2022-05-09 テキサス大学オースチン校(UT Austin)
東南極で新たに発見された氷点下の湖は、氷と気候変動の貴重な堆積物である可能性が高い A newly discovered subglacial lake in East Antarctica likely hosts a valuable sedimentary record of ice and climate change
Shuai Yan;Donald D. Blankenship;Jamin S. Greenbaum;Duncan A. Young;Lin Li;Anja Rutishauser;Jingxue Guo;Jason L. Roberts;Tas D. van Ommen;Martin J. Siegert;Bo Sun
Geology Published:May 09, 2022
The Princess Elizabeth Land sector of the East Antarctic Ice Sheet is a significant reservoir of grounded ice and is adjacent to regions that experienced great change during Quaternary glacial cycles and Pliocene warm episodes. The existence of an extensive subglacial water system in Princess Elizabeth Land (to date only inferred from satellite imagery) bears the potential to significantly impact the thermal and kinematic conditions of the overlying ice sheet. We confirm the existence of a major subglacial lake, herein referred to as Lake Snow Eagle (LSE), for the first time using recently acquired aerogeophysical data. We systematically investigated LSE’s geological characteristics and bathymetry from two-dimensional geophysical inversion models. The inversion results suggest that LSE is located along a compressional geologic boundary, which provides reference for future characterization of the geologic and tectonic context of this region. We estimate LSE to be ~42 km in length and 370 km2 in area, making it one of the largest subglacial lakes in Antarctica. Additionally, the airborne ice-penetrating radar observations and geophysical inversions reveal a layer of unconsolidated water-saturated sediment around and at the bottom of LSE, which—given the ultralow rates of sedimentation expected in such environments—may archive valuable records of paleoenvironmental changes and the early history of East Antarctic Ice Sheet evolution in Princess Elizabeth Land.