Central Atlantic Magmatic Province

node · earth · Circum-Atlantic; now North America, Africa, Europe and South America

A flood basalt province erupted around 201 million years ago as Pangaea began to rift apart, whose remnants are now scattered across four continents — eastern North America, northwest Africa, Iberia and northeastern South America — because the Atlantic opened through the middle of it. Its original extent is estimated at several million square kilometres, which would make it among the most areally extensive igneous provinces known. Its dating is closely tied to the end-Triassic extinction: high-precision ages place the main pulses within a few hundred thousand years of the Triassic–Jurassic boundary, and the sedimentary record across the boundary carries carbon-isotope excursions consistent with rapid injections of isotopically light carbon. The province is the second clear case in the record of a mass extinction coinciding with a large igneous province, which is why the flood-basalt hypothesis is treated as a general mechanism rather than a Siberian peculiarity. It is also the reason the K–Pg impact is usually discussed as the exception rather than the rule.