Análise estratigráfica de alta resolução do intervalo praguiano-neoemsiano (Formação Ponta Grossa), na borda leste da Bacia do Paraná, com base em dados geoquímicos e sedimentológicos

Abstract

This work is the result of detailed stratigraphic analysis on the sedimentary record of Praguian?Emsian later interval, established on core samples of four wells in the Paleozoic outcrop section, eastern edge of Paran? Basin. Data set was obtained by means of sedimentology, gamma spectrometry and organic geochemistry (total organic carbon and pirolysis Rock-Eval), and lately integrated. Thus, depositional events with varied frequencies have been identified. These depositional events were classified as being two depositional sequences of 3rd order, termed as ?B? and ?C?, and six sequences of 4th order, termed as ?B1?, ?B2?, ?B3?, ?B4?, ?C1? and ?C2?. These depositional events typify the relative sea level variations occurred during the studied interval. They were characterized by the systems tracts and stratigraphic surfaces identified. Sometimes, these variations occurred with high cyclicity through the time. The correlation of the wells of a N-S section made possible the discussion about the cont inuity and lateral expression of the transgressive and regressive maximums in the depositional sequences of 3rd and 4th orders, besides the possible local factors which conditioned the sedimentation and the environmental and sedimentary dynamics. The evaluation of facies attributes, integrated with the utilized tools, helped on the inquiring of the main controls on the sediment circulation, water column oxygenation ratio, and organic matter preservation. These data in set indicated normal marine environmental conditions, with punctuated moments of reduction in oxygenation ration, without, however, show effective anoxic events in the sedimentation environment. These informations about the sequence stratigraphy and sedimentology are important in the study of distribution of levels with hydrocarbons generation potential, throughout of Paran? Basin.