Palaeoenvironmental dynamics inferred from late Quaternary permafrost deposits on Kurungnakh Island, Lena Delta, Northeast Siberia, Russia
Palaeoenvironmental dynamics inferred from late Quaternary permafrost deposits on Kurungnakh Island, Lena Delta, Northeast Siberia, Russia
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俄罗斯西伯利亚东北部勒拿三角洲库隆纳赫岛晚第四纪永久冻土沉积物推断的古环境动力学
DOI：
10.1016/j.quascirev.2008.04.007
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发表时间：
2008
影响因子：
4
通讯作者：
M. Sierralta
中科院分区：
文献类型：
--
作者：
S. Wetterich;S. Kuzmina;Andrei A. Andreev;F. Kienast;H. Meyer;Lutz Schirrmeister;T. Kuznetsova;M. Sierralta
通过将几种化石生物指标（花粉、植物大化石、介形类、昆虫和哺乳动物骨骼）的数据与永久冻土沉积物的沉积学和冰石学数据相结合，重建了西伯利亚北极晚第四纪的古环境。该记录反映了白令陆桥的环境历史，涵盖了冰期/间冰期和场间/场间气候变化，重点是中魏希瑟利亚间场（50-32kyrBP）。库隆纳赫岛晚更新世至全新世的序列反映了冰缘地貌在不断变化的沉积模式下的发展，这些沉积模式在早魏希瑟世期间是曲流河流，在中晚魏瑟世期间是缓倾斜平原上的崩积物或洪积物，在全新世期间是受热喀斯特影响的。古生态记录表明，在中魏希瑟利亚间质期，寒冷大陆性气候条件下存在苔原草原植被。由于 32 和 17kyrBP 以及 17 和 8kyrBP 之间的序列中存在沉积间隙，所研究的露头中没有完整地体现出晚魏希瑟阶阶梯。然而，根据一些古生态学迹象，在更新世晚期，极端寒冷干旱条件下的北极苔原草原植被盛行。全新世期间，由于持续的沼泽化，苔原草原完全消失。最初形成亚北极灌木苔原，后来在全新世晚期冷却过程中退缩。
Late Quaternary palaeoenvironments of the Siberian Arctic were reconstructed by combining data from several fossil bioindicators (pollen, plant macro-fossils, ostracods, insects, and mammal bones) with sedimentological and cryolithological data from permafrost deposits. The record mirrors the environmental history of Beringia and covers glacial/interglacial and stadial/interstadial climate variations with a focus on the Middle Weichselian interstadial (50–32kyrBP). The late Pleistocene to Holocene sequence on Kurungnakh Island reflects the development of periglacial landscapes under changing sedimentation regimes which were meandering fluvial during the Early Weichselian, colluvial or proluvial on gently inclined plaines during the Middle and Late Weichselian, and thermokarst-affected during the Holocene. Palaeoecological records indicate the existence of tundra–steppe vegetation under cold continental climate conditions during the Middle Weichselian interstadial. Due to sedimentation gaps in the sequence between 32 and 17kyrBP and 17 and 8kyrBP, the Late Weichselian stadial is incompletely represented in the studied outcrops. Nevertheless, by several palaeoecological indications arctic tundra–steppe vegetation under extremely cold-arid conditions prevailed during the late Pleistocene. The tundra–steppe disappeared completely due to lasting paludification during the Holocene. Initially subarctic shrub tundra formed, which later retreated in course of the late Holocene cooling.