New biostratigraphic constraints show rapid emplacement of the Central Atlantic Magmatic Province (CAMP) during the end-Triassic mass extinction interval

Different lines of evidence suggest that the main trigger mechanism for the end-Triassic mass extinction was the release of volcanic and thermogenic gases during the emplacement of the Central Atlantic Magmatic Province (CAMP). However, the short duration of the biotic and environmental crisis and the magmatic activity hinders precise control on the relative timing between these events, especially when comparing the continental sedimentary record where there is no independent age control with the magmatic record. In order to disentangle the temporal relationships of the end-Triassic events, we have analyzed the palynology of the sedimentary strata interlayered with CAMP lava flows from eleven sites throughout Morocco (Western and Central High Atlas, Middle Atlas, Western Meseta). The recovered sporomorphs help to constrain the age of CAMP volcanism, allowing the stratigraphic correlation of the basaltic volcanism with the extinction and geochemical records such as carbon-isotope and mercury shifts, recorded in marine sedimentary successions worldwide. Our new data show that CAMP erupted almost entirely during the end-Triassic mass extinction interval, just before the Triassic–Jurassic boundary (Tr-J). Hence, a very rapid emplacement of the CAMP very likely triggered the carbon cycle and ecological disruption at the Tr-J boundary.