Variations in δ18O, δD, and the concentration of pollen and spores in an autochthonic heterogeneous massive ice on the Erkutayaha River in the southern part of the Yamal Peninsula

Abstract

The objective of our work is to study the new mas� sive ice deposit in the valley of the Erkutayaha River in the southern part of the Yamal Peninsula, determine the concentration of stable oxygen and hydrogen iso� topes in the ice and study the pollen and spore in the ice, to determine the conditions of ice formation based on these data, and show that massive ice in these region are of the heterogeneous autochthonic type and segregation (infiltrationsegregation) and injection genesis similar to those deposits that were recently studied in the regions near Yamal, on the Bovanenkov deposit (1) close to the Harasavey (2, 3) and Marre� Sale (4) settlements. The newly investigated outcrop of massive ice is located in the southern part of the Yamal Peninsula on the left bank of the Erkutayaha River (68 о 11'18" N, 68 о 51'39" E). This is the southernmost among the studied massive ice in the Yamal Peninsula. A massive ice approximately 100�m long exposes in the outcrop 15-18 m high that is embedded predominantly in the layered sand. The ice massive is most completely exposed in the cirques (figure). The massive ice is located just under the layer of the seasonal melting in the central part of the cirques. Here, it is sharply ele� vated and cut most likely by the postgenetic subaquatic melting. In the apical part of the cirques, the massive ice is covered by Holocene lacustrineswamp sedi� ments approximately 1 m thick. The ice layers sharply drop on both sides of the central part and in 15 m already the cover of the ice deposit appears at a depth of 8 m. The ice in the massive ice body has a suffi� ciently different cryotexture. This is predominantly the ice of four types: (1) pure ice, dullwhite with a large amount of gas xenogenic inclusions; (2) crystal� clear transparent ice sometimes with ground inclu� sions; (3) gray layered ice with steel shimmer, the lay� ers are parallel to the slope of the upper surface of the ice deposit; (4) gray block ice deposited as tiles. We distinguished the central dislocation part in the general structure of the deposit, a stock with vertically and subvertically located ice layers (the ice here is crystalclear and dirtygray with a large amount of mineral inclusions) and two peripheral parts com� posed of horizontally layered ice (the ice here is lay� ered, predominantly gray with a steel shimmer, dull� white, and block gray). The horizontal layers of these two parts of the deposit change to sloping at the con� tact with the central stock. Such contact evidences that the ice of the central stock influences the charac� ter of the horizontally layered ice bedding.