Younger Dryas and Early Holocene Peats from northern Far East Russia

Macrofossil remains from dated peat sections help clarify paleoclimate patterns inferred from subtle changes in the palynological data from the northern Russian Far East. These data show latitudinal range extensions for tree Betula, Larix gmelinii, and Picea sp., as well as the occurrence of tree-sized shrubs of Duschekia fruticosa and Salix sp. in areas that today are low shrub tundra. Ages of extralimital taxa suggest a postglacial thermal maximum between ∼11,000 and 8100 14C BP including a region-wide, warm Younger Dryas. This warm interval contrasts to other areas of Siberia where the thermal optimum is ∼9000–4000 14C BP. Additionally, macrofossils suggest that Holocene changes in northern treeline were not synchronous. In the Far East, treeline advance and retreat occurred earlier by ∼1000 14C y and ∼4000 14C y, respectively, as compared to other areas of Russia. Basal and minimum ages of peat deposits indicate that the Early Holocene was a particularly important time for peat initiation and accumulation across northern Siberia.