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A Victoria University of Wellington Antarctic Expedition was again mounted in the 1962-63 summer to carry out investigations of ice free regions in the vicinity of the Darwin Glacier, about 175 miles south of Scott Base (see fig. 1).
Financial aid for the expedition came from -
University Research Grants Committee
University of Wellington
National Science Foundation of America which supported
Dr. Rich and Mr. Smith.
This season it was decided to send a six man expedition so that it could operate as three two-man parties in the field. The personnel were:
Temporary Junior Lecturer, Geology Department, V.U.W. (Leader).
The personnel formed two distinct teams; one geological (I.W., T.H., J.K., W.P.), this team operating as two-man parties, and one glaciological (Dr. Rich and Mr. Smith).
As a safety factor and for a greater "social life", the parties camped together whenever possible, and where this was not possible contacted each other daily by radio.
After a reconnaissance of the Brown Hills and lower Darwin Glacier by Professor R.H. Clark and Mr. R.H. Wheeler in October 1961 it was decided to send an expedition into this region. It was planned that the expedition would map the Brown Hills (200 sq. miles) and then sledge (man-hauling) across glaciers to Darwin Mountains (200 sq. miles) and/or Tentacle Ridge (90 sq. miles). This was expected to occupy the 8-10 week field season. In case the glaciers could not be crossed the Taylor Valley (600 sq. miles) was considered as an alternative area to be mapped after Brown Hills.
As well as geological mapping and a glaciological study the expedition planned to collect botanical and zoological specimens wherever possible and take Meteorological records.
As the expedition was working further south and at higher altitudes than previous Victoria University parties, it was decided to outfit it with new equipment. (Most of the gear held by the university has served at least two seasons in Antarctica.) This year, for the first time, the larger part of the grant was allocated to Antarctic Division, D.S.I.R., and most of the equipment, clothing and food was bought through them. Antarctic Division also loaned the expedition a considerable amount of gear thus helping to keep the cost to the University down.
Reports summarizing the various fields investigated are given later.
The expedition mapped the Brown Hills region - this taking less time than allowed for as the geology was less complex than expected. As the party could not sledge across to Darwin Mountains or Tentacle Ridge, air support was asked for to allow the mapping of Darwin Mountains.
Due to the short length of time required in the Darwin Region it was decided to map Taylor Valley as well this season. As well as dealing with Taylor Valley itself the expedition spent a few days at Marble Point, a few miles north east of Taylor Valley. This work completes the detailed coverage by V.U.W.'s Antarctic Expeditions 1, 2, 3 and 4 in the "McMurdo Oases" - a largely ice-free region stretching from the Koettlitz névé north to McKay Glacier, an area of about 3,000 sq. miles.
Numerous samples of lichen and algae were collected from the Darwin region, and lichen, algae and moss from the Taylor Valley. Also collected from Taylor Valley were several species of "mites" and "springtails" and from along the coast samples of marine life.
As previous V.U.W. Antarctic Expeditions have also collected lichens, algae and moss and after handing them over to "interested" people outside the University have, in most cases, not received any indication that any work is being done on them, members of this year's expedition intend to do their own research work as far as possible, and at least publish a preliminary note on their findings.
Unfortunately, due to an accident while unloading a Globemaster, the expedition's Barograph and Thermograph were smashed, so no continuous records could be obtained.
Dr. Colin Bull spent five days with the expedition in the Taylor Valley, during which time he did a gravity traverse of the valley. (See report later.)
Dr. Rich and Mr. Smith left New Zealand on 10th November, a week before the rest of the party, and were present on a reconnaissance flight which found a ski landing site on the western side of Brown Hills. (Helicopter support could not be used as on previous expeditions as the area was outside helicopter range.) The party was flown in to this landing strip in two ski equipped Dakota flights on November 22nd. It was decided to sledge the gear around Bastion Hill and establish a base camp in a large valley N.E. of Bastion Hill. This was accomplished on the 23rd and 24th. From this base camp the parties radiated out doing their respective work.
After a careful look from Bastion Hill at the routes from Brown Hills to Darwin Mountains and Tentacle Ridge, it was decided that the crossing of the glaciers was definitely out for a Victoria University expedition. Ait support to take the geologists to Darwin Mountains was asked for and granted. The geologists having finished work in the Brown Hills returned to the landing site on Dec. 10th to cross to Darwin Mountains. However, bad weather delayed the flight for ten days during which time the glaciological team also finished their work in Brown Hills, and this allowed the expedition as a whole to be flown by Dakota to Darwin Mountains on December 20th, where they worked until December 28th when they were flown back to Brown Hills.
A few days were spent celebrating a belated Christmas, packing up base camp and sledging the gear back to the landing site to be taken back to Scott Base. The expedition arrived at Scott Base on 1st January.
On the 2nd January Messrs. Haskell and Prebble with Dr. Colin Bull (Leader VUWAE 2, Deputy Leader VUWAE 4 - now at Ohio State University) left by helicopter for Taylor Valley and established a camp at the western end of Lake Bonney. This also served as a reconnaissance flight to determine sites for food dumps. Messrs. Kennett and Smith flew in on the 3rd and Dr. Rich and Mr. Willis on the 5th.
Four food dumps were established with helicopter support at approximately 10 mile intervals along the valley between Solitary Rocks to the eastern end of Lake Fryxell. The expedition worked from west to east along the valley, retracing their steps as little as possible.
Dr. Bull spent five days with the expedition doing gravity and glaciological work. This reunion with Dr. Bull was most unexpected and was enjoyed by all.
The expedition was lifted by helicopter from Lake Fryxell to Marble Point on 16th January and the next four days were spent doing geology, glaciology and collecting marine organisms in this region.
The expedition returned to Scott Base on 20th January.
Dr. Rich and Mr. Haskell flew back to New Zealand while the remainder returned on January 28th.
Several factors arising from this expedition are recommended for consideration for future expeditions. These are:-
The successful work of VUWAE 6 marks virtual completion of geological mapping by Victoria University of Wellington of the known ice-free areas. Future large expeditions will depend on the existence of suitable areas found elsewhere in Antarctica. There is still scope for some small scale expeditions to look at specific problems and map a few isolated areas that have been inaccessible to earlier expeditions.
Victoria University of Wellington Antarctic Expedition No. 6 wishes to especially thank:-
Antarctic Division, D.S.I.R. (N.Z.) for allowing us to purchase our gear through them, loan of some gear, and material help during the time of the expedition.
The services of the United States of America for air transport to and from Antarctica and especially the air support received while in the field.
Lt. Col. Ron Tinker. Leader Scott Base, for all his help and assistance given while we were in Antarctica, and for taking such a personal interest in our welfare.
Mr. Bob Mason, U.S.A., R.P. representative, McMurdo, for help and assistance.
Personnel at Scott Base, especially Messrs. Bill Goss, Guy Mannering and Graham Jackson, for their help and hospitality while at Scott Base.
Professor Clark, Geology Department, Victoria University of Wellington, who has made these antarctic expeditions possible.
Other grateful acknowledgements are made to:-
No previous geological expeditions have visited the area. Air reconnaissance of the geology of the area in early 1962 indicated that the rocks were comprised mainly of the basement complex intruded by dolerite sills with Beacon Sandstone exposed in the western part. It was hoped that a study of the basement would enable correlation to be carried out with the stratigraphic sequences established near the Koettlitz Glacier by the 1960-61 VUWAE expedition. However the geology was found to be different from the Koettlitz area and consequently little correlation was attained.
Using aerial photographs taken by the U.S. Navy the geology of the Brown Hills and the Darwin Mountains was mapped for about 400 square miles. The stratigraphic sequence established for the Beacon sediments enables correlates with other nearby areas, especially that of the Beardmore Glacier area (Grindley - in press) where the sequence is essentially the same.
Basement rooks occur in the Brown Hills region and consist mainly of granitic rocks of uncertain age, probably pre-cambrian or cambrian, cut by a series of acid and basic (lamprophyric) dykes.
Metasediments are very rare. The main outcrop east of Diamond Hill consists of about 100 feet of black and white bands of quartz mica schists with interbedded metaquarzite. The surrounding granite passes gradationally into the metasediments and appears to have been formed by metasomatic replacement processes. Two thin discontinuous bands of similar metasediments interleaved in granite occur elsewhere.
Granitic rocks constitute almost all of the basement. Several distinct granite types were recognized. In some cases they were able to be mapped separately over fairly extensive areas but elsewhere they were interbedded or irregularly emplaced with respect to one another. They range in appearance from coarse grained porphyritic, with strong foliation, to uniformly fine grained varieties, and from leucocratic to melanocratic in composition. It was found that the fine grained leucocratic granite was younger than the coarser grained melanocratic granite. Samples were collected for radioactive age determinations by potassium-argon and Rubidium/strontium methods.
Dike rocks, both acid and basic, are commonly in the basement complex. Age relationships were established in most cases between various types. Acid types are leucocratic and consist mainly of quartz and feldspar, and range from coarse to fine grained. Lamprophyres of two principal types, fine grained schistose and coarser grained non-schistose, both containing abundant biotite, are common.
Tentative age relationships of some of the granites and the dikes are as follows:-
Coarse grained mesocratic - melanocratic foliated granite, often Morphyritic.
Over 1800 feet of low dipping Beacon sediment unconformably overlies the basement. At Bastion Hill the contact of basement and Beacon is well exposed. The granite is weathered to a depth of 6-15 feet below the unconformity. At least 60 feet of quartz pebble sandstone is exposed as the basal formation on Bastion Rill.
Ten miles to the south-west at Darwin Mountains, the most basal formation exposed is about 600 feet of well sorted, finely bedded, cross bedded orthoquartzite. Good specimens of Beaconites antarcticus Vialov are common.
The orthoquartzite is overlain by 200 feet of light green siltstone containing scattered weathered pebbles and boulders of granite and metasediments. Some horizons are made up of very finely banded alternating mudstone and siltstone - microscopic analysis of sections of these may reveal grading, indicating them to be varves. A representative collection of pebbles was made for sectioning in order to establish provenance. The formation is similar to Gridnley's tillite in the Beardmore Glacier area.
The tillite is overlain by a 1 inch to 1 foot layer of pebbles and boulders of weathered granite and metasediment similar to those scattered in the tillite below. The layer represents an erosion interval in which concentration of the pebble-boulders from at least 100 feet of the tillite occurred. Immediately above the pebble band a discontinuous carbonaceous band occurs containing poor leaf and stem impressions of Gloesopteris and Gangamopteris. This in turn is overlain by 2000 feet of massive grey sandstone with thin interbedded grit layers.
The highest Beacon examined was 50 feet of light grey finely banded mudstone and siltstone with occasional pebble bands and contraformational breccias.
Samples of Beacon were collected where favourable throughout the section for spore and pollen analysis.
Sills and dikes of the Ferrar Dolerite formation intrude the basement complex and the Beacon Sandstone. Two principal sills occur in Brown Hills - one intruding the basement and another at, or near the basement/Beacon contact. The two sills are in contact but the lower sill is chilled against the upper indicating separate Dolerite intrusions. In the Darwin Mountains dolerite is extensively intruded as irregular sills dikes and lenses (which were too irregular in most cases to serve as marker horizons.) Rafts of Beacon occur irregularly distributed within the dolerite mass both at Bastion Hill and in the Darwin Mountains.
No materials of economic importance were found.
Only very brief reports have been published on this area. J.D. McCraw of the New Zealand Soil Bureau has recently (1962) published a paper dealing with the distribution of scoria cones and patches of the Taylor Valley.
The main object of this phase of the expedition was to map the rocks of the basement complex in order to correlate the geological work completed to the north by previous VUWAW expeditions (McKelvey and Webb, Allen and Gibson), and mapping work completed in the south in the Koettlitz region by VUWAE No. 4. Expectations were achieved and the work in the Taylor Valley essentially completes the geological mapping programme of Victoria Land Dry Valley region. A map of the geology of southern Victoria Land can now be compiled, editing all previous mapping work by Antarctic expeditions.
Using the base map compiled by U.S.G.S. on a scale of 1 cm. to 1 kilometer and aerial photographs taken by the U.S. Navy, an area of 600 square miles was mapped (fig. 3).
Rocks belonging to the basement complex constitute most of the Taylor Valley. Like the Koettlitz area they consist of schists, quartzites, marbles and granitic rocks of uncertain age (probably Pre-Cambrian), which are cut by numerous acid and lamprophyric dikes and sills. Three belts of northerly-striking rocks occur, separated from one another by granitic masses.
The metasedimentary rocks were divided into two formations. The stratigraphic relationship of these are unknown.
Granitic rocks include the following types:
The foliation in the granites is parallel to the dip of the metasediments. Orbicular granite occurs in situ near the snout of the Taylor Glacier, near a granite-metasediment contact. It forms two discontinuous bands which are parallel to the foliation of the granite and the dip of the metasediments. Orbs average about 5 inches in diameter and each is encrusted with a dark hornblendic layer. The degree of packing of the orbs varies from widely dispersed to closely packed, but not close enough to distort the fairly regular forms.
The basement rocks are cut by a series of dike rocks, ranging from acid to basic in composition. Tentative age relationships are as follows:-
Medium-grained basic dikes with biotite as an important mineral. This is similar to the dike rocks in the Brown Hills in composition and in that it cuts the Ferrar Dolerite formation.
"Railway line porphyry" - of probable composite origin where dark porphyritic bands, 4-5 feet in width border an internal 6 foot leucocratic band. The contact between the two types is sharp with possible baking of the outer portion by a later leucocratic middle.
Fine grained schistose to non schistose lamprophyre.
Fine grained leucocratic pegmatite.
Aplite.
"Bonney Porphyry" - porphyry with uncommon phenocrysts and a dark fine grained groundmass.
"Vida Granite" - medium grained homogeneous rook with pink orthoclases.
"Varda Porphyry" - grey coarser grained groundmass with mafic blebs and larger phenocrysts.
"Taylor Porphyry" - grey, with small needle or rhomb-shaped phenocrysts, the phenocrysts being more abundant than the groundmass. The relative ages of the latter two are unknown.
Other dike rocks cutting granite in which the age relationships have not been established are:- Finegrained "dioritic" dike with euhedral crystals of biotite and much felspar.
Beacon sandstone outcrops on the bigger peaks west of the snout of the Taylor Glacier. The contact of the basement with the Beacon Series was in no place observed as an extensive dolerite sill followed the contact. Over 2,000 feet of Beacon Sandstone occur in the upper Taylor Valley. It consists of finely bedded to massive current bedded ortho quartzite, with occasional pebbles and manganese nodules, and abundant worm casts throughout. Near the base discontinuous red and green bands occur. No carbonaceous remains were observed.
The Ferrar Dolerite formation consists of widespread sills intruding the basement and Beacon groups. Two major sills are present, one at the basement-Beacon unconformity and the other within the Beacon Group itself. The lower dolerite sill dips at about 40 to the west.
Numerous cinder cones of olivine basalt occur within the upper part of the valley. Their distribution has recently been described by J.D. McCraw.
No materials of economic importance were found.
Preliminary Report on a GRAVITY TRAVERSE in the Taylor Valley, Antarctica; by Dr. C. Bull, Institute of Polar Studies Ohio State University.
As a guest of the Victoria University of Wellington Antarctic Expedition, 1962-3, the writer made a series of measurements of the acceleration due to gravity along the Taylor Valley, south Victoria Land, between McMurdo Sound and the terminus of the Taylor Glacier.
The limited value of gravity measurements along a single line is appreciated, but these measurements add to the regional gravity coverage of the area, a significate part of which has been made by earlier Victoria University of Wellington Antarctic Expeditions (1959-9 in the Wright Valley and 1960-1 in the area north of the Koettlitz Glacier.)
The instrument used was a Worden Master Geodetic Gravity Meter operated without thermostating, because power supplies were not readily available. The temperature calibration of the instrument is known but the results here reported have not been corrected for the small variations in instrument temperature. The corrections involved are negligible compared with errors arising from other sources.
Values of gravity were measured at 17 points along the valley, at approximately 2 km intervals. (Fig. 1) The value of gravity at the Base Station near the end of the Taylor Glacier was determined by two linkages (by U.S. Navy helicopter) with the established gravity stations at the U.S. McMurdo Station 13, and Scott Base Gravity Station 2. The traverse along the valley was made on foot, the interval between the two readings at the base station being 25 hours.
Gravity stations were located at geographic features which are easily recognizable on the existing aerial photographs and on the 1:50,000 planimetric and 1:100,000 topographic maps of the area produced by the United States Geological Survey, Special Maps Division, Washington.
The altitudes for the gravity stations given in this report were obtained with a small temperature-compensated hand altimeter. As given here they are probably not reliable to better than 50 feet, and at stations 10 to 16 inclusive the error may be larger. However the altitudes of the stations were measured again later in the season with better altimeters. Further, most of the stations are on the edges of lakes, the altitudes of which have been calculated by aerial triangulation methods during the process of map construction, by the U.S. Geological Survey. Final values for these altitudes should be correct to about 20 feet.
In reducing the data it has been assumed that all of the rock between the gravity stations and sea-level is of density 2.67 gm.cm.−3. No allowance has been made for the lesser density of the glacial deposits at the mouth of the valley, but the errors arising from this should not exceed 5 milligals. Terrain corrections have not-yet beep applied. These may amount to 10 milligals (1 milligal = 0.001 cm. sec−2.) at stations 11 to 16 inclusive, but elsewhere they should be smaller and the application of the correction will not appreciably alter the overall picture presented by the results.
Values of the Bouguer anomaly decrease westward from −55 milligals at the mouth of the valley to −137 milligals near the end of the Taylor Glacier. (Table 1) At the eastern end of the valley the gradient of the anomaly is approximately 3 milligals/kilometre, which is comparable with the gradients of 5 milligals/kilometre observed near the coast in the Wright Valley area, (C. Bull, "Gravity observations in the Wright Valley area of South Victoria Land", New Zealand Journal of Geology and Geophysics) and at the eastern end of the ice-free area north of the Koettlitz Glacier. (C. Bull, "Gravity
Such gradients are consistent with the existence of a north-south fault line along the coast, the eastern side being down-thrown. It has been considered that the Victoria Land mountain range, bounding the inland ice of eastern Antarctica from latitude 70°S to 85°S, is a horst structure and that the coastal north-south fault line is one limit of the horst. However, geophysical studies on the inland ice west of the Victoria Land mountain range have not provided good evidence for the existence of the fault which should mark the western limit of the horst structure.
The gradients of gravity along the Taylor Valley are also consistent with an abrupt increase in thickness of the crustal material of the earth from a value of about 17 kilometres in the Ross Sea area to about 40 kilometres under the western part of the Victoria Land range. Further geophysical considerations must await the integration of these results with the others previous obtained in the area.
It is a pleasure to thank all of the members of the Victoria University of Wellington Antarctic Expedition for their help and friendship, and particularly Messrs. T.R. Haskell and W.M. Prebble who accompanied me on the traverse. Operation Deepfreeze and the U.S. Antarctic Research Program authorities co-operated wholeheartedly. My part in the work of the expedition was supported by a grant from the United States National Science Foundation, (Ohio State University Research Foundation Project 1444).
Data of gravity stations in the Taylor Valley.
The units in columns 5, 6 and 7 are cm/sec2.
In the Darwin Glacier area indications of three distinct phases of glaciation were found. The initial phase was a complete covering of the area by ice except for several peaks which protruded as nunataks. (This phase after retreating left a ground moraine of boulders which have been stained brown by the formation of iron oxides and exhibit cavernous weathering. Other features noticed were the disintegration in situ of coarse grained boulders, exfoliation shells, salt encrustations, well developed polygonal ground, and some ventifacts in the Diamond Hill area.)
A later phase less extensive than the first was confined to valleys, cirques and glacier margins. (In the Darwin Mountains several cirques (5500 - 6000 ft a.s.l) showed lateral and terminal moraines formed during this period. The hanging glaciers in the Darwin Mountain area did not extend down to the Darwin or its present day tributaries. In the Brown Hills area the North and South glaciers flowed into the Darwin and the ice level was approximately 100 ft. higher than at present. The formation of frost polygons and iron oxides is not as well developed as in phase one. The cavernous weathering and salt formation are similar. Several-crevasse fillings were noted in the moraines at Brown Bills.)
A more recent advance of the ice is indicated by limited areas of lateral moraine along the Darwin and Hatherton Glaciers and by terminal moraine in Smith Valley and a small area in a cirque on Colosseum Ridge. (The rough outlines of the moraine heaps are being modified by solifluction which is causing slumping. No brown weathering, cavernous weathering, salt formations or lichens were noticed. In Smith Valley coal fragments are lying on the surface showing no signs of decomposition.)
Three glaciers were staked in this area. The Darwin Glacier was staked at its narrowest part between Diamond Hill and Cranfield Icefalls using six bamboo poles placed half a mile apart. North Glacier was staked just below the icefall with five poles one hundred yards apart. South Glacier was staked up the centre with six poles half a mile apart, two poles approximately on the firn line and a row of six poles across the glacier three miles from the glacier snout. The position of the poles relative to reference points on bedrock was found using a theodolite but no resurveying to check the ice movement was carried out.
Evidence for four phases of glaciation was found in the Taylor Valley. The accordance of summits of the Asgard and Kukri hills is not due to structural control and indicates an ancient ice planed surface. The Taylor Valley was carved out down to the high benches best preserved on the North side of the valley where they are 3800 ft. a.s.l. This was followed by an interglacial period during which the valley was probably deepened by fluvial action. The second glaciation formed benches 2100 ft a.s.l. on the slopes of the Kukri Hills. An early eruption of basalt now occurred and the basalt fragments on the 2100 ft benches were later covered by moraine from the third glacial advance, when ice refilled the valley to 2500 ft. (Heights in the vicinity of Lake Bonney.) After the ice retreated extrusion of basalt from numerous small vents took place. These are found on both valley walls west of Hussbaum Reigel between 2500 and 5000 ft. and overlie the moraine deposited during the first three glaciations.
After more downcutting, possibly by fluvial action, the Taylor Glacier readvanced and rose to the highest lateral moraine level visible near Lake Bonney (1050 ft.) The present-day hanging glaciers also advanced and coalesced with the Taylor Glacier.
The Ross Ice Shelf was much higher at this time (J. Holling: Journ. Glaciology) and flowed into the Taylor Valley up to the base of the bedrock exposed on Nussbaum Reigel. (Evidence for this is given by the presence of kenyaite pebbles in the moraine and by the lateral moraines 1500 ft a.s.l. near the coast which dip gently inland (Kenyaite outcrops in the Mt. Discovery and Koelitz Glacier areas to the south of the Taylor Valley.)
During the most recent retreat of the Taylor Glacier a cool phase or increase in precipitation caused the side glaciers to increase slightly in size. These have now also retreated leaving lateral moraines which overlie the lateral moraines of the Taylor Glacier. The glaciers in the Taylor Valley seem to have reached a state of equilibrium at present except for the Taylor Glacier itself which may be still slowly retreating.
left Lyttelton on Friday 14/12/62 on U.S.S. Arneb, and arrived in McMurdo Sould on Saturday 29/12. We stayed at Scott Base until Thursday 3/1/63, waiting for gear which was not unloaded from Arneb until 2/1. Benseman and Shirtcliffe arrived at Lake Bonney p.m. 3/1 with most of the gear, Popplewell bringing the remainder in a second helicopter flight in the evening, and base was set up in a hut at the eastern end of the lake.
4/1 and 5/1 were spent overcoming initial difficulties with ice drills and measuring techniques. 6/1 was again unproductive, much of the day being spent in the hut preparing for chemical analyses and trying without success to remedy the internal disorders of potentiometer and galvanometer.
From an early start on 7/1 good progress was made using spare measuring equipment. The daily routine consisted of making measurements in 3 holes before lunch and drilling another 3 during the afternoon, thus allowing at least 12 hours to elapse after drilling a hole before any measurements were made in it. The plan was to drill an initial line of 12 holes in the eastern half of the lake, north of the centre line, followed by 1 hole in the narrow neck joining the two halves, 3 in the western half of the lake, and finally a line of 5 in the eastern half, south of the centre line. This would have taken seven days, leaving four days at the end for such additional measurements as may have been found necessary, bottom sampling, photography of ice formations etc.
This programme was based on the initial request for two weeks in the field. Owing to transport difficulties time in the field had to be cut short, and we left p.m. Wednesday 9/1.
In all, temperature profiles were measured in 11 holes. Of these the first two were shallow and of limited use, the last included readings at a few depths only, and one contained an equipment error induced by last-minute haste. The remaining 7 profiles should provide good information.
A radiation profile was measured once only, and was hampered by cloud.
While Benseman and Shirtcliffe were engaged on these measurements, Popplewell investigated and collected samples from melt streams at the eastern end of the lake, and also a valuable set of samples from one hole in the lake. Chloride analysis was completed on these samples in the field as insurance against their loss, and further analysis will be continuing for some time in the laboratory.
The initial conclusion is that the high temperatures in the lake are due to the trapping of solar energy, but the details are not yet clear.
In order to complete the investigation the following work must be done
It would also be desirable to devote some time to a study of the ice cover and the mechanism of evaporation from it, get an estimate of the annual water inflow and salt accretion, take bottom samples, etc.
The total work remaining would probably occupy 3 men for a week from the time a routine was established - say 10 days in all.