Articles | Volume 9, issue 2
Research article
04 Mar 2015
Research article |  | 04 Mar 2015

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

H. A. Dugan, P. T. Doran, B. Wagner, F. Kenig, C. H. Fritsen, S. A. Arcone, E. Kuhn, N. E. Ostrom, J. P. Warnock, and A. E. Murray

Abstract. Lake Vida, located in Victoria Valley, is one of the largest lakes in the McMurdo dry valleys and is known to contain hypersaline liquid brine sealed below 16 m of freshwater ice. For the first time, Lake Vida was drilled to a depth of 27 m. Below 21 m the ice is marked by well-sorted sand layers up to 20 cm thick within a matrix of salty ice. From ice chemistry, isotopic composition of δ18O and δ2H, and ground penetrating radar profiles, we conclude that the entire 27 m of ice formed from surface runoff and the sediment layers represent the accumulation of surface deposits. Radiocarbon and optically stimulated luminescence dating limit the maximum age of the lower ice to 6300 14C yr BP. As the ice cover ablated downwards during periods of low surface inflow, progressive accumulation of sediment layers insulated and preserved the ice and brine beneath, analogous to the processes that preserve shallow ground ice. The repetition of these sediment layers reveals hydrologic variability in Victoria Valley during the mid- to late Holocene. Lake Vida is an exemplar site for understanding the preservation of subsurface brine, ice, and sediment in a cold desert environment.

Short summary
Lake Vida is one of the largest lakes in the McMurdo dry valleys, Antarctica, and has the thickest known ice cover of any lake on Earth. For the first time, Lake Vida was drilled to a depth of 27m. With depth the ice cover changes from freshwater ice to salty ice interspersed with thick sediment layers. It is hypothesized that the repetition of sediment layers in the ice will reveal climatic and hydrologic variability in the region over the last 1000--3000 years.