The identification of a ca. 2165–2163 Ma large igneous province on the Kaapvaal Craton in southern Africa with implications for chronostratigraphy, paleogeography and environmental change in the early Paleoproterozoic

Large igneous provinces (LIPs) are excellent spatial and temporal geological recorders. However, our understanding of LIPs is hindered by a lack of preservation and alteration of many LIPs through deep time. Several LIPs have been emplaced in the Rhyacian. These LIPs demonstrate a connection across the Superior, Wyoming and North Atlantic cratons. In this study we use new U-Pb ID-TIMS baddeleyite geochronology, petrography, geochemistry, paleomagnetic and rock magnetic data on mafic intrusions to show that the Kaapvaal Craton in southern Africa was possibly a part of this ‘clan of cratons’. New ages come from the Buffalo River Gorge Dyke Swarm on the south-easternmost region of the craton, dated herein at 2165 ± 6 Ma and 2163 ± 3 Ma. A younger 2148 ± 3 Ma dyke was also identified in the region. These dykes invite comparison to magmatic units within the upper Transvaal Supergroup, including the Hekpoort Formation basaltic andesites and the Machadodorp Member basalts, together with the Mashishing Dyke Swarm and various sills, with at least the Hekpoort recognised as a LIP in the ca. 2.22–2.14 Ga time frame. However, this new magmatic event is close in age to a reported ca. 2.16–2.14 Ga metamorphic event within the Transvaal Supergroup. In addition, a new Rhyacian magmatic barcode record for the Kaapvaal Craton is presented that can be compared with coeval LIPs in the Superior, Wyoming and North Atlantic cratons. We suggest that the Kaapvaal Craton was likely a near neighbour to these cratonic blocks at ca. 2.16–2.15 Ga when combining the new magmatic barcode record with a new tentative virtual geomagnetic pole at -57.4°N, 9.1°E (dp/dm of 20.2/22.9).