CONTRASTING U-PB AGES FROM PLUTONS IN THE BRAS-DOR AND MIRA TERRANES OF CAPE-BRETON ISLAND, NOVA-SCOTIA

U-Pb dates from zircon, titanite, and monazite in plutons of the Bras d'Or and Mira terranes of southern Cape Breton Island, combined with 40Ar/39Ar and other radiometric age data, indicate that the Bras d'Or and Mira terranes had separate magmatic and metamorphic histories until at least the Middle Cambrian and possibly until the Devonian. It is unlikely the the Mira and Bras d'Or terranes were juxtaposed before the Early Ordovician. -from Authors