Mackellar Formation

In the type area near Mt. Mackellar the Mackellar Formation contains several white and nonfossiliferous limestone beds up to 30 cm thick which extend for several meters. Brown-weathering gray limestone beds also occur in the lower part of the formation in the Queen Elizabeth Range. Elsewhere, limestone beds are not common in the Mackellar Eormation. The strontium in the lenticular limestone beds is enriched in radiogenic Sr (Eaure and Barrett 1973) which indicates that they were deposited by aqueous solutions of non-marine origin. 

Lindsay (1970a) suggested that the Mackellar Sea formed as a result of isostatic depression caused by the Early Permian continental ice sheet and that its extent decreased as the crust rebounded until the Mackellar Sea eventually evolved into an alluvial plain on which the overlying Fairchild Formation was deposited. 

The Mackellar Formation does not occur in the Darwin Mountains and in the Olympns-Boomerang area because the Mackellar Sea existed only south of these areas (see also Homer and Krissek 1991). 

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Fig. 10.9) exhibits columnar jointing up to 1 m from the contact with a sill of the Ferrar Dolerite (50 m) which itself displays columnar jointing. This kind of jointing also occurs in a sandstone bed at the top of the Mackellar Formation (Permian) in theQueen Alexandra Range (Baiett et al. 1986). 

The Pagoda Tillite in the Cumulus Hills was deposited on the eroded surface of the local basement complex consisting primarily of the Granite Harbor Intrusives (Chapter 6, Table 6.1). The Pagoda Formation is composed of tillite interbedded with sandstone containing microfloras of Early Permian (or Late Carboniferous) age (Askin and Schopf 1982). Tht Mackellar Formation which overlies the Pagoda Tillite consists of black shale and fine grained sandstone. It was succeeded by the sandstones of the Fairchild Formation, followed by the Buckley Coal Measures. 

Although the Devonian sandstones in southern Victoria Land, in the Beardmore Glacier area, and in the Ohio Range were deposited in shallow marine basins, most of the Permian and Triassic rocks formed in continental basins of Gondwana.The only exception may be the Mackellar Formation which was deposited in a stagnant body of water left behind after the Permian ice sheets had retreated from East Antarctica. 

Fig. 13.32 Portal Rock (aka Portal Peak) at the mouth of the TilUte Glacier in the Queen Alexandra Range exposes the Permian Mckellar Formation (Pm) which overlies the Pagoda TilUte (Pp). The Mackellar Formation at this location was intruded by a sill of the Jurassic Ferrar Dolerite (Jf). The geology of the Queen Alexandra Range was described by Barrett et al. (1986). The elevation of the summit of Portal Rock is 1,990 m a.s.l. which causes it to stand 390 m above the surface of the Lennox-King Glacier. Excerpt of the reconnaissance geologic map by Lindsay et al. (1973)...

Fig. 13.33 Portal Rock at 83°33 S and 165°36 E at the mouth of the Tillite Glacier contains a sill of the Ferrar Dolerite which intruded the Mackellar Formation of Permian age (Photo by T.M. Mensing)...

Fig. 3. Variation of the formation rate coefficient with composition of bulk solvent for the reaction of NiSl with NH3 in methanol—water mixtures. For explanation of solid and dashed lines see original paper. (From MacKellar and Rorabacher [72], by courtesy of The American Chemical Society.)...

The temperatures estimates are based on an average global temperature of 15°C (Fremouw, Buckley, Fairchild), 5°C for the Mackellar carbonates, 0°C for the Pagoda Formation, and 20°C for the Devonian Alexandra Formation... 

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