Pico T, Mitrovica J X, Mix A C
Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138, USA.
Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA.
Sci Adv. 2020 Feb 26;6(9):eaay2935. doi: 10.1126/sciadv.aay2935. eCollection 2020 Feb.
During the Last Glacial Maximum, expansive continental ice sheets lowered globally averaged sea level ~130 m, exposing a land bridge at the Bering Strait. During the subsequent deglaciation, sea level rose rapidly and ultimately flooded the Bering Strait, linking the Arctic and Pacific Oceans. Observational records of the Bering Strait flooding have suggested two apparently contradictory scenarios for the timing of the reconnection. We reconcile these enigmatic datasets using gravitationally self-consistent sea-level simulations that vary the timing and geometry of ice retreat between the Laurentide and Cordilleran Ice Sheets to the southwest of the Bering Strait to fit observations of a two-phased flooding history. Assuming the datasets are robust, we demonstrate that their reconciliation requires a substantial melting of the Cordilleran and western Laurentide Ice Sheet from 13,000 to 11,500 years ago. This timing provides a freshwater source for the widely debated Younger Dryas cold episode (12,900 to 11,700 years ago).
在末次盛冰期，广袤的大陆冰盖使全球平均海平面下降了约130米，露出了白令海峡的陆桥。在随后的冰消期，海平面迅速上升，最终淹没了白令海峡，连接了北冰洋和太平洋。白令海峡淹没的观测记录显示了两种在重新连接时间上明显矛盾的情况。我们使用重力自洽海平面模拟来调和这些神秘的数据集，该模拟改变了白令海峡西南部劳伦泰德冰盖和科迪勒拉冰盖之间冰消退的时间和几何形状，以符合两阶段淹没历史的观测结果。假设这些数据集是可靠的，我们证明它们的调和需要科迪勒拉冰盖和劳伦泰德冰盖西部在13000至11500年前大量融化。这个时间为广受争议的新仙女木寒冷期（12900至11700年前）提供了一个淡水源。
