1. Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, 2207 Main Mall, Vancouver, British Columbia V6T 1Z4, Canada
2. Manitoba Geological Survey, 360-1395 Ellice Avenue, Winnipeg, Manitoba R3G 3P2, Canada
3. Department of Earth Sciences, Western University, 1151 Richmond Street N., London, Ontario N6A 5B7, Canada