Atmospheric circulation, upwelling, and organic-rich rocks in the Mesozoic and Cenozoic eras

• Published in: Palaeogeography, palaeoclimatology, palaeoecology Vol. 40; no. 1; pp. 31 - 66
• Main Authors: Totman Parrish, Judith, Curtis, Rebecca L.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.1982
• ISSN: 0031-0182; 1872-616X
• DOI: 10.1016/0031-0182(82)90084-0

By using the basic principles of atmospheric circulation and analogies from present circulation patterns, it is possible to construct qualitative atmospheric circulation models on paleogeographic maps. The wind patterns predicted by these models then serve as the basis for predicting the locations of ancient upwelling zones. Atmospheric circulation and upwelling models for seven geologic stages in the Mesozoic and Cenozoic were constructed and the distribution of the upwelling zones compared with the distribution of organic-rich rocks. For all time periods together, the correlation was statistically significant. When the individual time periods were analyzed separately, the following pattern emerged: significant correspondence between upwelling zones and organic-rich rocks in the Triassic, middle early Cretaceous to late Cretaceous, and middle Paleogene to Neogene. No significant correspondence was found for the intervening times. Upwelling does not account for all organic-rich rocks; so-called anoxic oceanic events and transgressions play an important role in their deposition. It is suggested that upwelling contributes significantly to the pattern of organic-rich rock distribution, and is important in determining organic facies.