Timing, Duration and Character of Glaciation During the Late Paleozoic Ice Age

Christopher Fielding¹, Tracy D. Frank¹, and John L. Isbell^2
1Department of Geosciences, University of Nebraska-Lincoln, Lincoln, NE
²Department of Geosciences, University of Wisconsin-Milwaukee, Milwaukee, WI

The Late Paleozoic Ice Age (LPIA) was the longest period of Icehouse climate during the Phanerozoic, and the only time a vegetated Earth has both entered and exited such a long-term Icehouse state. Knowledge of the timing of glaciation within such a protracted interval (c. 66 million years) may assist in the prediction of source, reservoir and seal for hydrocarbon exploration in basins worldwide. This paper summarizes the results of a global compilation of data on the timing, duration and character of glaciation during the LPIA. Probably short-lived, precursor glaciations occurred at the Famennian/Tournaisian (Devonian/Mississippian) boundary and in the Visean in northern South America. The LPIA proper began at the base of the Serpukhovian (base Namurian, uppermost Mississippian) with glaciation initially restricted to South America and Australia. A major expansion of ice occurred at the base of the Bashkirian (Mississippian/Pennsylvanian boundary) and glaciations continued through the Early Pennsylvanian. Proxy records suggest that the Late Pennsylvanian was a time of relative warming, but some glacial events occurred through this time, particularly in southern Africa, South America, India and Arabia. A Gondwana-wide expansion of ice (with glacial ice also recorded in Siberia), occurred at the Pennsylvanian/Permian boundary, and a long-lived glaciation through the Asselian and early Sakmarian records the acme of the LPIA. Over much of Gondwana, ice sheets then decayed during the late Sakmarian, but several further discrete glaciations occurred in Australia and Siberia through the late Early and Middle Permian. Although the main events summarized above were apparently synchronous, individual glaciations varied in timing across Gondwana, suggesting that the eustatic sea-level record is a composite of events at different times in different parts of Gondwana and NE Asia.

AAPG Search and Discovery Article #90078©2008 AAPG Annual Convention, San Antonio, Texas