The Darwin Glacier region is located between the Carlyon and Darwin glaciers in southern Victoria Land, Antarctica (Fig. 1). Previous work on Ross Orogeny granitoids of the Darwin Glacier region is mutually conflicting. Haskell et al. (1965) mapped three plutons, the Carlyon Granodiorite, Mount Rich Granite and Hope Granite, Felder & Faure (1990) did not recognise the Hope Granite, and Encarnación & Grunow (1996) interpreted the entire area as underlain by a single intrusion, the Brown Hills pluton. Fieldwork during the 2000 field season and subsequent geochemical and geochronological analysis described here indicates the presence of three distinctive granitic suites, emplaced during Cambrian times. These include the Foggy Dog Granite (FDG) suite, the Darwin calcic suite and the Cooper Granodiorite.

Microstructural observations, phase identification, and hardness measurements of several ternary and quaternary A13Nb− and A13Ti-based alloys containing Ni or Fe have been carried out after homogenization at 1100°C. An L12 phase is formed in an (A1,Fe)3Ti-based alloy when a small amount of Nb is added. Conversely, in Al-Nb-Ni alloys whose compositions are based on Al3Nb, no L12 phase has been detected. In this case, alloys are either three-phase(B2, DO22 and Laves) or two-phase(B2 and Laves). The absence of the Ll2 phase formation in AlgNb-based alloys containing Ni is attributed to limited solubility of Ni in the Al3Nb compound. Rapidly solidified and slowly cooled specimens have also been analyzed.