Clays of yedoma suite

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, Department of Geography, Faculty of Geoecology of the North alla-vasilch@yandex.ru Other publications by this author

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

Introduction

Two terms are used to denote groundwater strata with an abundant content of re-vein ice: the edom complex and the ice complex. The total area they occupy reaches 350,000 ^km2. The strata of the edom complex are composed not only of ice-saturated powdery sandy loam-loamy soils, but also of ice-saturated sandy, sandy-gravel and even gravelly soils. Their thickness varies from 10 to 60 m, their length is many tens and hundreds of meters in the outcrops, and the content of re-vein ice in them reaches 30-50%. The authors briefly described the complex under consideration as follows: edoma is a highly silty (containing more than 50-90% of ice), usually rich in organic material (containing more than 1-2% of organic matter), silty and powdery sandy loam and fine sandy loam of the Late Pleistocene; in intermountain basins and on the slopes, edoma strata can be saturated with soil and crushed stone, and in In river valleys and deltas, edom strata may contain gravel and pebbles. The age of the edomous strata varies from 11.7 to 50 caliber thousand years and older. Edom sediments contain powerful (up to 15-20 meters or more in height and 1-3.5 m wide), often multi-tiered, syngenetic re-vein ice. Edom deposits exposed by outcrops, as a rule, emit a specific smell of the "old stable" due to decomposing organic matter ^[2,6]. In foreign literature, the term "yedoma" has been adopted, denoting a special type of highly silicate deposits with syngenetic re-vein ice.^[10]

Distribution of clay edom strata

The most famous areas of the north of Russia, where edomous strata are widespread, are the Kolyma and Yano-Indigir lowlands, as well as the Novosibirsk Islands and the valley of the Lena River and its tributaries. Extensive edoma arrays are found in the Leno-Anabar and Anabar-Khatanga regions (north of the Krasnoyarsk Territory and Yakutia), in Chukotka, and in the Magadan Region. Small edom massifs are found in the western regions of Siberia – the Yamal and Gydan peninsulas, as well as the Taimyr and lower reaches of the Yenisei, and in more southern regions of Siberia - for example, in the valley of the Aldan River, in southern Yakutia – south of 57 ° n – in the valley of the Olekma River and its tributaries, and even south of 55 ° S.S. – in the upper reaches of the region. Oud, Biryusa, Gutara.

The analysis of the granulometric composition of edomous sediments of Siberia and Alaska, performed in more than 770 samples from 23 edomous massifs, showed^[11] that sandy loam-loamy soils significantly predominate over clay and sandy soils (Fig. 1).

Fig. 1. Granulometric composition of edomous sediments of Siberia and Alaska in 23 edomous massifs (according to ^[11]): 1 – Colville (northern slope of De Long); 2 – Itkillik; 3 – Seward Peninsula (Ketlak River); 4 – Volt Creek tunnel; 5 – Cape Mammoth Fang; 6-7 – Ebe-Sise and Hardang Islands; 8 – Kurungnah Islands; 9 – Bykovsky Peninsula; 10 –Muostakh Islands; 11 – Buor Hai Peninsula; 12-16 – Novosibirsk Islands; 17 – Bolshoy Lyakhovsky Island; 18 – Oygos Yar; 19 – Duvanny Yar; 20 – Kytalyk (Berelekh river); 21 – Batagai megacity; 22-23 – Tabaga and Yukechi

The most interesting sections studied by the authors in the north of Russia are sections of the edom complex, composed mainly of clay, loamy and sandy loam soils, exposed in the outcrops of the re-vein complex near the village. Seyakha (height over 20 m), Edom near the village of Zeleny Mys (outcrop height over 40 m), Duvanny Yar (height about 55 m), Edom Bison (height up to 15 m), Stanchikovsky Yar (height about 35 m), Batagaysky megacity (height over 75 m), and Ice Cliff (height more than 25 m) in the valley of the Main river.

In Western Siberia, edom strata have been studied in Yamal in the Seyakhinsky Late Pleistocene syngenetic re-vein complex, which is exposed along the coast of the Gulf of Ob for more than 4 km, its height ranges from 22 to 24 m. The soil layer in the upper part of the outcrop is represented by a thick pack of yellow layered sand lying on sandy loams with peat interlayers (Fig. 2).

Fig. 2. Seyakhinskaya macrocyclitic edoma, piled on top of sand (a), underlain by sandy loam with interlayers of allochthonous peat (b)

In the cryolithological structure of this section, two macrocycles of vein development and their corresponding two parts of the section are clearly distinguished: the upper 9-12-meter part is characterized by the presence of narrow ice veins up to 1.5-2 m wide, and the lower 12-15-meter one with an abundant organic content, with polygonal-vein ice of late Pleistocene age up to 3 m wide.

The authors have repeatedly studied sections of the Omolono-Anyui edoma, which covers an area of more than 1,000 ^km2. A unique section of this edoma has been uncovered for more than 60 years in the Duvanny Yar outcrop in the lower reaches of the Kolyma River (Fig. 3).

The length of this outcrop, with a height of more than 55 m, along the right bank of the Kolyma River, is more than 10 km. The composition of sediments varies from clays to sand and peat. Several tiers of ice veins vertically penetrate the entire thickness of Edoma ^[3].

Fig. 3. Duvannoyarsk macrocyclitic edoma, composed mainly of clay soils

Fig. 4. Edoma in the Bison section, composed mainly of sandy loam and loam

The Bison section (fig. 4) is represented mainly by sandy loam deposits. Syngenetic ice veins with a vertical thickness of up to 9 m and a width of up to 2-2.5 m in the upper part are exposed in the circus with a height of about 20 m.^[2]

The authors studied a section of edom and sediments located on the outskirts of the village of Chersky, 300 m below the pier on the right bank of the Kolyma River. An edomous tab embedded in pre-Pleistocene rocks has been uncovered here. The sediments are represented by heavy dark gray sandy loam with a low organic content. The height of the outcrop is 20-25 m. Ice veins have been uncovered at a depth of 1-1.5 m. They are relatively narrow, with a width of no more than 1 m in the frontal section.^[5]

The edom sections described by the authors in the Main River valley are mostly desiccated, especially the Ust-Algansky and Ozerny sections of the Ice Cliff,^[4] however, among them there are strata represented by more finely dispersed soils (strongly dusty sands and sandy loams) - this is the Edom Ice Cliff^[12], and R.S. Shukhvostov et al.^[7] on the right bank of the Anadyr River, in its middle course, 12 km above the mouth of the Main River, 3 new sections of edom strata, composed of fine sands, often with a high proportion of sandy loam, have been described.

Among the edomous sections studied in the valley of the Indigirka River and its tributaries: Uyandina, Tirekhtyakh, Badyarikha, and Ogorokha, thin-layered dark gray sandy loams predominate, and light loams with a thickness of 20-30 m are found, containing cyclically occurring powerful syngenetic ice veins.^[8]

T.Opel and his colleagues, as part of a joint Russian-German expedition, examined the famous outcrop of Oygos Yar, on the shore of the Dmitry Laptev Strait.^[9] Typically edomous deposits in the section are represented by gray-brown desalinated sandy loams and loams with peat inclusions, which consist of buried cryogenic soils, fragments of branches, plant roots, and fine, dispersed plant detritus. Syngenetic re-vein ice has a vertical length of more than 20 m and a width of more than 3 m. According to radiocarbon dating, the Edom ice complex was formed approximately 49.4 to 36.3 thousand years ago. The huge variation in the values of δ18 ^O and δ2 H of pore and segregation ice inside the edom ice complex reflects mainly secondary fractionation processes rather than differing climatic conditions.^[9]

S. Wetterich and co-authors^[14,15] studied cryostratigraphy and isotopic composition in more than 500 samples of native re-vein ice on the island of Soboise in the Lena Delta. Three sediment profiles were selected in close proximity to each other to cover the entire section of permafrost rocks with a resolution of 0.5 m. The first profile covers the uppermost part of the outcrop between 24.2 and 15.5 meters, dating from 2,440 to 27,540 cal. years. The second profile, the adjacent outcrop of the landfill, was selected between 18.8 and 10.2 m, dating from 25,680 to 40,840 cal. years. The third and lowest profile was selected approximately 120 m to the east between 13.4 and 0.8 m. It is dated from 41,420 to more than 50,000 cal. years.^[14,15] The authors concluded that the edoma formed during MIS 3 with a predominance of sandy loam and fine sand was formed mainly as a result of the processes of the floodplain regime of accumulation of alluvial sediments and/or melt runoff, but may also include an Aeolian component.^[14]

A.V.Bartova ^[1] studied mainly loamy edom strata in three areas of the Kolyma lowland – on the coast of the East Siberian Sea and on the Maly and Bolshoy Anyui rivers. Near the coast in the eastern part of the site, on the Nekkeivey River, edoma overlaps a Neogene weathering crust – bluish-green clays with rounded "contractions" compacting towards the center (to crushed greenish-gray sandstones, the destruction of which probably formed this weathering crust). In the cliffs on the shore of the East Siberian Sea, gravel and pebbles, considered alluvium, lie under the loam of the edom stratum. Edoma in sections on the coast consists of dense, frozen, brownish-gray sandy loams and loams, with unclear or thin lenticular layering, with lenses and interlayers of peat, dusty sands, an abundance of plant detritus, vivianite grains and bright blue mineralization in contact with organic residues. In the outcrops in the lower reaches of the Kolyma, on the Maly and Bolshoy Anyui rivers (Molotkovsky Kamen, Krasnoe, Stanchikovsky Yar), a similar structure was observed^[1]: two levels of sandy loam and loam and a peat horizon separating them. The upper sandy loams and loams are stripped off, their horizontal layering is emphasized by interlayers and lenses of peat with a thickness from the first millimeters to the first centimeters, with inclusions of plant (woody) remains. Thickness of the thickness is more than 10 m. The peat horizon is represented by layered peat with remnants of herbaceous and woody vegetation. In some sections along the strike, the peat layer is replaced by detached sandy loams and loams, or by interbedding sandy loams and loams and peat, with a concentration of woody vegetation remnants at this level. The thickness is up to 2 m. The lower sandy loams and loams are gray, bluish on a fresh cut, with a thin (first millimeters) lenticular layering due to the alternation of lighter and darker layers (lighter correspond to larger, sometimes sandy sandy loams and loams, darker correspond to smaller ones), with inclusions of peat lenses, with scattered the layer contains plant remains (mainly stems of herbaceous plants), with bright blue vivianite grains and the same mineralization in contact with organic inclusions. The thickness of the layer is more than 20 m. In all the observed sections, re-vein ices are exposed, in most cases they are confined to the "upper" sandy loams and loams. The apparent "height" of the re-vein ice is 4.5-5 m.^[1]

The authors investigated syngenetic re-vein ice in the thickness of the slope edoma in the foothills of the Kular ridge in the valley of the stream. Bourguat. The absolute elevation of the edom sole ranges from 95 m near the stream to 110-120 m in the upper part of the slope, and the roof ranges from 105 to 140 m. In the section, there are both powerful syngenetic re-vein ice permeating the entire thickness, and cyclitic multi-tiered re-vein ice. In total, there are three to four tiers of ice veins, up to 3-3.5 m wide. They lie in the thickness of sandy loam containing thick layers of peat.^[13]

Edom, composed mainly of crushed stone with sandy loam and loamy aggregate

The granulometric composition of the slope edom deposits in the valley of the Utinaya River, the right tributary of the Kolyma River in its upper reaches, differs significantly at absolute heights of 330-335 m.^[6] The outcrop is a scalloped series of cliffs 3-4 m high, with a significant content of uncoated crushed stone 10-12 cm in size (Fig. 5), remnants of plants and wood. In this thickness, re-vein ice with a thickness of about 4 m and a width of 1.8–2 m has been uncovered.

Fig. 5. Edoma in the valley of the Utinaya River, composed mainly of crushed stone with sandy loam and loamy aggregate

Edoma with coarse-grained material has been found both in the northernmost latitudes (Bolshevik and Ellesmere Islands) north of 80°N, and far to the south in Western Sayan and Transbaikalia south of 55°N^[6]

The engineering and geological properties of natural massifs with inclusions of gravel and pebbles or gravel and crushed stone significantly affect the development of territories. This was especially evident during the construction of high-speed highways in Alaska (USA), and the mining of placer gold in the Magadan Region, Yakutia, and the Klondike.

Conclusions

1. Clay deposits (sandy loams, loams) are the most common type of precipitation composing the soil strata.

2. Among the clay edom sections, cyclically arranged re-vein ice is most often found, the heads of which (or pronounced lateral "shoulders") are confined to the interlayers of allochthonous (less often autochthonous) peat bogs.

3. Sloping clay edoms often contain inclusions of gravel and pebbles or gravel and crushed stone.