O grupo itararé (Neocarbonífero-eopermiano) entre porto amazonas (PR) e mafra (SC): Sedimentação gravitacional em contexto marinho deltaico com influência glacial

Abstract

Gravitational sedimentation from the permocarboniferous section of Paraná Basin is well known although still understudied. Mass-transport deposits (MTDs) as debris flows and slumps, beside turbidites, predominantly set up the stratigraphic framework of the Itararé Group in the area between Porto Amazonas (Paraná State) and Mafra (Santa Catarina State), eastern border of Paraná Basin. The reconnaissance of these deposits started from a detailed facies analysis, which has resulted on the differentiation of four main facies associations. The first one (facies association A1) is related to a glacially influenced deep-water environment as pelagic muds, rain-out deposits and ice rafted debris. Facies association A2 includes extensive mass transport deposits (MTD) and facies association A3 is composed of sand and mud turbidites. The forth one (facies association B) is related to shallow marine environment connected to deltaic deposits. The sedimentary stacking pattern from the facies associations suggests a marine progradation of the deltaic unit over deep water facies associations. It was accomplished, nevertheless, that the movements of the glaciers did not affected directly the studied depositional sites, but it had a great role on the generation and supply of proglacial sediments. MTDs also have relevant implications for paleoenvironment analysis and sequence stratigraphy.