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The conventional view of the late Paleozoic ice age is that it was a single long, protracted event some tens of millions of years in duration, with some internal waxing and waning of glacial ice masses. Recent research, however (much of it summarized in this volume), favors an alternative view that the late Paleozoic ice age was a series of shorter (1–8 m.y. duration), discrete glacial events separated by periods of warmer climate. Stratigraphic records show that the late Paleozoic ice age began with probably short-lived, localized glacial events in South America at the Late Devonian–Tournaisian boundary and in the Visean. These “precursor” events were followed at the start of the Serpukhovian (start of Namurian, latest Mississippian) by expansion of ice into other areas of Gondwana, corresponding to the commencement of the distinctive cyclothemic stratigraphy of paleotropical Euramerica. At the start of the Bashkirian (earliest Pennsylvanian), ice expanded further across South America, southern Africa, and Australia, and at the start of the Moscovian (early Pennsylvanian), into southern Africa, Oman, and Arabia. In the latter half of the Pennsylvanian, some evidence points toward climatic amelioration, although ice centers undoubtedly continued to occur. A massive expansion of ice occurred at the Pennsylvanian-Permian boundary, and glaciation became bipolar at that time. Ice sheets are inferred to have been at their maximum extent during the Asselian and early Sakmarian, after which they decayed rapidly over much of Gondwana. Glaciation continued, intermittently, in Australia and Siberia throughout the late Early and Middle Permian. While major events appear to have been synchronized globally, the timing of individual (1–8-m.y.-long) glaciations may have been asynchronous across Gondwana, producing a composite eustatic signal in far-field, cyclothem records.

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