Paleoarchean Continental Breakup of the Pilbara Craton

Abstract

Following deformation and magmatic activity of the 3325–3290 Ma Emu Pool Event (Chap. 5 ), deposition of the Sulphur Springs Group marked the beginning of crustal extension and rifting that led to the continental breakup of the Pilbara Craton. The extension and rifting are attributed to the arrival of the last major mantle plume to impact the Pilbara Craton. Melting of the mantle and crust resulted in an ultramafic–mafic–felsic volcanic cycle in the Sulphur Springs Group and the intrusion of granitic rocks of the 3274–3223 Ma Cleland Supersuite. The Sulphur Springs Group and the Fig Tree Group of the eastern Kaapvaal Craton are transitional successions from Paleoarchean large igneous provinces to Mesoarchean sedimentary basins. Deposition of the Sulphur Springs Group ended with breakup of the Pilbara Craton at c. 3220 Ma. The breakup was followed by the separation of at least three plates of continental crust and the evolution of intervening basaltic basins. It marked the beginning of plate tectonic processes in which Paleoarchean vertical deformation and crustal recycling were replaced by Mesoarchean horizontal deformation and melts derived from plate separation, collision, and subduction.