John Encarnación
Saint Louis University, St. Louis, Missouri

Abstract.  We present new paleomagnetic and isotopic data from the Transantarctic Mountains in East Antarctica that constrain the paleogeographic position of this region during the late Early and Middle Cambrian. Two new poles have been determined from volcanic and granitic rocks in the Scott Glacier area. The first pole is from the Wyatt and Ackerman formations (~525 Ma) and the Mt. Paine tonalite (40°E, 1°N, A95=6°, N=11 VGP’s).  The second pole is from the Zanuck granite (36°E, 7°S, A95= 9°, N=9 VGP’s).  These poles differ from the Gondwana Early Paleozoic reference poles and could indicate that the Scott Glacier area (and by geologic correlation, North Victoria Land, eastern Australia and West Antarctica?) was part of a terrane accreted to East Gondwana in the Cambrian.  Another possibility is that these new poles support rapid apparent polar wander in the late Early Cambrian and Middle Cambrian.  This apparent polar wander event could be related to rapid plate motions or to a true polar wander event.  Lastly, there may have been a local vertical axis rotation of the Scott Glacier area if the Wyatt pole is compared with the African Ntonya pole.  

(Tectonics, 2000, v. 19, pp.168-181)