Glacial Lake Victoria, a high‐level Antarctic Lake inferred from lacustrine deposits in Victoria Valley

Abstract

We present evidence of a large lake (Glacial Lake Victoria) that existed in Victoria Valley in the dry valleys region of Antarctica between at least 20 000 and 8600 14 C yr BP. At its highstands, Glacial Lake Victoria covered 100 km 2 and was ca. 200 m deep. The chronology for lake-level changes comes from 87 AMS radiocarbon dates of lacustrine algae preserved in deltas and glaciolacustrine deposits that extend up to 185 m above present-day lakes on the valley floor. The existence of Glacial Lake Victoria, as well as other large lakes in the dry valleys, indicates a climate regime significantly different from that of today at the last glacial maximum and in the early Holocene.

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

“…However, the radiocarbon dates impart a maximum age constraint on the ice, as it is almost impossible that samples were contaminated by young carbon, and indicate the top 27 m of ice formed after 6300 14 C yr BP. This aligns with the geomorphic reconstructions that indicate that Victoria Valley was filled with a deep (> 200 m) glacial lake prior to 8600 yr 14 C BP (Hall et al, 2002(Hall et al, , 2010, and the Ross Ice Shelf retreated from the mouth of the dry valleys between 6500 and 8340 14 C yr BP (Hall and Denton, 2000). Furthermore, it may be that the ice cover originated much later, as radiocarbon dates of the dissolved organic carbon fractions in the Lake Vida brine date between 2955 and 4150 14 C yr BP (Murray et al, 2012).…”

“…In Victoria Valley, it is theorized that the Lake Vida basin was occupied by a 200 m deep glacial lake 8600 14 C yr BP (Hall et al, 2002), after which lake levels began to decline. This lake is inferred to have had a water column (likely with an ice cover) that permitted sedimentation and led to the lacustrine deposits seen on the landscape today.…”

Surficial geology and geomorphology of eastern and central Wright Valley, Antarctica

“…The facts that Doorly drift consists only of glaciolacustrine sediments and that well-preserved deposits of infinite radiocarbon age exist only 1.5 km in front of the glacier margin suggest that Wright Lower Glacier was close to or inside of its present-day position at the LGM. A similar situation exists in adjacent Victoria Valley, where Victoria Lower Glacier was less extensive at the LGM (Chinn, 1987;Hall et al, 2002). In contrast, the coastal margin of the Wilson Piedmont Glacier expanded at the LGM, advancing over Marble and Gneiss Points and merging with the grounded Ross Sea ice sheet offshore .…”

Antarctic lakes suggest millennial reorganizations of Southern Hemisphere atmospheric and oceanic circulation

“…We obtained radiocarbon ages for the algal samples (Table S1) (8,10,12,(42)(43)(44). Approximately one third of the dates are conventional ages, run by M. Stuiver at the University of Washington in the 1970s and 1980s; the large errors on some of these samples reflect the difficulty in finding sufficient algae for this method.…”