Orogenies, Cratonization, and Post-Orogenic Granites

Abstract

Two late Mesoarchean orogenic events completed the tectonic evolution of the Pilbara Craton: the 2955–2919 Ma North Pilbara Orogeny and the 2930–2900 Ma Mosquito Creek Orogeny. The deformation of these events compressed and closed the Mallina and Mosquito Creek Basins and effectively completed cratonization. From 2900 Ma onwards, the Pilbara Craton remained a stable unit of continental crust until uplift, crustal extension, and rifting began the breakup of the craton (Chap. 12 ). The North Pilbara Orogeny was a major event of deformation, metamorphism, and granitic intrusion resulting from convergence between the Pilbara Craton and an exotic plate to the northwest (Chaps. 8 and 9 ). Effects of the event were concentrated in the Central Pilbara Tectonic Zone and Karratha Terrane, although compression also extended into the East Pilbara Terrane. Closure of the Mallina Basin at c. 2930 Ma resulted in deformation and metamorphism moving to the relatively thin crust of the Mosquito Creek Basin.