Ocean freshening near the end of the Mesozoic
Paleogeographic changes near the end of the Mesozoic (~66 Ma) reshaped ocean circulation and climate dynamics. Using geological proxies together with climate simulations, the study finds that Central American Seaway shoaling and restricted Arctic gateways jointly led to Arctic Ocean surface freshening and southward export of low-salinity waters. This combined scenario also increases stratification in key basins and matches Maastrichtian palynological, micropaleontological, and geochemical records across latitudes.