DESCRIPTION OF PERIGLACIAL PROCESSES PRESERVED IN APPALACHIAN BASIN PALEOSOLS OF LATE PALEOZOIC ICE AGE ONSET

Soils in cold, nonglacial environments can be affected by periglacial processes that may leave behind distinctive features. Many relict examples are found from the Pleistocene in the modern-day ground record. However, such features have seldom been observed in lithified paleosols. The boundary between the Late Devonian and Early Mississippian periods in the Appalachian Basin preserves sediments from the onset of the late Paleozoic Ice Age. We report ancient periglacial features found in late Famennian paleosols of these strata. Included here are patterned ground accommodating relicts with origin in deep seasonal frost and/or permafrost aggradation or its degradation. Most of these features are hosted in vertisols, an order rarely present in modern-day periglacial environments. The absence of vertic displacement of the wedge-shaped features indicates these soils were polypedogenetic. Recorded is a climatic change from a seasonal wet–dry environment to a periglacial climate. Given that there is a dearth of lithified frozen ground features studied so far, this interval in the late Paleozoic Ice Age is essential for understanding how such features can be identified in the rock record, allowing cold-climate paleosols—including paleo-Gelisols—to be found in other basins.