Research
Non-belspo (2000-ongoing)
Basal Ice at Lake Vostok
Project description
Our laboratory is actively involved
in the interpretation of the physico-chemical properties of the
basal ice of the Vostok ice core. A geochemical investigation
of the deepest part of the Vostok ice core between 3310 m, the
depth at which the palaeoenvironmental record present in the
ice above is lost, and the bottom of the core about 130 m above
subglacial Lake Vostok reveals two contrasted sections.
The upper section (3310- 3539 m depth) still consists of ice
of meteoric origin but subjected to widespread complex deformation.
This deformation has been analyzed in light of a δD- deuterium
excess diagram and information on microparticles, crystal sizes
and chemical elements distributions in that part of the core.
Such ice deformation occurred when the ice was still grounded
upstream from Vostok Station, in a region with subfreezing temperatures.
The lower section from 3539 m to the bottom of the core at3623
m depth is lake ice formed by freezing of subglacial Lake Vostok
waters. This is indicated by the isotopic properties (δD, δ180
and deuterium excess), by electrical conductivity measurements
(ECM), crystallography and gaz content of the ice. These ice
core data together with data on ionic chemistry favor an origin
of the lake ice by frazil ice generation in a supercooled (below
pressure melting point) water plume existing in the lake followed
by accretion and consolidation by subsequent freezing of the
host water.
Project team
Coordinator:
Prof Dr. Roland Souchez
Involved research group:
- Glaciology
lab-ULB
Tison Jean-Louis, Verbeke Véronique, Lelouchier Claire, El Amri Saïda - Laboratoire
des Sciences du Climat et de l’Environnement
CEA, Saclay, France - Laboratoire
de Glaciologie et de Géophysique de l’Environnement
Saint-Martin-D’Hères, France - Arctic
and Antarctic Research Institute
St. Petersburg, Russia
Involved Partners:
- Dr. J. Jouzel, Dr. P. Jean-Baptiste, Dr. F.
Vimeux, Dr. M. Stiévenard,
http://www-lsce.cea.fr/ - Dr. J.R. Petit, Dr. M. de Angelis, Dr. M. Legrand, Dr. J.-M.
Barnola, Dr. J. Simoes,
http://www-lgge.ujf-grenoble.fr/axes/contacts.shtml - Dr. V. Ya Lipenkov, Dr. J. Barkov,
http://www.aari.nw.ru/default_en.asp