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Thermokarst Lake to Lagoon Transitions in Eastern Siberia: Do Submerged Taliks Refreeze?
Journal of Geophysical Research: Earth Surface ( IF 3.5 ) Pub Date : 2020-07-20 , DOI: 10.1029/2019jf005424
Michael Angelopoulos 1, 2 , Paul Overduin 1 , Sebastian Westermann 3 , Jens Tronicke 2 , Jens Strauss 1 , Lutz Schirrmeister 1 , Boris K. Biskaborn 1 , Susanne Liebner 4, 5 , Georgii Maximov 6 , Mikhail N. Grigoriev 6 , Guido Grosse 1, 2
Affiliation  

As the Arctic coast erodes, it drains thermokarst lakes, transforming them into lagoons, and, eventually, integrates them into subsea permafrost. Lagoons represent the first stage of a thermokarst lake transition to a marine setting and possibly more saline and colder upper boundary conditions. In this research, borehole data, electrical resistivity surveying, and modeling of heat and salt diffusion were carried out at Polar Fox Lagoon on the Bykovsky Peninsula, Siberia. Polar Fox Lagoon is a seasonally isolated water body connected to Tiksi Bay through a channel, leading to hypersaline waters under the ice cover. The boreholes in the center of the lagoon revealed floating ice and a saline cryotic bed underlain by a saline cryotic talik, a thin ice‐bearing permafrost layer, and unfrozen ground. The bathymetry showed that most of the lagoon had bedfast ice in spring. In bedfast ice areas, the electrical resistivity profiles suggested that an unfrozen saline layer was underlain by a thick layer of refrozen talik. The modeling showed that thermokarst lake taliks can refreeze when submerged in saltwater with mean annual bottom water temperatures below or slightly above 0°C. This occurs, because the top‐down chemical degradation of newly formed ice‐bearing permafrost is slower than the refreezing of the talik. Hence, lagoons may precondition taliks with a layer of ice‐bearing permafrost before encroachment by the sea, and this frozen layer may act as a cap on gas migration out of the underlying talik.

中文翻译:

西伯利亚东部的喀斯特湖到泻湖过渡:淹没的塔利克斯会重新冻结吗?

随着北极海岸的侵蚀,它排泄了喀斯特地热湖,将其转变为泻湖,最终将其整合到海底多年冻土中。泻湖代表了热喀斯特湖过渡到海洋环境的第一阶段,可能是更多的盐分和较冷的上边界条件。在这项研究中,在西伯利亚Bykovsky半岛的Polar Fox泻湖进行了井眼数据,电阻率测量以及热量和盐分扩散的建模。北极狐泻湖是一个季节性隔离的水体,通过一条通道与提克西湾相连,导致冰盖下的超咸水。泻湖中心的钻孔显示出漂浮的冰块和盐冷的冻土床,盐冻的冷石棉床下面铺着一层薄的含冰多年冻土层,并且没有结冰的地面。测深仪显示,大多数泻湖在春季都有坚冰。在河床冰层地区,电阻率曲线表明未冻结的盐层被厚厚的再冻滑石层覆盖。该模型表明,热喀斯特湖的滑石淹没在盐水中时,它们的年平均底水温度低于或略高于0°C时可以重新冻结。之所以会这样,是因为新形成的含冰多年冻土的自上而下的化学降解要比滑石的重新冻结慢。因此,泻湖可能在滑坡被海水侵蚀之前,先用滑冰的永久冻土层对滑石进行预处理,而这种冻结层可以作为气体从下滑石中迁移的上限。电阻率曲线表明,未冷冻的盐水层位于一厚的冷冻滑石层之下。该模型表明,热喀斯特湖的滑石淹没在盐水中时,它们的年平均底水温度低于或略高于0°C时可以重新冻结。之所以会这样,是因为新形成的含冰多年冻土的自上而下的化学降解要比滑石的重新冻结慢。因此,泻湖可能在滑坡被海水侵蚀之前,先用滑冰的永久冻土层对滑石进行预处理,而这种冻结层可以作为气体从下滑石中迁移的上限。电阻率曲线表明,未冷冻的盐水层位于一厚的冷冻滑石层之下。该模型表明,热喀斯特湖的滑石淹没在盐水中时,它们的年平均底水温度低于或略高于0°C时可以重新冻结。之所以会这样,是因为新形成的含冰多年冻土的自上而下的化学降解要比滑石的重新冻结慢。因此,泻湖可能在滑坡被海水侵蚀之前,先用滑冰的永久冻土层对滑石进行预处理,而这种冻结层可以作为气体从下滑石中迁移的上限。因为新形成的含冰多年冻土的自上而下的化学降解要比滑石的重新冻结慢。因此,泻湖可能在滑坡被海水侵蚀之前,先用滑冰的永久冻土层对滑石进行预处理,而这种冻结层可以作为气体从下滑石中迁移的上限。因为新形成的含冰多年冻土的自上而下的化学降解要比滑石的重新冻结慢。因此,泻湖可能在滑坡被海水侵蚀之前,先用滑冰的永久冻土层对滑石进行预处理,而这种冻结层可以作为气体从下滑石中迁移的上限。
更新日期:2020-07-20
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