Cretaceous oceanic red beds as possible consequence of oceanic anoxic events

Feedbacks among geochemical cycles in response to decreasing global temperatures, increasing deep ocean circulation forced by high-latitude deep water formation along the Antarctic margin, and widening and deepening of the interconnections between the oceanic basins may have been responsible for the major paleoceanographic change from deposition of organic carbon-rich black shales during mid-Cretaceous, to world-wide deposition of Cretaceous Oceanic Red Beds (CORBs) in the Late Cretaceous. The presence of CORBs sandwiched between mid-Cretaceous OAEs may reflect major climate and paleoceanographic changes. In a contrast to extremely warm climates during the OAEs, the CORBs suggest cold periods, and therefore oscillating climate shifts, that have seldom been considered during modeling of Cretaceous greenhouse climate and global carbon cycling.