A contribution to regional stratigraphic correlations of the Afro-Brazilian depression – The Dom João Stage (Brotas Group and equivalent units – Late Jurassic) in Northeastern Brazilian sedimentary basins

High resolution stratigraphy of initial stages of rifting, Sergipe-Alagoas Basin, Brazil

“…The unit I corresponds litho-stratigraphically to the top of Serraria Formation and is characterized by multi-storey and multi-lateral, amalgamated, sandstone bodies with paleocurrent unimodal to SE toward the depocenter of the Afro-Brazilian Depression, that was located outside the borderlines of the present federal states of Sergipe and Alagoas as suggest the extension of this basin. The unit I, in this study, corresponds to the already documented as sequence II of Serraria Formation by Kuchle et al (2011) and suggests deposits of a wide perennial braided channel system established in humid climatic conditions during the initial moments of rifting and with similar deposits preserved in all territories that belonged to this depression. The unit II, which corresponds to the base of Feliz Deserto Formation, is characterized by a network of anastomosed fluvial channels separated by vegetated floodplains.…”

“…The paleocurrent and depositional systems distribution of units I and II indicate that these units occupied a depositional area larger than the Sergipe-Alagoas Basin itself. Data collected in outcrops and available in previous studies suggest that these units were deposited in a large sedimentary basin related to the initial stage of Neocomian rifting (Campos Neto et al 2007, Kuchle et al 2011. The Serraria Formation was deposited in the north flank of this large and shallow basin whose depocenter was located at the SE of Sergipe-Alagoas Basin (Kuchle et al 2011).…”

“…Data collected in outcrops and available in previous studies suggest that these units were deposited in a large sedimentary basin related to the initial stage of Neocomian rifting (Campos Neto et al 2007, Kuchle et al 2011. The Serraria Formation was deposited in the north flank of this large and shallow basin whose depocenter was located at the SE of Sergipe-Alagoas Basin (Kuchle et al 2011). This accumulation phase has been called Rift Initiation Tectonic System Tract by Kuchle and Scherer (2010), instead of the term Pre-Rift attributed by Campos Neto et al (2007), that is restricted to rocks that are completely unrelated to the rifting process, consisting of sedimentary basement upon which taphrogenic processes will act (Prosser 1993, Bosence 1998, Scherer et al .2014.…”

“…The unit I has sedimentological-stratigraphical characteristics and paleocurrent patterns suggesting that the Rift Initiation Tectonic System Tract is characterized by incipient extensional stress generating a wide synclinal depression, associated to the low rate, continuous and uniformly distributed tectonic activity (Morley 2002, Kinabo et al 2007, Kuchle et al 2011. The predominance of multi-storey amalgamated sandstone bodies without deposits from outside channel along this unit indicates low accommodation creation rate and is related to a uniform A/S ratio with positive-close to 0 values (Martinsen et al 1999, Scherer et al2014.…”

“…Nevertheless, there is a lack of detailed studies on characterization of depositional systems and stacking patterns of the basin for each evolutionary stage, even more in the early stages in which the identification of depocenters, the depositional systems and their distributions in basins are poorly understood (Kinabo et al 2007, Morley 2002, Kuchle et al 2011, Scherer et al 2014.…”