Lakes of the Ice-Free Valleys

The chloride ion in the streams and lakes of the ice-free valleys is conservative which means that it accumulates in the lakes because the chloride salts of most major as well as trace metals are highly soluble. Consequently, the flux of chloride ions that enter a lake annually and the total inventory of chloride in the lake can be used to calculate the chloride age of the lake which is defined by ... 

Fig. 19.28 The carbon-14 dates of dried algal mats that are interbedded with lacustrine sediment in Taylor Valley that formed when the mouth of the valley was blocked by the grounded Ross Ice Shelf. The pattern of variation of C-dates and corresponding elevations suggests that the lakes reached their highest levels for about 5,300 years from 21,200 to about 16,000 years bp. Subsequently, the lake levels began to decline until about 8,300 years bp. Algal mats are still growing in the warm brine at the bottom of Lake Bonney and in the other deep lakes in the ice-free valleys (Data from Stuiver et al. 1981)...

The importance of chemical weathering in the geochemistry of the ice-free valleys of southern Victoria Land is also indicated by the presence of bicarbonate ions and of molecular silicic acid (H SiO ) in the streams and lakes of this area. These constituents are released into solution in surface water by the incongru-ent dissolution of alumino-silicate minerals such as microcline ... 

The last chapter in the geologic history of the ice-free valleys is concerned with the geochemical evolution of the lakes and ponds several of which contain dense brines overlain by layers of dilute water under a permanent cover of ice. These lakes and the associated meltwater streams give the ice-free valleys the appearance of oases on a very cold continent buried under snow and ice. The water in the lakes is warmed by solar radiation that penetrates 4 m of permanent ice and up to 60 m of water in the case of Lake Vanda. 

Jones LM, Faure G (1978) A study of strontium isotopes in lakes and surficial deposits of the ice-free valleys, southern Victoria Land, Antarctica. Chem Geol 22 107-120 Jones LM, Faure G (1968) Origin of the salts in Taylor Vrilley. Antarctic JUS 3(5) 177-178... 

Certain places in the ice-free valleys have been designated Sites of Special Scientific Interest (SSSIs), in order to protect ongoing scientific research or to preserve them in pristine condition for possible future study. This action was taken by the seventh Antarctic Treaty Consultative Meeting (ATCM VII) in 1972 and is contained in Recommendation VII-3 (Stonehouse 2002, p. 369). The SSSI sites in the ice-free valleys are Barwick Valley (Fig. 3.6), the area between the Canada Glacier and Lake Fryxell (Taylor Valley), and the Linnaeus Terrace... 

The geologists who accompanied Robert Scott and Ernest Shackleton to Antarctica were amazed when they entered the mountains of southern Victoria Land and discovered the ice-free valleys such as Wright Valley in Fig. 10.1 (Sections 1.4, 2.3, and 3.1). The modem traveler entering the ice-free valleys by helicopter from McMurdo is similarly affected because the wide U-shaped valleys present a familiar view of sandy plains dotted with lakes and ponds filled with liquid water and of meltwater streams that flow from alpine glaciers descending from the high mountain ranges that frame these valleys. 

Development of meltwater streams and lakes, formation of arctic soil impregnated with salts, and establishment of colonial algae, lichens, moss, and nematodes in the ice-free valleys... 

The principal lakes of southern Victoria Land that attract attention by their size and by the salinities and chemical compositions of the brines they contain are Lake Vida in Victoria Valley (Calkin and Bull 1967), Lake Vanda and Don Juan Pond in Wright Valley, Lake Bonney, Lake Hoare, and Lake Fryxell in Taylor Valley, and Lake Miers in the ice-free valleys along the Koettlitz Glacier (Matsubaya et al. 1979 Matsumoto et al. 1993 Lyons and Finlay 2008). 

In spite of the harsh climate that characterizes the Transantarctic Mountains, bacteria, algae, lichens, and moss grow in sheltered places in the soil and some plants have adapted by becoming endolithic. Even mites and nematodes have been discovered in the ice-free valleys and algal mats thrive in the warm brines that occur at the bottom of the largest and deepest lakes. 

Lake Bonney in Fig. 10.3 is located in the western part of Taylor Valley about 30 km from the coast. It is about 6 km long, 1 km wide and is 32 m deep. The lake has two lobes that are connected by a narrow channel which has widened and deepened during the twentieth century because of the increase of the water level in the lake (Shirtcliffe 1964 Jones and Faure 1968, 1978 Chinn 1993). Lake Bonney is perennially covered by ice that is about 4 m thick but during the summer a moat less than 10 m wide forms around the periphery of the lake, while the eastern end of the lake actually becomes ice-free. 

Fig. 10.1 Wright Valley In southern Victoria Land is ice-free and contains the Onyx River which flows inland from Lake Brown worth at the base of the Wright Lower Glacier near the...

Fig. 19.17 Taylor Valley is not entirely ice-free because the Taylor Glacier descends from the polar plateau and terminates at Lake Bonney (Fig. 3.7). Taylor Valley also contains several additional meltwater lakes including Mummy Pond between the Matterhorn and Suess glaciers, lakes Chad and Hoare between the Suess and Canada glaciers, and Lake Fryxell between the Canada and Commonwealth glaciers (not shown), all of which...

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