Stratigraphy of Lake Vida, Antarctica: hydrologic implications of 27 m of ice

The Cryosphere

J. P.Warnock¹  A. E.Murray¹  N. E.Ostrom¹  B.Wagner¹  E.Kuhn¹  S. A.Arcone¹  P. T.Doran¹  F.Kenig¹  H. A.Dugan¹  C. H.Fritsen¹ 

DOI  :  10.5194/tc-9-439-2015

学科分类：地球科学(综合)

来源: Copernicus Publications

【 摘 要 】

Lake Vida, located in Victoria Valley, is one of the largest lakes in theMcMurdo dry valleys and is known to contain hypersaline liquid brine sealedbelow 16 m of freshwater ice. For the first time, Lake Vida was drilled to adepth of 27 m. Below 21 m the ice is marked by well-sorted sand layers upto 20 cm thick within a matrix of salty ice. From ice chemistry, isotopiccomposition of δ¹⁸O and δ²H, and ground penetrating radarprofiles, we conclude that the entire 27 m of ice formed from surfacerunoff and the sediment layers represent the accumulation of surfacedeposits. Radiocarbon and optically stimulated luminescence dating limit themaximum age of the lower ice to 6300 ¹⁴C yr BP. As the ice coverablated downwards during periods of low surface inflow, progressiveaccumulation of sediment layers insulated and preserved the ice and brinebeneath, analogous to the processes that preserve shallow ground ice. Therepetition of these sediment layers reveals hydrologic variability inVictoria Valley during the mid- to late Holocene. Lake Vida is an exemplarsite for understanding the preservation of subsurface brine, ice, and sedimentin a cold desert environment.

【 授权许可】

Unknown