.gif)
REPORT ON ELEVENTH VICTORIA UNIVERSITY OF WELLINGTON ANTARCTIC EXPENDITION. NOVEMBER AND DECEMBER 1966
Introduction
Three independent, two-men parties were in the field. One comprising Dr. H. W. Wellman and A. R. Duncan were studying weathering processes and Quaternary geology, one comprising Dr. D. N. Christoffel and I. M. Calhaem attempted to determine geothermal gradients in the bed of sea off McMurdo, and one comprising Mr. Ian Smith and Mr. Vince Neall studied dyke swarms in the Wright Valley and at Nussbaum Riegel. Dr. H.W. Wellman was the scientific leader and Mr. Ian Smith the Field Leader. The reports for the three parties are given separately below.
Weathering processes and Quaternary Geology H. W. Wellman and A. R. Duncan
At Wright Valley for 10 days, mostly near Lake Vanada, with a two day trip as far east as Meserve Glacier. At Marble Point for five days. At Mt Falconer for three days. At Nussbaum Riegel for five days. During a day trip from Scott Base a half-hour was spent at Cape Bird.
Lake Vanda Area
One of the members of the party had spent several weeks in the area previously and some tentative conclusions on the weathering processes had been reached, and the purpose of the trip was to check their validity.
Soils and salt Fretting
Wellman and Wilson have suggested that salt fretting is in important erosive agent where soluble salts are abundant. The Wright Valley is the classic area for the process. The soils were studied in more detail than they had been previously because it is thought that salt fretting within the soils, although less obvious, is more important than the spectacular cavernous weathering of boulders that stand above soil level. Within the area we examined there are at least two main soil types: on arid soil which covers most of the Wright Valley and is never flushed out by water, and a non-arid soil which is flushed out annually by melting snow. The arid soils contain much soluble salt and have well defined horizons. They require detailed study in roder to find the processes that control horizon formation. The uppermost horizon is normally deseribed as being "lag gravels", inferring wind transport of fines. Wind is important but does not explain all the profiels observed.
Wet Bands
On previous expeditions a bandwhich appears to be permanently damp flanks the western side of the valley and extends for several kilometres. It also occurs around the sides of lakes and borders stream courses. The most interesting wet bands are these distant from obvious water sources. All were explained as being related to the snouts of glaciers which have now retreated. They are important for glacial correlation and have a profound effect on weathering, rocks on the wet bands being considerably more weathered than those on either side. Differential weathering caused by the wet bands makes it impossible to place soils in order of age solely from the degree to which they have been weathered.
Pedimentation
Pediments, the term being used in a broad sense, and not glacial features, are the most striking landscape forms to be seen in the middle part of the Wright Valley. Pediments are essentially a flattish surface with a knick separating it from a steeper surface above. The knick is the critical part. It is related to the way in which rock waste is broken down. To produce a knick the material has to be broken down to a size that can be transported away and the breaking down has to be done in a single step, from large to fine and without appreciable material of intermediate sizes. Salt fretting does this very thing, breaking rocks at one step into their component crystals. At Lake Bull, the name given to a small lake in the Wright Valley, about a mile east of the east end of Lake Vanda, pedimentation is actively in progress, salts being supplied during the flooding of the Onyx River, and the fretted material being wind transported. The flooding carries the salts away from all except the edge of the lake and prevents salt fretting from pitting the lake bed itself. Higher pediments are also attributed to salt fretting, but the controlling details are less well understood.
Maximum Wind Velocities.
Below Bull Pass and on the south side of the valley just east of Lake Vanda are two places in Wright Valley that appear to be subject to extremely high westerly winds. Pebbles up to 2 inches in length have been transported for as much as 0.5 km from their source outcrop. In an attempt to find how strong these winds are and how often they blow, a set of primitive maximum velocity indicators were set up on the Lake Vanda Peninsula in 1964. The indicators consisted of a series of tins of different squatness filled with sand and set up on flat rock surface. In December 1966 it was found that the beer cans had been blown over by westerly winds and that the squatter tins had not. At some time in the last few years there must have been a gale very much stronger than any I have experienced. I would estimate a velocity of about 100 knots and suggest that an experiment should be made in a wind tunnel or at an airport to obtain a more accurate value, as it will be important to know what is to be expected if a hut is to be built in the valley.
Elevated Beach Ridges.
- A[unclear: R]2(0.2), B:2.2. (0.2), C 3.1 (0.2), D 3.9 (0.2), E 6.0 (1.4), F 7.2 (0.6), G 9.2 (0.5), H 10.4 (0.2), I 11.3 (?), J 13.1 (0.2), K 115.0 (0.9), L 18.1 (1.0)
In Northern Norway a similar but more numerous series of ridges that have been attributed to isostatic uplift are reasonably well dated by four radio-carbon samples. Isostatic uplift is generally assumed to be a continuous and not an intermittent process, and isostatic continuity in Finland is substantiated by tilt observed on lakes during the past 40 years. Uplift but not the formation of specific beach ridges can be attributed to the isostatic movement, and their formation must be due to some intermittent factor, either directly climatic or to some small sea-level oscillations. The radio carbon samples indicate that the time interval between the formation of the Norwegian ridges is remarkably uniform with a value of almost
page 3
exactly 400 years. Because of the uniform interval, and because, the rate of isostatic uplift has been decreasing while sea level has remained substantially stationary the vertical interval between successive Norwegian beach ridges has progressively decreased with tine for the last 6,000 years.
In South Victoria Land there is no general agreement on the age of shore line features of the kind we measured near Marble Point. However, it is possible that the 400 year cycle may well operate, and this is made likely by progressive decrease in the vertical interval between successive beach ridges indicated by the values given above. The progressive decrease in vertical interval indicates that the ridges are a single series and not, for example, in part 100,000 or more years old and in part less than 6,000 years old. The distance over which the ridges were observed is too small to determine the small tilt that is likely to have taken place, and because the difficulties in correlation it is unlikely that the direction and tilting can be established anywhere in South Victoria Land. One clear relation was observed: the older and higher ridges progressively cut out towards the south. The cut-out is attributed to the southerly retreat of the Ross Ice Shelf while the beach ridges were being cut.
Geothermal heat flow studies from Ocean floor west of McMurdo
The thermal gradient probe used was constructed in the Physics workshop of Victoria University and is 6 ft long and 1 inch in diameter. It has 24 differential thermocouples extending over a length of 4.5 ft and has a built-in heater to determine thermal conductivity of the sediments it penetrates. Sea ice served as a convenient working platform and the probe was lowered through an existing hole in the ice and through a new hole that was drilled.
Unfortunately, because of hard bottom conditions, only one gradient measurement appeared to be successful. It indicated a heat flow of about 1.9 micro-calories per cm per second and is slightly above the generally accepted world average value. It is important for future work that more stations be occupied in the hope of finding-softer bottom conditions.
A Weddel Seal co-operated in providing an interesting Zoological sideline to the geophysical work. He, or she, repeatedly visited us at one of the holes, often with a fish in its mouth. On one occasion we were able to take a live fish in good condition from the seal. It weighed 651bs and was 4.9 ft long and proved to be a species. Dissostichus mawsoni that had not previously been fully described. The fish and behaviour of the seal are to be the subjects of a short paper.
Dykes at Nussbaun Riegel
During November and December 1966, 25 days were spent at Nussbaun Riegel, to the east of Lake Bonney and to the south of a arcuate gorge in the Taylor Valley. Nussbaun Riegel stands several thousand feet above the Taylor Valley and is connected with the Kukri Hills to the south by a moraine-mantled platform.
Igneous dykes have been reported from as far north as Admiralty Range and as far south as the Darwin Mountains. Nussbaum
page 4
Riegel contains one of the best exposed and most readily accessible dyke swarms and the various petrological types were collected and the field relations of the dykes determined.
The dykes were previously mapped as being entirely lamprophyres but the more detailed studies have showm that they are more correctly termed dolerites. One is possibly a quartz porphyry.
Most of the dykes strike at right angles to the general strike of the basement rock, and are dextrally displaced by three faults, the amount of displacement at each fault being about 200 ft and the sense of displacement dextral.
The dyke rocks are at present being studied in detail and samples are being prepared for K/Ar dating.
Acknowledgements
The expedition was made possible by financial and other assistance from several organizations and individuals, to all of whom we are extremely grateful. The University Grants Committee and Victoria University of Wellington provided financial assistance. The United States authorities provided transport to and from New Zealand and within South Victoria Land.
The Antarctic Division of the Department of Scientific and Industrial Research arranged our transport and provided accommodation while we were at Scott Base.
We would specially like to thank Professor Clark, Geology Department, for his help and continued interest in the University Antarctic Expeditions.
As with previous expeditions, the greatest possible help and co-operation was forthcoming from the Leader and staff at Scott Base. We would like to take this opportunity of thanking Mr. Colin Clark and his colleagues very warmly.
ANTARCTIC PUBLICATIONS
WEBB, P. N. and McKeLVEY, B. C., 1959: Geological Investigations in South Victoria Land, Antarctica. Pt I - Geology of Victoria Dry Valley. N. Z. J. Geol. Geophys. 2: 120-136.
McKELVEY, B. C. and WEBB, P. N., 1959: Geological Investigations in South Victoria Land, Antarctica. Pt II - Geology of Upper Taylor Glacier Region. N. Z. J. Geol. Geophys. 2: 718-728.
BULL. C. and IRVING, E., 1960: The Paleomagnetism of some Hypabyssal Intrusive Rocks from South Victoria Land, Antarctica. Geophys. Jour. Roy. Astron. Soc., Vol. 3, No. 2: 211-224.
BULL. C., 1960: Gravity Observations in the Wright Valley Area, Victoria Land, Antarctica. N. Z. J. Geol. Geophys. 3: 543-52.
McKELVEY, B. C. and WEBB, P. N., 1961: Geological Reconnaissance in Victoria Land, Antarctica. Nature, Vol. 189, No. 4764: 545-547.
CLARK, R. H., 1960: Geological Work in Antarctic Dry Valleys. Report of International Geological Congress XXI Session, Norden, 1960, Pt. XXI.
McKELVEY, B. C. and WEBB, P. N., 1962: Geological Investigations in Southern Victoria Land, Antarctica. Pt. 3 - Geology of Wright Valley. N. Z. J. Geol. Geophys. 5: 143-62.
BULL, C., IRVING, E. and WILLIS, I., 1962: Further Palaeomagnetic Results from South Victoria Land, Antarctica. Geophys. Jour. Roy. Astron. Soc., Vol. 6, No. 3, 320-336.
ALLEN, A. D. and GIBSON, G. W., 1962: Geological Investigations in Southern Victoria Land, Antarctica. Part 6 - Outline of the Geology of the Victoria Valley Region. N. Z. J. Geol. Geophys., Vol. 5, No. 2, 234-242.
ALLEN, A. D., 1962: Geological Investigations in Southern Victoria Land, Antarctica. Part 7 - Formations of the Beacon Group in the Victoria. Valley Region. N. Z. J. Geol. Geophys., Vol. 5, No. 2, 278-294.
BULL, C., McKELVEY, B. C., and WEBB, P. N., 1962. Quaternary Glaciations in Southern Victoria Land, Antarctica. Jour. Glaciology, Vol. 4, No. 31, 63-78.
[unclear: GUNN], B.M. and WALCOTT, R. I., 1962: The Geology of the Mt. Markham Region, Ross Dependency, Antarctica. N. Z. J. Geol. Geophys., Vol. 5, No. 3, 407-26
GIBSON, G. W., 1962: Geological Investigations in Southern Victoria Land, Antarctica. Part 8 - Evaporite Salts in the Victoria Valley Region. N. Z. J. Geol. Geophys. 5, No. 3, 361-74.
[unclear: JOHANNESSON], J. K. and GIBSON, G. W., 1962: Nitrate and Iodate in Antarctic Salt Deposits. Nature, Vol. 194, No. 4828, 567-68.
BULL C., 1962: Gravity Observations in the Koettlitz Glacier Area, Southern Victoria Land, Antarctica. N. Z. J. Geol. Geophys., Vol. 5, No. 5, 810-19.
page 2
WILSON, A. T. and WELLMAN, H. W., 1962: Lake Vanda: an Antarctic Lake. Nature, vol. 196, No. 4860, pp. 1171-1173.
WELLMAN, H. W. and WILSON, A. T., 1962: Stored Solar Heat at Lake Vada. Antarctic, pp. 102-103.
WELLMAN, H. W., 1963: Sponge Spicule Pebbles at Hut Point Peninsula, Antarctica. Nature, Vol. 197, No. 4868, p. 681.
WELLMAN, H. W., 1963: Transport of Pebbles over Smooth Ice in Antarctica. Nature, Vol. 197, No. 4868, p. 681
FLANK, H. R., COOPER, R. A., WHEELER, R. H., and WILLIS, I. A. G., 1963: Geology of the Koettlitz - Blue Glacier Region, Southern Victoria Land, Antarctica. Trans. Roy. Soc. N. Z., Vol. 2, No. 5, pp. 79-100.
WEBB, P. N., 1963: Geological Investigations in Southern Victoria Land, Glacier Region. N. Z. J. Geol. Geophys. 6, pp. 361-387.
WELLMAN, H. W. and WILSON, A. T., 1963: Salts on Sea Ice in McMurdo Sound, Antarctica. Nature, Vol. 200, No. 4905, pp. 462-463.
WELLMAN, H. W., 1964: Later Geological History of Hut Point Peninsula, Antarctica. Trans. Roy. Soc. N. Z., Vol. 2, 10, pp. 147-154.
BASKELL, T. R., 1964: Thermal Metamorphism of Beacon Group Sandstone of the Taylor Valley, Antarctica. Nature, Vol. 201, No. 4922, p. 910.
CLARK, R. H., 1964: The Oases in the Ice. Antarctica, pp. 321-330.
HOARE, R. A., POPPLEWELL, K. B., HOUSE D. A., HENDERSON, R. A., PREBBLE, W. M., and WILSON, A. T., 1964: Lake Bonney, Taylor Valley, Antarctica: a Natural Solar Energy Trap. Nature, Vol. 202, No. 4935, pp. 886-888.
BASKELL, T. R., KENNETT, J. P., PREBBLE, W. M., SMITH G., and WILLIS, I. A. G., 1964: The Geology of the Middle and Lower Taylor Valley of South Victoria Land, Antarctica. Trans. Roy. Soc. N. Z., Vol. 2, no. 12, pp. 169-186.
BASKELL, T. R., KENNETT, J. P., and PREBBLE, W. M., 1964: Geology of the Brown Hills and Darwin Mountains, Southern Victoria Land, Antarctica. Trans. Roy. Soc. N. Z., Vol. 2, No. 15, pp. 231-248.
BASKELL, T. R., KENNETT, J. P. and PREBBLE, W. M., 1964: Basement and Sedimentary Geology of the Darwin Glacier Area, East Antarctica. SCAR (S. A.).
[unclear: DEUT]SCH Sarah and WEBB, P. N., 1965: X:2 Sr/Rb Dating on Basement Rocks from Victoria Land; Evidence for a 1000 million year old event. Antarctic Geology, SCAR Proceedings 1963.
HOARE, R. A., POPPLEWELL, K. B., HOUSE, D. A., HENDERSON, R. A., PREBBLE, W. M. and WILSON, A. T., 1965: Solar Heating of Lake Fryxell, a permanently ice-covered Antarctic Lake. Jour. Geophys. Research, Vol. 70 No. 6, pp. 1555-1558.
SMITH, G. I.
page 3
CLARK R. H., 1965: Investigations in the Koettlitz and Surrounding Areas. Bulletin of the U. S. Antarctic Projects Officer, Vol. VI, N,. 7, pp. 71-72.
WILSON, A. T., 1964: Origin of the Ice Ages: An Ice Shelf Theory for Pleistocene Glaciation. Nature 201, 147.
WILSON, A. T., 1964: Evidence from Chemical Diffusion of a Climatic Change in the McMurdo Dry Valleys 1,200 years ago. Nature 201, 176.
WILSON, A. T. and HEINE, A. J., 1964: The Chemistry of Ice-Shelf Brines. J. Glaciology 5, p. 265.
WILSON, A. T. and HOUSE, D. A., 1965: Fixation of Nitrogen by Aurora and its contribution to the Nitrogen Balance of the Earth. Nature 205, p. 793.
WILSON, A. T., 1965: Geochemical Studies in the Antarctic. Polar Record.
WILSON, A. T., 1965: Escape of Algae from Frozen Lakes and Ponds. Ecology, Vol. 46, No. 3.
MORTCLIFFE, T. G. L. and BENSEMANN, R. F., 1964: A Sun-heated Antarctic Lake. J. Geophys. Res., vol. 69, No. 16, pp. 3355-3359.
[unclear: BILL] R. A. I. and HEINE, A. J., 1965: Seismic Refraction Measurements on the McMurdo Ice Shelf, Antarctica. Jour. Glaciology, Vol. 5, No. 42.
MORTCLIFFE, T. G. L., 1965: Lake Bonney, Antarctica: Cause of the Elevated Temperatures. Jour. Geophys. Research, Vol. 69, No. 24, pp. 5257-5268.
WILSON, A. T. and HOUSE, D. A., 1965: Chemical Composition of South Polar Snow. Jour. Geophys. Res., Vol. 70, No. 22, pp. 5515-5518.
HENDERSON, R. A., PREBBLE, W. M., HOARE, R. A., POPPLEWELL, K. B., HOUSE, D. A. and WILSON, A. T., 1966: An Ablation Rate for Lake Fryxell, Victoria Land, Antarctica. Jour. Glaciology, vol. 6, No. 43, pp. 129-133.
WILSON, A. T., 1966: Variation in Solar Insolation to the South Polar Region as a Trigger which induces instability in the Antarctic Ice Sheet. Nature, Vol. 210 No. 5035, pp. 477-478.
HOARE R. A., 1966 Problems of Heat Transfer in Lake Vanda, a Density Stratified Antarctic Lake. Nature, Vol. 210, No. 5038, pp. 787-789.
[unclear: BILL] Robin A., 1966: A Seismic Reconnaissance in the McMurdo Sound Region, Antarctica. Jour. Glaciology, Vol. 6, No. 44, pp. 209-221.
HOUSE D. A., HOARE, R. A., POPPLEWELL, K. B., HENDERSON, R. A., PREBBLE, W. M., and WILSON, A. T., 1966: Chemistry in the Antarctic. Jour. Chem. Educ., Vol. 43, p. 502.
[unclear: MC]WELL, C. R., BROOKS, R. R. and WILSON, A. T., 1967: Trace Element Content of Antarctic Lakes. Nature, Vol. 213, No. 5072, pp. 167-168.
[unclear: BRADLEY], J. and PALMER, D. F., 1967: Ice-cored Moraines and Ice Diapirs, Lake Miers, Victoria Land, Antarctica. N. Z. J. Geol. Geophys., Vol. 10, No. 2, pp. 599-623.
[unclear: WELL] R. A. I., 1967: Lake Miers, South Victoria Land, Antarctica. N. A. J. Geol. Geophys.