Other formats

    Adobe Portable Document Format file (facsimile images)   TEI XML file   ePub eBook file  

Connect

    mail icontwitter iconBlogspot iconrss icon

Victoria University Antarctic Research Expedition Science and Logistics Reports 1971-72: VUWAE 16

VWAE 16B - PART 1

page 16

VWAE 16B - PART 1

On November 18 four helos took the party of four, Askin, Barrett, Bright and Chinn, with tents, two Sno-tric toboggans, 3 sleds, 100 gallons of petrol, and other supplies, to the foot of Mistake Peak on the north side (77° 26.1′S; 160° 12.5′E; map elevation 2550 m) arriving about 12.30. The weather was clear and calm. However the wind rose in the evening and remained most of the time until November 25 above 15 knots. Most of the geology accomplished in this period was of a reconnaissance nature, so that our work when the weather improved was more efficient.

Although the toboggans were started and mixtures adjusted as soon as we landed in the field, we had difficulty starting the engines during the period of high winds (see report by Chinn to Leader, Scott Base. We also found that even after the engines were warm they could not develop enough power initially to move the toboggan without our pushing. Fortunately the performance improved considerably after the machine had run for about 20 minutes, presumably as the rubber track limbered up. Even so toboggan 1 was capable of pulling a 400 lb. sled up a smooth slope of only 3°. Toboggan 2 soon developed a slipping clutch, which Chinn remedied by stretching the clutch springs slightly. The toboggan was not as fast (4 mph max.) but could pull half as much again up the same slope. Toboggan performance was thus adequate, but somewhat disappointing.

During the period November 26 to December 2 the weather was clear and calm and a great deal of work was accomplished. As well as local work close helo support was requested to follow a visit by filmmakers from Scott Base. The 40 minutes flying time available allowed us to reach Skew Peak, a previously unvisited and rather inaccessible peak 10 km north of Mt. Bastion. A partial section and some Triassic plants discovered during the 1 hour stop. By December 2 most of the mapping of the Shapeless Mountain area was completed and proved to be a far more difficult and complex job than had been envisaged. Also a variety of well-preserved Triassic plants, including fern fronds, bamboo-like stems, grass-like leaves, small seeds and a flower were found on a platform 2 km northwest of the summit of Shapeless Mountain. The reason for the complexity of the geology and the shapeless character of the massif is that the area was the site of major explosive volcanic eruptions 150 to 180 million years ago. These have thrown up huge blocks of Beacon sandstone several hundred metres, tilting some to near vertical attitudes. Large dykes of volcanic breccia, representing this explosive phase were described and mapped for the first time from this part of Antarctica.

The party moved to Mt. Bastion (77° 18.9′S; 160° 26.5′E; map elevation 2450 m) on December 3, and the following day were confined to camp by whiteout and heavy snowing. From December 5 to 9 the sequences at the south end of Robison Peak and on the east ridge of Mt. Bastion were measured. The Bastion section, which extended down for 1200 m (4000') from the summit was made especially difficult by a page 17 snow accumulation of 10 cm in the December 2-4 period. Wind and whiteout after December 7 added to our difficulties. Helicopters supporting U.S. Geological Survey surveyors in the area brought mail on December 5, and were viewed enviously by two of the party as they began the climb up from low on the face of Bastion. However the work was completed on December 9, and in addition areas around Gibson Spur and west of Skew Peak were mapped.

On December 10 the party attempted to move to Mt. Fleming, but shortly after leaving Bastion blizzard conditions developed and we successfully navigated by compass to the Mistake Peak base. The weather cleared early next morning and we moved immediately to Mt. Fleming (77°32.8′S; 160°06′E; map elevation 2150 m). As soon as camp was established work was begun and we measured and mapped until late evening. By the following morning the blizzard had picked up again, and did not subside until 1900 hours. We then set out to complete the essential description at Fleming, and recovered 200 lbs. of excellently preserved Glossopteris leaves at a locality discovered the previous evening. In addition Glossopterid leaves were found in continuous sequence with and only 30 cm above the glacial beds, thus providing an opportunity to determine the age of the tillite more or less directly for the first time. Suspecting that the weather would not last, we rose after a brief sleep (Dec 13/0800) and while Askin and Bright completed the remaining essential descriptions Barrett and Chinn began moving camp and making a trail of rocks towards Mistake Peak for several miles, where a helo pick-up had been arranged for the following morning. However the fog moved in from the east at amazing speed, and by 1200 visibility was reduced to 50 metres. After a misty rendezvous with Askin and Bright the party made a temporary camp at the end of the marked route and informed Scott Base of their position. However shortly afterwards the whiteout lifted and the party arrived at Mistake Peak at 2200 ready for pickup the following day.

The December 14 pick-up was delayed for six days mainly because of indifferent weather in the pick-up area (December 16 and 17) or in the McMurdo area. The party planned to move to Mt. Feather and then be returned to Scott Base on December 21. However on December 19, when no helos were scheduled, it was decided to delay the Mt. Feather visit until the second phase of the season's work. Pick-up and return to Scott Base was affected at 1100 on December 20 on the second attempt.