Journal of paleolimnology, 2006-12-27, Vol.37 (1), p.89-104
Byline: Martin Melles (1), Julie Brigham-Grette (2), Olga Yu. Glushkova (3), Pavel S. Minyuk (3), Norbert R. Nowaczyk (4), Hans-W. Hubberten (5) Keywords: Siberian Arctic; Quaternary; Paleolimnology; Paleoclimate; Organic geochemistry; Carbon isotopes The ca. 13 m long sediment core PG1351, recovered in 1998 from the central part of Lake El'gygytgyn, NE Siberia, was investigated for lithostratigraphy, water content, dry bulk density (DBD), total organic carbon (TOC), total nitrogen (TN), total sulphur (TS) and biogenic silica (opal) contents, and for TOC stable isotope ratios ([delt[a].sup.13]C.sub.TOC). The event stratigraphy recorded in major differences in sediment composition match variations in regional summer insolation, thus confirming a new age model for this core, which suggests that it spans the last 250 ka BP. Four depositional units of contrasting lithological and biogeochemical composition have been distinguished, reflecting past environmental conditions associated with relatively warm, peak warm, cold and dry, and cold but more moist climate modes. A relatively warm climate, resulting in complete summer melt of the lake ice cover and seasonal mixing of the water column, prevailed during the Holocene and Marine Isotope Stages (MIS) 3, 5.1, 5.3, 6.1, 6.3, 6.5, 7.1--7.3, 7.5, 8.1 and 8.3. MIS 5.5 (Eemian) was characterized by significantly enhanced aquatic primary production and organic matter supply from the catchment, indicating peak warm conditions. During MIS 2, 5.2, 5.4, 6.2 and 6.4 the climate was cold and dry, leading to perennial lake ice cover, little regional snowfall, and a stagnant water body. A cold but more moist climate during MIS 4, 6.6, 7.4, 8.2 and 8.4 is thought to have produced more snow cover onaPSthe perennial ice, strongly reducing light penetration and biogenic primary production inaPSthe lake. While the cold--warm pattern duringaPSthe past three glacial--interglacial cycles is probably controlled by changes in regional summer insolation, differences in the intensity of the warm phases and in the degree of aridity (changing snowfall) during cold phases likely were due to changes in atmospheric circulation patterns. Author Affiliation: (1) Institute for Geophysics and Geology, University Leipzig, Talstrasse 35, D-04103, Leipzig, Germany (2) Department of Geosciences, University of Massachusetts, Morrill Science Building, Box 35820, Amherst, MA, 01003, USA (3) North East Interdisciplinary Research Institute Far East Branch, Russian Academy of Sciences, 16 Portovaya Street, Magadan, 685000, Russia (4) GeoForschungsZentrum, Telegrafenberg C321, D-14473, Potsdam, Germany (5) Alfred Wegener Institute for Polar and Marine Research, Research Unit Potsdam, Telegrafenberg A43, D-14473, Potsdam, Germany Article History: Registration Date: 08/05/2006 Received Date: 09/02/2004 Accepted Date: 09/08/2005 Online Date: 09/12/2006 Article note: This is the seventh in a series of eleven papers published in this special issue dedicated to initial studies of El'gygytgyn Crater Lake and its catchment in NE Russia. JulieBrigham-Grette, Martin Melles, Pavel Minyuk were guest editors of this special issue.
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