Evolution of subsea permafrost landscapes in Arctic Siberia since the Late Pleistocene: a synoptic insight from acoustic data of the Laptev Sea
Evolution of subsea permafrost landscapes in Arctic Siberia since the Late Pleistocene: a synoptic insight from acoustic data of the Laptev Sea
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自晚更新世以来北极西伯利亚海底永久冻土景观的演变：来自拉普捷夫海声学数据的天气洞察
DOI：
10.1007/s41063-015-0011-y
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
H. Kassens
中科院分区：
文献类型：
--
作者：
P. Rekant;H. Bauch;T. Schwenk;A. Portnov;E. Gusev;V. Spiess;G. Cherkashov;H. Kassens
利用高分辨率地震资料，研究了北极西伯利亚拉普特夫海东部陆架海底多年冻土特征的演化和形态多样性。识别出几种地震相。这些变化涉及在上一次全球海侵之前、期间和之后影响拉普特夫海域的重大环境变化。由于这个浅陆架是柏林纪陆块的一部分，我们认为一个突出的地下地震基底面是以前陆地永久冻土表的顶部。确定了五个在几何形状、反射模式、深度和永冻土顶部连续性方面不同的区域。在可见的地方，沉积物的上部70米由表生和同生冻结的贫冰沙沉积组成，可能是末次冰期早期的海洋同位素阶段(MIS5和MIS4)。紧随其后的是晚冰期富冰相，解释为MIS3至MIS2。早期全新世(MIS1)以层状良好的泻湖和滩涂沉积为特征。根据放射性碳测年沉积岩心的验证，这些沉积物被具有越来越多的海洋特征的中晚期全新世沉积所覆盖。
Using high-resolution seismic data, this study aims at investigating the evolution and morphological diversity of subsea permafrost features on the eastern Laptev Sea shelf, Arctic Siberia. Several seismic facies were recognized. These relate to the major environmental changes, which affected the Laptev Sea area before, during, and after the last global transgression. Because this shallow shelf was part of the Beringian landmass, we consider a prominent subsurface seismic basal reflector as the top of the former terrestrial permafrost table. Five zones differing in geometry, reflection patterns, depths, and continuity of the permafrost top are identified. Where visible, the upper 70 m of the sediments consists of epigenetically and syngenetically frozen ice-poor sandy deposits at the base, possibly of early last glacial age, marine isotope stages (MIS) 5 and 4. These are followed by late glacial, ice-rich facies interpreted to be MIS 3 to 2. The early Holocene (MIS 1) features well-stratified lagoonal and taberal deposits. As verified by radiocarbon-dated sediment cores, these deposits are overlain by middle to late Holocene sediments with an increasingly marine signature.