Evolution of the Cretaceous Ocean‐Climate System

Abstract

The Cretaceous period (ca. 136–66 Ma) of Earth history offers a significant opportunity to better understand global processes and their variations. Cretaceous marine and terrestrial strata are extremely widespread in outcrop, subcrop, and ocean basins. Much of the Cretaceous period had a globally warm, equable, mostly ice‐free climate that is generally viewed as about as far removed from our current glacial icehouse world as that of any other time in the Phanerozoic. This extreme greenhouse world had polar ocean temperatures of 15 C, which, for contrast, is our current global average.As Al Fischer points out in the foreword of the book, The Cretaceous was the last [greenhouse] period for which accurate global reconstructions of ocean‐continent distribution can be made. The development of calcareous plankton, near the end of Jurassic time, provides a record of oceanic life far better than that available for earlier periods, and one directly comparable to todays planktonic communities.