Nimrod Group, Miller Range

Fig. 5.1 The central Transantarctic Mountains include the area between the Nimrod and Beardmore Glaciers. The Byrd Glacier in the north and the Shackleton Glacier in the south are off this map. The basement rocks of this area crop out along the coast and are overlain by sandstones of the Beacon Supergroup farther inland. The only exceptions are the Miller and Geologist Ranges at the head of the Nimrod Glacier (Fig. 5.2) where the Nimrod Group is exposed (Adapted from Gunner 1976...

Table 5.5 Whole-rock Rb-Sr age determinations of Hope Granite from plutons that intruded the Nimrod Group metasediments in the Miller Range and the Beardmore and Byrd Groups in the coastal mountains between the Nimrod and the Shackleton Glaciers (Gunner 1971a, b, 1974, 1976 Gunner and Matttinson 1975 Borg et al. 1990) (Numbers in parentheses represent the number of samples analyzed) ...

Even more problematic is the hornblende migmatite on Spear Nunatak which is composed of layers of hornblende and of quartz-plagioclase (andesine) that have been folded and metamorphosed to the amphibolite facies (Fig. 7.7). Murtaugh (1969) considered the migmatites to be the oldest rocks in the Wisconsin Range and Minshew (1967) tentatively correlated them to the Nimrod Group of the Miller Range (Section 5.1.1). 

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