Vegetation and climate history in the Laptev Sea region (Arctic Siberia) during Late Quaternary inferred from pollen records

Abstract

Th/U) were analyzed for pollen and palynomorphs. The records reveal the environmental history for the last ca 200 kyr. For interglacial pollen spectra, quantitative temperature values were estimated using the best modern analogue method. Sparse grass-sedge vegetation indicating arctic desert environmental conditions existed prior to 200 kyr ago. Dense, wet grass-sedge tundra habitats dominated during an interstadial ca 200e190 kyr ago, reflecting warmer and wetter summers than before. Sparser vegetation communities point to much more severe stadial conditions ca 190e130 kyr ago. Open grass and Artemisia communities with shrub stands (Alnus fruticosa, Salix, Betula nana) in more protected and moister places characterized the beginning of the Last Interglacial indicate climate conditions similar to present. Shrub tundra (Alnus fruticosa and Betula nana) dominated during the middle Eemian climatic optimum, when summer temperatures were 4e5 C higher than today. Early-Weichselian sparse grass-sedge dominated vegetation indicates climate conditions colder and dryer than in the previous interval. Middle Weichselian Interstadial records indicate moister and warmer climate conditions, for example, in the interval 40e32 kyr BP Salix was present within dense, grasssedge dominated vegetation. Sedge-grass-Artemisia-communities indicate that climate became cooler and drier after 30 kyr BP, and cold, dry conditions characterized the Late Weichselian, ca 26e16 kyr BP, when grass-dominated communities with Caryophyllaceae, Asteraceae, Cichoriaceae, Selaginella rupestris were present. From 16 to 12 kyr BP, grass-sedge communities with Caryophyllaceae, Asteraceae, and Cichoriaceae indicate climate was significantly warmer and moister than during the previous interval. The presence of Salix and Betula reflect temperatures about 4 C higher than present at about 12e11 kyr BP, during the Allerød interval, but shrubs were absent in the Younger Dryas interval, pointing to a deterioration of climate conditions. Alnus fruticosa, Betula nana, Poaceae, and Cyperaceae dominate early Holocene spectra. Reconstructed absolute temperature values were substantially warmer than present (up to 12 C). Shrubs gradually disappeared from coastal areas after 7.6 kyr BP when vegetation cover became similar to modern. A comparison of proxy-based paleoenvironmental reconstructions with the simulations performed by an Earth system model of intermediate complexity show good accordance between the regional paleodata and model simulations, especially for the warmer intervals.

PERMAFROST AND PERIGLACIAL FEATURES | Yedoma: Late Pleistocene Ice-Rich Syngenetic Permafrost of Beringia

“…According to Andreev et al (2011), the period of Yedoma formation in Siberia was characterized by sparse grass-sedge tundra growing in an extremely cold and dry climate during MIS 4, tundra-steppe vegetation with higher productivity in a more moderate and humid climate during MIS 3, and sparse grass-tundra present in the cooler and drier climate of MIS 2. Nevertheless, the presence of algal spores and remains of other aquatic organisms (e.g., hydrophytes, ostracods) found in many samples indicates the existence of small freshwater ponds in low-center polygons.…”

“…The paleoecosystem associated with Yedoma, often called Mammoth Steppe or steppe tundra in eastern Beringia (e.g., Guthrie, 1990) or Tundra-Steppe in western Beringia (e.g., Yurtsev, 1982), combined elements found in both cold tundra and dry steppe environments. The climate was more continental in the late Pleistocene Arctic than today, and reconstructions from Siberia indicate colder winters and warmer summers, suggesting stronger seasonal gradients in temperature and precipitation (e.g., Andreev et al, 2011). Because of the polygonal patterned ground relief, the tundra-steppe landscape was characterized by a patchwork-like distribution of vegetation communities at a local scale.…”

Late Pliocene and Early Pleistocene vegetation history of northeastern Russian Arctic inferred from the Lake El'gygytgyn pollen record

“…Sedimentary archives from the Arctic Ocean can have a much longer time range, but their paleoenvironmental significance often is hampered by slow, partly discontinuous deposition and poor age control (e.g., Nowaczyk et al, 2001;Moran et al, 2006). In the terrestrial Arctic, continuous paleoenvironmental archives are widely restricted to the Holocene and, in a few cases, to the last glacial/interglacial cycle, due to repeated glaciations that led to disturbance of many of the older sediment sequences (e.g., Andreev et al, 2004Andreev et al, , 2009Andreev et al, , 2011Lozhkin et al, 2007;Lozhkin and Anderson, 2011, and references therein). Where older sediments occur, they usually are fragmented and have rather poor age control (e.g., Matthews and Telka, 1997;Ballantyne et al, 2010;Rybczynski et al, 2013).…”

Holocene climate conditions in central Yakutia (Eastern Siberia) inferred from sediment composition and fossil chironomids of Lake Temje

“…the transfer functions) are established. There are few examples of quantitative palaeoclimate reconstructions in Siberia, and those are mainly from pollen studies Müller et al, 2009;Andreev et al, 2011;Tarasov et al, 1999Tarasov et al, , 2009). To date, there is only one quantitative temperature reconstruction inferred from aquatic diatoms in central Siberia (Kumke et al, 2004).…”