U-Pb ages of plutonic and metaplutonic rocks in southern Borborema Province (NE Brazil): Timing of Brasiliano deformation and magmatism - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of South American Earth Sciences Année : 2008

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

Olivier Bruguier
  • Fonction : Auteur
  • PersonId : 861964
Delphine Bosch

Résumé

The Borborema Province of northeastern Brazil is divided into three main domains: northern, central, and southern. Several U-Pb zircon ages of plutons and orthogneisses became available in the recent years in the central and northern domains, but similar results are scarce in the southern domain. This study reports U-Pb dates for single zircon grains from one orthogneiss (Jupi orthogneiss) and two plutons (Cachoeirinha syenitic pluton and Cabanas granite) south of the East Pernambuco shear zone system (EPSZ). The results provide geochronological constraints on the timing of deformation and magmatism in this part of the southern domain and allow correlations with the central domain. The Jupi orthogneiss was emplaced and deformed during development of the regional flat-lying foliation. A Pb-206/U-238 weighted apparent mean age of 606 +/- 8 Ma is interpreted as the crystallization age of the protolith of the orthogneiss and consequently the age of high-grade Brasiliano metamorphism. The NNE-trending Cachoeirinha pluton is only locally affected by strike-slip deformation, whereas the ENE-trending Cabanas granite is intensely affected by deformation related to the EPSZ. The 587 8 Ma and 573 4 Ma ages of the Cachoeirinha pluton and Cabanas granite, respectively, bracket the main period of activity of the EPSZ. Tectonomagmatic activity in the study area is similar to the age of Brasiliano events in the central domain, north of the EPSZ. In addition, xenocrystic zircons in the Jupi orthogneiss and Cabanas granite are interpreted as inherited from Paleoproterozoic source rocks, suggesting the presence of widespread reworked old crust in the southern domain, similar to the central domain. These results support the idea that the central and southern domains belonged to the same crustal block before the onset of the Brasiliano orogeny.

Dates et versions

hal-00411394 , version 1 (27-08-2009)

Identifiants

Citer

S. P. Neves, Olivier Bruguier, Delphine Bosch, J. M. R. Silva, G. Mariano. U-Pb ages of plutonic and metaplutonic rocks in southern Borborema Province (NE Brazil): Timing of Brasiliano deformation and magmatism. Journal of South American Earth Sciences, 2008, 25 (3), pp.285-29. ⟨10.1016/j.jsames.2007.06.003⟩. ⟨hal-00411394⟩
93 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Mastodon Facebook X LinkedIn More