Late paleozoic paleoclimates

Abstract

In summary, the late Paleozoic was a time of dramatic climatic shifts, punctuated by glaciation events. Clues to these climate changes can be found in sediments, the stable isotopic composition of marine carbonates, and the biogeographic distribution of land plants and marine animals. Late Devonian glaciation (Glacial I of Isbell et al., 2003), which started the interval, appears more similar to Late Ordovician “hot-house” glaciation than subsequent ice-house glaciations in the mid-Carboniferous-to-Permian and late Cenozoic (Raymond and Metz, 2004). The glaciation event that began in the late Serpu-kohovian or at the Mississippian-Pennsylvanian boundary (Glacial II of Isbell et al., 2003) appears very similar to late Cenozoic glaciation. During both intervals, the poles were cold, the equator was warm, and there was abundant biogeographic differentiation. Unlike the hot-house glaciations of the Late Ordovician and Late Devonian, Pennsylvanian-Permian glaciation was not marked by mass extinction. Sources differ on the continuity of glaciation in the mid-to-late Pennsylvanian (mid Westphalian through Stephanian) and after the Middle Permian (Veevers and Powell, 1987; Frakes et al., 1992; Bruckschen et al., 1999; Crowell, 1999; Isbell et al., 2003). However, the persistence of biogeographic differentiation throughout the Pennsylvanian to the end of the Permian argues for steep latitudinal temperature gradients, cold poles, and warm, wet equatorial climates until the end of the Paleozoic (Ziegler et al., 1981; Rees et al., 2002).