Latest Triassic marine Sr isotopic variations, possible causes and implications

Terra Nova, 24, 130–135, 2012 Large igneous provinces have been suggested to trigger global environmental perturbations and, in turn, major biotic crises. The high resolution of marine biostratigraphy is here applied to constrain the detailed timing of the Central Atlantic Magmatic Province onset. Analyses of biogenic apatite from stratigraphically well‐constrained Tethyan realm conodont samples indicate two significant shifts of the oceanic 87Sr/86Sr composition during the latest Triassic: a rapid drop of 87Sr/86Sr during the lower Rhaetian, followed by an increase during the upper Rhaetian. These shifts are positively correlated with synchronous variations of oceanic 187Os/188Os and they may be attributed to a rapid emplacement and erosion of the Central Atlantic Magmatic Province, followed by a rapid increase in continental weathering. These interpretations require a short duration for the Rhaetian stage (