By Late Cretaceous or early Tertiary time, the diversification and proliferation of angiosperm-deciduous ecosystems resulted in higher rates of mineral weathering. This increase in the global average weathering rate would have caused a decrease in atmospheric carbon dioxide and, hence, global cooling. The magnitude of this decrease is quantitatively explored here by developing a formulation for global weathering which combines ecosystems that differ in their fractional global coverage and intrinsic rates of weathering. Incorporating this formulation into models—specifically, several previously developed global steady-state models of the geochemical cycle of carbon between the atmosphere and carbonate rocks—gives results that show signifi-cant global cooling from the evolution of the angiosperm-deciduous ecosystems. This cooling may vary from a few degrees up to 10°C. In this way, deciduous ecosystems with high rates of mineral weathering could have contributed to the evolution during the past 100 m.y. of a cooler Earth and thus were a factor in producing conditions that enhanced their global proliferation.

This content is PDF only. Please click on the PDF icon to access.

First Page Preview

First page PDF preview
You do not currently have access to this article.