Ground-ice stable isotopes and cryostratigraphy reflect late Quaternary palaeoclimate in the Northeast Siberian Arctic (Oyogos Yar coast, Dmitry Laptev Strait)
Ground-ice stable isotopes and cryostratigraphy reflect late Quaternary palaeoclimate in the Northeast Siberian Arctic (Oyogos Yar coast, Dmitry Laptev Strait)
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DOI：
10.5194/cp-13-587-2017
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发表时间：
2017-06
影响因子：
4.3
通讯作者：
T. Opel;S. Wetterich;H. Meyer;A. Dereviagin;M. Fuchs;Lutz Schirrmeister
中科院分区：
文献类型：
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作者：
T. Opel;S. Wetterich;H. Meyer;A. Dereviagin;M. Fuchs;Lutz Schirrmeister
抽象。为了重建西伯利亚北极东北部的古气候和古环境条件，我们研究了奥约戈斯亚尔海岸（德米特里拉普捷夫海峡）的晚第四纪冻土。Kuchchugui套（112.5 ± 9.6 kyr）和Krest Yuryakh套（102.4 ± 9.7 kyr）的热岩溶湖沉积物的新红外激发发光年龄分别提供了新的大量地质年代学数据，并阐明了Dmitry Laptev海峡地区在海洋同位素阶段（MIS）5的景观历史。冰稳定同位素数据与8个冰冻地层单位的冰冻岩石学信息一起提出，并由附近的Bol'shoy Lyakhovsky岛的数据补充。我们的冰楔稳定同位素的组合记录作为过去冬季气候条件的代理，涵盖了约20万年，并补充了孔隙和分离冰的稳定同位素，反映了每年的气候条件覆盖的冻结过程。我们的冰楔稳定同位素数据表明，东北西伯利亚北极冬季气候条件在第四纪晚期，特别是冰期和间冰期之间的重大变化，但也在过去的几千年到几个世纪。冰复合冰楔的稳定同位素值表明，大约200 kyr前（MIS7）的寒冷到非常寒冷的冬季温度，大约100 kyr前（MIS5）的非常寒冷的冬季条件，大约60和30 kyr前之间的非常寒冷到温和的冬季条件，以及末次冰盛期（MIS2）的极端寒冷的冬季温度。更温暖的冬季条件反映了广泛的热岩溶发育MIS5c和全新世冰楔稳定同位素。现代冰楔稳定同位素最为富集，证明了北极最近冬季的变暖。因此，冰楔为基础的重建冬季气候条件的变化增加了大量的信息，来自存储在永久冻土中的古生态代理，并允许过去的气候动态的季节性趋势之间的区别。未来在冰楔测年方面的进展以及改进冰楔气候信息的时间分辨率可能有助于充分探索冰楔的古气候潜力。
Abstract. To reconstruct palaeoclimate and palaeoenvironmental conditions in the northeast Siberian Arctic, we studied late Quaternary permafrost at the Oyogos Yar coast (Dmitry Laptev Strait). New infrared-stimulated luminescence ages for distinctive floodplain deposits of the Kuchchugui Suite (112.5 ± 9.6 kyr) and thermokarst-lake deposits of the Krest Yuryakh Suite (102.4 ± 9.7 kyr), respectively, provide new substantial geochronological data and shed light on the landscape history of the Dmitry Laptev Strait region during Marine Isotope Stage (MIS) 5. Ground-ice stable-isotope data are presented together with cryolithological information for eight cryostratigraphic units and are complemented by data from nearby Bol'shoy Lyakhovsky Island. Our combined record of ice-wedge stable isotopes as a proxy for past winter climate conditions covers about 200 000 years and is supplemented by stable isotopes of pore and segregated ice which reflect annual climate conditions overprinted by freezing processes. Our ice-wedge stable-isotope data indicate substantial variations in northeast Siberian Arctic winter climate conditions during the late Quaternary, in particular between glacial and interglacial times but also over the last millennia to centuries. Stable isotope values of ice complex ice wedges indicate cold to very cold winter temperatures about 200 kyr ago (MIS7), very cold winter conditions about 100 kyr ago (MIS5), very cold to moderate winter conditions between about 60 and 30 kyr ago, and extremely cold winter temperatures during the Last Glacial Maximum (MIS2). Much warmer winter conditions are reflected by extensive thermokarst development during MIS5c and by Holocene ice-wedge stable isotopes. Modern ice-wedge stable isotopes are most enriched and testify to the recent winter warming in the Arctic. Hence, ice-wedge-based reconstructions of changes in winter climate conditions add substantial information to those derived from paleoecological proxies stored in permafrost and allow a distinction between seasonal trends of past climate dynamics. Future progress in ice-wedge dating and an improved temporal resolution of ice-wedge-derived climate information may help to fully explore the palaeoclimatic potential of ice wedges.