Caracterização petrográfica e litogeoquímica dos mármores e rochas calcissilicáticas do Vale do Jacurici, Bahia: condições paleoambientais e processos fosfogenéticos

Gama, Mariana Andriotti; Misi, Aroldo; Sá, José Haroldo da Silva; Oliveira, Luis Rodrigues dos Santos de; Ribeiro, Tatiana Silva

doi:10.11606/issn.2316-9095.v21-161794

Cited by 2 publications

(1 citation statement)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…It is also pointed out that both the RMMUB and the VJC are embedded in the same lithotypes, metasediments of marine/plataformal origin, metamorphosed into high amphibolite to granulite facies, composed of olivineserpentine -marbles, diopside and calc-silicate granulites, and belonging to the TNIC (Gama 2014;Ribeiro 2016). The RMMUB is located around 60km from a mineralized body in Cr, in the region of Laje Nova associated with the VJC.…”

Section: Metallogenic Potentialmentioning

confidence: 99%

Geological Characterization, Lithogeochemistry and the Metallogenic Potential for Chromium of the Riacho do Mocambo Mafic-Ultramafic Body, Northeast of the São Francisco Craton, BA, Brazil

Câmara,

Sá,

Oliveira

et al. 2023

Anu. Inst. Geociênc.

View full text Add to dashboard Cite

In the geotectonic context of the Salvador-Curaçá Orogen, north portion of the São Francisco Craton, an association of mafic-ultramafic (M-UM) rocks was identified and described in this paper as the Riacho do Mocambo Mafic- Ultramafic Body (RMMUB). Despite being located approximately 60 km from the Vale do Jacurici Complex (VJC), the host of Brazil’s largest reserves of Cr, the RMMUB has never been associated with this Complex in regional geologic mapping projects. When it is mentioned in the bibliography, the M- UM rocks of the RMMUB are genetically related to the São José do Jacuípe Suite (SJJS). While the VJC is described as differentiated sills, associated with a synorogenic to a tardi-orogenic event, the SJJS is interpreted as fragments of an Archean-Paleoproterozoic oceanic crust or as a Gabbro- Anorthosite Stratiform Complex. Such contrasting genesis raised doubts about the RMMUB’s origin and field work along with geochemical analyses were carried out in order to better understand the possible source of the RMMUB. In the field, the RMMUB exhibits an elongated shape of small thickness (7 km of extension by less than 100 m of apparent thickness), displayed concordantly with the Tanque Novo-Ipirá Complex metasediments. In the mapped outcrops it is possible to observe the rhythmic and gradual alternation amid the lithotypes of the RMMUB, varying from serpentinite to metagabbro, suggesting that it is a layered igneous body. The geochemical results support the primitive aspect of the ultramafic rocks of this body (MgO up to 38 wt.%; Ni up to 2972 ppm; Cr up to 7799 ppm) and suggest that the RMMUB shows distinctive characteristics from the SJJS, but similar ones with magma of the VJC such as geochemical signatures, source, depth, and tectonic environment. The discovery of this new M-UM body in an area of great metallogenic fertility opens a potential for the identification of new Cr mineralization and magmatic sulfides of Ni, Cu, and EGP, in the Salvador- Curaçá Orogen, São Francisco Craton, the northeast region of the state of Bahia.

show abstract

Section: Metallogenic Potentialmentioning

confidence: 99%