The Transantarctic Fault Zone

Robinson and Splettstoesser (1986) speculated that the Transantarctic fault zone, which separates East and West Antarctica, is the border between two lithospheric plates which were placed in juxtaposition in the course of the break-up of Gondwana. This hypothesis was supported by Scharnberger and Scharon (1972) who reported that the virtual geomagnetic poles derived from igneous rocks indicate that East and West Antarctica were originally located on different lithospheric plates. 

Robinson and Splettstoesser (1986) also noted that the East and West Antarctic plates did not collide forcefully because the rocks of the Beacon Supergroup and of the Ferrar Group are not folded and thrust-faulted. In addition, the Transantarctic fault zone cannot be a normal fault because the geology of West Antarctica differs profoundly from the Transantarctic Mountains. Robinson and Splettstoesser (1986) also considered that the Transantarctic Mountains cannot be located on the passive margin of a continental rift that split the Antarctic plate because passive rift margins elsewhere do not reach the high elevations of the Transantarctic Mountains. Perhaps other processes have enhanced the elevation of the Transantarctic Mountains. 

Schmidt and Rowley (1986) assumed that a continental rift formed between East and West Antarctica and subsequently widened into the Transantarctic Rift System by extension and thinning of the continental crust. At about the same time, continental flood basalts were erupted and dolerite sills were intruded into the flat-lying sedimentary Beacon rocks of the Transantarctic Mountains on the East Antarctic side of the rift. This tectono-magmatic activity was an immediate precursor to the break-up of Gondwana. 

These authors also assumed that in pre-Jurassic time Marie Byrd Land in Fig. 15.12 was located adjacent to northern Victoria Land and was later moved to its present position in West Antarctica by strike-slip motion along the Transantarctic rift. Schmidt and Rowley (1986) attributed the movement along the Transantarctic rift system to seafloor spreading between Queen Maud Land and Africa in Fig. 15.8a. In other words, the Transantarctic rift system may be a Late Jurassic transform fault of the Weddell-African rift. 

Gondwanide orogeny which was presumably caused by compression of the subduction zone that was located along the paleo-Padfic coast of Gondwana. 

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