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Those hectic days of packing and planning in the spring of 1968 are now almost forgotten and even our recent summer in Antarctica seems an age away. Alas, the enjoyment and excitement of the field season is over, and we now contemplate a desk loaded with field notes. It was a privilege to help organise and lead this expedition and a most pleasant one in which to participate As with all expeditions the success of this year's venture depended entirely on the many and varied contributions made by the expedition members themselves. Versatility of skills was one of the striking attributes of this year's team, and I cannot recall our being hold up by any problem for very long. As the summer progressed we developed from an awkward, clumsy bunch to an efficient, versatile and closely knit team. Under those conditions party leadership is a pleasure and I wish to express my gratitude to my colleagues for the cheerful and driving manner in which tasks both scientific and menial were approached and executed.
The participation of New Zealand university students in the New Zealand Antarctic Research Programme continues to be a successful and valuable undertaking. Not only does it increase our scientific knowledge of the Antarctic continent, but much more important, it teaches the participating student a sense of responsibility, resourcefulness, leadership and patience. Under difficult conditions and in isolation ho comes to have a better understanding of himself and his colleagues. This experience is, then, a valuable addition to conventional university education and contributes to the emergence of a more mature graduate.
I have pleasure in presenting the immediate report of VUWAE 1968/69.
This last summer season saw VUWAE's twelfth season of fieldwork in the Ross Dependency. This year, VUWAE undertook four projects:
All projects were successfully completed. A short report on each project is presented by project leaders in subsequent pages.
The 1968/69 party was made up as follows:
At a meeting convened by Professor R.H. Clark during A.N.Z.A.A.S. (Christchurch) in January 1963, Peter Webb and Barrie McKelvey were invited to be leader and deputy leader respectively of the VUWAE 1963/69 expedition. These two were charged with the selection of personnel, and programme and logistic planning. Applications for two student geologist vacancies were called in May 1968 and drew about fifteen applicants. Messrs Kohn and Gorton were selected for the positions. Jim Cousins was involved with the geothermal heat-flow project during the previous summer and was automatically selected to continue this project. Burton Murrell came into the party as a late replacement for Mr C. Vucetich. Although financially independent, Russell Blong (a Ph.D. student at University of Sydney) was invited to carry out his programme within the VUWAE party. Two field assistants were required during the first phase of the geological programme. Here, Mr R. Thomson, Superintendent of Antarctic Division, arranged for Messrs Mauri and Oilier, both members of the Italian Antarctic Expedition, to assist us.
The expedition was supported financially by a grant from the University Research Grants Committee. This grant was used to purchase such items as food, clothing, stationery, etc., and to cover insurance of personnel and instruments. Financial aspects of the expedition were in the hands of Mr John Andrews, Science Faculty Clerk.
A considerable amount of gear was already available in the VUWAE Antarctic store. This included such items as primuses, small tents, sleeping bags, kitchen utensils, small radios, etc. Hew purchases were mainly replacement items (tea towels, pot mits, etc.) and spare parts (primus spares, etc.). A number of field items, not
Special equipment, cameras, tapes, etc. were borrowed from the Department of Physics and Department of Geology.
As this year's programme included a sledging journey it was thought advisable to use standard sledging rations rather than the heavier VUWAE dry valley rations. In the course of the season the geological party consumed ten boxes of 20-man-day rations. These were purchased from Scott Base. Twenty-one were issued and eleven later returned to either Scott Base or Vanda Station. Messrs Cousins, Murrell and Blong used food from the VUWAE store at Scott Base.
At the end of the season all stocks of loose VUWAE food were packed into 10 x 20-man-day rations. This should provide ample food for next year's activities.
Messrs Kohn, Gorton and Webb attended the Antarctic Training Week at Waiouru in August 1968. This proved a most valuable experience and allowed us to meet and discuss our summer programme with the future Scott Base leader and his staff. We were able to state our field requirements, with the result that important preparations of gear were completed by the time we arrived at Scott Base. We made many friends with the future Scott Base staff during the training week, and as a result, received their closest co-operation in Antarctica.
A visit to the Boomerang Range was proposed as part of the geological programme for VUWAE during the 1967/68 season. It was intended that the party be moved from Ross Island to the Boomerang Range area by helicopter. This operation was cancelled when it was realised that the distances and elevations were beyond the operating capabilities of the available helicopters. The programme was postponed for one year. during the ANZAAS meeting at Christchurch in late January 1963, Professor R.H. Claris:, Dr A. Wright, Dr B.C. McKelvey and Dr P.N. Webb met to discuss the VUWAE geological programme for the 1968/69 season. Dr Wright was to have led the 1967/68 visit to the area. At this meeting it was decided that, subject to their obtaining leave, Messrs Webb and McKelvey would be leader and co-leader respectively of the party, and be responsible for organising the logistics and scientific programme of the expedition.
On 1st April details of the proposed party movements, the helicopter and Hercules support required, and the weights involved, were submitted to Antarctic Division. This plan was accepted by Antarctic Division and passed on to Deep Freeze headquarters later in the year.
During the winter and spring of 1968 Drs McKelvey and Webb prepared a number of geological memoranda which summarised earlier geological work in the area between the Boomerang and Olympus Ranges, and set forth a possible geological programme for this area. These were circulated to the other expedition members.
At the request of VUWAE the U.S. Navy VX-6 squadron flew a photo trimet run along the Boomerang Range from its southern tip northwards to the head of the Taylor Glacier in the spring of 1967. These and other photographs were studied in detail before proceeding south.
Discussions were held with Guyon Warren, New Zealand Geological Survey, Christchurch, prior to our departure. Mr Warren was a member
For logistic reasons the geological programme was divided into two phases. The first phase involved visits to ranges and nunataks around the Skelton Névé. This was accomplished by using toboggans and sledges and included visits to Boomerang Range, Warren Range, Portal Mountain and Mt Metschel nunatak. The second phase was carried out by helicopter and took in visits to Table Mountain, Knobhead Mountain, Aztec Mountain, Maya Mountain, Kennar Valley, Mt Fleming, and the western Asgaard and Olympus Ranges. For the first phase the four man geological party was assisted by two members of the Italian Antarctic Expedition. During the second phase the party was reduced to the four geologists.
The geological party spent a total of 78 days in Antarctica. Division of time is as follows:
The figure of 30 days spent on geology is actually calendar days. On most days the party split into units of two men, thereby achieving a figure nearer 60 field days. Of the 13 lost days, only two or three were due to weather conditions in our working area. The remainder were caused by bad weather at McMurdo Sound or servicing problems with aircraft. The quite high figure of 18 days spent at Scott Base was caused by factors beyond the control of the VUWAE party; for instance, McKelvey's plane was delayed in Christ church for five days and the programme set back by this amount. The time at Scott Base was, however, necessary for the complete overhaul of the toboggans.
Considering conditions, I feel that we made good use of our time and as a unit worked efficiently. Although these figures prove little, they may be of interest:
Thus about 60% of our time in Antarctica was spent on the geological programme.
The first reference to this area is probably that mentioned in Scott's The Voyage of the ‘discovery’. In the account of his return from the western journey onto the plateau in 1903 Scott notes in the entry for December 10 (Chapter XVIII), We had not been going for more than an hour in the afternoon, however, when Evansș sharp eye sighted the land, and soon some isolated nunataks appeared on both bows..... Later we rose several mountain peaks to the S.E., but cloud hangs so persistently about them that I cannot recognise anything". Two days later the party (Scott, Evans and Lashly) arrived back at Depot Nunatak. It seems likely that the peaks which they observed to the southeast would be the Lashly Mountains and some of the peaks in Warren Range, Boomerang Range and perhaps the Worcester Range.
A Map of the District near the ‘Discovery’ Winter Quarters (prepared by Lieut. Mulock, with geological information by Ferrar) was published by the National Antarctic Expedition in 1906. The area now referred to as the Skelton Névé is blank except for large lettering “Inland Ice”. Mulock shows two peaks to the south of Depot Nunatak, referred to as Lonely Peaks and Far West Mountain. Both had elevations in excess of 8,000 feet.
The topographic Map of McMurdo Sound Region (prepared by Debenham and published in 1923) which accompanied the British Antarctic Expedition 1910-13 (Terra Nova) reports does not improve on Mulock's map in the Skelton Névé area. Mulock's Lonely Peaks and Par West Mountains are referred to as Lashly Mountains on this map.
Although Scott and Shackleton's southern sledge journeys took them past the mouth of the Skelton Glacier (their Skelton Inlet) they were always at too low an elevation and too far out from the coast to gain any appreciation of the inland topography. However, had these early parties climbed one of the peaks on the southern side of the Taylor Glacier, they would have commanded an excellent view of the
After aerial reconnaissance of the major coastal glaciers during the early stages of the Trans Antarctic Expedition, Gunn selected the Skelton Glacier as the most favourable overland route between the McMurdo Sound and the Inland Plateau. In the following four summers this route was to become a major highway as the many tractor and dog teams plied their way to and from the plateau.
In late January and February 1957 Brooke, Ellis, Ayres, and Douglas sledged to the T.A.E, Plateau Depot by way of the Skelton Glacier, Skelton Névé and The Portal. Mulgrew also joined this party for a short period and climbed a small rock spire on the slopes of Portal Mountain as the party moved eastwards back across the Névé. Douglas and Brooke climbed Névé Nunatak during the same journey but no other rock climbs are recorded by this party. In October 1957, Miller and Marsh with dogs, and Hillary, Ellis, Balham and Mulgrew with tractors, ascended the Skelton Glacier and traversed the Skelton Névé on their way to the Plateau Depot. No mapping or geological work was undertaken by these groups. This was left until January 1958 when the T.A.E. Northern Party, consisting of Gunn, barren, Brooke and Douglas, arrived in the area after sledging down from the Mackay Glacier. This group spent about a week in the area, making geological visits to Escalade Peak, the Alligator Peak region, and Allemand Peak. Topographic survey stations were established on Escalade, Allemand Peak, and on another high unnamed peak further to the south in the Boomerang Range. Geological and topographic results of this visit to the area are contained in a bulletin and maps (scale 1:250,000) published by Gunn and Warren in 1962. Later in the summer of 1958, Sir Vivian Fuchs crossed the Skelton Névé on his way between Plateau Depot and Scott Base.
In the post T.A.E. era two further tractor traverse parties used this route. In November 1953 Bert Crary, accompanied by Dr T. Bat her ton, led a U.S.I.G.Y. seismic party through the area and on to the plateau, returning along the same path in January 1959. In October 1959 a U.S.A.R.P. traverse, which included New Zealander
Three maps of this area have appeared in the last twelve years. The N.Z.M.S. 135 map was published by the Lands and Survey, Wellington, in June 1957. This relied heavily on topographic data from the early expeditions but contained new information on the Steel ton Glacier and Skelton Névé areas. The rough outlines of the Boomerang Range, Portal fountain, The Portal, Névé and Halfway Nunataks, and Clinker Bluff are indicated on this map, being based on survey data gathered in the early days of the Trans Antarctic Expedition.
In March 1961 the Lands and Survey, Wellington, published the provisional edition of N.S.H.S. 175/3 at a scale of 1:250,000.
The most recent map of the area is one published in 195 by the U.S. Geological Survey at a scale of 1:250,000 (Reconnaissance Series - Mt Harmsworth). This map was compiled in 1963 from aerial photos taken between 1956 and 1961.
The Skelton Névé may be regarded as a large ice basin separated from the inland plateau on the west by a string of ranges and nunataks and bounded on the east by the Royal Society and Worcester Ranges. The major entry of ice occurs through The Portal and over adjacent ice falls; the major outlet through the Skelton Glacier to the Ross Ice Shelf. There are also direct connections to the Mulock and Ferrar Glaciers to the south and north respectively. The Skelton Névé is approximately fifty miles long in a NE-SW direction, and thirty miles wide in NW-SE direction. The névé attains its highest elevation of around 1600 to 2000 metres in the north (in the region of The Portal) but drops progressively westwards and southwestwards to about 1200 metres. The western and southwestern portion of the névé receives little snow or ice and shows all the signs of progressive stagnation and retreat, leaving a series of lateral moraines along the sides of
The first recce flight took place on 3rd December, at the tail end of a fuel supply flight to Byrd Station. Some two hours were spent over the Skelton Névé and Taylor Glacier area obtaining photographs and searching out a landing site. Robin Foubister, Leader Scott Base; Bill Lucy, Deputy Leader, Scott Base; and Graham Connell, Public Relations Officer, also participated in the reconnaissance flights. The latter acted as photographer during the flight.
During the last decade investigations of Beacon Group rocks have been undertaken alone the entire length of Victoria Land. Naturally enough, the more accessible areas have received a great deal of attention, the more inaccessible have been barely scratched. The Beacon Group exposures in the type area west of McMurdo Sound have witnessed hundreds of investigators. Since 1907, when Ferrar's initial account of these rocks appeared, there have been more than forty papers published on the Beacon sediments of this area alone. The rocks of this area are now quite well known although many stratigraphic and nomenclatural problems remain. The basic stratigraphy is now known through most of Victoria Land and it is now possible to compare, contrast and correlate Beacon Group sediments over great distances. Nevertheless, outstanding differences between areas have emerged.
Important differences in the stratigraphy of the Beardmore and Taylor Glacier areas have been highlighted in recent syntheses. Most of these occur in pre-Permian sediments. For example, tillites were reported north and south of the Beardmore Glacier region but were apparently absent in the Taylor Glacier region; Devonian fish faunas were present just south of the Taylor Glacier area but had not been seen in the Beardmore Glacier region. Later, it became apparent that the stratigraphy of the Beardmore area could be traced as far north as the Darwin Glacier area, i.e. only 150 miles south of the classic Taylor Glacier area. Why then did the tillite of the Darwin Glacier
Despite the great number of Investigators who have visited the Wright-Taylor area, many critical problems had been overlooked or greatly simplified, and much work regained to be done. Therefore, the second phase of this year's geological programme included a re-evaluation of the Beacon Group in the type area. Having done this we were then in a better position to discuss stratigraphic problems between the Boomerang Range in the south and the Olympus Range in the north.
I do not intend to provide detailed results and discussion here. Results may be briefly summarised as follows:
Fish material consists of fin-spines, plates, skull plates, jaws, teeth, etc. These occur in red and green Aztec Siltstone, usually confined to narrow horizons out reworked and disseminated in to higher levels. Concentrated fossil pavements are common at some localities.
From my brief remarks on the geological results it should be apparent that the geological programme was a great success. The geological results will be published in either the N.Z.J. Geology and Geophysics or the Trans. Roy. Soc. N.Z. General summaries of the expedition will appear in the Polar Record (Cambridge), in Antarctic (N.Z. Antarctic Society), and in the Newsletter of the Geological Society of New Zealand.
A geothermal heat-flow probe for in situ measurements of both temperature gradient and thermal conductivity in sediments has recently been designed by D.A. Christoffel and I.M. Calhaem of the Physics Department, V.U.W. The aim of the expedition was to test this equipment at depths of up to 2,000 feet, and to obtain geo thermal heat-flow readings in McMurdo Sound, Antarctica. (Good results have already been obtained by Christoffel and Calhaem, using similar equipment, in Wellington Harbour). Normally such measurements are taken from a ship, but in McMurdo Sound the relatively thin (about 8 feet thick) sea-ice provides an ideal platform from which to work. To simplify the experimental work all of the equipment has been designed to pass through a 4 inch diameter sipri hole, which takes about three quarters of an hour to drill through ice of this thickness.
To obtain a heat-flow reading, at least three feet of sediment is required on the ocean bottom. The heat-flow probe is six feet long, and contains a 150 cm long thermocouple thermometer, which for good results must be embedded in the sediment for at least half of its length.
In a virtually unmapped area like McMurdo Sound, the only way to find mud is by trial and error. I used a piston-corer capable of obtaining a six foot long cylindrical core sample of the sediment. Its operation is quite simple. It is lowered on the end of a steel cable until it is about 20 feet from the bottom. Then it is released automatically from the cable and free-falls the rest of the way. Its momentum is sufficient to drive it into the sediment. It is then retrieved by means of a 20 foot long recovery loop which still connects it to the steel cable.
It will penetrate anything softer than solid rock, so if no core at all is brought up it can safely be assumed that the ocean bottom at that point is rocky. If, however, sufficient sediment is found, the procedure is as follows:
First a temperature gradient measurement is taken, and then a thermal conductivity measurement. The heat-flow can be calculated from these by a law analogous to Ohms law. For confirmation of the thermal conductivity readings the core samples are brought back to the university for further testing.
The expedition lasted from l6th November until 18th December 1963. A little over three weeks of this time was spent on the sea-ice between Ross Island and Butter Point. Altogether twenty-one attempts were made to find mud, and three were successful. The following table shows the results of each attempt.
(For location of each site see the accompanying map)
On the whole the floor of McMurdo Sound seems to be rocky, but small pockets of mud do exist. Their presence seems to be due to the following factors:
Thus there are many places, as yet unexplored, in this area where future heat-flow work may be profitably carried out.
For most of the time I was in the field (and for the few days beforehand at Scott Base while preparing equipment for the field) I was ably assisted by Bruce Brookes (assistant maintenance officer of Scott Base staff). For the last week, unfortunately, he was required for work at Scott Base and his place was taken by Simon Cut field, a member of the Vanda wintering over team. To both I wish to give my sincere thanks for their help.
I also wish to thank Robin Foubister and other Scott Base staff for their help and co-operation, and all others who helped to make the expedition possible.
As it was felt that a central location was probably most practical it was decided to dump all gear and stores at a base-camp half way up the eastern shore of Lake Fryxell.
While at Scott Base duties consisted mainly of checking equipment, and checking, painting and filling fuel and kerosene cans for the Boomerang Range and Dry Valleys parties; and one day general duties (ice party, shovelling snow, etc.).
A base camp was established on the north corner of a delta opposite the peninsula on the eastern shore of Lake Fryxell. The first four days were spent in general reconnaissance of the middle part of the valley, observation of local phenomena, e.g. polygons, salt deposits, sand entrained on down valley sides of boulders, ridges; removal of varnish, solifluction and other flow phenomena, stream channels, screes, etc. No progress was made towards recognition of till strata until the type section of Wellman and
The impression of a universal homogeneous mantle of till is reinforced by the thinning of the patina on the surface of all exposed boulders on the up-valley side, apparently due to the sand-blasting effect of the down valley gale (this effect is not so obvious in the Taylor Valley as in the Wright, but one such gale was experienced in each valley, that at Vanda gusting up to 59 knots). Sand entrained behind boulders during such winds tends to be partly dispersed after a week or so by the persistent north-easterly. McCraw divided his surfaces on the basis of “light” and “dark” moraine. This is a dubious distinction as (a) it may belong to the Kenyte Till where this is thin, and in the process of deposition the underlying volcanic till member has been cut and involved in the upper till; or (b) it may belong to another deposit, typified in this case by apparently undisturbed olivine basalt scoria patches often ten metres across and 25 cm thick, which apparently thinly overlies the Kenyte Till to the southeast of Fryxell and extends beyond it around the 500 metre bench on Nussbaum, and probably into the upper valley.
Each till member has a typical suite of rocks which can be recognised. This suite receives additions from local sources (as (a) above) but retains its essential characteristic. The Upper Till Member of the Taylor Formation carries boulders of kenyte and a medium grained dolerite, the underlying Volcanic Till Member has a high percentage of scoriacious sand and gravel, while the more recent advances from the east wall consist almost entirely of material derived from the Kukri Hills basement of granite, quartzite and marble.
Bedrock is exposed in the valley floor in the vicinity of Vanda Station but thin drift mantling the southern valley wall has been described as moraine. Quaternary deposits were examined superficially from above Don Juan Pond to Wright Lower Glacier. At the confluence of the valleys near the west end of Lake Vanda a sequence of moraines was examined in some detail, and these are the limit of recent down valley glaciation. This does not necessarily imply an
The presence of a 5 cm pecten layer in the deposits at the foot of Bull Pass which can only be satisfactorily interpreted as in place, implies that the Wright valley was once an arm of the sea. Local glaciers have extended into the valley floow at the Meserve Glacier, and these show a number of advances and retreats. These carry abundant olivine basalt scoria which has been dated greater than three million years (Denton & Armstrong, 1968). This is restricted to the flood plain of the Onyx River on the Vanda side and is not present in the loopMoraine, which without a doubt advanced inland. However, scoria is again present in the younger moraine at the Wright Lower Glacier, but there was insufficient time to determine whether the source was the Clark Glacier, the Newall Glacier, or the Wilson Piedmont proper. No kenyte was seen in this valley.
The hypothesis is proposed that
The writer wishes to acknowledge the generous assistance of both the Scott Base and Lake Vanda Station staff.
Between 29th November-8th January I carried out the following programme within the framework of the VUWAE party:
Although my original intention had been to investigate soli-fluction and/or talus slopes various circumstances inclined me to examine meltwater channels and alluvial fans. Eventually, it would seem that the results obtained will be more worthwhile, some attempt being made to relate geomorphic processes to a variety of postglacial events, particularly in the Vf right Valley. The completed project will include studies of talus slopes; hopefully in the Wright Valley some features of slope development will be tied to an absolute chronology.
At this stage complete answers cannot be expected. A variety of samples have been collected which should aid understanding of a number of slope and fluvial processes, both present and past. Further fieldwork, reading and laboratory analysis will be necessary before even approximate answers can be found. For these reasons the present report is interim and general.
Three groups of interrelated phenomena were examined: meltwater channels, deltas, and alluvial fans.
Little attention has been paid to the role of meltwater channels in landsurface sculpture in Victoria Land. As rainfall is negligible, almost all water in channels is meltwater. Only general observations (of both channel walls and channel bed) have been made to date. Little that is new or original has come from this general study other than recognition that processes associated with meltwater affect enormous area of the valley floors, particularly on the southern side of Lake Fryxell (Taylor Valley). No attempt has yet been made to map the extent and character of various meltwater deposits and forms (this mapping constitutes part of next year's field programme).
The following features have been noted:
At the present time the processes and mechanisms leading to the formation of these features are imperfectly understood. A number of samples have been collected which may help to elucidate some problems. Further understanding of present-day processes and morphology should lead to reappraisal of the history of the meltwater channels, particularly in relation to old fan and delta systems formed during higher lake levels around both Lake Fryxell and Lake Vanda.
At present it is impossible to rank the processes in order of magnitude or relative importance. Indications are that processes are slow. Those that occur at readily observable rates such as sandflows, siltflows, low-angled fans, etc. are probably ineffectual in maintaining any gross modification of channel form. Detailed reexamination and re-measurement at regular intervals over lengthy periods will be required before each process can be placed in perspective but such observations must be undertaken if rates of land-surface sculpturing in Victoria Land are to be determined.
A series of deltaic deposits along the southern margin of Lake Fryxell was also examined in some detail.
Several workers have described these features as deltaic deposits formed at the time of higher lake levels. Evidence that these features are in fact deltas, includes: fairly horizontal fine bedding, presence of beds of finely laminated silts, general surface morphology, etc. All these criteria are, however, also consistent with fan formation and in my view it is not yet possible to determine whether these features formed inside or outside the lake margin, although there is little doubt that most are “graded” to old lake levels. Similar comments are applicable to the deltaic deposits formed on the margin of ancestral Lake Vanda.
The slopes connecting one deltaic surface to another (the riser) are of interest. Whilst these deposits are very unstable, the slope deposits only veneer the original deltaic/fan deposition. This suggests that, either the delta/fans are very young or that downslope movement, even on very unstable slopes, is extremely slow. Slopes on deltas above meltwater channels, where the channel has trenched through the deposits, also have only a veneer of slope deposits parallel with the present slope, lying unconformably on truncated horizontal sediments. While these slopes may be actively undercut by meltwater, they are similar to those which have been unaffected (except by downslope movement and wind) since the lake level fell. Furthermore, the importance of snow drifting and wind has not yet been ascertained.
In the Wright Valley attention was focused on one alluvial fan at the north east corner of Lake Vanda. Current processes on the fan surface are similar to those outlined for other meltwater channels. This fan is of considerable interest as it offers several good exposures which are useful in reconstructing the postglacial history of Lake Vanda. The alluvial deposits of the fan are underlain by till - it is not yet known which till. There is some evidence of a higher, steeper, and older fan surface which has been dissected. The
A series of beach ridges have been cut across the lower third of the fan to a height c. 55 m above present lake level. Wellman and Wilson (pers. comm.) have obtained an algal 14C date from this top surface of 3000 ± 50 years. A further sample from this level has been collected to check this date (sample 5). Algal samples have also been collected from four other levels. Samples 1 and 2 are from delta/fan surfaces respectively 22 and 25 metres above present lake level. These deltas have formed on the central channel of the three. As sample 5 also comes from adjacent to this channel and the fan/delta surfaces occur at many intervals down to present lake level along the channel, it is evident that this channel has been in use since the lake level was highest (i.e. approximately 3000 years). While the westernmost channel was also in use at this time it was not continuously so - deltaic/fan deposits being absent below about 45 m. At 23.5 metres on this channel an algal layer was collected from an old beach ridge. This ridge is cut in till, although there is some possibility that the deposit is actually a mudflow derived from till. If so this sample gives a minimum age for the flow as well as an age for the lake level 23.5 metres. The till shows evidence of cryoturbations/involutions. The sample thus provides a minimum age for these features even though their origin is not yet clear.
Since the algae grew at this site a frost wedge has formed on the beach ridge in the till, some of the algae having fallen into the wedge in V-shaped bands typical of ice wedge features. Sample 3 thus provides a maximum age for the ice wedge. Furthermore, it would appear that involutions and ice wedges cannot form at the same time as they almost certainly require completely different permafrost conditions. Both the frost wedge and the algae have since been covered by young streamflood/mudflow deposits; the algal date also gives a maximum date for this younger deposit. As the frost wedge is apparently now inactive, and has no surface expression, it is presumably a fossil ice wedge (as far as I know the first reported occurrence of a fossil ice wedge in Antarctica).
Sample 4 was collected near sample 3, at 20.5 metres above
The five samples collected have intrinsic value in that they establish a chronology for the history of Lake Vanda. Dr T. Torii (Chiba Institute of Technology) has also collected 5 algal samples from the north side of Lake Vanda. While the exact elevations at which he collected his samples are not known to me, two of them come from 5-15 metres above present lake level, and one from about 45 metres. Thus a fairly complete chronology should be available.
The samples collected should also have other values (such as providing maximum ages for the overlying deposits). Samples 3 and 4 considered together provide some measure of the rate of slope development under certain circumstances. Other samples will give, on further field investigation, fairly reliable estimates of rates of deposition on the alluvial fan surface as well as indications of the periods when each meltwater channel was in use. Such interpolation will be approximate but a rough estimate of rates of erosion/deposition will still be superior to our present understanding of rates of geomorphic processes in this part of the Wright Valley.
As the lake levels which cut across the fan surface also cut across talus slopes to the west of the fan it should be possible to gain further knowledge of rates of processes from this area. General reconnaissance observations along these lines were begun but are not reported here; more detailed work was held up by the lack of precise levelling equipment, bottom samplers, etc. The details required to make full use of this chronology have been included in the outline of fieldwork for the 1969/70 field season.
I would like to thank Mr R.B. Thompson, Superintendent of Antarctic Division, D.S.I.R., and Professor R.H. Clark of V.U.W. for their respective parts in arranging for me to undertake fieldwork in Antarctica. My thanks also to Burt Murrell for his cheerful companionship, culinary capabilities and critical comment, while in
The expedition wishes to acknowledge, with gratitude, financial assistance provided by the University Research Grants Committee. To Professor Clark we extend our thanks for his assistance, guidance, and interest in our programme.
We wish to express our gratitude to Robin Foubister and his staff at Scott Base for the personal interest they took in our work and the assistance given the expedition both at Scott Base and in the field.
I am happy to acknowledge the generous assistance provided during the season by members of the U.S. Navy VX-6 squadron. In particular, I must mention the crews of C130 (Hercules), 313 and 319; Lcdr Stewart, Maj. Noll, Maj. Cantrell, Lt Vivian, and Lt Lasher; and helicopter commanders Lt Freeman and Lt La Rochelle.
Carlo Mauri and Alessio Ollier, our two field assistants on the Boomerang Range trip, spent many cold and uncomfortable hours waiting for us while we measured our way up and down sections and laboriously collected fossil material. We wish to express our gratitude for their assistance and surprising patience and hope that there were other aspects of this trip which proved a compensation.
Our thanks to Bob Thomson and his Antarctic .Division staff for assistance with logistic and clerical matters.
Our grateful thanks are extended to John Ricker and staff at the U.S.A.R.P. headquarters, McMurdo.
Barrie McKelvey expresses his gratitude to the University of New England, Armidale, for leave to participate in this expedition.
Similarly, Peter Webb thanks Dr Kear and Dr Hornibrook for granting leave from the N.Z. Geological Survey for the duration of the expedition.
John Andrews is thanked for attending to the financial aspects of
Denis Rainey provided maps and air photos from the Lands and Survey collections.
Our special thanks to Mrs M. Brown, Micropaleontology Section, N.Z. Geological Survey, Lower Hutt for preparing the typescript of this immediate report.
And lastly, may I take this opportunity of thanking all the members of this year's party for the contributions they made to this most enjoyable venture.