T104 Pulse of the Earth: Geochronology and Paleomagnetism of Large Igneous Provinces, the Key to Reconstructing Precambrian Supercontinents
Monday, 29 October 2007
1:30 PM - 5:30 PM
KEY PALEOMAGNETIC POLE FROM THE WOONGARRA / WEELI WOLLI LARGE IGNEOUS PROVINCE, PILBARA CRATON, AUSTRALIA: A LINK BETWEEN SUPERCRATONS?
Paper number: T104-3
Program: Technical Sessions
Time: 2:05 PM – 2:20 PM
Authors
Abstract
The near-equatorial position of Pilbara at 2.45 Ga allows, but does not require, a direct connection with the Superior craton as determined by data from the Matachewan dyke swarm in Canada. If geomagnetic polarity constraints are honored for the precisely coeval Woongarra / Weeli Wolli and Matachewan "N" poles at 2446-2449 Ma, then a direct connection is only permitted by the allowance of uncertainties in both results. If Pilbara and Kaapvaal were indeed connected in the Vaalbara supercraton, then a combined apparent polar wander path may be constructed from both regions when rotated into their original relative orientation. In this case, regardless of which Vaalbara reconstruction is considered among several published variations, a long-lived (2.45-2.22 Ga), direct connection with Superior is not permitted by the paleomagnetic data. This result is a telling example of how a single pole comparison may permit a "closest approach" connection between cratons, but often those allowable connections may be refuted by other paleomagnetic data when considered together in temporal context.