Plume Tectonics and the Development of Stable Continental Crust

Abstract

The early phase of a new mantle plume may result in areas of basaltic volcanism and crustal reworking 1?2 ´ 103 km across. Uplift of pre-existing continental crust by up to 800 metres may be sufficient to initiate large-scale tectonic processes, particularly extension. Conduction of heat from a hot plume layer emplaced into the uppermost mantle can result in considerable anatectic reworking of pre-existing continental crust, and in the formation of a granitic upper crust; the Late Archaean reworking of the eastern Yilgarn Block of Western Australia, most of which occurred over a relatively brief time interval 2660?2690 Ma ago, provides a possible example. The magmatic development, and time and length scales inherent in plume-initiated continental reworking are similar for postulated ancient and modern examples, and it is inferred that plume-initiated magmatism and tectonics may play an important role in the development of internally differentiated continental crust.