Impact of continental motion and dynamic glaciations on low-latitude climate during the Carboniferous: The record of the Wyoming Shelf (Western United States)

摘要: Abstract The dynamic character of the Late Paleozoic Ice Age is evident from glacial deposits, but its impact on tropical climate not well constrained. Global changes in are overprinted longer-term paleogeographic variations, resulting a complex time–space distribution climate-sensitive lithologies. significance such lithologies Carboniferous successions western United States has been fully explored. In this study, we provide new interpretations for paleoclimatic context Amsden and Tensleep Formations (Pennsylvanian, Northern Wyoming, USA). Formation consists basal sandstone member overlain by red siltstones containing pisolites. Very large-scale (~ 10 m) cross-bedding within indicates deposition an erg environment. Iron pisoid-rich layers overlying suggest evolution toward more humid conditions. Persistent arid conditions during middle Pennsylvanian suggested eolian sandstones calcretes Formation. These formations were deposited karst topography that developed top lower to Mississippian Madison Group. Although development karstic features implies prevailed late Mississippian, evaporites evidence early dolomitization formation it was under relationships argue long-term return Pennsylvanian. This trend can be explained northward drift ~ 15°S ~ 12°N. A comparison with contemporaneous records reveals diachronous across Pangaea, climatic documented Wyoming Shelf being reached later eastern North America. indicate plate motion considerably overprints records. Departures trend, presence deposits Formation, record overprinting shorter periods change.