Protozooplankton and Microzooplankton Ecology in Lakes of the Dry Valleys, Southern Victoria Land

2013 ◽  
pp. 255-267 ◽  
Author(s):  
Mark R. James ◽  
Julie A. Hall ◽  
Johanna A. Laybourn-Parry
Keyword(s):  
Dry Valleys ◽  
Victoria Land

scholarly journals Large Salt Beds on the Surface of the Ross Ice Shelf Near Black Island, Antarctica

1981 ◽  
Vol 27 (95) ◽  
pp. 11-18 ◽  
Author(s):  
Howard Thomas Brady ◽  
Barry Batts
Keyword(s):  
Thin Layer ◽  
Dry Valleys ◽  
Ice Shelf ◽  
Mcmurdo Sound ◽  
Extensive System ◽  
Ross Ice Shelf ◽  
Victoria Land ◽  
Marine Algal ◽  
Algal Mat

AbstractAn extensive system of mirabilite (Na2SO4· 10H2O) beds has been mapped on the Ross Ice Shelf near Black Island. The salt beds are normally underlain by a thin layer of mud and their surface is covered by a non-marine algal mat and boulder lag. These authors suggest the salt has been formed by the displacement of sub-ice-shelf brines to the ice-shelf surface. Evidence also suggests that other terrestrial mirabilite beds in the McMurdo Sound area were formed in the same manner and deposited by the Ross Ice Shelf during its Wisconsin retreat from McMurdo Sound. Mirabilite salt in the dry valleys, southern Victoria Land, may have also originated from melt waters which dissolved ice-shelf mirabilite beds.

Limited Pliocene/Pleistocene glaciation in Deep Freeze Range, northern Victoria Land, Antarctica, derived from in situ cosmogenic nuclides

2003 ◽  
Vol 15 (4) ◽  
pp. 493-502 ◽  
Author(s):  
PETER OBERHOLZER ◽  
CARLO BARONI ◽  
JOERG M. SCHAEFER ◽  
GIUSEPPE OROMBELLI ◽  
SUSAN IVY OCHS ◽  
...  
Keyword(s):  
Cosmogenic Nuclides ◽  
Dry Valleys ◽  
Climate Regime ◽  
Erosion Rates ◽  
Terra Nova Bay ◽  
New Information ◽  
Victoria Land ◽  
Exposure Ages ◽  
Middle Pliocene

The question of how stable the climate in Antarctica has been during the last few million years compared to the rest of the planet is still controversial. This study attempts to add new information to the discussion by reconstructing the timing and spatial extent of glacial advances in northern Victoria Land over tens of thousands to millions of years. In Terra Nova Bay region, surface exposure ages and erosion rates of glacially rounded bedrock and glacial erratics have been determined using the cosmogenic nuclides 3He, 10Be and 21Ne. Three morphological units have been analysed. They yield minimum ages of 11 to 34 ka, 309 ka, and 2.6 Ma, respectively. Erosion rates were as low as 20 cm Ma−1 since middle Pliocene time. Taking erosion into account, the oldest surface is 5.3 Ma old. Pleistocene glacier advances had considerable extent, reaching up to 780 m above modern ice levels, but have been restricted to the valleys since at least mid-Pliocene. The existence of landscapes of mid-Pliocene age in northern Victoria Land implies that the climatic stability of the McMurdo Dry Valleys is not unique within the Transantarctic Mountains, but rather the expression of a constantly cold and hyperarid climate regime in entire Victoria Land.

Suite subdivision and petrological evolution of granitoids from the Taylor Valley and Ferrar Glacier region, south Victoria Land

1992 ◽  
Vol 4 (1) ◽  
pp. 71-87 ◽  
Author(s):  
Robert W. Smillie
Keyword(s):  
Upper Mantle ◽  
Structural Control ◽  
Geological Mapping ◽  
Dry Valleys ◽  
Crustal Extension ◽  
Calc Alkaline ◽  
Taylor Valley ◽  
Victoria Land ◽  
Early Palaeozoic ◽  
Dyke Swarms

Detailed geological mapping and geochemical analysis of early Palaeozoic granitoid plutons and dykes from the Taylor Valley and Ferrar Glacier region in south Victoria Land reveal two distinct suites. This suite subdivision-approach is a departure from previous lithology-based schemes and can be applied elsewhere in south Victoria Land. The older calc-alkaline Dry Valleys 1 suite is dominated by the compositionally variable Bonney Pluton, a flow-foliated concordant pluton with an inferred length of over 100 km. Plutons of this suite are elongate in a NW-SE direction and appear to have been subjected to major structural control during their emplacement. The younger alkali-calcic Dry Valleys 2 suite comprises discordant plutons and numerous dyke swarms with complex age relationships. Field characteristics of this suite indicate that it was passively emplaced into fractures at higher levels in the crust than the Dry Valleys 1 suite. Whole-rock geochemistry confirms this suite subdivision based on field relationships and indicates that the two suites were derived from different parent magmas by fractional crystallization. The Dry Valleys 1 suite resembles Cordilleran I-type granitoids and is inferred to be derived from partial melting of the upper mantle and/or lower crust above an ancient subduction zone. The Dry Valleys 2 suite resembles Caledonian I-type granitoids and may have resulted from a later episode of crustal extension.

scholarly journals Formation of thrust-block moraines at the margins of dry-based glaciers, south Victoria Land, Antarctica

1996 ◽  
Vol 22 ◽  
pp. 68-74 ◽  
Author(s):  
Sean J. Fitzsimons
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Freezing Point ◽  
Water Pressure ◽  
Lacustrine Sediment ◽  
Dry Valleys ◽  
Bed Deformation ◽  
Sedimentary Structures ◽  
Victoria Land ◽  
Subglacial Meltwater

Several dry-based alpine glaciers in the Dry Valleys of south Victoria Land, Antarctica, have prominent end moraines. Examination of their morphology, structure and sedimentology shows they consist of blocks of sand, gravel and organic silt within which sedimentary structures unrelated to entrainment and transportation by ice are well preserved. The nature and preservation of sedimentary structures, together with the presence of algae mats in the sediment, suggest formation by proglacial entrainment, transportation and deposition of frozen blocks of lacustrine sediment. Previous explanations of the formation of thrust-block moraines, including those that stress the importance of elevated pore-water pressure and Weertman’s ice-debris accretion hypothesis, depend on the presence of subglacial meltwater or the 0° C isotherm being situated close to the glacier bed. These models appear inappropriate for cold, dry-based glaciers because their basal temperatures are well below freezing point and they rest on deep permafrost. Three alternative models for the formation of thrust-block moraines at the margins of dry-based glaciers are examined in this paper: block entrainment of sediment associated with frozen-bed deformation; entrainment by overriding and accretion of marginal-ice and debris aprons; and transient wet-based conditions associated with glaciers flowing into ice-marginal lakes.

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