Sedimentology and paleoecology of late Paleozoic high-latitude, glaciogenic deposits in the Tepuel Basin, Patagonia, Argentina

PAULS KATHRYN N; FRAISER MARGARET L; ISBELL, JOHN; PAGANI MARÍA A; TABOADA ARTURO C

Congreso; GSA Annual Meeting; 2013

The glacial and non-glacial intervals of the Late Paleozoic Ice Age (LPIA) are of great interest due to their similarities with changing climate regimes during the Pleistocene. The changes and adaptations of the biota can also serve as a proxy for understanding future trends in Earth?s climate system. Most of the known LPIA marine faunal data come from low-latitudinal regions, and have been used as a global proxy. However, modern organisms in the tropics and polar regions respond differently to changing climate, and the same can be proposed for paleocommunities during the LPIA. The hypothesis of this study is that in high-paleolatitude regions, glacial and non-glacial communities were ecologically dissimilar. It is important to understand the capacity of different global climate regimes and the adaptability of the faunas that lived within them. This study focuses on a high-latitude shelf-edge to slope fauna from the Tepuel-Genoa Basin in Chubut Province in Patagonia, Argentina in order to better understand the responses of a high-latitude fauna to changing environmental conditions, and to develop a more robust understanding of climate change and its impacts on the biosphere. During field work, data were collected from six fossil beds, and a 276-meter stratigraphic section was measured and described from the Pampa de Tepuel Formation. The data suggest that the composition of the paleocommunities reflects changes in the local environment from intraglacial to post-glacial faunal assemblages within the Lanipustula biozone. Evidence of slide blocks forming at the shelf edge, along with the change in abundance and diversity within the fossil beds, are strong indicators of changing environments produced during a sea level lowstand when clastic systems reached the shelf edge. By continuing research on the LPIA, we may be better able to understand the fundamental factors of species and ecosystem instability because of the substantial environmental and climatic shifts that occurred.