The Late Cretaceous Western Interior Seaway as a model for oxygenation change in epicontinental restricted basins

摘要

Deoxygenation is a critical problem facing the ocean as the world warms, and has the potential to effect coastal upwelling zones, shelf areas influenced by high runoff and nutrification, and restricted and semi-restricted basins. The mechanisms that drive deoxygenation in these diverse environments are still not fully understood, in part because the modern record of redox change is short and anoxia is still relatively rare in the modem ocean. Here, we address this problem of scale by studying deoxygenation in the geologic past. We summarize decades of individual studies of benthic foraminifera to generate a record of bottom water oxygen change in the Cretaceous Western Interior Sea (WIS) of North America over similar to 13 myr (Cenomanian-Campanian), spanning two major sea level cycles. The WIS was prone to major changes in dissolved oxygen content throughout its long history, sometimes directly antiphase to trends in the global ocean.