Paleoclimate and ecology of Cretaceous continental ecosystems of Japan inferred from the stable oxygen and carbon isotope compositions of vertebrate bioapatite

We investigated the environmental conditions that prevailed in continental ecosystems recorded sedimentary deposits of Japan during Cretaceous through analysis oxygen and carbon isotope compositions phosphate (?18Op) apatite-bound carbonate (?18Oc ?13Cc) vertebrate teeth bones. Local surface water ?18Ow values were calculated using known phosphate-water fractionation equations. Anomalously low local waters strongly suggest a significant contribution high-altitude precipitation from nearby mountains to waters. Mean air temperatures estimated global meteoric ?18Omw value – Annual Air Temperature relationship, compared fish apatite ?18Op values. mean annual precipitations (MAP) relationship existing between MAP C3 plant ?13Cp value, latter being apatite-diet 13C-enrichment applied plant-eating sauropod ornithopod dinosaur ?13Cc Reconstructed climate changed cool temperate warm temperate, relatively cold dry Late Hauterivian Barremian warmer seasonally more humid Aptian Albian, even Cenomanian-Coniacian. Proposed thermal evolution Early is compatible with absence thermophilic taxa such as crocodylomorphs before fossil record Japan.