A contribution to the geology and glaciology of the western part of the Australian Antarctic Territory

Reconnaissance surveys based on the A.N.A.R.E. Station at Mawson (lat. 67Â° 36' S., long. 62Â° 53' E.) have covered Enderby Land, Kemp Land, MacRobertson Land and Princess Elizabeth Land between latitudes 67Â° and 74Â° South and longitudes 50Â° and 80Â° East. Less than one percent of this area consists of rock outcrops, the remainder being covered by permanent snow and ice. Coastal outcrops and islands occur at Amundsen Bay, in the King Edward VIII Gulf Stefansson Bay Mawson area, and in the Larsemann Hills Vestfold Hills area. Parts of the coastline show evidence of submergence, on which is superimposed a smaller uplift. Inland ranges occur in Enderby Land and to the south of Mawson. The latter, comprising the Prince Charles Mountains and their southern extension, rise to heights of more than 9,000 feet above sea level, and their northern portion is extensively block-faulted. Most of the outcrops consist of basement rocks of probable Precambrian age. Rocks of sedimentary origin are now represented by garnetiferous quartzite, hornfels, quartz-feldspar-garnet gneiss, and granular gneiss. The dominant igneous rocks are granitic gneisses and hybrid gneisses with minor aplite, pegmatite, gabbro, norite, pyroxenite, and hypersthenic. Several large bodies of charnockitic granite intrude other rocks of the basement complex, and are regarded as products of palingenesis. In several areas, the complex is intruded by dolerite dykes, believed to be of Mesozoic age, and by minor basalts, which may be late Tertiary or Recent. At the Amery Locality, about 250 miles south-east of Mawson, an area of about 200 square miles consists of flat-lying Permian arkosic sandstones and grits with minor pebble beds and coal seams. These are tentatively correlated with the Beacon Formation of Victoria Land. Both high-level and low-level moraines have been noted, and the latter include lateral, medial, terminal, and ground moraines. No mineral deposits of economic importance have so far been discovered in the area, but traces of copper, iron, manganese, coal, and radioactive minerals are recorded. Measurements of ablation, accumulation, horizontal movement, neve densities, and neve temperatures were obtained and the mass and heat economy of the ice cap was investigated. Near Mawson, blue ice predominates in the ablation zone, which extends to a height of about 2,400 feet above sea level. Melt-water streams, cryoconite holes, flow structures and crevassing were observed in this zone. Above this elevation, accumulation predominates and the plateau consists largely of neve, with a strong development of sastrugi and depositional layering. However, local areas of blue ice, often with severe crevassing, occur close to many of the larger inland rock exposures. These inland portions of the ice cap are drained by several major glaciers, the largest being the Lambert Glacier, more than 200 miles long and up to 30 miles wide, which feeds the Amery Ice Shelf 250 miles east of Mawson.

Tags: AQ, Bulletin, Earth Sciences, GA Publication, Published_External, geology
Organization: Geoscience Australia Data