Late Quaternary paleoenvironmental reconstructions from sediments of Lake Emanda (Verkhoyansk Mountains, East Siberia)

Abstract

Continuous pollen and chironomid records from Lake Emanda (65°17′N, 135°45′E) provide new insights into the Late Quaternary environmental history of the Yana Highlands (Yakutia). Larch forest with shrubs (alders, pines, birches) dominated during the deposition of the lowermost sediments suggesting its Early Weichselian [Marine Isotope Stage (MIS) 5] age. Pollen‐ and chironomid‐based climate reconstructions suggest July temperatures (TJuly) slightly lower than modern. Gradually increasing amounts of herb pollen and cold stenotherm chironomid head capsules reflect cooler and drier environments, probably during the termination of MIS 5. TJuly dropped to 8 °C. Mostly treeless vegetation is reconstructed during MIS 3. Tundra and steppe communities dominated during MIS 2. Shrubs became common after ~14.5 ka bp but herb‐dominated habitats remained until the onset of the Holocene. Larch forests with shrub alder and dwarf birch dominated after the Holocene onset, ca. 11.7 ka bp. Decreasing amounts of shrub pollen during the Lateglacial are assigned to the Older Dryas and Younger Dryas with TJuly ~ 7.5 °C. TJuly increased up to 13 °C. Shrub stone pine was present after ~7.5 ka bp. The vegetation has been similar to modern since ca. 5.8 ka bp. Chironomid diversity and concentration in the sediments increased towards the present day, indicating the development of richer hydrobiological communities in response to the Holocene thermal maximum.

Quaternary environmental and climatic history of the northern high latitudes – recent contributions and perspectives from lake sediment records

“…1). A 6.1 m long core from this lake was investigated for pollen and chironomids, the results of which were used to employ transfer functions for July temperatures (both) and annual precipitation (pollen only; Andreev et al, 2022). The data obtained provide detailed information on climatic changes in the region; however, their timing has some uncertainties, since some of the ages suggested by the pollen data differ distinctly from those presented earlier by Baumer et al (2021) based on radiocarbon dating.…”