High‐latitude vegetation and climate changes during the Mid‐Pleistocene Transition inferred from a palynological record from Lake El'gygytgyn, NE Russian Arctic

Abstract

A continuous pollen record from Lake El'gygytgyn (northeastern Russian Arctic) provides detailed information concerning the regional vegetation and climate history during the Mid‐Pleistocene Transition (MPT), between 1091 ka (end of Marine Isotope Stage (MIS) 32) and 715 ka (end of MIS 18). Pollen‐based qualitative vegetation reconstruction along with biome reconstruction indicate that the interglacial regional vegetation history during the MPT is characterized by a gradual replacement of forest and shrub vegetation by open herbaceous communities (i.e. tundra/cold steppe). The pollen spectra reveal seven vegetation successions that have clearly distinguishable glacial‐interglacial cycles. These successions are represented by the intervals of cold deciduous forest (CLDE) biome scores changing from high to low, which are basically in phase with the variations of obliquity from maxima to minima. The dominating influence of obliquity forcing on vegetation successions contradicts with the stronger power of eccentricity, as demonstrated by the result of wavelet analysis based on landscape openness reconstruction. This discrepancy shows that a single index is insufficient for catching signals of all the impacting factors. Comparisons with vegetation and environmental changes in the Asian interior suggest that global cooling during the MPT was probably the key force driving long‐term aridification in the Arctic region. The accelerated aridification after MIS 24–22 was probably caused by the additional effect of the Tibetan Plateau uplift, which played an important role on intensification of the Siberian High and westerly jet systems.

Forest Steppe-Like Vegetation Near Cherskiy (West Beringia) During the Early Pleistocene Olyorian Period Reconstructed Using Plant Macrofossils

“…Cold steppe biome scores in the pollen record significantly increased from this point in time onwards indicating accelerated aridification. The long-term cooling and aridification trend observed in the El'gygytgyn record corresponds with global ice-sheet expansion, sea-level lowering, coast-line shifts, shelf exposure and an intensified Siberian High and is considered additionally strengthened by the Tibetan Plateau uplift (Zhao et al, 2018).…”

“…Prior to the EMPT, the amplitude of climate fluctuations was smaller and the duration of climate cycles was shorter, which possibly resulted, in West Beringia, in relatively dry, cool but more moderate climate that became progressively colder in the course of the EMPT but remained more stable than in other parts of the Holarctic. The palynological record from the composite sediment core of Lake El'gygytgyn, ICPD Site 5,011-1, about 467 km SE of the Cherskiy Ovrag provides valuable information on the regional history of vegetation and climate in West Beringia over the EMPT interval, i.e., between 1,091 and 715 kyr (Zhao et al, 2018). The pollen data indicate shrub tundra and cold steppe communities alternatingly dominating over the major part of the studied Early Olyorian period until MIS 24 (from 1,091 until 930 kyr) with Poaceae, Cyperaceae and Artemisia pollen and high contents of Selaginella rupestris spores prevailing during cold phases and increased amounts of Betula and Alnus (shrub birch and shrub alder) with sporadic occurrences of Larix during warm stages.…”

The Environment at Lake El’gygytgyn Area (Northeastern Russian Arctic) Prior to and After the Meteorite Impact at 3.58 Ma

“…Pollen assemblages of PZ III in section 118 (Figure 3) are dominated by Betula, Alnus and Pinus. In the El'gygytgyn pollen record (e.g., Lozhkin et al, 2007Lozhkin et al, , 2017Matrosova, 2009;Andreev et al, 2014;Zhao et al, 2018Zhao et al, , 2019, similar pollen assemblages have only been reported from the Late Pleistocene. During PZ III of section 118, larch forests with stone pines, shrub alders, dwarf birches, and ericaceous low shrubs in underbrush dominated the vegetation cover.…”

Vegetation and climate during the penultimate interglacial of the northeastern Russian Arctic: the Lake El'gygytgyn pollen record

“…) and during the mid‐Pleistocene Transition (Zhao et al . ). These studies also synthesized Arctic vegetation dynamics and corresponding orbital settings during different interglacials.…”