Palaeoclimatic Information from Stable Water Isotopes of Holocene Ice Wedges on the Dmitrii Laptev Strait, Northeast Siberia, Russia

The stable isotopic composition (delta O-18, delta D, d) of three Holocene-age ice wedges at the Dmitrii Laptev Strait, Russia (Oyogos Yar coast, 72.78 degrees N, 143.58 degrees E) was studied at high resolution (100 to 200 samples each) in order to develop palaeoclimatic records. AMS C-14 ages of organic matter in the ice prove the Late Holocene age of the studied horizontal ice-wedge profiles and indicate syngenetic growth associated with sediment accumulation. Co-isotopic relationships of wedge ice close to the Global Meteoric Water Line point to a good suitability for palaeoclimate studies and all three profiles show similar isotopic features. A general Late Holocene winter warming trend is inferred from delta O-18 data changing from about -26 parts per thousand to values of -23 parts per thousand to -21 parts per thousand, with periods of marked variability superimposed on the trend. This trend is accompanied by a shift in the d excess from 8 parts per thousand-11 parts per thousand to 5 parts per thousand-8 parts per thousand, probably caused by varying proportions of differing moisture sources for precipitation. The highest winter temperatures and an increased influence of regional moisture in recent decades may reflect ongoing Arctic climate change. Copyright (c) 2010 John Wiley & Sons, Ltd.