Karoo large igneous province: Brevity, origin, and relation to mass extinction questioned by new 40Ar/39Ar age data

Abstract

The peak activities of continental flood basalts are currently considered as huge and brief (1 m.y.) magmatic events, with strong implications for geodynamics and biotic turnover. New 40Ar/39Ar dates on the Karoo flood basalts (southern Africa) show a longer duration of magmatism (8 m.y., with 6 m.y. for the main volume) with an apparent south-to-north migration, along with briefer distinctive pulses inside the province. This suggests that the Karoo province does not fit the general plume model invoked for most continental flood basalts (including the Karoo) and may explain the absence of a major contemporaneous mass extinction.