engleski

Evidence from Carbonate Platforms Bearing on Climate, Salinity, Dasycladalean Diversity, and Marine Anoxic Events During the Late Jurassic–Early Cretaceous Greenhouse

Carbonate platforms are sensitive recorders of environmental change through geologic time. Climatically induced changes in sea level or changes in subsidence are expressed through migration of sediment belts that are recorded in the accumulating sedimentary succession. Changes in nutrient levels are recorded in shifts in the biotic community and, if eutrophic levels are reached, platforms may drown due to breakdown in carbonate production. This study focuses on the ~ 60 Ma Late Jurassic–Early Cretaceous period, which was originally considered to have had uniform greenhouse conditions. Available climate proxy data, however, such as oxygen isotope data (δ18O) from deep sea cores, the paleontologic data, and the 87Sr/86Sr and carbon isotope data of Jurassic and Cretaceous carbonates, indicate that there were major cooling and warming events that likely affected global ice volume, sea level, and the accumulating sedimentary and microfossil record of carbonate platforms.

carbonate platform; oceanic anoxic event; greenhouse

nije evidentirano