A dynamic saline groundwater system mapped beneath an Antarctic ice stream
A dynamic saline groundwater system mapped beneath an Antarctic ice stream
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DOI：
10.1126/science.abm3301
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发表时间：
2022-05-06
期刊：
影响因子：
56.9
通讯作者：
Michaud, Alexander B.
中科院分区：
文献类型：
--
作者：
Gustafson, Chloe D.;Key, Kerry;Michaud, Alexander B.
南极洲的快速流动的冰流耗尽了冰盖，其速度受到冰下水系的调节。目前对这些水系统的了解仅限于冰床界面附近的浅部，但假设更深的地下水也可能影响冰流。在这里，我们使用大地电磁和被动地震数据从Whillans冰流，南极洲西部，提供深冰下地下水的第一次观测。我们的数据显示，在一个大于1毫米厚的沉积盆地中，地下水的体积比已知的冰下系统大一个数量级以上。垂直盐度梯度表明古海水之间的交流在深度和现代基础上的融水。我们的研究结果提供了新的约束冰下水系统，影响冰流和冰下生态地球化学过程。
Antarctica's fast-flowing ice streams drain the ice sheet, with their velocity modulated by subglacial water systems. Current knowledge of these water systems is limited to the shallow portions near the ice-bed interface, but hypothesized deeper groundwater could also influence ice streaming. Here, we use magnetotelluric and passive seismic data from Whillans Ice Stream, West Antarctica, to provide the first observations of deep sub-ice stream groundwater. Our data reveal a volume of groundwater within a >1-kilometer-thick sedimentary basin that is more than an order of magnitude larger than the known subglacial system. A vertical salinity gradient indicates exchange between paleo seawater at depth and contemporary basal meltwater above. Our results provide new constraints for subglacial water systems that affect ice streaming and subglacial biogeochemical processes.