CONTRIBUIÇÃO A GEOLOGIA DAS REGIÕES DE JAGUARIAIVA E LAMBEDOR, PARANÁ

The present paper deals with some aspects of the Devonian Stratigraphy of the State of Parana, Brazil. Most authors subdivide these Devonian deposits in two formations: Furnas below and Ponta Grossa above. The lithology of the Furnas is predominantly formed by middle to coarse-grained sandstones and some interbedded conglomeratic beds and thin micaceous shale layers. The lithology of the Ponta Grossa is made up of finely laminated argillaceous, micaceous shale with very minor interbedded siltstone and fine sandstone layers. Coarse sandstones occur in the top of the Devonian sequence in Lambedor. In Cândido de Abreu these beds were revealed through petroleum wells. Similar beds outcroping near the top of the Devonian sequence in Jaguariaiva are noticed here by the first time. The Early Devonian age of these beds is proved by the occurrence above them of 5 meters of sandy shale with fossils. The thicknesses of these sandstone beds are always relatively small. In Jaguariaiva they are about 24 meters thick. The interbedding of coarse sandstones and shales near the top of the Devonian sequence demonstrates a relatively important flutuation of sea level before the final regression of the Early Devonian sea. It is also added in the present paper, new evidences to reinforce the conclusion already attained by one of us that a thick sequence of sandstone beds covering the Devonian sequence in Lambedor, considered by some authors as Devonian, is actually fluvio-glacial, permocarboniferous. Varvite and tillite outcrop in the base of this sandstone sequence and conglomerates, possibly fluvio-glacial, occur in the middle and near the top of it. Shales and sandstones similar to the Devonian ones are the predominant lithologtes of the pebbles of one of these conglomerates which suggest reworking of Devonian deposits by fluvio-glacial agents.