Metalliferous Mineralization in the Western Antarctic Peninsula

Abstract

This work involved the study of various types of mineralisation at a number of localities, during two season's field-work in the Anterctic Feninsula. A number of additional localities of minor mineralisation have also been described. Mineralisation described in previous literature is listed. The "Quartz-Pyrite” rocks of the South Shetland Islands have been investigated and field-work and laboratory studies have shown them to consist of three types of hydrothermally altered lavas; advanced argillic, intermediate ergillic and phyllic alteration. These deposits appear to have formed by solfataric-epithermal alteration. A porphyry copper-molybdenum deposit hes been discovered north of Charity Glacier, Livingstone Island, that shows metallogenetic zonation from a bornite-chalcopyrite-molybdenite core to an outer zone of galena-sphalerite-chalcopyrite. Breccia dykes and propylitic alteration of the host tonalites are associated with the mineralisation. A porphyry molybdenum deposit has also been discovered on Argentine Islands, north west Graham Land. Molybdenite occurs along sheet joints in granodiorite and is surrounded by thin cuartz-pyrite and thick quart-magnetite veins. Quartz-monzonite dykes are associated with the molybdenite. The deposit shows zonation from a core of phyllic alteration (associated with molybdenite) to an outer propylitic zone. A porphyry copper deposit also occurs on Horseshoe Island, Merguerite Bay. Chemical date using atomic absorption spectrometery and electron microprobe methods has shown the igneous rocks associated with these deposits to be calc-alkaline and the sulphides to be similar to those in other calc-alkaline deposits. A model is proposed for the mineralisation in the Antarctic Peninsula. Tectonically, it shows some similarity to the Andean Cordillera of South America. It is proposed that a porphyry copper belt is present along the western side of the Antarctic Peninsula, which is followed eastwards by a polymetallic belt, both of which run parallel to the trend of the Antarctic Peninsula,