A BOREHOLE RECORD OF LATE QUATERNARY PERMAFROST ON KURUNGNAKH ISLAND (Lena delta, northeastern Siberia): RECONSTRUCTION OF DEPOSITION ENVIRONMENTS
L.B. Khazin1,2, I.V. Khazina1, O.B. Kuzmina1,2, D.E. Ayunov1, N.A. Golikov1,3, L.V. Tsibizov1,2
1A.A. Trofimuk Institute of Petroleum Geology and Geophysics, Siberian Branch of the Russian Academy of Sciences, pr. Akademika Koptyuga 3, Novosibirsk, 630090, Russia
2Novosibirsk State University, ul. Pirogova 2, Novosibirsk, 630090, Russia
3Novosibirsk State Technological University, pr. Karla Marksa 20, Novosibirsk, 630073, Russia
Keywords: Ostracod, palynomorph, moisture content, particle size distribution, magnetic susceptibility, Pleistocene, Holocene, Lena delta, East Siberia
Abstract
Paleoenvironmenal reconstructions have been made from a multidisciplinary study of a borehole permafrost record on Kurungnakh Island (Lena delta). According to data on palynomorphs and ostracods, the clay silt units from the 10.58 to 13.54 m and 1.58 to 10.3 m core depth intervals were deposited in the Late Pleistocene (during the Karginian interstadial) and Early-Middle Holocene, respectively. The sediments were studied in terms of moisture contents, grain size distribution, mineralogy, and magnetic susceptibility, and the results were compared with published evidence from nearby natural outcrops. Quite a cold oligotrophic lake existed in the area during the Karginian period, and the deposition was interrupted by a gap recorded at a core depth of about 11 m. In the Early and Middle Holocene, the area was covered with shrub tundra vegetation.
DOI: 10.15372/RGG2019045
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