REASSESSING THE TEMPERATURE HISTORY OF THE ORDOVICIAN OCEAN

Paleotemperature curves may be distorted by uneven sampling distributions and latitudinal temperature differences, which were overlooked during the Ordovician paleotemperature reconstructions. Using well-screened oxygen isotope temperature data (4,949 records), we found that the previously published temperature curve, especially based on bulk-rock δ¹⁸O data, was ~10℃ biased on average. After sampling corrections, the reassessed paleotemperature curves revealed Early Ordovician temperature decreased with lower magnitudes of ~5℃ and decoupled temperature change and biodiversity in the tropical area, casting doubt on climate-driven diversification.