Nova contribuiçao ao conhecimento da formação Rio Claro (T) na Folha Rio Claro (SP)

• Autor(a) principal: Perinotto, José Alexandre de Jesus [UNESP]
• Data de Publicação: 2006
• Outros Autores: Etchebehere, Mario Lincoln de Carlos, Zaine, José Eduardo [UNESP], Saad, Antonio Roberto [UNESP]
• Tipo de documento: Artigo
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://www.periodicos.rc.biblioteca.unesp.br/index.php/geociencias/article/view/451; http://hdl.handle.net/11449/69322
• topic: Rio Claro; Rio Claro formation; Tertiary; alluvial fan; conglomerate; contour map; formation mechanism; Mesozoic; Paleozoic; quartz; quartzite; sandstone; Brazil; Sao Paulo [Brazil]; South America

The Rio Claro Formation mainly occurs in the county of Rio Claro (SP) lying unconformably on Paleozoic and Mesozoic rocks. Its thickness is 30-40 m. It shows fine to coarse, regular to poor sorted, Triable sandstones and conglomerates with quartzite and quartz clasts in the base. Thin layers of mudstone occur interbeded. Stratigraphic maps had been elaborated in recent analyses allowing to improve the knowledge about the formation. The biggest thicknesses occur on the east part of the studied area. The coarse/fine clastic ratio map demonstrates that fine sediments are concentrated in the east side, and suggests the existence of barriers which conditioned perennial water body (or bodies) where decantation took place (east, south and southeast sides). The structural contour map of the Rio Claro Formation base indicates a NW/SE trough which was the main depositional axis. The integrated analysis demonstrates that the formation is formed by lacustrine, fluvial and debris flows deposits whose source area was located on NW side, with coalescent alluvial fans from where braided to psamitic meandering fluvial channels came. The location of the source area suggests no link with the Corumbataf River paleo-terraces.