Cretaceous Thermal Maximum

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Cretaceous Thermal Maximum, also known as Cretaceous Thermal Optimum, was a period early in the Late Cretaceous notable for its dramatic increase in global temperatures.


Carbon dioxide levels reached astounding heights and the sea levels elevated. Plants such as plankton became "glassy" and temperatures increased. Scientists predicted that the Cretaceous Thermal Maximum occurred during the Cenomanian/Turonian transition based from the fact that there was a major downfall in global climate. It was also shown to be the most extreme carbon cycle recorded in the past 100 million years.[1][2]


Late Cenomanian sea surface temperatures in the equatorial Atlantic Ocean (~33°C) were substantially warmer than today (~27-29°C).[1] They may have been as high as 36°C.[3] The interval of peak warmth in the Turonian has been attributed to very high atmospheric CO2 and possibly enhanced by the changing geography of the oceans including an "Atlantic Gateway".[2] However, during the Turonian age, several pronounced but relatively short-lived cooler intervals punctuate this otherwise remarkably stable interval of extreme warmth and shows that rapid tropical sea surface temperature changes occurred during the Cretaceous thermal maximum, and implies that even the mid-Cretaceous "super-greenhouse" climate may have been less stable than previously thought.[1]

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  1. ^ a b c Foster, A., et al. "The Cretaceous Thermal Maximum and Oceanic Anoxic Event 2 in the Tropics: Sea- Surface Temperature and Stable Organic Carbon Isotopic Records from the Equatorial Atlantic." American Geophysical Union, Fall Meeting 2006. The Smithsonian/NASA Astrophysics Data System. Web. 20 Oct. 2009. <>
  2. ^ a b Poulsen, Christopher J., Andrew S. Gendaszek, and Robert L. Jacob. "Did the rifting of the Atlantic Ocean cause the Cretaceous thermal maximum?" Geology 31.2 (2003): 115-118. Web. 20 Oct. 2009. <>.
  3. ^ Wilson, Paul A., Richard D. Norris, and Matthew J. Cooper. "Testing the Cretaceous greenhouse hypothesis using glassy foraminiferal calcite from the core of the Turonian tropics on Demerara Rise." Geology 30.7 (2002):607-610. Web. Oct.2009.<>.