GSA Annual Meeting in Denver, Colorado, USA - 2016

Paper No. 223-1
Presentation Time: 1:30 PM


HUBER, Brian T., Department of Paleobiology, Smithsonian Institution, National Museum of Natural History, P.O. Box 37012 MRC 121, Washington, DC 20013,

The climate of the Cretaceous Period underwent considerable change from generally “cool greenhouse” conditions during the Berriasian through late Aptian (~145-113 Ma), “warm greenhouse” temperatures from the early Albian through early Cenomanian (~113-98 Ma), and “hot greenhouse” conditions from the middle Cenomanian through late Santonian (~98-84 Ma) with maximum sea surface temperatures (SSTs), reached during the Turonian (94-90 Ma), estimated as 36–42°C at 10°N and up to 30°C at 60°S. The Campanian-Maastrichtian (83-66 Ma) experienced long-term cooling with high latitude SSTs dropping to 6°C by the mid-Maastrichtian. Climate model outputs indicate that during the peak of the hot greenhouse climate pCO2 was 4-8x higher than during the Holocene. The primary cause for changes in Cretaceous climate has been widely attributed to variations in the flux of pCO2 sourced from arc and/or flood basalt volcanism. This is supported by correspondence between timing for peak eruption of the Caribbean Plateau eruption from 93-89 Ma, but the largest volcanic event of the Cretaceous occurred much earlier, during the early Aptian (125-120 Ma) eruption of the Ontong Java and Manihiki Plateaus when the global climate was much cooler. Such a discrepancy cannot be resolved by geochemical carbon cycle models as they indicate too broad a range of pCO2 variations, and existing geochemical proxies lack the resolution necessary to characterize Cretaceous pCO2 changes. Until such uncertainties are better resolved consideration of volcanic CO2 as a primary forcing mechanism for Cretaceous climate change will remain open for debate.