Lake Vostok behaves like a ‘captured lake’ and may be near to creating an Antarctic jökulhlaup

ABSTRACT. The most well known sub-glacial lake is probably Grímsvötn under Vatnajökul, Iceland, from where jökulhlaups regularly burst forth. It is created by thermal melting under the ice cap. The Antarctic Lake Vostok, on the other hand, is considered to be located over a region with normal geothermal heat transfer, where it can exist because the ice is so thick that its base is at the pressure melting point. This makes it a candidate for testing the Captured Ice Shelf (CIS) hypothesis, which states that the motion of a totally confined ice shelf creates a hydrostatic seal in the form of an ice rim over the threshold. The CIS hypothesis may offer a source of water for the controversial Laurentian jökulhlaups inferred from field data, implicated in dramatic climatic changes. Here I show that Lake Vostok agrees with the hypothesis, and that it may be on the verge of a jökulhlaup, which could create an ice stream and regional downdraw. The result also implies that the lake may well be of pre-glacial origin, and that it may have experienced jökulhlaups also during previous interglacials.

The last paragraph of the article reads:

"The most profound implications of the CIS hypothesis are, however, predicted to come in our understanding of ice sheet dynamics during the Ice Ages. The possibility of a giant Laurentian CIS appears worth examining, as it might explain observed rapid climatic fluctuations, sudden transgressions, and inferred mega-scale sub-glacial outburst floods."

Comment to “Outburst flooding and the initiation of ice-stream surges in response to climatic cooling: A hypothesis”. Ulf Erlingsson. Geomorphology 86(1-2):214-216 (2007). [Abstract]

Lake Vostok behaves like a ‘captured lake’ and may be near to creating an Antarctic jökulhlaup. Ulf Erlingsson. Geogr. Ann. 88A(1):1-7 (2006). [ Abstract | pdf ]

Measurements and Calculations of Sedimentation in a Flushed Reservoir Resulting in a Sediment Budget. Regulated Rivers: Research and Management 16:279-306 (2000; Margareta B. Jansson, Ulf Erlingsson). [ Abstract | pdf ]

Development of Methods for Nearshore Sediment Transport and Sorting Studies as Applied in Southernmost Sweden, Baltic Sea. Ulf Erlingsson. J. Coastal Res. Special Issue 26:107-114 (1998).

The 'Captured Ice Shelf' hypothesis and its applicability to the Weichselian glaciation. Ulf Erlingsson. Geogr. Ann. 76A(1):1-12 (1994). [ pdf | doc ]

A computer model along a flow-line of an Ice Dome-'Captured Ice Shelf'. Ulf Erlingsson. Geogr. Ann. 76A(1):13-24 (1994). [ pdf | doc | CIS.mov ]

The Submarine Morphology of Surtsey Volcanic Group. Surtsey Res. Progress Rep. X:45-56 (1992; John O. Norrman, Ulf Erlingsson). [ pdf ]

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