The Dufek intrusion of Antarctica

Abstract

The mostly ice-covered, stratiform mafic Dufek intrusion of the northern Pensacola Mountains occupies an area of more than 50,000 km 2 and has an interpreted thickness of 8-9 km. It is thus one of the world' s largest igneous bodies of this type. It has many petrologic similarities with resource-rich intrusions such as the Bushveld Complex (South Africa) and the Stillwater Complex (Montana), but its potential for resources is poorly known. The occurrence in the Dufek intrusion of magmatic ore deposits similar to those of other layered mafic intrusions seems likely. Among possible resources, platinum group elements (PGE) would have greatest economic feasibility for exploitation. The Dufek intrusion is of Jurassic age and coeval with Ferrar magmatism of the Transantarctic Mountains. It was emplaced within a multiple-deformed mobile belt of Triassic and older age adjoining the craton of East Antarctica. Cumulates of earliest origin, presumably in part ultramafic, and those of a 2-to 3-km-thick intermediate interval are not exposed. Mafic cumulates of nearly 2-km-thick exposed sections in Dufek Massif and stratigraphically higher in the Forfestal Range show chemical and mineralogic differentiation trends of Fe enrichment comparable to those of other major stratiform intrusions. Sulfide minerals are markedly more abundant in the higher part of the intrusion, where highest PGE abundances are found. However, a possible comparison with the Bus hveld's PGE-rich Merensky Reef suggests greatest resource potential in the Dufek's concealed basal section, which requires drilling for evaluation.

Glacial geomorphology and cosmogenic 10Be and 26Al exposure ages in the northern Dufek Massif, Weddell Sea embayment, Antarctica

“…Its geology has been described by Behrendt et al . (1974), Ford (1976, 1990) and Ford et al . (1978) and geophysically surveyed by Ferris et al .…”

“…The total area of the Dufek Massif is 11 668 km 2 and its highest point is England Peak (2150 m). Its geology has been described by Behrendt et al (1974), Ford (1976Ford ( , 1990 and Ford et al (1978) and geophysically surveyed by Ferris et al (1998). Studies of its meteorology are limited, but mean annual temperature inferred from nearby ice boreholes lies between -24.968C, 32 km due north of the Davis Valley on the Ford Ice Piedmont in December 1957 (Aughenbaugh et al 1958), and -98C in December 1978 in the Enchanted Valley, 26 km to the south (Boyer, personal communication 2000).…”