![]() Gabrielli, Paolo Planchon, Frederic Barbante, Carlo Boutron, Claude F. Ultra-low rare earth element content in accreted ice from sub-glacial Lake Vostok, Antarctica Subsequent consolidation of the developed loose ice crystals results in the accretion of ice to the ceiling of the lake. The characteristics of the isotopic composition of the lake ice indicate that ice formation in Lake Vostok occurred by frazil ice crystal generation due to supercooling as a consequence of rising waters and a possible contrast in water salinity. Possible implications for the water circulation of Lake Vostok are developed. A small lake water salinity can be reasonably deduced from the chemical data. The investigation of chemical and isotopic properties in the lake ice from the Vostok ice core gives clues to the mechanisms involved in ice formation within the lake. Ice formation in subglacial Lake Vostok, Central Antarctica The tectonic processes provided the space for a unique habitat and recent minor tectonic activity could have the potential to introduce small, but significant amounts of thermal energy into the lake. Lake Vostok is a tectonically controlled subglacial lake. The physiographic setting of the lake has important consequences for the ice flow and thus the melting and freezing pattern and the lake's circulation. Magnetic and gravity data are distinct east and west of the lake, as is the roughness of the subglacial topography. Our data show that Lake Vostok is located along a major geological boundary. The ice flow across the lake and the landscape setting are closely linked to the geological origin of Lake Vostok. We present the first comprehensive maps of ice surface, ice thickness and subglacial topography around Lake Vostok. Thus the geological origin of Lake Vostok is a critical boundary condition for the subglacial ecosystem. ![]() The influx of thermal energy, however, is limited to contributions from below. Melting and freezing at the base of the ice sheet, which slowly flows across the lake, controls the flux of water, biota and sediment particles through the lake. Lake Vostok, located beneath more than 4 km of ice in the middle of East Antarctica, is a unique subglacial habitat and may contain microorganisms with distinct adaptations to such an extreme environment. ![]() Ice cover, landscape setting, and geological framework of Lake Vostok, East Antarctica ![]()
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