In-situ δO and Sr/Sr proxies in an unconformable clastic unit at the Ordovician-Silurian transition.

Clastic successions found in the carbonate platform of continental margin during the Ordovician-Silurian Transition (OST) period are archives for interpreting paleo-depositional systems. Here, we report in-situ δO and Sr/Sr isotope chemo-stratigraphy for an unconformable clastic unit from the Cathaysia terrane that rifted off the Gondwana Supercontinent in the Early Paleozoic Era. Our results suggest a depositional proxy and model for geological events attributed to rapid changes in the sedimentary environment during the OST period.