Geochemistry and geochronology of pre-Brasiliano rocks from the Transversal Zone, Borborema Province, Northeast Brazil

Emplacement and deformation of the Cachoeirinha pluton (Borborema province, NE Brazil) inferred through petrostructural studies: Constraints on regional strain fields

“…1c), so the southern domain, at least near the studied area, consists of Paleoproterozoic-age crust. These data are similar to the dominant zircon U-Pb and Nd model ages of basement rocks north of the EPSZ (Van Schmus et al, 1995;Brito Neves et al, 2001;Mariano et al, 2001;Sá et al, 2002;Neves et al, 2004). The orthogneisses display a flat-lying foliation whose development is attributed to an early contractional event during the Brasiliano orogeny, according to a zircon Pb-evaporation age of 630 Ma in an orthogneiss south of the town of Caruaru (Fig.…”

“…Rb-Sr whole-rock dating of the Cachoeirinha pluton yields an age of 570G25 Ma (Pessoa et al, 1978). The isochron was constructed using 18 points, including three analyses of country rock, and a decay constant of (Sá et al, 2002;Guimarães et al, 2004) and Pb-Pb (Neves et al, 2004) methods, respectively; numbers next to filled circles are whole-rock Nd-model ages (in Ma) Guimarães et al, 2004). 1.47!10 K11 a K1 . A recalculated age of 579G28 Ma was obtained using the presently adopted constant of 1.42!…”

U–Pb ages of plutonic and metaplutonic rocks in southern Borborema Province (NE Brazil): Timing of Brasiliano deformation and magmatism

“…The 1.7-1.5 Ga granitic gneisses and metaanorthosites ( Fig. 8 and Table 2) that are also found in the central domain and interpreted as anorogenic intrusions emplaced after the Transamazonian orogeny (Accioly et al, 2000;Sá et al, 2002). It is perhaps significant that one zircon grain in the Cabanas granite yielded an age of 1560 ± 16 Ma, which opens up the possibility that rocks of this age can also be identified in the southern domain.…”

“…It is also suggested in the southern domain by Sm-Nd isotopic data from plutons and country rocks Osako, 2005) and now confirmed by the age of inherited zircons in the Jupi orthogneiss and Cabanas granite. Orthogneisses have ages mostly in the range 1.97-2.13 Ga and are considered the basement for younger igneous, metaigneous, and metasedimentary rocks (Sá et al, 2002;Neves et al, 2004Neves et al, , 2006. The 1.7-1.5 Ga granitic gneisses and metaanorthosites ( Fig.…”

“…Simplified geological map of eastern Borborema Province showing available geochronological U-Pb and Pb-Pb ages for igneous and metaigneous rocks. All ages are U-Pb zircon ages in Ma except that labeled 1.58-168 Ga (Mo), which corresponds to monazite ages in Ga. Sources of data: Accioly et al (2000), Sá et al (2002), , Neves et al (2004), Neves et al (2006), this work. (Almeida et al, 2002; are similar in age (575-570 Ma) to the Cabanas granite (Table 2).…”