GEOCHEMICAL AND SEDIMENTOLOGICAL INVESTIGATION OF POSSIBLE DEVONIAN-MISSISSIPPIAN GLACIATION IN THE APPALACHIAN BASIN, PENNSYLVANIA

The Late Paleozoic Ice Age (LPIA) was the last major icehouse climate (low CO₂, glaciers at low paleolatitudes) in Earth’s history before the Cenozoic, and it lasted from the Devonian Period (Famennian) until the late Permian (Wuchiapingian). This makes the LPIA an analog for understanding today’s climate. The majority of glaciation during the LPIA occurred on the southern supercontinent of Gondwana. However, there has been evidence described for Devonian-Mississippian alpine glaciation in the Appalachian Basin, which was located in the paleotropics. The purpose of my research is to look for evidence of glaciation in central Pennsylvania during the LPIA and to characterize the environments and paleoclimate. Several locations were visited across central Pennsylvania and stratigraphic sections were measured. Samples were collected for analysis by X-Ray Fluorescence (XRF) and Inductively-Coupled-Plasma Mass Spectrometry (ICP-MS) at Michigan State University. Geochemical data was used to determine the chemical weathering and provenance of the Catskill, Spechty Kopf, and Pocono Formations. Preliminary results suggest that chemical weathering of the landscape remained consistently high across all three formations, typical for humid conditions. Additionally, there was little change in the provenance of the sediments between formations/locations. This may suggest that if glaciation occurred, it was not as widespread as previously reported. No direct sedimentological evidence of glaciation was observed and diamictites were likely formed by debris flows. However, the transition in environments from meandering to braided streams may suggest a change in paleoclimate (possibly related to distal glaciation) or tectonism. Further work needs to be done to understand the extent of possible glaciation in this region. This study can help improve our understanding of the paleoclimate in the tropics during the late Paleozoic icehouse and the global distribution of glaciation.