A. Glacial Studies

1. An ice velocity and ablation pole network was placed and surveyed in Taylor Glacier. The surveying was done twice, early and late in the expedition, and included the 18 pole network placed by Sillars (Barrett et al 1976) at the snout in 1975.

   Approximate movement data (in metres) for some poles are given below (J. Palmer, Lands and Survey Department, Hokitika; pers. comm.). Figures in parentheses indicate the periods between surveys.

   A4	4.4	(27-30.12.75 to 22-24.10.76)
   B4	4.1	(27-30.12.75 to 22-24.10.76)
   C4	4.0	(27-30.12.75 to 22-24.10.76)
   A4	5.6	(27-30.12.75 to 3.1.77)
   B4	5.2	(27-30.12.75 to 3.1.77)
   C4	5.0	(27-30.12.75 to 3.1.77)
   D6	0.8	(1-2.11.76 to 6.1.77)
   E4	2.3	(1-2.11.76 to 6.1.77)

2. The ranges in ablation measurements (in centimetres) in the 7 lines of the 56 pole network are given below. Figures in parentheses indicate the periods between measurements.

page 8

• Ice temperature measurements were undertaken in 2 holes in Taylor Glacier, to depths of 17.5 and 15.0 m respectively. The mean annual temperatures and heat flow gradients at the two sites were determined to be as follows:-

  Hole 1	(660 m elevation);	− 16.2 ± 0.5°C;	0.22°C.m−1.
  Hole 2	(1266 m elevation);	− 22.7 ± 0.5°C;	0.25°C.m−1.

• Supraglacial pebble sampling was undertaken at 33 sites on the glacier in an attempt to determine whether various lithologies have differing rates of breakdown under the processes of 'fast-shattering' and 'freeze-thaw'. Englacial and proglacial pebble samples were collected to determine the degree of rounding and/or facetting on pebbles of different lithologies. Englacial pebble fabrics were also done to supplement those done in the 1975-76 season.
• Ten days were spent at the Thiel Earth Sciences Laboratory sectioning and describing ice samples collected from Taylor Glacier. This work involved determining general trends in the petrography between various types of ice, which will be related to the origins of englacial debris and clean ice layers.
• Initial observations on the Hobbs, Blue and Garwood Glaciers indicate that debris accumulations, in these high debris content alpine glaciers, is more likely to be supraglacial as opposed to a probable subglacial origin for Taylor Glacier debris.
• Gravity profiles perpendicular to the flow of the Taylor glacier were carried out along lines A, D, E, F, G. An additional longitudinal profile was carried out from D line to Lake Bonney. In total ninety gravity stations were occupied.

Due to the large density contrast between ice and rock, the resulting bouguer anomalies may be interpreted in terms of ice thickness.

The initial reduction of data from G line gives a maximum anomaly of − 59 mgal, indicating a thickness of ice of the order of 1000 metres. However previous work with a radio echo sounder (Calkin, 1974) indicates an ice thickness of 800 metres.

Thus any plausible interpretation model must include a layer of lower density sediments between the ice and basement.

References:

Barrett, P., Collen J., Eggers, A., Palmer A., Robinson, P., Sillars, K., 1976. Immediate Report of Victoria University Antarctic Expedition 1975-76.

Calkin, P.E., 1974. Subglacial Geomorphology surrounding the Ice Free Valleys of Southern Victoria Land, Antarctica. J. Glaciology, v.13(69), p.415-29.

page 9

B. Salt Studies

1. Sampling in Kennar Valley and around Taylor Glacier completes a programme of sampling from the coast to the Lashly Mountains 90 km to the west, at the edge of the polar plateau.
2. Microscopic examinations of various salt samples were undertaken in the field and at Scott Base to help elucidate the patterns of salt crystal growth. The examinations indicate that wind erosion of surface salt deposits is extensive in some deposits.
3. Surface and soil temperatures and frozen level depths were measured on several basalt cones on the slopes of Mt. Discovery. These show that sunnier slopes tend to have shallower frozen levels indicating that more moisture is present in such soils for salt dissolution and distribution.

4. The area of mineral discharge (Black et al, 1965) at the snout of Taylor Glacier was closely examined. Another saline discharge has occurred since the summer of 1975/76, mainly on the lateral stream delta. A cold (min. temp. − 7.8°C) saline spring was found flowing in late November, near the source of the lateral discharge. Such a spring does not appear to have been observed previously although Hamilton et al (1962) describe a saline "ice platform" at this location which was probably similar to the saline ice build-up from this most recent discharge. Estimated spring flow rates show some diurnal variation and possibly a relationship with spring temperature. No simple relationship exists between flow and air temperature and/or pressure.

   The orange coloured layers in the glacier around the glacier discharge site were mapped. They do not outcrop more than 200 m from the site. Other englacial dirt layers on the surface further up Taylor Glacier appear to be mainly diffuse, low concentration rock debris layers, although one sharp high concentration layer containing mainly (basaltic?) tephra was found. These layers were previously believed to be extensions of the orange layers at the snout.

5. The volume percentage of tephra in englacial layers was measured for layers in the glacier between Mts. Morning and Discovery and in the Fang Glacier windscoop. Volume percentage is a useful parameter for distinguishing direct airfall deposits from wind deposited tephra and for describing englacial debris layers generally.
6. Snow free areas around the summits of Mts. Morning and Discovery were examined for traces of 'volcanic' salts such as are found on Mt. Erebus and the Fang. None were found.
7. The large (up to 20 m high) snow and ice features around the summits of Mt. Morning and Discovery were examined and ice sample densities measured. Their external and internal structures indicate that they are snow depositional features modified by strong mainly southerly winds. Direct condensation from clouds appears to be an important accumulation process. Although some of the "towers" on Mt. Discovery resemble the fumarole towers of Mt. Erebus, present day geothermal activity is not the cause of the Mt. Discovery and Mt. Morning structures. Structures similar to the latter are found on certain Marie Byrd Land volcanoes and were considered by Le Masurier and Wade (1968) to indicate fumarolic activity there. In the light of this season's work such a conclusion may be unsoundly based.

page 10

References:

Black, R.F., Jackson, M.L. and Berg, T.E. (1965). Saline Discharge from Taylor Glacier, Victoria Land, Antarctica. J. Geol. v.73(1), p. 175-81.

Hamilton, W., Frost, I.C., and Hayes, P.T. (1962). Saline Features of a Small Ice Platform in Taylor Valley, Antarctica. U.S. Geol. Survey Prof. Paper 450-B, p. 73-75.

Le Masurier, W.E. and Wade, F.A. (1968). Fumarolic activity in Marie Byrd Land, Antarctica. Science v.162, p. 352.

C. Moss Ecology

1. Areas where moss found:

   Areas around streams below the Rhone, Hughes and Calkin Glaciers in the Taylor Valley, the moraines below the Hobbs Glacier and in the Salmon, Garwood and Towle Valleys, and in the Scott Base, McMurdo Station area.

2. Areas searched, sometimes briefly, where moss was not found:

   Kennar and Beacon Valleys, area below La Croix Glacier and the side of the Taylor Valley around Lake Bonney not near melt streams below alpine glaciers. Although a week was spent searching in the Northwind Valley east of the Towle Valley, no moss was found.

3. Most patches of moss found below 330 m altitude were on sandy 'soil'. The few patches found in the Towle Valley above 1000 m were in cracks in dolerite blocks.
4. Algae and lichens were recorded from most of the areas visited. Most outcrops or rocks of Beacon sandstone had blue green algae growing just below the rock surface. Algae, such as Nestor sp. were frequently found in pools and other wet areas and lichens in rock cracks and on the surface of rocks.
5. Detailed quantitative surveys of moss were done below the Rhone, Calkin and Hughes Glaciers and on the delta below the snout of the Hobbs Glacier.
6. Sponophytes on Bryum antarcticum were collected from the Hobbs, Cape Chocolate area. Sponophytes (the sexual reproductive stage of a moss) have been recorded from Victoria Land only twice before.
7. Mosses were studied to 1300 m altitude in the Towle Valley, having previously only been recorded up to about 300 m altitude in Continental Antarctica.
8. The Garwood valley near the Garwood Glacier snout had the highest cover of moss of the areas studied.
9. Air spore samples were collected daily but these have not yet been studied.page 11
10. Fresh algae was collected from Lake Fryxell and Lake Vanda for C₁₄ dating standards for use by the Institute of Nuclear Sciences.
11. Soils were sampled for tests for microorganisms, pH, carbon and nitrogen content.
12. The ecological data recorded in the field will be analysed by computer for correlations between environmental factor and presence and absence, and cover of species.
13. Identification of specimens collected will be done by Botany Division, D.S.I.R., and Dr. S.W. Greene, Institute of Polar Studies, Great Britain.
14. A mummified seal was found beside the west side of the Northwind Glacier about 2 km from the snout. A mummified penguin was seen near the head of the Towle Valley.

D. Fry Glacier region

1. The previously geologically unmapped area of approximately 1500 sq.km was completely mapped. This area extends from the Convoy Range in the west to the Kirkwood Range and lower Fry Glacier in the east, and from Trinity Nunatak in the north to Benson Glacier and Mt. Razorback in the south.
2. Beacon Supergroup sediments were studied in detail at at least 14 sites. Most of the sediments which were exposed were mainly the Arena Sandstone and Beacon Heights Orthoquartzite of the Devonian Taylor Group.
3. The Aztec Siltstone, the topmost formation of the Taylor Group, was missing. It appears to have been eroded off by ice in the Permian - Carboniferous. The Metschel tillite was deposited on this surface, but as the climate improved much of the tillite was removed and a coal-bearing sequence, the Weller Coal Measures, was deposited.
4. The sandstone forms large rafts "floating" in Ferrar dolerite. This was emplaced as sheets in the Jurassic and now forms the most common rock type in the area.

E. Mt. Erebus

1. The temperature of the lava of Mt. Erebus was measured for the first time, using a Leeds-Northrup Co. Optical Pyrometer. A value, uncorrected for emissivity, of 980 ± 20°C was obtained.
2. The lava lake has slightly expanded in area since December 1975.
3. The activity of the volcano in December 1976 was less than it has ever been during monitoring periods since they commenced in December 1972. During the 10 day period spent at the summit, no eruptions were heard and no fresh bombs seen. However quite loud "whooshing" sounds from the Inner Crater were relatively common.
4. It is possible that major slumping may be commencing in the non lava half of the Inner Crater.page 12
5. The geothermal cave system (Giggenbach, 1976) near the camp has changed significantly, due to partial collapse of the roof and floor in places, and inblown snow. Air and soil temperatures in and around the "seismological chamber" have increased in places and decreased in others, as have tunnel and chamber diameters. Access to the "seismo" chamber was more difficult than in previous years and may become even more difficult as blown snow accumulates inside the entry chamber. Easier access may be possible via the chamber below an enlarged tower forty metres up-slope from the usual one.

Stronger variable winds than in previous years inside the "seismo" chamber indicate that the new exit has altered the convection system and possibly the "delicate heat balance" (Giggenbach, 1976) inside the cave system. Certainly there is much more snow and ice inside the entry chamber than in previous years.

Reference:

Giggenbach, W.F., 1976. Geothermal ice caves on Mt. Erebus, Ross Island, Antarctica. N.Z.J. Geology Geophysics, v.19(2), p.365-72.