Abstract The 1.6975–1.965 Ma (MIS 60–MIS 74) portion of the El'gygytgyn Lake record includes two key chronostratigraphic markers in the Calabrian–Gelasian boundary (1.806 Ma) and the Olduvai paleomagnetic excursion (1.77–1.95 Ma). It also provides the first paleovegetation information for these times from the eastern Arctic. Palynological data indicate the dominance of Larix forest and forest-tundra during warm and cool intervals, which differs sharply from the herb tundra which characterized glacial intervals of the Middle and Late Pleistocene. These forests likely included tree species of Betula and Alnus and perhaps Populus and Chosenia. The persistence of Larix indicates summer temperatures were warmer than present. Pinus pumila, a typical interglacial taxon, is restricted to MIS 65 and MIS 71, suggesting other intervals experienced dry winters. Cool and warm periods are clearly marked by vegetation changes during the Late Gelasian Stage, but a dominance of Poaceae pollen and reduction in Alnus pollen during the Early Calabrian Stage mutes the climatic fluctuations. The loss of Alnus perhaps relates to decreases in seasonal temperatures.

中文翻译：

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北极东部环境变化1.6975-1.965 Ma，来自俄罗斯东北部El'gygytgyn湖的孢粉学调查

摘要 El'gygytgyn 湖记录的 1.6975-1.965 Ma (MIS 60-MIS 74) 部分包括卡拉布里亚-格拉斯边界 (1.806 Ma) 和奥杜威古地磁偏移 (1.77-1.95 Ma) 的两个关键年代地层标记。它还提供了这些时期来自北极东部的第一个古植被信息。孢粉学数据表明落叶松林和森林苔原在暖冷区间占主导地位，这与以中更新世和晚更新世冰川区间为特征的草本苔原截然不同。这些森林可能包括桦木树和赤杨树树种，也可能包括杨树和 Chosenia。落叶松的持续存在表明夏季气温比现在高。Pinus pumila 是典型的间冰期分类群，仅限于 MIS 65 和 MIS 71，表明其他间隔经历了干燥的冬天。凉爽和温暖时期的明显标志是晚格拉斯阶段的植被变化，但早卡拉布里亚阶段禾本科花粉的优势和桤木花粉的减少使气候波动减弱。Alnus 的消失可能与季节性温度的降低有关。