1. The CREWES Project, Dept. of Geology and Geophysics, The University of Calgary, 2500 University Drive N.W., Calgary, Alberta T2N 1N4, Canada. Emails:
2. Lithoprobe, Dept. of Geology and Geophysics, The University of Calgary, 2500 University Drive N.W., Calgary, Alberta T2N 1N4, Canada.