REGIONAL METAMORPHISM IN TRANSFORM ZONES DURING SUPERCONTINENT BREAKUP - LATE PROTEROZOIC EVENTS OF THE SCOTTISH HIGHLANDS

A new model for regional metamorphism within major strike-slip zones i s presented that may be applicable to the generation of many small met amorphic terranes. Long-lived transform zones developed during contine ntal break-up are prone to alternating local compression and extension . Periodic closure of pull-apart basins, formed within such zones, cau ses internal thickening of the sediment pile and formation of small lo w- or medium-grade metamorphic terranes, with well-defined, frequently reactivated margins. The Late Proterozoic Dalradian and Moine blocks of the Scottish Highlands are examples of such regional metamorphic te rranes generated during the prolonged breakup of the Rodinia supercont inent.