Subglacial Lakes In Antarctica Research Articles

Constraints on hydrothermal processes and water exchange in Lake Vostok from helium isotopes.

Lake Vostok, the largest subglacial lake in Antarctica, is covered by the East Antarctic ice sheet, which varies in thickness between 3,750 and 4,100 m (ref. 1). At a depth of 3,539 m in the drill hole at Vostok station, sharp changes in stable isotopes and the gas content of the ice delineate the boundary between glacier ice and ice accreted through re-freezing of lake water. Unlike most gases, helium can be incorporated into the crystal structure of ice during freezing, making helium isotopes in the accreted ice a valuable source of information on lake environment. Here we present helium isotope measurements from the deep section of the Vostok ice core that encompasses the boundary between the glacier ice and accreted ice, showing that the accreted ice is enriched by a helium source with a radiogenic isotope signature typical of an old continental province. This result rules out any significant hydrothermal energy input into the lake from high-enthalpy mantle processes, which would be expected to produce a much higher 3He/4He ratio. Based on the average helium flux for continental areas, the helium budget of the lake leads to a renewal time of the lake of the order of 5,000 years.

Lake Vostok - the International Challenge

In the last decade the notion of large subglacial lakes in Antarctica has attracted increasing attention. Lake Vostok is by far the largest of approximately 63 subglacial lakes now known in Antarctica, and the one about which most is known. The possible exploration of Lake Vostok was the subject of a very successful workshop held in Cambridge, UK, in September, 1999, sponsored by the Scientific Committee on Antarctic Research (SCAR) with the support of many others, and organized and hosted by the British Antarctic Survey.