Arcabouço geotectônico da região da Faixa Riacho do Pontal, nordeste do Brasil: dados aeromagnéticos e gravimétricos

Geochemistry of the Serra das Melancias Pluton in the Serra da Aldeia Suite: a classic post-collisional high Ba-Sr granite in The Riacho do Pontal Fold Belt, NE Brazil

“…Recent studies based on isotopic and geochemical data presented by Caxito et al (2014) attest to a MORB-type tholeiitic affiliation for the Monte Orebe Complex basic metavolcanic rocks, suggesting oceanic crust remnants in the region. This evidence is supported by gravimetric geophysical data presented by Oliveira (1998), attesting to a Bouger anomaly characterized by positive-negative pairs, which may indicate an old suture zone between two crustal blocks of distinct composition and density. Therefore, the remnants of oceanic crust would mark suture zones, suggesting a subduction setting, with the generation of the Serra da Aldeia Suite plutons related to the late stage, by means of the Brasiliano-Pan African collage.…”

“…Such features were recognized thanks to geophysical studies developed by Oliveira (1998), which allowed the division of the orogen, from south to north, in external zone, central zone and internal zone.…”

“…This complex is constituted by a metavolcano sedimentary sequence composed mainly of basic metavolcanics (actinolite greenschists, amphibolites, metatuffs), with intercalations of ultramafic and metasedimentary rocks, such as metachert, garnet mica schists, graywacke and quartz schists (Caxito 2013). Based on geophysical studies, Oliveira (1998) suggests the existence of a suture zone in the region, as evidenced by Bouger anomalies with positive-negative pairs. A recent study by Caxito et al (2014) showed a mid-ocean ridge basalt (MORB) type affinity for the basic metavolcanics, with a whole-rock Sm-Nd isochron at around 819 ± 120 Ma.…”

“…According to Oliveira (1998), the Riacho do Pontal Fold Belt is divided from south to north in three domains (external, central and internal) with distinct lithological and tectono-metamorphic characteristics. The northwestern region of the orogen, which is restricted to the internal domain, is characterized by intense late-to post-orogenic magmatism (Brito Neves et al 2015).…”

Geologia, Estratigrafia E Petrografia Do Complexo De Brejo Seco, Faixa Riacho Do Pontal, Sudeste Do Piauí

“…Sua estruturação é fruto de uma tectônica brasiliana (630-530 Ma), compressiva-transpressiva, vergente para sul, responsável pelo imbricamento de escamas tectônicas sobre o Cráton do São Francisco (Brito Neves, 1975;Angelim, 1988;Jardim de Sá et al 1992;Brito Neves et al 1995, Angelim & Kosin, 2001. Foi dividida de norte para sul em três zonas principais ( Fig.1; Angelim et al 1998;Oliveira, 1998;2008;Caxito, 2013;Caxito et al 2014a):…”