An introduction to ice ages, climate dynamics and biotic events: the Late Pennsylvanian world

Abstract

AbstractThe Late Pennsylvanian was a time of ice ages and climate dynamics that drove biotic changes in the marine and non-marine realms. The apex of late Paleozoic glaciation in southern Gondwana was during the Late Pennsylvanian, rather than the early Permian as inferred from more equatorial Pangaea. Waxing and waning of ice sheets drove cyclothemic sedimentation in the Pangaean tropics, providing an astrochronology tuned to Earth-orbital cycles, tied to climatic changes, reflected in aeolian loess and palaeosol archives. Vegetation change across the Middle–Late Pennsylvanian boundary was not a ‘Carboniferous rainforest collapse’, but instead a complex and drawn out step-wise change from one kind of rainforest to another. Changes in marine invertebrate and terrestrial vertebrate animals occurred across the Middle–Late Pennsylvanian boundary, but these did not lead to substantive changes in the organization of those communities. The base of the Upper Pennsylvanian is the base of the Kasimovian Stage, and this boundary needs a GSSP to standardize and stabilize chronostratigraphic usage. To avoid further chronostratigraphic confusion, the Cantabrian Substage should be abandoned, and the traditional Westphalian–Stephanian boundary should be returned to and recognized as the time of major floristic change, the lycospore extinction event.