Warm Water Benthic Foraminifera Document the Pennsylvanian-permian Warming and Cooling Events – The Record from the Western Pangea Tropical Shelves

Shallow warm water benthic foraminifera (SWWBF), including all larger fusulinids (symbiont-bearing benthic foraminifera), are among the best indicators of paleoclimate and paleogeography in the Carboniferous and Permian. The distribution of benthic foraminifera in space and time constrain important tectonic, paleogeographic and climatic events at a global scale. The North American shelves during Pennsylvanian and Permian time - though geographically within the tropical belt - are characterized by temperate environments with significantly lower foraminifera diversification and rare occurrences of warm water Tethyan forms, that are in general appear in the region as a migration entities. Such environments allow documentation of warming episodes associated with sudden immigration of warm water and exotic forms of SWWBF that evolved elsewhere into the area. First occurrence datum (FOD) of the forms exotic to North America during warming episodes are always delayed in respect of their First Appearance Datum (FAD) elsewhere. The time of delay and taxonomic diversity of fusulinids in North America shelves depended on the scale and intensity of the warming episodes. Cooling events, on the other hand, are associated with decreased taxonomic diversity and appearances of endemic forms characteristic only of temperate water provinces. The occurrence of these forms in Boreal and North American provinces appears to be isochronous, as their environments are uniform and induce their uniform and isochronous distribution. Several warming and cooling episodes during Pennsyllvanian-Permian time are recognized. The differences between taxonomic variations in each event could potentially be used for provisional estimation of the degree of climatic change. A strong link between biotic and climatic events in North American province and the similarity of biotic changes in the North American and other provinces suggests that paleoclimatic events in North American province were controlled by global factors.