Lake Vanda, Wright Valley

The physical and biochemical properties of the lakes of southern Victoria Land were reviewed and interpreted by Chinn (1993) who identified the lakes by name and indicated their locations in Appendix 19.9.2. Many of these lakes and ponds are small, most are ice covered, and some are frozen right down to the bottom. Some of the lakes contain meltwater of low salinity while others are density stratified and contain brines of varying salinity. The chanical compositions of the water in the different brine lakes reflect the local environmental conditions that govern their on-going evolution. The water levels of the saline lakes and ponds in closed basins have been rising since the summer of 1968/69 when sys-tranalic observations commenced. Information recorded in 1903 indicates that the level Lake Bonney in Taylor Valley has been rising since that year (Chinn 1993). 

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). 

Wright Valley is a closed basin because its mouth is blocked by the Wilson Piedmont Glacier. Therefore, the water of Lake Vanda can escape only by evaporation of liquid water and by sublimation of ice. Consequently, the salts that are dissolved in the glacial meltwater have accumulated in the soil of Wright Valley (Keys and Williams 1981), in the water of Lake Vanda, and in the saline ponds listed in Appendix 19.9.2. 

Records of the level of Lake Vanda have been kept since the summer of 1968/69 when New Zealand 

The level of Lake Vanda depends on the balance between the volume of water that enters the lake annually and the volume of water that is lost by sublimation of the ice cover. The annual discharge of the Onyx River, which is the principal source of water entering the lake, has varied erratically (Fig. 19.3 lb) in response to the amount of snow and ice that melt in the Wright Valley. The discharge of the Onyx River peaked during the summer of 1970/71 at about 15 x 10 m which 

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Cape Roberts Science Team (1998) Background to CRP-1, Cape Roberts Project, Antarctica. Terra Antartica 5(1) 1-30 Carlquist S (1987) Pliocene Nothofagus wood from the Transantarctic Mountains. ALISO ll(4) 571-583 Cartwright K, Treves SB, Torii T (1974) Geology of DVDP 4, Lake Vanda, Wright Valley, Antarctica. Dry Valley Drilling Project (DVDP) Bull 3 49-74... 

Cutfleld SK (1974) Hydrological aspects of Lake Vanda, Wright Valley, Victoria Land, Antarctica. New Zealand J Geol Geophys 17 645-657... 

Green WJ, Ferdelman TG, Canfield DE (1989) Metal dynamics in Lake Vanda (Wright Valley, Antarctica). Chem Geol... 

Jones LM, Faure G (1967) Origin of salts in Lake Vanda, Wright Valley, southern Victoria Land, Antarctica. Earth Planet Sci Lett 3 101-106... 

Fig. 3.5 The western end of Wright Valley in southern Victoria Land is framed by the Olympus Range in the north and the Asgard Range in the south. Ice from the East Antarctic ice sheet of the polar plateau enters the valley via the Airdevronsix icefaU and forms the Wright Upper Glacier. The Labyrinth at its base was carved by meltwater streams flowing under pressure at the base of a glacier that once flUed the Wright Valley. Lake Vanda is peren-...

Fig. 10.5 The Wright Valley in southern Victoria Land slopes west, away from the coast, and contains the Onyx River which flows from Lake Brownwoith at the foot of the Wright Lower Glacier to Lake Vanda at the western end of the valley (Fig. 3.5). The Asgard Range south of Wright Valley supports several valley glaciers which were named by Professor R.L. Nichols after...

The crustal characteristics of the Jurassic doler-ites of Antarctica and Tasmania relate these rocks to each other and set them apart from Jurassic dolerite in southern Africa and Brazil. This point was emphasized by Compston et al. (1968) in a direct comparison of Rb-Sr systematics of Mesozoic basaltic rocks in southern Victoria Land, Tasmania, South Africa, and South America. In addition, these authors reported K-Ar dates for plagioclase and pyroxene from a pegmatoid in the Lake Vanda sill in Wright Valley of southern Victoria Land. The results indicated a Middle Jurassic age for the Ferrar Dolerite, in agreement with the age of the Tasmanian Dolerite and the K-Ar dates of the Wisanger Basalt on Kangaroo Island of South Australia reported later by McDougall and Wellman (1976). 

Subsequently, Compston et al. (1968) published additional K-Ar dates of plagioclase and pyroxene from a dolerite siU near Lake Vanda in Wright Valley. These dates ranged from 153.9 to 169.2 Ma and were combined in Fig. 13.4 with the K-Ar dates published by McDougall (1963). 

Other features of Wright Valley that have attracted attention are Lake Vanda and the associated ponds (Don Juan and Canopus), the origin of soil salts and brines, the Onyx River and related meltwater streams, the invasion of seawater into the valley, and the plants and animals that inhabit the soil and lakes of Wright VaUey (Tedrow andUgolini 1963). 

The lakes that exist in Wright and Taylor valleys at present still contain algae that grow in the warm brines at the bottom of the largest lakes (e.g.. Lake Vanda in Wright Valley and Lake Bonney in Taylor Valley). 

Fig. 19.29 Lake Vanda in Wright Valley is fed by meltwater from the Onyx River (Fig. 10.1) which flows only during the summer (late December and January). The ice that covers the...

Fig. 19.30 Lake Vanda occupies the lowest area of Wright Valley about 30 km west of the terminus of the Wright Lower Glacier. The lake is 5.6 km long, 1.5 km wide, and 69 m deep. It has a perennial ice cover that is about 4 m thick except for the moat of open water that forms along the shore during the...

Fig. 19.31 (a) The level of Lake Vanda in Wright Valley has been increasing in steps and has begun to flood the area around it. (b) The total volume of water discharged annually into Lake Vanda by the Onyx River has fluctuated with a major spike in 1970/71 and more regular increases starting in 1981/82 until 1986/87. The water accumulates in Lake Vanda except for losses by sublimation of the ice cover at an average of 32.6 12.5 cm/ year (Data from Chinn 1993)... 

The remarkably abundant flora that exists in Lake Vanda and in the water of other lakes in southern Victoria Land defies the harsh climatic conditions of the surface. For example, the average annual temperature in Wright Valley at Lake Vanda is -19.8°C and the rate of meteoric precipitation is less than 10 mm/year. Although algae thrive in the lakes, fish and other kinds of animals with backbones have not been observed in any of the lakes in southern Victoria Land (Benoit and Hall 1970 Cameron et al. 1970 Horowitz et al. 1972 Parker and Simmons 1978 Parker et al. 1982 Love et al. 1983 Vincent and Howard-Williams 1989 Aiken etal. 1991 Simmons et al. 1993) (See also Lyons et al. 1984). 

Fig. 19.37 The Onyx River flows west (away form the coast) and discharges into Lake Vanda located 28 km west of Lake Brownworth. It carries water only during the summer in December and January. The water originates by melting of ice in the Wright Lower Glacier and of the alpine glaciers along the south wall of Wright Valley (Photo by G. Faure)...

Jones et al. (1967) first reported that the average 8 Sj./86Sr ratio of 15 water samples from a depth profile of Lake Vanda is 0.7149 0.0(X)1 which is identical within analytical error to the Sr/ Sr ratio of 0.7146 0.0002 of strontium in the water of the Onyx River. On the other hand, the Sr/ Sr ratios of strontium in Lake Vanda and the Onyx River differ markedly from the average Sr/ Sr ratio of the Cenozoic basalt of the McMurdo Volcanics (0.7043) and from the average Sr/ Sr ratio of two samples of seawater from the Ross Sea (0.7094). These results indicate unequivocally that the strontium at all levels in Lake Vanda and in Onyx River did not originate from marine sources or by weathering of Cenozoic basalt or volcanic ash in Wright Valley. 

Don Juan Pond in Fig. 19.22 is located at 77°34 S and 161°lLEina topographic basin in the South Fork of Wright Valley about 8 km southwest of Lake Vanda. The pond is about 315 m long, 116 m wide, and less than... 

Wright Valley, Antarctica the Lake Vanda data are at 70 m depth also < 0.045 ppm I the Don Juan Pond is late in the summer evaporation period (Goguel and Webster, 1990 Webster and Goguel, 1988). 

Figure 2.26 Location map of Lake Vanda and the Don Juan Pond, Wright Valley, Antarctica (Harris and Cartwright, 1981 1991, American Geophysical Union, reproduced by their permission).

Goguel, R. L., and Webster, J. G. (1990). Trace Element Concentrations in Lake Vanda, the Onyx River and Don Juan Pond, Wright Valley, Antarctica. New Zealand Antarctic Record 10(1), 2-8. 

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