[1] Univ Ottawa, Ottawa Carleton Geosci Ctr, Ottawa, ON K1N 6N5, Canada
[2] Univ Ottawa, Dept Earth Sci, Ottawa, ON K1N 6N5, Canada
[3] Geol Survey Canada, Ottawa, ON K1A 0E9, Canada
[4] Univ Aix Marseille 3, Europole Mediterraneen Arbois, F-13545 Aix En Provence 04, France
[5] BHP Petr Ltd, London SW1V 1LH, England