Pollen spectra in Holocene ice wedges in the floodplain of the Lyakkatosyo River (Eastern Yamal, Russia)

Vasil'chuk Alla Constantinovna ORCID: 0000-0003-1921-030X Doctor of Geography Leading Researcher; Laboratory of Geoecology of the North; Lomonosov Moscow State University 119991, Russia, Moscow, Leninskie Gory, 1,, of. geographical Faculty, NIL Geoecology of the North alla-vasilch@yandex.ru Other publications by this author

introduction

Ice veins are formed as a result of cracking and successive accumulation of elementary veins. Cracking does not occur every year and is not necessarily in the axial part.^[1] Due to the complex "vertical" mechanism of re-vein ice formation, an assessment of ice sampling methods for various types of analysis is required. In our opinion, the direction of sampling and its frequency are determined by the task at hand. Some researchers prefer to take samples from re-vein ice horizontally,^[2,3] when it is necessary to obtain a general characteristic. However, in order to get an idea of the sequence of ice formation, horizontal selection may not be enough. Sampling of re-vein ice for palynological analysis has its limitations. In particular, the concentration of pollen and spores in re-vein ice is rarely high, so it is necessary to take samples of sufficient volume for analysis. Ice for palynological analysis must be carefully isolated during sampling: if fresh pollen gets on the surface of the sample, it will be impossible to distinguish it from pollen that is stored in ice, since pollen in ice often has high preservation.^[4,5]

The purpose of this article is to investigate palynospectrums from recycled ice obtained from samples during vertical and horizontal sampling, taking into account the chemical composition of the studied ice veins. Holocene ice veins on the southern border were selected to assess the interpretative possibilities of the results of palynological analysis of re-vein ice the northern Arctic tundra, where pollen productivity is already quite high, which makes it possible to obtain conditioned counting material.

AREA, FACILITIES AND RESEARCH METHODS

Location and structure of the section

Due to the special mechanism of re-vein ice formation, the problem of horizontal and vertical sampling for palynological analysis from re-vein ice is considered. Studies of Holocene re-vein ice were carried out by A.K. and Yu.K. Vasilchuk in the lower reaches of the Lyakkatose River on the Yamal Peninsula (Fig. 1, 2). On the right bank of the river, re-vein ice was uncovered in the outcrop of a high floodplain. Their height was 3-4 m, width 1.2-1.5 m. The surface of the high floodplain in the studied area is represented by a polygonal roller relief, polygons are often contoured with open frost-breaking cracks (Fig. 3,4).

Fig. 1. Layout of the Holocene polygonal massif with re-vein ice in the lower reaches of the Lyakkatose River (69⁰2604s.w., 72⁰1227s.d), in the central part of the Yamal Peninsula: 1 - location of the studied section

As a result of overburden events on the river during the research period, a flood was recorded: the rise in the river level was 2.5 m, the reduced parts of the high floodplain and the low floodplain were flooded.

Fig. 2. Relief of the Lyakkatose River valley in the east of Yamal

Fig. 3. The position of the site in the valley of the Lyakkatose river in the east of Yamal

Fig. 4. The position of the site and the studied ice veins in the valley of the Lyakkatose River in the east of Yamal

Vegetation

The site is located near the southern border of the northern hypo-Arctic tundra^[6] hemiprostrate-shrub-lichen-moss polygonal tundras dominate within the site. They contain shrubs Betula nana, Salix lanata, shrubs Empetrum subholarcticum, Salix nummularia, Dryas octopetala, Vaccinium vitis-idaea ssp. minus, Ledum decumbens, as well as Carex arctisibirica, Arctagrostis latifolia, Dupontia fisheri, D. psilosantha, Deschampsia borealis and D. Brevifolia, from Bryum purpurascens, Pleurozium schreberi, Drepanocladus aduncus, Polytrichum spp., Aulacomnium turgidum, etc.).

The climatic characteristics of the research site are given according to the data of the Seyakh weather station closest to the site (70⁰17 s.w., 72⁰52 v.d.). For the period from 1951 to 2023, the average annual temperature of pltcm was -9.3°C.^[7] The coldest month is February, the average air temperature in this month varies from -37.0 to -13.7°C. The absolute minimum air temperature is recorded in the village. Seyakha (-44.7 °C) 06.01.2015,^[8] and in the warmest month – July, the average monthly temperature fluctuates +4.0 – +15 °C. The amount of precipitation ranges from 187 to 490 mm/year.^[9] Permafrost rocks have a continuous distribution laterally and vertically. Their capacity exceeds 290-300 m, and the temperature at the depth of zero annual fluctuations is about -5, -4°C.^[10]

The structure of the high floodplain section

The structure of the sediments of the high floodplain in this area has been studied based on the results of drilling. A well laid 1.5 m from the shore has been opened:

0-0.05 m – moss turf;

0.05-0.22 – brown peat with sandy loam, thawed;

0.22-0.3 m – sandy loam is gray with red spots, frozen. The cryotexture is massive, the iciness is 5%;

0.3-0.6 m – gray sandy loam, frozen, cryotexture thin- and medium-lire, iciness 80%;

0.6-7.1 m – overlapping of sand horizons with different cryotexture and iciness from 5 to 10%.

The ice veins lie at a depth of 0.5-0.7 m, the ice veins in the upper part are gray cloudy, the main part of the ice veins is represented by white cloudy ice with vertical layers of transparent ice, the severity of which decreases from the center to the edges of the vein; the content of mineral impurities in the ice decreases from top to bottom. In the axial part of one of the veins, mineral impurities amounted to about 40%.

Methods of field sampling and palynological determinations

Sampling for spore-pollen analysis was carried out taking into account the morphometric features of the ice veins: The number of elementary veins and their length were taken into account. The samples were taken with a specially made ring ice drill, which allowed very clean, undivided samples to be selected, the volume of each sample was 1 ^dm3, i.e. 1 liter. Each selected sample was washed with meltwater formed at the very beginning of the melting of the sample ice, to exclude the ingress of fresh pollen. Each ice sample was poured into a glass vial. In the laboratory, sediment from the bottom of the vial, which had been standing for at least 24 hours, was selected for analysis of pollen and spores. The processing of pollen samples included precipitation evaporation, deflocculation using KOH, centrifugation, filtration through sieves of 40 microns, 10 microns and 2 microns, and placing pollen samples in glycerin. The percentages are calculated based on the sum of pollen from trees, shrubs and grasses, as well as spores. The identification of pollen and spores was carried out under a light microscope at 400x magnification on the basis of the author's palynological collection in the Laboratory of Northern Geoecology of Lomonosov Moscow State University, the Russian pollen database of pollen,^[11] as well as using determinants. Birch pollen is divided into sections Betula sect Betula (woody forms) and Betula sect. Apterocaryon (shrubby and shrubby birch species). Pine pollen was identified as the pollen of Scots pine (Pinus sylvestris) and Siberian pine (Pinus sibirica) based on the author's collection of surface specimens and herbarium from the study area, as well as the author's reference pollen collection. Due to the relatively low concentration of pollen, all microfossils in the resulting concentrate fraction of 10-40 microns were counted. A fraction of 2-10 microns was used to identify small Bryales spores. The concentration was calculated as the ratio of the counted pollen grains to the sample volume.

A borehole (Point 188-YuV) on the surface of the floodplain uncovered an ice vein (PLL 1) at a depth of 0.6- 0.7 m.^[12] Above the head of the vein lies a horizontal ice sheet with a thickness of 3 cm, extending along the entire coastal zone. The sediments overlying the vein are highly acidic, the cryotexture ranges from microlensoid-layered to incompletely lattice, inclusions and peat primers are found. Above the axial part of the vein along the crack there is a sprout with a width of 7 cm in the upper part. Samples for palynological analysis were taken along the axis of the vein and horizontally at a depth of 1.2 m, samples for chemical analysis were taken along the axis (Fig. 5).

Fig. 5. Sampling scheme of their re-vein ice in sediments of the high floodplain of the Lekkato River Se: a – PZHL1 (point 186-YuV): 1 – brown thawed peat 2 – frozen gray sandy loam; sand; 3 – re-vein ice; 4 – STS; 5 – ice sampling points for chemical analysis; 6 – sampling points for palynological analysis

RESULTS AND DISCUSSION

The high concentration of pollen and spores – 800-900 copies/l in the veins on the Lyakkatos river made it possible to compare the results of horizontal and vertical selection with a sufficient degree of accuracy. The composition of the taxa in the palinospectrums horizontally and vertically coincides almost completely, but there are differences even at the level of comparison of the total composition. The palinospectrums characterizing the ice vein horizontally and vertically showed significant differences in the ratio of the main components of the palinospectrums. Due to the fact that the horizontal distance between the elementary veins is much smaller, there are noticeable fluctuations in the pollen content of tree species and shrubs. The minimum pollen content of tree species (19%) is fixed at a depth of 1.6 m, and horizontally at a distance of 0.7 m from the axis (17%), however, the palin spectra differ markedly. Palinospectrums from horizontal sampling samples are characterized by the dominance of spores, mainly green mosses, while palinospectrums along the axis are characterized by a much lower content of spores (22-33%) and pronounced fluctuations in their content. Siberian cedar pollen prevails among the pollen of tree species (5-25%), the maximum is marked at a distance of 0.5 m from the axis (horizontal selection). Scots pine pollen is constantly found (1-10%), the maximum of pine pollen coincides with the localization of the maximum content of Siberian cedar pollen. The main difference between the horizontal and vertical palin spectra in the group of tree species is the different pollen content of spruce and birch. If along the vein axis the pollen of spruce (2-13%) and birch (6-14%) is constantly observed, then in the palinospectrums of horizontal sampling, spruce pollen (2-4%) is noted only up to 0.3 m from the vein axis, and birch (2-14%) up to 0.4 m away from the vein.

Fig. 6. Spore-pollen diagram of Holocene re-vein ice on the high floodplain of the Lyakkatose River: a): a – vertical selection, b – horizontal selection: 1 – tree pollen; 2 – shrub pollen; 3 – pollen of herbaceous plants; 4 – spores

A similar distribution can be traced in the group of shrubs. Dwarf birch pollen (4-17%) can be traced up to 0.4 m from the vein axis, the maximum content is 0.1 m from the axis, its presence is constant along the vein axis (5-18%). The differences in the content of alder pollen (2-13%) are even more pronounced: it disappears from the composition of vertical selection palinospectrums at a depth of 1.6 m, and it is constantly found in horizontal selection palinospectrums. The pollen content of grasses and shrubs also varies, although it is mainly represented by pollen from wind-pollinated cereals and sedges: in the axial part of the ice vein, the pollen of grasses and shrubs varies between 17-39%, and in the horizontal its content is noticeably less (6-10%). The pollen of various grasses is represented by the families of heather, rosaceae, cloves and legumes. At a depth of 1.6 m

Palin spectra similar in composition were detected in only one case. samples The sample closest to the center of the vein at a distance of 0.1 m from the axis from a depth of 1.2 m is characterized by approximately the same palinospectrum as the palinospectrum of the sample from a depth of 1.2 m from the central part of the ice vein. Differences are noted in the group of grasses and shrubs, and spores, while the pollen of tree species and shrubs is contained in almost identical quantities (Fig. 7). That is, the differences relate rather to local components of the palinospectrum, while the regional signal was reflected in the palinospectrums in the same way.

Fig. 7. The total composition of palinospectrums (%) in an ice vein at a depth of 1.2 m: a – the central (axial) part, b – at a distance of 0.1 m from the axis: 1 – tree pollen, 2 – shrub pollen, 3 – pollen of grasses and shrubs

It is quite natural that there is no general sequence of culminations of certain pollen taxa. This means that cracking in this area occurred chaotically and not necessarily along the axial part of the ice vein.

The differences are primarily determined by the depth of cracking, the magnitude of which may vary under the influence of several factors.

The lower parts of the ice vein "tails" are "preserved" at some point, no new portions of ice get into them, while the ice vein itself grows in height. Thus, in the horizontal section of the head of even a Holocene vein, we can trace only the final part of the process of its formation. Note that the cracking process is chaotic and cracking in 30% of cases does not take place in the center of the vein. As more and more cracking and accumulation of elementary veins occur on the surface of the vein, its lower part leaves the zone of active cracking. As a result, by taking samples of syngenetic vein ice along the vertical axis, we select groups of elementary veins that accumulated sequentially and therefore we can talk about the possibility of restoring the sequence of certain landscape events by spectra. With horizontal sampling, this is possible only with simultaneous AMS dating of ice and, of course, with the laying of several horizontal profiles, moreover, the larger the vertical dimensions of the vein, the greater the number of such horizontal sampling profiles is necessary.

Table 1

The content and composition of water-soluble salts in re-vein ice in the lower reaches of the Lyakkatose River (from N.A. Budantseva, Yu.K. Vasilchuk^[12])

Table 2

The content and composition of spore-pollen spectra in re-vein ice in the lower reaches of the Lyakkatose River

The mineralization of the ice veins differs: in the first vein, the mineralization is generally low, from 48 to 88 mg/l, with the exception of the upper part of the vein, in which the mineralization is 182 mg/l. For the second vein, ice mineralization, with the exception of the upper ice layer, varies in the range of 150-200 mg/l (Table 1, Fig. 8). The composition of ions in the ice of both veins is dominated by bicarbonates (from 12.2 to 85.4 mg/l), chlorides (from 10.6 to 37.2 mg/l) and the sum of sodium and potassium (from 2.8 to 53.4 mg /l). It is significant that the lowest values of the Na+ K sum correspond to the lowest pH values – 4.5-4.7, the highest values of the Na⁺ + K⁺ sum correspond to the highest pH values – 7.1–7.5 (see Table 1).

Fig. 8. Variations in the values of mineralization and the content of basic ions in re-vein ice in the floodplain of the Lakkatose River

Pollen and spores on the surface and in the snow thickness are the main resource of palinospectrums in re-vein ice

Snow cover is the main source of the formation of re-vein ice, therefore it can be considered as a depositing medium for pollen and spores entering the re-vein ice. Pollen and spores are found in snow in any natural landscapes in which snow cover is preserved during the low-temperature season. The presence of pollen or spores in the snow proves that long-range pollen is involved in the palin spectra. In the circumpolar regions, the concentration of pollen is very low: from 1 to 15 pollen grains per liter of melted snow, while in the polar glaciers their concentration is higher, and amounts to several hundred pollen grains. The concentration of pollen and spores in underground ice in the field of permafrost development averages 10-500 specimens/l, in some cases reaching thousands or more specimens.^[4,5]

Pollen and spores in the snow and on the surface of polar glaciers. Pollen and spores fall on the surface of the snow cover in the Arctic desert zone, in the tundra, and in the forest zone. Most long-range pollen grains cannot be distinguished from local pollen in the summer pollen rain. But during the winter, when the pollen of local plants is absent, it is possible to obtain evidence of the participation of long-range pollen in palin spectra. The concentration of pollen and spores entering the surface of the snow cover during the winter season, and the composition of the palinospectrums can vary greatly from year to year. The composition of palinospectrums in snow cover and in mountain and polar glaciers can serve as an illustration of this.

Spore-pollen characteristics of snow in the north of Finland. Winter pollen rain in the vicinity of Helsinki has been studied for two years.^[13] It is known that individual dust particles fall into the upper parts of the air masses and are transported over very long distances. Based on this study, an attempt was made to find out the origin of exotic pollen in Late Pleistocene deposits.

The problem of ephedra pollen transfer is also considered. Ephedra pollen is often found in Late Pleistocene, Holocene and modern Finnish sediments. This is the pollen of two species of ephedra (Ephedra distachia E. fragilis). In the winter of 1965 and 1969, red snow fell on the territory of Finland and Sweden. According to the palynological analysis of this snow, a conclusion was obtained about the source of the material – the southern regions of the Russian steppes. However, only one pollen grain of ephedra was found in the 1965 snowfall. Currently, the main place where ephedra grows is the Black Sea and Caspian steppes, where the dust that turned the snow red was just forming. Those pollen grains of ephedra, which are occasionally found in the deposits of Flanders (Holocene period), may have a similar origin.

The grass pollen content in the 1969 snowfall was very high, and this may explain the presence of pollen from steppe vegetation in ancient sediments. Pollen of steppe plants such as Chenopodiaceae, Rumex, Plantago, Brassicaceae, Polygonum, Compositae, Artemisia was found in lake and marsh deposits of late Flanders. They are usually considered as indicators of prehistoric human impact (CIP). It is possible that some of the pollen was not related to primitive man. Most long-range pollen grains cannot be distinguished from local ones in the summer pollen rain. But during the winter, when pollen from native plants is absent, evidence of the presence of long-range pollen can be obtained. Therefore, an experiment was set up to capture pollen in winter.^[13]

Snow samples were radiated from snow profiles and from pollen traps. In 1985-86, sections of the snow cover in layers. No pollen was found from November to December. But, an amazing thing, pollen accumulated in the traps almost all winter from 1.11. to 31.3. Pollen trapped in November and, especially in December, was not formed in Finland. The palinocomplex is characterized by a predominance of pollen from birch, cereals and wormwood, as well as pollen from grasses such as, for example, nettle, compound flowers, haze, madder, sorrel.^[13] In December-January, the pollen content of cereals reached 50%, and wormwood about 10% of the total composition of the spectrum.

In March, the highest percentage of alder pollen was observed, which obviously reflected the spring pollen rain. In the snow sampled on March 19, the alder pollen content was already significantly lower. Pollen grains were found in sections of the snow cover after December. This year's snow contained about 75 grains per cm2. At a depth of 30-40 m, snow contained in abundance both tree pollen and grass pollen, their composition was similar to that obtained from pollen traps. In general, the results of this year confirmed the wind drift of pollen from areas not covered by snow cover.

In 1986/87, the data obtained on pollen from snow differed significantly. A very large amount of pollen was found in the lower layers of the snow cover, where layers of brown snow were observed. At the same time, it was obvious that the pollen was formed in the vicinity closest to the sample collection site: the presence of spruce grains along with a high content of pine and birch pollen, as well as haze and cereals, suggest a local origin of the palinospectrums. There are spores of ferns growing nearby, as well as rye pollen, which grows in a nearby field. The formation of brown snow layers is associated with local wind transport. Strong winds formed peculiar snow dunes, carrying snow from the field to the slopes. The lower layers also contained a large amount of mineral mass and pollen. The surface samples contained large amounts of alder and hazel pollen. Cellular structures were observed in both types of pollen.^[13]

No exotic pollen was found in this study, such as (Oleaceae) was discovered by Lundqvist and Bengsson. All types of herbaceous pollen could belong to the local flora. At least one grain of cultivated cereals is found in each section of the snow cover. They are quite heavy and are not adapted for long-range transport.

The data obtained indicate that this pollen could only be transferred together with the dust. It should be noted that corn pollen was found in red snow in 1965 and 1959. Northern territories such as Finland have constant snow cover throughout the winter. Theoretically, no flowering occurs at this time. If we exclude the effect of pollen from eroded soil entering the snow, then all pollen in the snow should be far-bearing from those areas where flowering occurs or from eroded soils from areas without snow cover.^[13]

The source from where the pollen got into the snow cannot be determined precisely. However, the ratio of pollen of woody and herbaceous plants is the same as in the palin spectra from the snow cover in 1969. The value of the pollen content is low 75-200 copies/cm2 compared with the annual intake, for example, in the Helsinki area it is 5000-6000 copies /cm2. These data were obtained from traps in 1982 and 1983. Aeolian material from the fields could affect these values. The study of pollen content gives an approximate idea of which pollen can be supplied as long-range. Usually its content does not exceed several hundred dust particles per 1 ^cm2. Pollen intake into lake sediments of the subboreal and subatlantic Holocene time in southern Finland exceeds this value by tens of times. If we assume that a similar soil material with pollen was supplied, for example, to the sediments of Flanders, then the pollen that is considered an anthropogenic indicator may be far-bearing. If the pollen content of woody plants is more than 1000 copies, this pollen can be determined more accurately. Ephedra pollen can be a tool for this determination. Indicators of ancient settlements are very rare in the palin spectra of lakes and swamps.^[13]

Spore-pollen characteristics of snow and ice in the Polar Urals. The work of T.G.Surova (on the snowfields of the Polar Urals^[14,15] was carried out at about 67 ° C. They were devoted to identifying the relationship between the composition of vegetation and the abstract spore-pollen spectra in areas of high and low snow accumulation. At the same time, samples were taken from the ice of the Oleniy glacier, seasonal snow firn area of the IGAN glacier ice of the IGAN glacier (No. 20,22,23,24).

Samples were taken at an altitude of 1000-1200 m above sea level. Samples from the soil surface reflect the average pollen rain over several years, while the number of years or seasons that are reflected in the composition of the spore-pollen spectra from snow cover and ice is determined by the sampling parameters.

Ice samples are characterized by a low content of Scots pine pollen, probably reflecting the seasonal influx of pollen onto the glacier surface.

Siberian cedar pollen is contained in an amount close to the maximum in comparison with surface soil samples in the valley of the Bolshaya Hadata River.

Larch pollen is not found either in snow cover or in ice,^[14,15] perhaps this is due to the fact that when falling on snow, larch pollen is rapidly destroyed due to being in fresh water.^[16]

In surface samples of soils and sod, the content of larch pollen, although it does not reflect its role in local plant associations, indicates its presence. The pollen content of spruce, tree birch, and willow is approximately the same as the content of their pollen in soil samples. The content of alder pollen is quite high. in the snow cover, but in the ice its content is minimal compared to soil samples.

Compared with soil samples, the pollen content of dwarf birch is slightly lower. A characteristic feature of palinospectrums made of ice and snow is the complete absence of grass pollen and green moss spores. But the spore content of sphagnum mosses exceeds 50% of the total number of counted pollen grains and spores. The content of spores of millipede ferns is also noticeably high.^[15,16] Palin spectra from snow cover and ice in this case, in our opinion,^[17] reflect the winter-spring component of the regional pollen rain, since the pollen of grasses blooming in summer

Since moist air masses coming from the west are delayed by mountain ranges, and due to warmer, drier and longer summers on the eastern slope of the Polar Urals, larch and birch forests are found 100 km north and much higher in the mountains than on the western slope. The upper border of the forest in the southern part of the Polar Urals in the Urals is represented by birch and fir, in the Trans–Urals by spruce and larch. Rare birch and larch forests are found in the northern part of the Polar Urals and on the eastern slopes along river valleys, on the western slopes along river valleys mainly shrubby species of willows and birches. The southern border of the Siberian cedar's range is located in this area at 66 °c. Interestingly, the growing conditions closer to the top of the mountain range are better than in flat areas. The reason lies in good drainage and a more favorable temperature regime due to the fact that colder, and therefore denser and heavier air flows down from the mountains and stagnates in valleys and flat areas. in the Polar Urals, the mountain-tundra and subgolic belts are clearly defined. Tree species are the main source of pollen. Siberian larch Larix sihirica Ledeb. in the subholtz belt of the southern part of the Polar Urals, it forms sparse woodlands, and in the mountain-forest belt it forms closed stands. In the northern part of the Polar Urals, along the valleys of the Baydarat (and its tributaries), Shchuchya, Laptayakha rivers, sparse forests form along the southern slopes of the mountains, and in the valleys of Nyarovey-Hadaty and B. Hadaty, closed stands appear, often with an admixture of spruce. South of B. Hadata in the mountainous part along the river valleys, larch is common. In the foothills of the eastern macroscline and in the lowland forest tundra, it is the main forest-forming species. Siberian spruce (Picea obovata Ledeb.) is common in the subholtz and mountain forest belts in the southern part of the Polar Urals, forms an admixture to larch stands, less often dominates. In the northern part of the Polar Urals, north of the Khadat river, in the valley of which it dominates in places. In lowland forest tundra it is common, more often as an admixture to larch. Siberian pine, Siberian cedar Pinus sihirica Du Tour is found in river valleys, along the outskirts of peat bogs; very rarely, the northernmost single locations are recorded near the lake. Grumpily, in the valley of the Nelka River.^[17]

In typical plant communities of the Southern part of the Polar Urals, the tundra-shrub-moss-lichen mountain tundras confined to rocky-gravelly slopes, the soil–forming rock is loam, the total projective coverage is about 70-100%. Grasses are quite rare, dominated by shrubs Vaccinium uliginosum subsp.microphyllum, Ledum decumbens. The projective coverage of mosses ranges from 10-20% (Racomitrium lanuginosum) to 30-40% (Limprichtia revolvens (Sw.) Loeske, Hylocomium splendens (Hedw.) Schimp. in B.S.G. are also found).^[17]. In the plant communities of yernikov shrubby (herbaceous)-lichen-moss mountain tundra in the southern part of the Polar Urals, Ledum decumbens and Vaccinium uliginosum subsp. microphyllum (PP = 20-60%) mainly grow under a shrub layer with a height of 7-20 cm and a closeness of 0.4. The moss cover is mosaic,^[17] represented mainly by green mosses. Among the herbs there are representatives of the saxifrage and buckwheat families. The vegetation cover around the glacier is unclosed, the projective cover does not exceed 30%. Plants of the Poaceae, Ranunculaceae, Saxyfragaceae, and Polygonaceae families were found in the form of small curtains near the glacial lake.

The obtained results of the palynological study demonstrated that the palin spectra from the surface of the Romantic Glacier^[17] differ significantly from the palin spectra of surface samples in the tundra zone.^[16] First of all, the palin spectra from the glacier surface differ in the abundance and diversity of pollen from thermophilic trees, the percentage of pollen from thermophilic rocks totaled 8-22%. These are mainly Tilia and Corylu s, the presence of pollen from Carpinus, Acer, Quercus, Fraxinus, Ulmus was noted. At the same time, Tilia pollen (1-6%) is found in almost all samples, Corylus pollen (2-3.5%) is almost as common. Carpinus pollen (0.4-1.2%) was observed in the snow of the sampling year and in ice, Ulmus and Fraxinus pollen was noted in snow and firn. The pollen of Pinus sylvestris and Betula sect dominates the palin spectra. Albae. If the high content of birch pollen is due to the fact that both in the Urals and in the Trans-Urals it participates in the composition of mountain forests, then the lower content of P. sibirica pollen probably indicates that the Romantics glacier is mainly affected by air masses coming from the southwest, where pine dominates the forests. The presence of Picea and Abies pollen, as participants in phytocenoses in the Subholtz belt, is quite natural in almost all samples, on average 4-5%. The insignificant participation of shrub pollen is in accordance with their practical absence in the vicinity. The sparse vegetation in the vicinity of the glacier is reflected in considerable detail in the palin spectra on its surface. Pollen from the families Saxyfragaceae, Ericaceae, Caryophyllaceae, Polygonaceae (Polygonum bistorta), Rosaceae and others was noted. The presence of pollen from Poaceae, Ranunculaceae was recorded in pollen spectra of the bottom water of a glacial lake, in snow and ice. Polypodiaceae (11-19%) and Sphagnum (14-27%) predominate among the spores, although their habitats are removed a considerable distance from the glacier. The maximum concentration of pollen and spores was noted in pure ice of 579 copies/l, the minimum -231 copies/l – also in pure ice.

We found a small amount (1-3%) of Poaceae and Cyperaceae pollen, as well as Polypodiaceae spores in pollen spectra obtained from the surface of a snowfield in the area of the village. Polar (Polar Urals) (66°25'23"N, 64° 29' 51"E). However, pollen from cereals and sedges, as well as fern spores, were not detected in the pollen spectra of a small glacier located nearby ^[17]. The latter is characterized by a higher content of Pinus sylvestris (26-36%), P. sibirica (9-16%), Betula sect. Nanae (8-11%) and Sphagnum spores (18-26%), while the Ericaeae pollen content does not exceed 1%. Bryales and Equisetum spores are not found in the pollen spectra of either snow or ice.[17

Palinospectrums from a snowfield on the Kara Sea beach on the Mammoth Peninsula (71°55' 43"N, 76°10' 44" E) are characterized by an abundance of Ericales pollen (25-30%), Poaceae and Cyperaceae pollen (19-30%), insignificant participation of Betula sect.Nanae (6-12%) and grass pollen (9-15%), along with a fairly high level of long-range pollen (Pinus sylvestris + P. sibirica-9-11%). The spores found in snowfields and on the surface of sea ice are Bryales (10-27%) and Sphagnum (4-6%). The content of redeposited palynomorphs is small, no more than 1-3%. The palin spectra of snowfields reflect the composition of the surrounding vegetation cover, but contain long-range components in noticeable quantities. The ratio of pollen and spores of regional and local components relative to long-range ones is determined by the pollen productivity of anemophilic plants of local and regional phytocenoses.

The composition of the palin spectra on the surface of the Romantics Glacier largely reflects the features of atmospheric circulation on the southern slope. If we compare the results obtained with the results obtained by T.G.Surova on the IGAN glacier[15], then the difference is noticeable. The IGAN glacier is located at an altitude of 1000-1200 m above sea level. The palin spectra of the IGAN glacier are characterized by the predominance of Pinus sibirica and Betula sect pollen. Nanae. Siberian cedar pollen is contained in an amount close to the maximum in comparison with surface soil samples in the valley of the Bolshaya Hadata River. Ice samples are characterized by a low content of Pinus sylvestris pollen, probably reflecting seasonal pollen supply to the glacier surface, while pine pollen dominates on the Romantics Glacier. Larch pollen is not found either in the snow cover or in the ice,^[16] perhaps this is due to the fact that, getting on the snow, larch pollen quickly collapses due to being in fresh water. Larch pollen is also not found on the Romantics Glacier. A characteristic feature of the ice and snow palinospectrums on both glaciers is the complete absence of grass pollen and green moss spores. But the content of spores of sphagnum mosses in the spore-pollen spectra of the IGAN glacier exceeds 50% of the total number of counted pollen grains and spores. The content of spores of millipede ferns is also noticeably high ^[18]. This confirms that the spores of these plants are well tolerated by the wind, the thick sporina does not allow the spores trapped on the ice to collapse. In our opinion, the palin spectra from snow cover and ice in this case reflect the winter-spring component of the regional pollen rain, since pollen from grasses blooming in the summer season is absent in the palin spectra of the IGAN glacier. On the Romantics glacier, the pollen of herbs of local species is contained in small quantities, but its composition is quite diverse. Perhaps this is facilitated by local winds and possibly blizzard transport, which is very intense in this area. It is obvious that the Romantics Glacier and the IGAN glacier are under the influence of different air masses. The presence of pollen from linden, elm, hazel, maple and other broad-leaved species in the ice and snow cover of the Romantics Glacier indicates, in our opinion, the movement of air masses from south to north along the Ural Ridge during the flowering period of broad-leaved species in May-June. This is also evidenced by the high percentage of pollen of scots pine, which is not found in the Polar Urals, but grows in the Northern Urals. It is known that, on average, the distance to which pollen is transported under favorable conditions (wind speeds of 23-39 km/h and the presence of appropriate atmospheric structures) is 1000-2500 km.^[16] According to the variety of palinotaxons represented in the spectra, it can be said that the palin spectra of the surface samples of the Romantics glacier are close to the palin spectra that were determined on the Vavilov dome.^[18] It is obvious that the reasons for this similarity are different. On the Vavilov dome, pollen deposition occurs as a result of the introduction of mid–latitude frontal storms into the Arctic zone - this is an important feature of the synoptic regime of the high Arctic, which most contributes to the introduction of long-range pollen, as well as pollen and spores from tundra and forest-tundra areas.

Spore-pollen characteristics of snow and ice in Yamal. The palin spectra of snowfields of river and sea ice are formed in the same mode as the palin spectra of glaciers, i.e. the palinomorphs of both the summer and winter seasons accumulate here. The palinospectrums of snowfields undergo a transformation associated with the mode of existence of snowfields. During the summer, during the melting of snow, pollen and spores partially drain from the surface of the snowfields. Table 3 shows the samples most saturated with pollen and spores, the content of pollen and spores, which are typical for those tundra subzones where they were selected.

Table 3. Composition of pollen and spores in the snow of Yamal, Gydan (%)

It should be noted that the content of pollen grains and spores with discontinuous disorders is close for all samples from 22.2 to 26.4% of the total of counted pollen grains and spores.

Pollen and spores trapped in the snow end up in water with low mineralization. Larch pollen and pollen of other species with a low content of sporopollenin are rapidly destroyed in such an environment.^[16]

The presence of pollen grains with discontinuous disturbances is also due to the destructive effect of ice crystals when the temperature on the surface of ice or snow drops below zero. In general, the composition of snowfield palinospectrums is close to the composition of subfossilic soil samples and corresponds to zonal palinospectrums in terms of the content of long-range soil.

The composition of the palin spectra of snowfields, river and sea ice, as well as the composition of the palin spectra of mountain and polar glaciers, reflects the seasonality of pollen and spore accumulation. Thus, in the palin spectra of snowfields and ice floes selected in August, the content of local pollen is much higher, wormwood pollen is noted even on the surface of a snowfield in the Arctic tundra.

If we compare the palin spectra of the snowfield, samples from which were taken in August, and palin spectra from the ice floe of the Gulf of Ob, from a sample taken in early July, then there is a noticeable difference in the content of pollen of shrubs. In the July sample, the pollen of shrubs, mainly dwarf birch, occurs sporadically and reflects the possibility of long-range transport.

While on the surface of the snowfield in August, the pollen of shrubs in the area of Cape Kamenny in Yamal is more than 10%. Note the frequent occurrence of spores of sphagnum mosses and centipede ferns in August palinospectrums, this reflects their local origin.

The analysis of the composition of palinospectrums isolated from the surface of sea and Guba ice demonstrated the proximity of the composition of palinospectrums from snowfields and ice floes. This made it possible to establish that the studied ice floes were not brought by the current from other areas.

When pollen grains and spores fall on the surface of a snowfield or ice, they undergo additional destruction during freezing and melting of water on the surface of a snowfield or ice floe. The percentage of palynomorphs with discontinuous disorders in all samples exceeds 20% and ranges from 21% to 26.4%.

In the samples of surface samples from the soil cover in the same areas, the content of palynomorphs with discontinuous disturbances averages 3-5%.^[16] However, on the surface of the soil cover, damaged pollen and spores are destroyed fairly quickly, and on the surface of the snowfield they persist a little longer.

The July palin spectra that we isolated from the surface of ice floes and snowfields are very similar to palin spectra from re-vein ice. They also reflect pollen rain, consisting mainly of long-range components.

Since the main source of food for re-vein ice is melted snow water, the composition of pollen and spores in the thickness of the snow cover corresponds to the composition of the palin spectra of re–vein ice. A sample of freshly fallen snow, taken in January from the village. Harasaway (table. 4) contained a small amount of pollen. However, the composition of the palinospectrum is very indicative, it clearly demonstrates which pollen is carried even in winter. These are pollen from Scots pine, heather, wormwood and spores of sphagnum mosses. All these palynomorphs can get into the re-vein ice in the spring.

Table 4. Composition of palinospectrums from freshly fallen snow in the cryolithozone (copies)

The composition of the palinospectres from the snow that fell in the area of the Bison section in the lower reaches of the Kolyma turned out to be very interesting. An underdeveloped pollen of various grasses was found in the snow, three-bordered with a smooth, thin, easily crumpled exina without morphological signs.

In Late Pleistocene palinospectrums, the content of such pollen can reach 60-80%. However, such pollen is practically not found in modern surface samples, and the rate of its destruction is very high.

It is eaten faster by microfauna. In the snow that fell at the end of the second decade of August, there was more such pollen than other pollen grains.

In our opinion, the high content of underdeveloped pollen in the snow models the conditions of the Late Pleistocene. Snow probably fell on flowering plants and their pollen was preserved in the snow cover and in syngenetically frozen sediments. In spring, underdeveloped pollen grains fell into the re-vein ice during snowmelt.

Thus, underdeveloped pollen of various grasses got into the snow cover, into the deposits of the forming ice complex and into syngenetic re-vein ice as a result of a sharp temperature change when snow fell on flowering plants.

Once again, we emphasize that in winter snow in the cryolithozone and in re-vein ice, the presence of long-range woody pollen, as well as wormwood and heather is recorded.

It is quite natural that there is no general sequence of culminations of certain pollen taxa. This means that cracking in this area occurred chaotically and not necessarily along the axial part of the ice vein.

To interpret the data of the palynological analysis, we will also consider the chemical characteristics of ice veins in the floodplain of the Lyakkatose River. PLL 1 was located in the lower part of the high floodplain of the Lyakkatose River, and PLL 2 was slightly higher. This was reflected in the peculiarities of the chemical composition of the ice veins. In PLL 1, mineralization in the range from 1.4 -3.0 m is 48-88 mg/l and only at a depth of 0.7-1.3 m, mineralization increased to 188 mg/l. In PPL 2 (which was studied palynologically), the minimum dry residue content is 90 mg/l at a depth of 0.7-0.8 m, but in general, the mineralization of ice is much higher: 152-196 mg/l. The pH value in PH 1 corresponds to the average value for snow cover 6.2-6.45.

In PLL 1 on the floodplain of the Lyakkatose River, the ratio Cl^–/ SO ₄ ^2– is characterized by values 4.24-6.15, which demonstrates the influence of the waters of the Gulf of Ob, which could be carried out through flooding as a result of overburden phenomena, similar to which we observed during field work. This ratio is slightly lower in the ice of PZHL 2. In the depth range of 0.7-1.15 m, the ratio of Cl^–/ SO ₄ ^2– was 3.16-5.76, and in the range of 1.2-2.3 m, this ratio has values of 0.54-1.15, i.e. ice in the lower part of the vein accumulated with minor participation of flooding by river waters.

Probably, the influence of the waters of the Gulf of Ob can explain the noticeable presence of spruce pollen, which is unusual for the re-vein ice of Yamal.^[16] It is known that spruce pollen is quite well tolerated by water, and somewhat worse, compared to pine pollen, with the help of wind. The entry of spruce pollen into the re-vein ice in this case can be associated with flooding of the floodplain of the Lyakkatose River by the waters of the Gulf of Ob. This is confirmed by the findings of spruce pollen on the surface of ice floes from the Gulf of Ob

Snow cover is the main source of the formation of re-vein ice, therefore it can be considered as a depositing medium for pollen and spores entering the re-vein ice. Pollen and spores are found in snow in any natural landscapes in which snow cover is preserved during the low-temperature season. The presence of pollen or spores in the snow proves that long-range pollen is involved in the palin spectra. In the circumpolar regions, the concentration of pollen in snow is very low: from 1 to 15 pollen grains per liter of meltwater, their concentration is higher in the snow cover of polar glaciers, and amounts to several hundred pollen grains, this is due to the fact that pollen and spores fall on the snow of polar glaciers all year round, and in the tundra, only when A stable snow cover is being formed. The concentration of pollen and spores in the underground ice in the field of permafrost development averages 10-500 specimens/l, in some cases reaching thousands or more specimens.^[4,5]. Information about pollen and spores contained in winter snow is of interest. A sample of freshly fallen snow, possibly subjected to blizzard transport, taken in January from the village. Kharasaway contained a small amount of pollen (see Table 4). However, the composition of the palinospectrum is very indicative, it clearly demonstrates which pollen is carried even in winter. These are pollen from Scots pine, heather, wormwood and spores of sphagnum mosses. Pollen and spores of these plants can get into the re-vein ice from the snow in the spring, when the snow begins to melt. Palin spectra similar in composition were obtained by V.V.Ukraintseva, who studied snow at the North Pole. We also note the importance of the factor of snowstorm transport for the formation of palinospectres in snow. In the winter season, snowstorm transport over the earth's surface by wind, the speed of which exceeds 5 m/s, is a frequent atmospheric phenomenon in Yamal. During the entire low temperature season, pollen and spores that have fallen on the surface of the snow cover move when blizzards occur, which are observed here in Yamal from September to May.

A palinospectrum of snow that fell in August in the lower reaches of the Kolyma River (see Table. 4) it contained almost no spores, the pollen of tree species is represented by far-bearing pollen of Scots and Siberian pines, there was no pollen of larch, which dominated the vegetation cover at the point of snow removal. Since snow is characterized by low mineralization, pollen with a low content of sporopollenin, which includes larch pollen, is rapidly destroyed in such an environment.^[16] The palinospectrum from the August snow contained a noticeable amount of local pollen of various grasses. Obviously, this is one of the ways that local pollen and spores get into the re-vein ice. Of course, provided that snow falls and does not melt until spring, then pollen and spores contained in the lowest layers of the snow cover can get into the re-vein ice during the snowmelt period.

The July-August palinospectrums isolated by us from the surface of ice floes and snowfields are very similar to palinospectrums from re-vein ice, but differ from palinospectrums of surface samples. They also reflect pollen rain, consisting mainly of long-range components.

Since the main source of food for re-vein ice is melted snow water, the composition of pollen and spores in the thickness of the snow cover generally corresponds to the composition of the palin spectra of re–vein ice.

Conclusions

1. Pollen and spores on the surface and in the snow thickness are the main source of the formation of palinospectres in re-vein ice.

2. A comparison of the results of palynological analysis of samples of horizontal and vertical sampling directions in re-vein ice showed that there is no general sequence of culminations of certain pollen taxa. This proves the chaotic nature of the cracking process relative to the axis of the vein in this area.

3. Vertical and horizontal sampling for palynological analysis complement each other, therefore, in order to obtain complete palynological information, both horizontal and vertical sampling must be performed. The advantage of the data obtained by vertical sampling is that we get a normal time series of events. With horizontal selection, taking into account the chaotic nature of cracking, we obtain information about individual events, but not about their sequence, which requires additional dating, for example, ¹⁴ With AMS microinclusions of organic matter or pollen concentrate.

4. Synchronous palin spectra in re-vein ice are characterized by a close percentage of long-range pollen and spores (regional signal), the content of local components may vary markedly.