Ferrar dolerite, Antarctica

During an investigation of zeolites from Northern Victoria Land, Antarctica, numerous zeolitic species, among which the pentasils are predominant, were found in the Jurassic Ferrar Dolerites of Mt. Adamson heulandite, stellerite, stilbite, mordenite, erionite, levyne. 

The crustal characteristics of the Jurassic doler-ites of Antarctica and Tasmania relate these rocks to each other and set them apart from Jurassic dolerite in southern Africa and Brazil. This point was emphasized by Compston et al. (1968) in a direct comparison of Rb-Sr systematics of Mesozoic basaltic rocks in southern Victoria Land, Tasmania, South Africa, and South America. In addition, these authors reported K-Ar dates for plagioclase and pyroxene from a pegmatoid in the Lake Vanda sill in Wright Valley of southern Victoria Land. The results indicated a Middle Jurassic age for the Ferrar Dolerite, in agreement with the age of the Tasmanian Dolerite and the K-Ar dates of the Wisanger Basalt on Kangaroo Island of South Australia reported later by McDougall and Wellman (1976). 

Fig. 13.22 Mount Achernar at 84°12 S and 160°56 E contains three sills of Ferrar Dolerite which intruded srmdstones of the Permian Buckley Formation. The underlying basement rocks ace not exposed in this area. Mount Achernar is located a short distance west of Coalsack Bluff (Section 11.2.2 Fig. 11.9B) and of Mt. Sirius which contains a deposit of Neogene till on its summit Excerpt of the topographic map Buckley Island, Antarctica SV 51-60/3 published in 1967 by the US Geological Survey...

Kibler EM (1981) Petrogenesis of two Ferrar Dolerite srils, Roadend Nunatak, Transantarctic Mountains, Antarctica. MSc thesis. The Ohio State University, Columbus, OH Kruger FJ, Marsh JS (1982) Significance of Sr/ Sr ratios in the Merensky cyclic unit of the Bushveld complex. Nature 298 53-55... 

Marsh BD (1996b) Sill sequence as piecemeal layered intm-sions and finks to volcanism Evidence from the Ferrar dolerites of Antarctica. EOS, Trans Amer Geophys Union 77 S292... 

Fleming TH, Elliot DE, Heimann A, Foland KA (1997) Ar/ Ar geochronology of Feriar Dolerite sills from the Transantarctic Mountains, Antarctica Implications for the age and origin of the Ferrar magmatic province. Geol Soc Amer Bull 109 533-546... 

Fig. 15.12 According to a proposal by Schmidt and Rowley (1986), the Antarctic plate was split by a rift that developed during the Jurassic Period. This rift caused the eruption of basalt flows and the intrusion of dolerite sills of the Ferrar Group in the Transantarctic Mountains along the raised margin of the rift valley. Marie Byrd Land, which was originally located adjacent to northern Victoria Land, moved to its present position in West Antttfctica by right-lateral motion along the Transantarctic rift system tmd the EUsworth Mountain block was rotated clockwise out of alignment with the Transantarctic Mountains at about the same time. These displacements of blocks of continental crust were caused by transform faults that developed in the spreading ridge that separated Africa from Queen Maud Land of East Antarctica (Adapted from Fig. 1 of Schmidt and Rowley (1986))...

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