texture-forming 70-140 mg/l. The salt composition, in general, has the following dependence Cl^– > HCO ₃^– > SO ₄ ^2– and Na ⁺ + K⁺ > Ca ²⁺ > Mg ²⁺, which indicates the marine origin of the water.^[28]

Interesting data were obtained by M.A.Velikotsky and Yu.V.Mudrov^[16] when studying the distribution of salts in various types of ice. In milky white ice, the largest amount of salts (143 mg/l) is observed in the middle of the lens, and in transparent (160 mg/l and 213 mg/l) - in its upper and lower parts.

According to the observations of V.V.Orlyansky^[21], the deposits of underground ice are confined to the contact zone of sandy and clay deposits. He notes the close relationship between the shapes and sizes of ice bodies and the nature of deformations of the clay layer sole. Lenticular ice deposits are confined to dome-shaped deformations on the sole of a clay stratum with a distance between the wings of folds on the sole of several tens of meters and an amplitude of about 10-20 m. The chemical composition of the underground ice exposed in the abrasive ledge of the seashore in the area of the settlement Kharasaway is characterized mainly by a bicarbonate- and sulfate-chloride-sodium composition with a dry residue content of 10-80 mg/l.^[21]

Chemical analysis of the ice from the second terrace shows that all the ice is fresh, much less often slightly saline, their mineralization ranges from 40 to 700 mg/l, and the ionic composition varies in area and depth. The ratio between the different anions does not remain constant. Ices belonging to the bicarbonate class have an acidic reaction, to sulfate and chloride – slightly acidic and neutral. The degree of mineralization of the ice and the degree of salinity of the sediments containing these ices vary significantly. There is a sharp decrease in salinity as we approach the ice deposit.

Formation ice on the shore of Lake Neito. Formation ice in the sandy-clay thickness in the lake area. It forms horizontal or slightly inclined complex deposits, in which G.I. Dubikov ^[17,18] identified 3 types of ice. 1). Ice A is milky white, opaque, with a minimum (no more than I%) content of mineral impurities and a large number of gas bubbles with a diameter of 0.5-3.5 mm. The ice is coarse-crystalline, non-layered, of blocky composition and is always confined to the upper parts of the formation deposits. 2). Ice B is glassy, transparent, coarse and fine crystalline, dark in color in outcrops, contains rare inclusions of clay particles and suspensions of sandy and clay particles, as well as rare gas bubbles in areas of small crystals. This type is observed in all parts of the formation deposits and is widespread both independently and in combination with other types. 3). Ice is always black in color, contains a large amount of mineral impurities and is often referred to as ice ground. Impurities in composition do not always correspond to the surrounding rocks, alien mineral inclusions are often found: sandy clays with gravel inclusions. Inclusions have the form of a ground suspension "floating" in ice, small fragments of layered clay and clumps of clay particles. Significant differences have been revealed in the chemical composition of these three types of formation ice deposits. Mineralization, the content of the Cl^-ion and the Na⁺/Ca ²⁺ ratio increases from ice A to ice B due to an increase in the amount of mineral impurities. In the same direction, the ratio of EMd ²⁺/ECl^- decreases, and the predominant bicarbonate-chloride-sodium type of ice is replaced by sodium chloride or chloride-bicarbonate-sodium. In formation ice, the content of Na+ ions significantly prevails over the content of Ca ²⁺ and Md ²⁺ ions, especially in the ice ground. The ratio of EMd ²⁺/ECl^- for all types of ice (average values for ice A - 0.83; for ice B - 0.49 and for ice B - 0.2) is typical for marine-type waters. The salt composition of the ice of reservoir deposits has a dependence of HCO ₃^- > Cl^- > SO ₄ ^2- (65% of cases) and Na ⁺ > Ca ^{2 +} > Md ²⁺ (81% of cases), which is also inherent in marine-type waters.^[17,18]

Formation ice in the valley of the Seyakha river (Turbid). In the coastal outcrops of the Seyakha River, the apparent thickness of the layers is 5-10 m, less often up to 20 m, and the apparent length is 100-150 m.^[17] Horizontally overlying ice layers consist of parallel layers of pure ice alternating with interlayers of ice contaminated with mineral inclusions (from sandy turbidity to angular fragments of dense clay) measuring 3-4 mm. The ice is poorly mineralized (0.02–0.06 g/l), the ionic composition is dominated by bicarbonates, magnesium, calcium and sodium with an increased chloride content near contacts with the host rock.[20 p. 141]

Formation ice in the sediments of the first terrace of the Gyda river. Deposits of the first terrace at the mouth of the river.The Gyda dates back to the Pre–Holocene period - 10-14 thousand years ago ^[12]. At the village.Gyda formation lenticular deposits are found in paragenesis with re-vein ice. Layers of ice up to 0.4 m high and up to 8 m wide lie here in the torn-off layers of sand composing the terrace.

Table 4. Mineralization and ionic composition of the stratum intracrustal infiltration-segregation ice near the village Gyda. From Y.K. Vasilchuk^{[3, vol. 2. pp. 38-39]}

We note a noticeable similarity in the ionic composition of the stratum intracrustal infiltration-segregation ice near the village. Gyda with newly explored deposits in Yamal.

Formation ice in the middle reaches of the Tanama River. The data on the salinity of the Late Pleistocene stratum ice deposit in the middle reaches of the Tanama River are informative. Here, different parts of the formation are characterized by significantly different mineralization.^[9] In the apical part of the formation, fluctuations in the degree of mineralization are observed from 90 to 390 mg/l, while in the distal part it ranges from 40 to 150 mg/l. This gives reason to think that either the formation has been in seawater for a long time (silt was formed from it), if it is allochthonous, or ice formed as a result of the introduction of water from aquifers of different degrees of mineralization takes part in the formation of the formation, if it is intra-soil-autochthonous (the second seems less likely to us).

The possible marine origin of the soils is also indicated by their chemical composition. Even in the sands from the upper part of the section, the mineralization exceeds 0.2%, and in loams it reaches 0.6%, which indicates a saline sedimentation medium. The mineralization of ice is also very indicative. The chemical composition of the formation is similar to that of modern soldered ice in the Kara Sea, the mineralization value in it reaches 194-390 mg/l, and sulfates (45-178 mg/l) and chlorides (36-51 mg/l), characteristic of sea ice, predominate in it.^[9]

Formation ice near the village. Ust is a port on the Yenisei. In 1965, B.I.Vtyurin described deposits of segregational ice in three outcrops on both banks of the river.The Yenisei River. Initially, he attributed to the segregation type only 2 low-power stratified deposits of underground ice found in the coastal-lake sandy Late Sanchug or Kazantsev deposits on the right bank of the Yenisei 6 km below Ust-Port. The first layer, with a capacity of 0.4 m, was passed at a depth of 5.8-6.2 m from the surface of the terrace, the second, with a capacity of 0.75 m, at a depth of 7.6–8.35 m. The layer of mottled powdery sand separating them has an undisturbed clear horizontal layering. In the roof of the upper layer, the sandy loam is silty and fine-grained powdery sand with a noticeable horizontal layering. In the sole of the lower layer there is a multi–grained horizontally layered, with bundles of obliquely wavy and wavy-layered sand. In places, the ribbon-like layering is quite clearly manifested.

The contacts of the ice and soil layers are clear, straight at the top and finely wavy at the bottom. The ice is very clean in the upper layer and with a significant amount of gas impurities and dusty particles and sand in the lower one. Accordingly, the size of the ice grains of the upper layer is larger than the lower one. The crystallographic orientation is ordered, mainly vertical. Chemical analysis of the ice of both layers showed a sodium bicarbonate composition and low mineralization (about 50 mg/l), slightly increasing (up to 90 mg/l) in the lower part of the second layer.

The Ice Mountain formation deposit. The widely known (up to 40 m high) Ice Mountain deposit, located at the latitude of the Arctic Circle on the Yenisei, was attributed by V. I. Solomatin, E. G. Karpov and many others to the buried glacier type. Meanwhile, the distribution of salts in the ice needs careful analysis and comments – here the mineralization ranges from 10-80 mg/l in the upper part of the deposit to 200-340 mg/l in its middle and lower parts. And although the qualitative composition of the salts here is not marine and bicarbonates and calcium predominate, but it is by no means alpine, that is, the glacial origin of the deposit does not follow from the analysis of the chemical composition. This circumstance is not noticed by the supporters of the glacialist version, perhaps only N. N. Romanovsky (oral remark) gave an interesting interpretation of this: increased mineralization may be a consequence of salt saturation as a result of groundwater circulation under the body of a warm glacier and their subsequent freezing in the form of ice on contact with glacier ice, that is, in this interpretation, Ice The mountain is not glacial ice, but the paragenesis of glacial and glacial ice bodies.

To understand the nature of the ice in the Ice Mountain deposit, the most important thing for us is that it is most likely of Late Pleistocene age (and even probably older than 40 thousand years ^[7]) and as well as located nearby – in the lake area. The Makovskoye deposit described by Yu. A. Lavrushin survived the Holocene "optimum" period, testifying to the continuity of the existence of permafrost rocks in these relatively southern regions of the West Siberian cryolithozone.

S.M.Fotiev^[27] having compared the chemical composition of most formation ice with the chemical composition of surface and groundwater and having found great similarity in the chemical composition of formation deposits with lake waters, concluded that lake waters are the only source of fresh water capable of providing regular intake of huge volumes of fresh water into the frozen marine saline sediments and the formation of powerful (up to 30-50 m), sustained along the stretch of ice layers. In this respect, our conclusions and those of S.M.Fotiev largely coincide, in any case, according to our data, lake waters are, if not the only, then the most important source of nutrition for formation ice.^[3]

According to the ratio Cl^- /SO ₄ ^2- the three studied deposits of formation ice in the central and southern parts of Yamal are close to the composition of the glacier in the valley of theSeyakha (Muddy) and with the segregation ice on the first terrace of the island.White (Table 5).

Table 5 . The ratio of chlorides and sulfates in formation ice and possible sources of water supply to them, north of Western Siberia

Conclusions

1. The ionic composition of 3 powerful stratified ice deposits in the central and southern parts of Yamal has been studied: a) Bovanenkovo, on the shore of Lake.Hanikosito; b) in the upper reaches of the Mordyakha River and c) in the valley of the Yerkutayakha river. All of them belong to ultra-fresh ice with a concentration of basic ions from 20 to 40 mg/l.

2. In the ionic composition of the Bovanenkovo formation ice, on the shore of Lake.Hanikosito is noticeably dominated by Na⁺ cations, reaching 38.95 mg/l in cloudy ice and K⁺ up to 21.76 mg/l in highly bubbly transparent ice. The average concentration of chlorine anions is 3.13 mg/l, and of sulfates is 1 mg/l.

3. The ionic composition of the formation ice in the upper reaches of the Mordyakha River is noticeably dominated by Na⁺ cations, reaching 68.51 mg/l in the ice ground and 6.1 mg/l in crystal and vitreous. The average concentration of chlorine anions in the ice formation in the upper reaches of the Mordyakha River varies markedly in different types of ice and amounts to 2.27 mg/l, and sulfates - 2.36 mg/l.

4. In the ionic composition of the formation ice in the valley of the Yerkutayakha river, approximately equal amounts of Na+ cations are observed, reaching 3.64 mg/l, K⁺ and Mg ²⁺ up to 2.71 and 2.56 mg/l. The cations are dominated by NO ₃^- and sulfates (SO ₄ ^2-) up to 5.61 and 6.35 mg/l, respectively. The average concentration of chlorine anions in the formation ice deposit in the valley of the Yerkutayakha River varies in different types of ice and amounts to: 0.76 mg/l in crystal and milk-white ice, 1.46 mg/l in gray ice of horizontal interlayers, and 1.48 mg/l in vertically layered ice of the central stem. Approximately equal amounts of Na⁺ cations up to 3.64 mg/l, as well as K⁺ and ^Mg2+ up to 2.71 and 2.56 mg/l are observed in the ionic composition of the formation ice in the Yerkutayakha River valley. The cations are dominated by NO ₃^- and sulfates (SO ₄ ^2-) up to 5.61 and 6.35 mg/l, respectively.

6. The ionic composition of the 3 studied powerful deposits of stratum ice in the central and southern parts of Yamal is closest to the ionic composition of Holocene intracranial stratified ice deposits near the village. Sabetta and Late Pleistocene infiltration-segregation ice near the village. Gyda. This is the basis for the probabilistic attribution of the studied formation ice to deposits of the intragrund type that arose during autochthonous freezing of inter-permafrost aquifers.

Thanks

The author is grateful to N.A. Budantseva, D.Y.Nekrasov, J.Yu.Vasilchuk, I.G.Shorkunov and L.B. Bludushkina for the materials provided and assistance in field research.