Tracking connection and restriction of West Gondwana São Francisco Basin through isotope chemostratigraphy

Sedimentary provenance in the southern sector of the São Francisco Basin, SE Brazil

“…Similar results were also obtained for the Carrancas Formation by Uhlein et al (2016). This data set is compatible with a very close igneous source for the conglomerates and a small area of sediment sources, derived mainly from the basement valley walls in which they were deposited , Guacaneme et al 2017. As transgression progressed and flooded the craton, the area of sedimentation extrapolated the limits of these valleys, resulting in deposition of the fine sediments in a larger area and apparently increasing the number of source areas that were initially restricted to the valley walls (Fig.…”

“…The basal unit of the Bambuí Group is the Sete Lagoas Formation (Fig. 2), which is mostly composed of carbonate rocks with very negative δ 13 C values at the base (Alvarenga et al 2007, Kuchenbecker et al 2016, Paula-Santos et al 2017. This geological record is in agreement with the Snowball hypothesis (Hoffman et al 1998, Hoffman & Schrag 2002) that postulates at least three periods of extreme climatic shifts during the Cryogenian and Ediacaran Figure 1.…”

“…The occurrence of the unit described by Guacaneme et al (2017) in Inhaúma city area is emblematic, as the conglomerate is clearly deposited in a basement valley and only has clasts of the leucogranite, which can be observed in the valley walls (Fig. 9).…”

“…Provenance studies in the Carrancas Formation conglomerates reveal a wide range of clast assemblage varying from monomitic (Guacaneme et al 2017) to oligomitic (Kuchenbecker 2011) and polimitic , Uhlein et al 2016. The occurrence of the unit described by Guacaneme et al (2017) in Inhaúma city area is emblematic, as the conglomerate is clearly deposited in a basement valley and only has clasts of the leucogranite, which can be observed in the valley walls (Fig.…”

“…Although some works have discussed a possible unconformity at the base of the Sete Lagoas Formation (Martins & Lemos 2007, Zalán & Romeiro-Silva 2007, stratigraphic (Kuchenbecker et al 2016), sequence stratigraphic , Perrella Jr. et al 2017 and isotope chemostratigraphic data (Paula-Santos et al 2017, Perrella Jr. et al 2017 argue against the existence of an unconformity at the base of the Bambuí Group, and suggest a continuous deposition through the cap carbonates to the Cloudina bearing strata.…”