Earth’s Cryosphere, 2011, Vol. XV, No. 2, p. 3-13

ANCIENT ALAS COMPLEXES OF NORTHERN YAKUTIA (PART 1)

T.N. Kaplina

Industrial and Research Institute for Engeneering Survey in Construction, 105187, Moscow, Okruzhnoi pr., 18, Russia, tatianakaplina@mail.ru

In addition to the Late Pleistocene Ice Complex deposits (the Yedoma Suite), the cross-sections of high Yedoma level of the northern Yakutia also contain fragments (relics) of ancient Ice Complexes. There are Ice Complexes of the lower, middle and upper Pleistocene. The youngest (relief-generating) and the thickest Ice Complex was greatly reworked by thermokarst during the transition from Pleistocene to Holocene, which resulted in widespread Holocene Alas Complexes in the lowlands. The ancient Alas Complexes, visible traces of revamping of the ancient Ice Complexes by thermokarst, can be often found in the cross-sections of the Yedoma level. These Alas Complexes underlie the young Ice Complex. The article describes ancient, buried Alas Complexes in the cross-sections of the Duvannyi yar on the Kolyma, on the left bank of the Indigirka river – on the Allaikha river (part 1) and on the shores of the Dmitri Laptev Strait (part 2). The ancient Alas Complexes possess common structural features and had resulted from the lake thermokarst, followed by sedimentation in the alases. Their structural features are similar to those of Holocene Alas Complexes.

Key words: Northern Yakutia, Pleistocene, ancient Ice Complex, thermokarst, ancient Alas Complex.

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