The borehole at the southern par t of subglacial Lake Vostok has been drilled into an ice lay er ... more The borehole at the southern par t of subglacial Lake Vostok has been drilled into an ice lay er that has been refrozen from the lake water. This ice layer contains random sediment inclusions, eight of which have been studied using state-of the-art analytical techniques. Six inclusions comprise soft aggregates consisting mainly of clay-mica minerals and micron-sized quartz grains while
Multichannel seismic data from the eastern parts of the Riiser-Larsen Sea have been analyzed with... more Multichannel seismic data from the eastern parts of the Riiser-Larsen Sea have been analyzed with a sequence stratigraphic approach. The data set covers a wide bathymetric range from the lower continental slope to the abyssal plain. Four different sequences (termed RLS-A to RLS-D, from deepest to shallowest) are recognized within the sedimentary section. The RLS-A sequence encompasses the inferred pre-glacial
... involve both sediment gravity flows and contour currents ( [Hollister and Elder, 1969] , [And... more ... involve both sediment gravity flows and contour currents ( [Hollister and Elder, 1969] , [Anderson et al., 1979] and [Wright and Anderson, 1982] ), and are characterized by differing styles of sedimentation and sedimentary architectures ( [Kuvaas and Kristoffersen, 1991] , [Kuvaas ...
Developments in Earth and Environmental Sciences, 2008
Seismic stratigraphic studies and scientific drilling of the Antarctic continental margin have yi... more Seismic stratigraphic studies and scientific drilling of the Antarctic continental margin have yielded clues to the evolution of Cenozoic climates, depositional paleoenvironments and paleoceanographic conditions. This paper draws on studies of the former Antarctic Offshore Stratigraphy Project and others to review the geomorphic and lithostratigraphic offshore features that give insights into the long-duration (m.y.) and short-term (k.y.) changes that document
Multichannel seismic reflection data from the Cosmonaut Sea margin of East Antarctica have been i... more Multichannel seismic reflection data from the Cosmonaut Sea margin of East Antarctica have been interpreted in terms of depositional processes on the continental rise. A major sediment lens is present below the upper continental rise along the entire Cosmonaut Sea margin. The lens probably consists of sediments supplied from the shelf and slope, being constantly reworked by westward flowing bottom
Lake Vostok is located at the edge of vast upland of East Antarctic (Precambrian) Crystalline Shi... more Lake Vostok is located at the edge of vast upland of East Antarctic (Precambrian) Crystalline Shield and represents a typical extensionally-induced intracontinental rift zone. Type indicators of rift nature are: width (60-80 km) and length (about 300 km) of the lake depression; several (3-5) kilometers of sediments (modeled from gravity data) infilling the lake graben, considerable amplitudes of faults bounding the lake (up to 2 km in bedrock relief and in excess of 5 km in basement topography), half-graben-like structures (rotated crustal blocks) at flanks of the lake traceable to crustal extension; along-strike segmentation of the depression (the presence of two isolated basins, recognized from seismic and gravity data); knee-shaped spatial configuration of the lake and existence of diagonal fractures (displayed in bedrock topography) normally nascent in conditions of tensional stress. The rift graben of Lake Vostok is considered to be a part (branch) of more spacious rift system,...
During two Antarctic ficld seasons, western Dronning Maud Land and eastern Coats Land were covere... more During two Antarctic ficld seasons, western Dronning Maud Land and eastern Coats Land were covered by airborne radio-ccho sounding surveys, conducted in combination with magnetic and gravity measurements along the 50 NW-SE-directed tracks, totalling about 11 200 km and spaced 20 km apart. The data were collected in analogue form and then processed to compile ice surface, ice thickness and bedrock topography maps in I : 2 500 000 scale which gave a new and/or more detailed information on the region than previous compilations. The maps show that western Dronning Maud Land is domina ted by a large mountainous area with altitudes up to 2800 m ineluding rock outcrops of Annandagstoppane, Borgmassivet, Kirwanveggen and Heimefrontfjella. Upland terrains of Vestfjella and Mannefallknausane have an isolated position and are surrounded by a plain with bedrock depressions of 600 m deep below sea level. A narrow strip of north-eastern Coats Land studied by radio-echo soundings exhibits a smooth...
Ribosomal RNA gene sequence data indicates that both glacial and accretion (re-frozen lake water)... more Ribosomal RNA gene sequence data indicates that both glacial and accretion (re-frozen lake water) Vostok ice samples are exceedingly clean in regard to microbe content. This makes ice sample decontamination (from drilling fluid and human activity) a crucial issue. The 4km thick ice sheet and the 0.8 Ma transit time to reach the lake make a severe constrain on the transit of microbes. At present no any evidence for revived microbes is reported for deep glacial Vostok ice core. This is probably due to the presence of liquid water films at the grain boundaries and the dissolved oxygen which both may be harmful for microbial cells/DNA survival. Even more horrible conditions are faced by microorganisms when they are released in the open lake since oxygen is expected to be in excess here (up to 1.3 g/l) making the open lake a 'cold oxygen reactor'. Such a high oxygen tension can be highly toxic and even chemically destructive for living cells and DNA. Indeed, until now we have no ...
4 Polar Marine Geosurvey Expedition (PMGE), St. Petersburg, Russia (antarctida@peterlink.ru) Summ... more 4 Polar Marine Geosurvey Expedition (PMGE), St. Petersburg, Russia (antarctida@peterlink.ru) Summary Cretaceous Gondwana breakup between East Antarctica and India was accompanied or followed by emplacement of the Kerguelen Plateau Large Igneous Province (LIP), north of Prydz Bay. In 2007, deep crustal seismic and helicopter-magnetic surveys were conducted along a corridor between the southern Kerguelen Plateau and the outermost Prydz Bay. These surveys were designed to investigate breakup processes and the effect that the igneous activity had on the formation of the passive margin of East Antarctica and also the apparent oceanic crust between the plateau and the Antarctic margin in the Princess Elizabeth Trough (PET). Preliminary data analysis and modeling reveal a wide zone of highly extended continental crust on the margin of Mac.Robertson Land and that the southernmost Kerguelen Plateau is generally of continental affinity. Seismic velocities and magnetic data indicate an oceanic...
The Lambert Graben is a deep crustal depression currently occupied by the Lambert Glacier and its... more The Lambert Graben is a deep crustal depression currently occupied by the Lambert Glacier and its tributaries. The mapped area extends from 76°S to 66°S and trends in a north north-easterly direction, paralleling the direction of the graben. It incorporates the southern and northern Prince Charles Mountains (PCM) of Mac. Robertson Land, outcrops along the Ingrid Christensen Coast to the Vestfold Hills, and Prydz Bay including the continental shelf. The regional geology is outlined by TIN91, and references therein, and summarised below. The PCM are one of the greatest concentrations of exposed bedrock in the interior of Antarctica. Systematic investigation of the region began in 1954, and has continued to present day, involving geologists from Australia, Great Britain, Germany, Holland, Russia and China. The PCM contain rock units ranging in age from Archaean to Recent. The predominant rock types are Proterozoic upper amphibolite to granulite facies orthogneiss and paragneiss, intrus...
Geophysical investigations carried on the East Antarctic margin between 25E and 70E by RV "A... more Geophysical investigations carried on the East Antarctic margin between 25E and 70E by RV "Akademik Alexander Karpinsky" (Russian Antarctic Expedition) showed magnetic anomaly consequence from M16 to M0 (with half spreading rate between 1.4 and 2.7 cm/yr) for the eastern Riiser-Larsen Sea (which is very similar to that of western Riiser-Larsen Sea) and from M11A to M8 (with half spreading
Study of fine mineral particles detected on the surface congelation ice core from a depth 3768.4-... more Study of fine mineral particles detected on the surface congelation ice core from a depth 3768.4-3769.3 m, indicates they represented 85-90% iron oxide with nickel, zinc, and copper admixture and have a technological origin. Their formation is probably due contact of water with the metal drill bit. The remaining 5-10% particles are predominantly silt and clay silicates with dimension up to 70 mkm. There are particles of quartz up to 30 microns and calcium carbonate (calcite identified) with size about 10 mkm in the cores of frozen water. Calcium carbonate may crystallize after water penetration into the well hole. Based on the obtained data the following main conclusions are (all of them refer to the top of the water column at Vostok Station): 1) on the basis of an extremely small amount of suspended particles in water, which went into well, we can conclude that the lake has a very high transparency; 2) rapid oxidation of the drill shows relatively high oxygen content in the water o...
The borehole at the southern par t of subglacial Lake Vostok has been drilled into an ice lay er ... more The borehole at the southern par t of subglacial Lake Vostok has been drilled into an ice lay er that has been refrozen from the lake water. This ice layer contains random sediment inclusions, eight of which have been studied using state-of the-art analytical techniques. Six inclusions comprise soft aggregates consisting mainly of clay-mica minerals and micron-sized quartz grains while
Multichannel seismic data from the eastern parts of the Riiser-Larsen Sea have been analyzed with... more Multichannel seismic data from the eastern parts of the Riiser-Larsen Sea have been analyzed with a sequence stratigraphic approach. The data set covers a wide bathymetric range from the lower continental slope to the abyssal plain. Four different sequences (termed RLS-A to RLS-D, from deepest to shallowest) are recognized within the sedimentary section. The RLS-A sequence encompasses the inferred pre-glacial
... involve both sediment gravity flows and contour currents ( [Hollister and Elder, 1969] , [And... more ... involve both sediment gravity flows and contour currents ( [Hollister and Elder, 1969] , [Anderson et al., 1979] and [Wright and Anderson, 1982] ), and are characterized by differing styles of sedimentation and sedimentary architectures ( [Kuvaas and Kristoffersen, 1991] , [Kuvaas ...
Developments in Earth and Environmental Sciences, 2008
Seismic stratigraphic studies and scientific drilling of the Antarctic continental margin have yi... more Seismic stratigraphic studies and scientific drilling of the Antarctic continental margin have yielded clues to the evolution of Cenozoic climates, depositional paleoenvironments and paleoceanographic conditions. This paper draws on studies of the former Antarctic Offshore Stratigraphy Project and others to review the geomorphic and lithostratigraphic offshore features that give insights into the long-duration (m.y.) and short-term (k.y.) changes that document
Multichannel seismic reflection data from the Cosmonaut Sea margin of East Antarctica have been i... more Multichannel seismic reflection data from the Cosmonaut Sea margin of East Antarctica have been interpreted in terms of depositional processes on the continental rise. A major sediment lens is present below the upper continental rise along the entire Cosmonaut Sea margin. The lens probably consists of sediments supplied from the shelf and slope, being constantly reworked by westward flowing bottom
Lake Vostok is located at the edge of vast upland of East Antarctic (Precambrian) Crystalline Shi... more Lake Vostok is located at the edge of vast upland of East Antarctic (Precambrian) Crystalline Shield and represents a typical extensionally-induced intracontinental rift zone. Type indicators of rift nature are: width (60-80 km) and length (about 300 km) of the lake depression; several (3-5) kilometers of sediments (modeled from gravity data) infilling the lake graben, considerable amplitudes of faults bounding the lake (up to 2 km in bedrock relief and in excess of 5 km in basement topography), half-graben-like structures (rotated crustal blocks) at flanks of the lake traceable to crustal extension; along-strike segmentation of the depression (the presence of two isolated basins, recognized from seismic and gravity data); knee-shaped spatial configuration of the lake and existence of diagonal fractures (displayed in bedrock topography) normally nascent in conditions of tensional stress. The rift graben of Lake Vostok is considered to be a part (branch) of more spacious rift system,...
During two Antarctic ficld seasons, western Dronning Maud Land and eastern Coats Land were covere... more During two Antarctic ficld seasons, western Dronning Maud Land and eastern Coats Land were covered by airborne radio-ccho sounding surveys, conducted in combination with magnetic and gravity measurements along the 50 NW-SE-directed tracks, totalling about 11 200 km and spaced 20 km apart. The data were collected in analogue form and then processed to compile ice surface, ice thickness and bedrock topography maps in I : 2 500 000 scale which gave a new and/or more detailed information on the region than previous compilations. The maps show that western Dronning Maud Land is domina ted by a large mountainous area with altitudes up to 2800 m ineluding rock outcrops of Annandagstoppane, Borgmassivet, Kirwanveggen and Heimefrontfjella. Upland terrains of Vestfjella and Mannefallknausane have an isolated position and are surrounded by a plain with bedrock depressions of 600 m deep below sea level. A narrow strip of north-eastern Coats Land studied by radio-echo soundings exhibits a smooth...
Ribosomal RNA gene sequence data indicates that both glacial and accretion (re-frozen lake water)... more Ribosomal RNA gene sequence data indicates that both glacial and accretion (re-frozen lake water) Vostok ice samples are exceedingly clean in regard to microbe content. This makes ice sample decontamination (from drilling fluid and human activity) a crucial issue. The 4km thick ice sheet and the 0.8 Ma transit time to reach the lake make a severe constrain on the transit of microbes. At present no any evidence for revived microbes is reported for deep glacial Vostok ice core. This is probably due to the presence of liquid water films at the grain boundaries and the dissolved oxygen which both may be harmful for microbial cells/DNA survival. Even more horrible conditions are faced by microorganisms when they are released in the open lake since oxygen is expected to be in excess here (up to 1.3 g/l) making the open lake a 'cold oxygen reactor'. Such a high oxygen tension can be highly toxic and even chemically destructive for living cells and DNA. Indeed, until now we have no ...
4 Polar Marine Geosurvey Expedition (PMGE), St. Petersburg, Russia (antarctida@peterlink.ru) Summ... more 4 Polar Marine Geosurvey Expedition (PMGE), St. Petersburg, Russia (antarctida@peterlink.ru) Summary Cretaceous Gondwana breakup between East Antarctica and India was accompanied or followed by emplacement of the Kerguelen Plateau Large Igneous Province (LIP), north of Prydz Bay. In 2007, deep crustal seismic and helicopter-magnetic surveys were conducted along a corridor between the southern Kerguelen Plateau and the outermost Prydz Bay. These surveys were designed to investigate breakup processes and the effect that the igneous activity had on the formation of the passive margin of East Antarctica and also the apparent oceanic crust between the plateau and the Antarctic margin in the Princess Elizabeth Trough (PET). Preliminary data analysis and modeling reveal a wide zone of highly extended continental crust on the margin of Mac.Robertson Land and that the southernmost Kerguelen Plateau is generally of continental affinity. Seismic velocities and magnetic data indicate an oceanic...
The Lambert Graben is a deep crustal depression currently occupied by the Lambert Glacier and its... more The Lambert Graben is a deep crustal depression currently occupied by the Lambert Glacier and its tributaries. The mapped area extends from 76°S to 66°S and trends in a north north-easterly direction, paralleling the direction of the graben. It incorporates the southern and northern Prince Charles Mountains (PCM) of Mac. Robertson Land, outcrops along the Ingrid Christensen Coast to the Vestfold Hills, and Prydz Bay including the continental shelf. The regional geology is outlined by TIN91, and references therein, and summarised below. The PCM are one of the greatest concentrations of exposed bedrock in the interior of Antarctica. Systematic investigation of the region began in 1954, and has continued to present day, involving geologists from Australia, Great Britain, Germany, Holland, Russia and China. The PCM contain rock units ranging in age from Archaean to Recent. The predominant rock types are Proterozoic upper amphibolite to granulite facies orthogneiss and paragneiss, intrus...
Geophysical investigations carried on the East Antarctic margin between 25E and 70E by RV "A... more Geophysical investigations carried on the East Antarctic margin between 25E and 70E by RV "Akademik Alexander Karpinsky" (Russian Antarctic Expedition) showed magnetic anomaly consequence from M16 to M0 (with half spreading rate between 1.4 and 2.7 cm/yr) for the eastern Riiser-Larsen Sea (which is very similar to that of western Riiser-Larsen Sea) and from M11A to M8 (with half spreading
Study of fine mineral particles detected on the surface congelation ice core from a depth 3768.4-... more Study of fine mineral particles detected on the surface congelation ice core from a depth 3768.4-3769.3 m, indicates they represented 85-90% iron oxide with nickel, zinc, and copper admixture and have a technological origin. Their formation is probably due contact of water with the metal drill bit. The remaining 5-10% particles are predominantly silt and clay silicates with dimension up to 70 mkm. There are particles of quartz up to 30 microns and calcium carbonate (calcite identified) with size about 10 mkm in the cores of frozen water. Calcium carbonate may crystallize after water penetration into the well hole. Based on the obtained data the following main conclusions are (all of them refer to the top of the water column at Vostok Station): 1) on the basis of an extremely small amount of suspended particles in water, which went into well, we can conclude that the lake has a very high transparency; 2) rapid oxidation of the drill shows relatively high oxygen content in the water o...
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