Cambro-Ordovician palaeomagnetic and geochronologic data from southern Victoria Land, Antarctica: revision of the Gondwana apparent polar wander path

Abstract

SUMMARY We present new palaeomagnetic and isotopic data from the southern Victoria Land region of the Transantarctic Mountains in East Antarctica that constrain the palaeogeographic position of this region during the Late Cambrian and Early Ordovician. A new pole has been determined from a dioritic intrusion at Killer Ridge (40Ar/39Ar biotite age of 499±3 Ma) and hornblende diorite dykes at Mt. Loke (21°E, 7°S, A95=8°, N=6 VGPs). The new Killer Ridge/Mt. Loke pole is indistinguishable from Gondwana Late Cambrian and Early Ordovician poles. Previously reported palaeomagnetic poles from southern Victoria Land have new isotopic age constraints that place them in the Late Cambrian rather than the Early Ordovician. Based upon the new palaeomagnetic and isotopic data, new Gondwana Late Cambrian and Early Ordovician mean poles have been calculated.