Ciclicidade Ao Tempo Do Andar Buracica (Neobarremiano) Da Bacia Do Recôncavo

Abstract

CYCLICITYIN THE BURACICASTAGE (LATEBARREMIAN) OF THE RECONCAVOBASIN. The Buracica Stage (Late Barremian) of the Reconcavo basin is characterized by the cyclic succession of fluvial, deltaic and lacustrine sediments of the Sao Sebastiao Formation, which can be divided into 6 third order and 20 fourth order stratigraphic sequences. Oxigen stable isotope study indicates a major climatic control over the architecture of those sequences. The cyclestratigraphic study of this interval, based on the orbital cycles of Milankovitch, suggests that the 3'd order sequences were deposited in a time span of 413 ka, equivalent to the period of the long eccentricity. The 4 th order sequences are correlated with the obliquity cycles, with a time span of38 ka and 49 ka. Based on these results, the total time span for the deposition of the Buracica sediments is of2,48 Ma.

Lake level oscillations recorded in Buracica Stage (Barremian, Early Cretaceous) of Recôncavo Basin, Bahia State (N.E. Brazil)

“…The Recôncavo Basin, the former leading oil-producing basins in Brazil (Ghignone and Andrade 1970;Morais 2013), studied since the 1950s, is currently classified as a mature basin in terms of oil exploration (Hallack 2019). Many works were performed to study its geological aspects (e.g., Viana et al 1971;Petri 1972;Cohen 1985;Milani and Davison 1988;Regali and Viana 1989;Arai et al 1989;Magnavita 1992Magnavita , 2000Silva 1993;Caixeta et al 1994;Magnavita et al 1994Magnavita et al , 2003Magnavita and Silva 1995;Bruhn 1999;Silva et al 2000;Destro et al 2003;Santos, 2005); however, many questions remain to be clarified, namely that are related to the factors that conditioned its sedimentary filling.…”