EM - Escola de Minas

URI permanente desta comunidadehttp://www.hml.repositorio.ufop.br/handle/123456789/6

Notícias

A Escola de Minas de Ouro Preto foi fundada pelo cientista Claude Henri Gorceix e inaugurada em 12 de outubro de 1876.

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20221

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Tem arquivos: SimAssunto: search.filters.subject.Epeiric sea

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    Late Permian siliceous hot springs developed on the margin of a restricted epeiric sea : insights into strata-confined silicification in mixed siliciclastic‐carbonate successions.
    (2022) Varejão, Filipe Giovanini; Warren, Lucas Veríssimo; Alessandretti, Luciano; Rodrigues, Mariza Gomes; Riccomini, Claudio; Assine, Mario Luis; Cury, Leonardo Fadel; Faleiros, Frederico Meira; Simões, Marcello Guimarães
    Hot springs are sources of carbonate minerals in modern settings; however, few fossil structures are recorded in successions older than the Quaternary due to their enhanced erosional potential. >4500 siliceous mounds are recognized in a well-defined level from the upper part of the Permian Teresina Formation (Parana ́ Basin, SE Brazil). Additionally, a new mound level is here reported for the first time about 15 m below the main occur- rence. Remarkable lithological, mineralogical, paleontological and geochemical features characterize the mounds of both levels, pointing to a hydrothermal origin. Therefore, these structures are here called as hot springs. These were originated subaerially, on the margins of a closing epeiric sea developed on a large intra- continental sag basin. Hydrothermal fluids were sourced from deep circulating basin waters that erupted through intraplate deep-rooted faults. Our data suggests that these hot springs were active during distinct cycles of base level variations. Strata-confined silicification was enhanced during periods of high evaporation and hydrother- mal exudation. Finally, the vertical and lateral facies associations of the Permian hot spring succession are compared with modern sites, and implications for the recognition of syn-depositional hydrothermally precipitated silica in ancient sedimentary basins are discussed.