Brachiopods and paleoecological studies in the Pennsylvanian of the Great Basin (United States)

详细信息    Brachiopods and paleoecological studies in the Pennsylvanian of the Great Basin (United States)

• 出版日期：2004.
• 页数：1 v. :
• 第一责任说明：Alberto Perez-Huerta.
• 分类号：a553.3 ; a543 ; a545.42
• ISBN：0496836188(ebk.) :

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02h0029355 20120611133510.0 cr un||||||||| 120611s2004 xx ||||f|||d||||||||eng | 3136420 0496836188(ebk.) : CNY371.35 NGL NGL NGL a553.3 ; a543 ; a545.42 Perez-Huerta, Alberto. Brachiopods and paleoecological studies in the Pennsylvanian of the Great Basin (United States) [electronic resource] / Alberto Perez-Huerta. 2004. 1 v. : digital, PDF file. Adviser: Savage, Norman M. Thesis (Ph.D.)--University of Oregon, 2004. Brachiopod faunas from the Pennsylvanian of the Great Basin, U.S.A., were studied to determine the biotic response of these brachiopods to long and short-term environmental changes. These changes are related to climatic and eustatic sea-level variations linked to the glaciation on Gondwana and paleogeographic changes related to the formation of Pangea. Brachiopods were recorded in shallowing-upward carbonate cycles in the context of a carbonate ramp. Results show that eustatic oscillations of sea-level are likely the origin of cyclic stacking patterns, especially those with dominance of small scale cycles. Seventy species belonging to forty-one genera of brachiopods were recognized in the Pennsylvanian early Bashkirian-late Moscovian). These taxa belong to twelve recurrent brachiopod communities in cyclic carbonate sequences. Many of these taxa and all the communities are described for the first time in Pennsylvanian sequences of western North America. Paleoecological analyses were focused on understanding factors controlling the distribution of brachiopods within the cycles and the patterns of extinction---origination on a regional scale. Results suggested that the availability of nourishment, which varies with fluctuations in relative sea-level, is a significant paleoecological control. This factor appears to influence the body size, abundance, and population variability of some taxa within brachiopod communities. The analysis illustrates short-term patterns of biotic response to environmental change. Patterns of extinction---origination at species level revealed an extinction event at the Desmoinesian-Missourian boundary and three origination events at the Mid-Carboniferous and the Missourian-Virgilian boundaries and in the Desmoinesian. The extinction event is related to a warming episode at the end of the Desmoinesian. The origination events appear to be related to migration of faunas from South America and Russia. These migrations may be a response to new oceanic currents developed as a result of paleogeographic changes that accompanied the formation of Pangea. These events of extinction and origination suggest the existence of a long-term biotic relationship to climatic and paleogeographic changes during the Pennsylvanian. Brachiopoda, Fossil ; Paleontology ; Paleoecology Great Basin. ; Pennsylvanian. ; Great Basin. Electronic dissertations. aeBook. aCN bNGL http://pqdt.bjzhongke.com.cn/Detail.aspx?pid=QA8E4Qy2JLE%3d NGL Bs1459 rCNY371.35 ; h1 bs1204