Implications of Cretaceous Climate for Patterns of Sedimentation

Eric Barron, Lisa Cirbus-Sloan, Eddy Kruijs, William Peterson, Richard Shinn, James L. Sloan

Paleogeography and climate are two essential ingredients for a global perspective of processes and patterns in sedimentary rocks. Extensive knowledge in sedimentology has been derived from a largely inductive approach of examining specific sequences and environments and inferring a larger and more general principle. Geographic position and climate offer the opportunity for additional deductive approaches in sedimentology. By considering the whole in conjunction with an understanding of physical climate processes, independent predictions can be verified by specific observations.

The large climatic and geographic differences between the Cretaceous Period and the Holocene are a good illustration of the potential of a global sedimentary geology perspective. Three very different examples illustrate this potential: (1) storms and the sedimentary record, (2) upwelling and marine productivity, and (3) precipitation, continental runoff, and coastal sedimentary input.

Climate models in conjunction with Cretaceous geographic reconstructions yield the following conclusions. (1) Hurricane and winter storms are predicted to have been quite common in the Cretaceous, but the distribution of storms was strongly tied to continental position and sea level. (2) Planetary warmth and paleogeography operated in concert to more than double total continental rainfall in comparison with the present day. Much of this rainfall was geographically local and is strongly associated with areas of coal, kaolin, and marine sedimentary input. (3) The combination of predicted precipitation, runoff, and wind-induced upwelling provide a more comprehensive forecast of marine productivity than would any single factor. These three components have been combined to derive climate controls on patterns of sedimentation.

AAPG Search and Discovery Article #91030©1988 AAPG Annual Convention, Houston, Texas, 20-23 March 1988.