ABSTRACT

The texture and the detrital and secondary mineralogy of the 2000 feet of Permian Beacon rocks at Mt. Fridtjof Nansen, Mt. Wade and Cape Surprise are described and discussed.

The thin discontinuous basal conglomerate is thought to be of glacial origin on the basis of texture and field occurrence. This conglomerate and the overlying 600 feet of shallow water sediments were derived from terrain that was partly granitic and partly high-grade metamorphic; the source of the sediments of the overlying coal measures was a terrain consisting mainly of metasedimentary and high-grade metamorphic rocks. The source area probably was part of a larger old Antarctic shield.

Thermal metamorphism of thin calcareous layers at Mt. Fridtjof Nansen has produced grossularite and prehnite, implying temperatures of at least 300°C. as far as 200 feet from dolerite sills. The presence of pink zircons indicates an upper temperature limit of 450°C. Laumontite in the upper part of the coal measures at Mt. Fridtjof Nansen and Cape Surprise may have resulted from the alteration of volcanic ash.