The Paleoproterozoic (centred at ∼2.054 Ga) Bushveld LIP is one of the largest intracratonic LIPs in the world. Its components are primarily distributed within the Archean Kaapvaal Craton. This study reports dyke-like and sill-like norite intrusions from Lose quarry within the Mahalapye Complex, a Paleoproterozoic granitoid-migmatitic gneiss terrane along the northern edge of Kaapvaal Craton. Field relations indicate the norite postdate the ∼2.061 Ga diorite gneiss and predate the ∼2.039 Ga granodiorite. Significantly, it exhibit structures indicative of comingling with ∼2.053 Ga leucosome/leucogranite, a product of partial melting of diorite gneiss. The cross-cutting relations provide unequivocal evidence that the norite and the leucogranite were liquid at the same time, and should be of similar age. Fe-rich orthopyroxene (X Mg = 0.43–0.46) constitutes the dominant mafic mineral in the norite. Geochemical characteristics of the Mahalapye Complex norites are similar to those of marginal facies norites from the Bushveld Complex (B1 sills) and Molopo Farms Complex layered intrusions, two of the prominent constituents of the Bushveld LIP. This is the first solid evidence that the original extent of the Bushveld LIP covered an area larger than the current known limits of the Archean Kaapvaal Craton – into the youngest and westernmost terrane of the high-grade Limpopo Complex. The potential of high-grade terranes along Archean cratonic margins as locales to look for LIP fragments is explored.
All Science Journal Classification (ASJC) codes
- Geochemistry and Petrology