Geology of the northern Borborema Province, NE Brazil and its correlation with Nigeria, NW Africa

Abstract

The Borborema and Benin-Nigeria provinces of NE Brazil and NW Africa, respectively, are key areas in the amalgamation of West Gondwana by continental collision during the Brasiliano/Pan-African orogenies. Both are underlain by complex basement: Nigeria has c. 3.05 Ga Archaean crust but no known Palaeoproterozoic rocks .2.0 Ga; in NE Brazil, 2.6-3.5 Ga Archaean rocks form small cores within Palaeoproterozoic gneiss terrains affected by plutonism at c. 2.17 Ga. Both regions exhibit Late Palaeoproterozoic (c. 1.8 Ga) rift-related magmatism and metasedimentary sequences overlying the basement. The Seridó Group of NE Brazil (,0.65 Ga) is similar to the Igarra Sequence in SW Nigeria. The Ceará Group, which may date back to c. 0.85 Ga, is a passive margin deposit on crust thinned during initiation of an oceanic domain. In both provinces, basement and sedimentary cover were involved in tangential tectonics that resulted in crust-thickening by nappe-stacking associated with closure of this ocean. Frontal collision between c. 0.66 and 0.60 Ga later evolved to an oblique collision, generating northsouth continental strike-slip shear zones at c. 0.59 Ga. In NE Brazil, the main Pan-African suture is probably buried beneath the Parnaíba Basin. The Transbrasiliano Lineament, interpreted as the prolongation of the Kandi-4850 Lineament in Hoggar, may represent a cryptic suture. Opening of the Atlantic Ocean in the Mesozoic led to the break-up of Pangaea (and West Gondwana) and the consequent individualization of the South America and Africa continents, each one containing part of the Brasiliano/Pan-African fold belt. The Borborema Province (Almeida et al. 1981) in northeastern Brazil (Fig. 1) was built during the Brasiliano/Pan-African orogeny, as the result of convergence and final collision of the São LuisWest Africa and São Francisco -Congo cratons, in the context of West Gondwana amalgamation.The present structural framework of the province (Fig. 2) dates from the end of the Brasiliano/ Pan-African orogeny, forming a mosaic of independent domains juxtaposed along large crustal-scale shear zones (Vauchez et al. 1995) in a continental-scale collage (Van Schmus et al. 1998).Since the first attempts to reconstruct West Gondwana, the similarity of geological features between NE Brazil and NW Africa were used to argue for the juxtaposition of the two continents. However, there is still much uncertainty, and correlation between the two domains remains imprecise . The northern part of the Borborema Province, north of the Patos Lineament, and the Benin -Nigeria province are the key for correlation between the continents (Fig. 2). Integration of recent geological and geochronological data allows re-evaluation of the geological framework of the two provinces and provides new insights for the correlation between the two provinces.

U-Pb (LA-ICPMS) zircon ages and Nd isotopes for granitoids of the Tamboril-Santa Quitéria Complex, Ceará Central Domain[/title]: [subtitle]implication for neoproterozoic syncollisional magmatism in north Borborema Province

“…This province covers an area of approximately 450,000 km 2 in northeastern Brazil and its final configuration results from the convergence of the Amazon, São Luis/West African and São Francisco/Congo cratons during the Brasiliano/ Panafrican collage of West Gondwana (Brito Neves and Cordani, 1991;Trompette, 1994) (Figure 1). Recently, several isotopic studies, specially U-Pb and Sm-Nd data, have helped distinguish different tectono-magmatic domains in the Borborema Province (e.g., Arthaud, 2007;Arthaud et al, 2008; Oliveira, Windley, Araújo, 2010;de Araujo et al, 2010bde Araujo et al, , 2012bSantos et al, 2010;Van Schmus, Kozuch, Brito Neves, 2011). On the basis of U-Pb ages and crustal Nd signatures, the northern Borborema Province (northward of the Patos lineament) can be divided in three main geological domains : (i) Médio Coreaú Domain (or NW Ceará), (ii) Ceará Central Domain and (iii) Rio Grande do Norte Domain (Figure 2).…”

“…Figure 3 is also represented. Arthaud et al, 2008). In general, granitic/granodioritic pink granitoids and diatexites predominate, with some local participation of less evolved dioritic to tonalitic rocks Santos et al, 2007).…”

“…The Tamboril-Santa Quitéria Complex (TSQC) is one of the largest Neoproterozoic plutonism in the northern Borborema Province Castro, 2004;Arthaud et al, 2008) (Figures 1 and 2). It is an anatectic/ igneous association characterized by a number of magmatic pulses that occurred in the 650-610 Ma interval (e.g.…”

“…The structural pattern points to magma emplacement concomitant with tangential deformation, with a ubiquitous syn-to late-magmatic deformation followed by injection of less deformed, younger magmas Figure 1. Pre-drift reconstruction of NE Brazil and NW Africa in the late Neoproterozoic -early Paleozoic interval (Arthaud et al, 2008). Geological map of the Ceará Central Domain (CCD) and the surrounding geological framework adapted from Fetter et al (2003) and Cavalcante et al (2003).…”

Granulite-facies metamorphism at ca. 570-580 Ma in the Porangatu Granulite Complex, central Brazil: implications for the evolution of the Transbrasiliano Lineament

“…The mega-shear zone is exposed from Argentina and Paraguay, through central Brazil, and may be traced through northeastern Brazil into western Africa, where it is known as the Kandi Lineament. The total length of the lineament is estimated to be approximately 4,000 km, making it the most extensive shear zone on Earth (Schobbenhaus Filho et al 1975, Trompette 1994, Oliveira & Mohiak 2003, Arthaud et al 2008, Attoh & Brown 2008, Santos et al 2008b, Cordani et al 2013, Cacama et al 2015.…”