Regional metamorphism in transform zones during supercontinent breakup: Late Proterozoic events of the Scottish Highlands

Abstract

A new model for regional metamorphism within major strike-slip zones is presented that may be applicable to the generation of many small metamorphic terranes. Long-lived transform zones developed during continental break-up are prone to alternating local compression and extension. Periodic closure of pull-apart basins, formed within such zones, causes internal thickening of the sediment pile and formation of small low- 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 terranes generated during the prolonged breakup of the Rodinia supercontinent.