Salt weathering processes in the dry valley regions of South Victoria Land, Antarctica

1974 ◽  
Vol 11 (8) ◽  
pp. A164
Author(s):  
J.H. Johnston,
Keyword(s):  
Salt Weathering ◽  
Weathering Processes ◽  
Victoria Land ◽  
Dry Valley

The formation of silt from quartz dune sand by salt-weathering processes in deserts

1979 ◽  
Vol 2 (2) ◽  
pp. 105-112 ◽  
Author(s):  
A.S. Goudie ◽  
R.U. Cooke ◽  
J.C. Doornkamp
Keyword(s):  
Salt Weathering ◽  
Dune Sand ◽  
Weathering Processes

scholarly journals Ice-Sheet flow in the Vicinity of Southern Victoria Land, Antarctica: Implications for Glacial Chronology

1979 ◽  
Vol 24 (90) ◽  
pp. 483
Author(s):  
David J. Drewry
Keyword(s):  
Ice Sheet ◽  
East Antarctica ◽  
Small Surface ◽  
The North ◽  
Ice Surface ◽  
Glacial Chronology ◽  
Victoria Land ◽  
Dry Valley ◽  
Radio Echo Sounding ◽  
Taylor Glacier

Abstract Systematic radio echo-sounding during three seasons since 1971–72 has produced data on the configuration of the ice sheet in East Antarctica. In the sector extending inland from southern Victoria Land, the ice sheet exhibits a large ridge which drives ice towards David Glacier in the north and Mulock and Byrd Glaciers to the south. Within 100 km of the McMurdo dry-valley region soundings along ten sub-parallel lines (c. 10 km apart) provides detail on ice surface and flow patterns at the ridge tip. A small surface dome lies just inland of Taylor Glacier. The surface drops by 100 m or more before rising to join the major ridge in East Antarctica.

Benthic primary production in two perennially ice-covered Antarctic lakes: patterns of biomass accumulation with a model of community metabolism

2001 ◽  
Vol 13 (1) ◽  
pp. 18-27 ◽  
Author(s):  
I. Hawes ◽  
D. Moorhead ◽  
D. Sutherland ◽  
J. Schmeling ◽  
A.-M. Schwarz
Keyword(s):  
Microbial Mats ◽  
Carbon Fixation ◽  
Experimental Studies ◽  
Biomass Accumulation ◽  
Net Photosynthesis ◽  
Incident Radiation ◽  
Benthic Primary Production ◽  
Antarctic Lakes ◽  
Victoria Land ◽  
Dry Valley

A mathematical model was used to simulate interannual patterns of biomass accumulation within benthic microbial mats of two Antarctic lakes. Lakes Hoare and Vanda are in the Dry Valley region of Southern Victoria Land, and are both perennially ice covered. The model combines experimentally derived observations of light/photosynthesis relationships and rates of respiration of mats from a range of depths in these lakes, with data on incident radiation and the optical properties of the ice and water column. The model was used to estimate daily and annual production and, using measured carbon content, the potential vertical accumulation of the mats over a year. An annual pattern of photosynthesis was predicted for both lakes, with net production from October to February and net respiration at other times. Predicted rates and patterns of net photosynthesis were remarkably similar in the two lakes, despite differences in light climate: the ice of Lake Hoare transmits 1–4% incident radiation, whereas that of Lake Vanda transmits up to 20%. Maximum daily rates of 15–20 μg carbon cm−2 were predicted to occur at approximately 10 m depth in both lakes. Maximum annual rates of carbon fixation (at 10–12 m depth) in both lakes were c. 1.2 mg carbon cm−2 equating to approximately 0.1–4 mm vertical accumulation of mat each year. Experimental studies of microbial mats in the lakes revealed horizontal laminations of similar thickness to model estimates, supporting the hypothesis that these were annual layers. Differences between model estimates and observations were found in deeper water in Lake Vanda, where considerably more material accumulated than was predicted.

scholarly journals Weathering Processes and Mechanisms Caused by Capillary Waters and Pigeon Droppings on Porous Limestones

Minerals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 18
Author(s):  
David Benavente ◽  
Marli de Jongh ◽  
Juan Carlos Cañaveras
Keyword(s):  
Chemical Effect ◽  
Salt Weathering ◽  
Capillary Water ◽  
Material Loss ◽  
Weathering Processes ◽  
Geochemical Study ◽  
Pigeon Droppings ◽  
Deterioration Process ◽  
Dehydration Processes ◽  
Physical And Chemical

This investigation studies the physical and chemical effect of salt weathering on biocalcarenites and biocalcrudites in the Basilica of Our Lady of Succour (Aspe, Spain). Weathering patterns are the result of salty rising capillary water and water lixiviated from pigeon droppings. Surface modifications and features induced by material loss are observable in the monument. Formation of gypsum, hexahydrite, halite, aphthitalite and arcanite is associated with rising capillary water, and niter, hydroxyapatite, brushite, struvite, weddellite, oxammite and halite with pigeon droppings. Humberstonite is related to the interaction of both types of waters. Analysis of crystal shapes reveals different saturation degree conditions. Single salts show non-equilibrium shapes, implying higher crystallisation pressures. Single salts have undergone dissolution and/or dehydration processes enhancing the deterioration process, particularly in the presence of magnesium sulphate. Double salts (humberstonite) have crystals corresponding to near-equilibrium form, implying lower crystallisation pressures. This geochemical study suggests salts precipitate via incongruent reactions rather than congruent precipitation, where hexahydrite is the precursor and limiting reactant of humberstonite. Chemical dissolution of limestone is driven mainly by the presence of acidic water lixiviated from pigeon droppings and is a critical weathering process affecting the most valuable architectural elements present in the façades.

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