Produção Nacional
FORMAÇÃO IAPÓ: GLACIAÇÃO CONTINENTAL NO LIMITE ORDOVICIANO/SILURIANO DA BACIA DO PARANÁ
1998; Sociedade Brasileira de Geologia; Volume: 28; Issue: 1 Linguagem: Inglês
10.5327/rbg.v28i1.612
ISSN2317-4889
AutoresMário Luís Assine, Carlos José Souza de Alvarenga, José Alexandre J. Perinotto,
Tópico(s)Geology and Paleoclimatology Research
ResumoThe lapo Formation is a thin and widespread unit, generally less than 20 m thick and covering discontinuously an area of hundreds of thousand square kilometers. The main facies is massive diamictites, which display pebbles and cobbles in a mud matrix, some of them faceted and striated. The massive diamictites are considered subglacial tillites. The facies association includes stratified diamictites, conglomerates, massive and stratified sandstones, and fine laminated facies with dropstones. The glaciation in the Ordovician/Silurian boundary is well constrained and its correlation with other Gondwanan basins suggests maximum glacial in the Iate Ashgillian age. The lapo Formation is overlain by early Llandovery post-glacial transgressive shales of the Vila Maria Formation. It is herein proposed a modcl of glaciomarine stratigraphic architecture in a glaciated continental margin to explain the origin of the lapo Formation.
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