Geological and isotopic characteristics of granites from the Western Pernambuco-Alagoas Domain: implications for the crustal evolution of the Neoproterozoic Borborema Province

作者：da Cruz Rodrigo Fabiano^*; Pimentel Marcio Martins; de Aguiar Accioly Ana Claudia; Rodrigues Joseneusa Brilhante

来源：Brazilian Journal of Geology, 2014, 44(4): 627-652.

DOI：10.5327/Z23174889201400040008

• Neoproterozoic Orogen
• U-Pb Geochronology
• Sm-Nd Isotopes
• Entremontes Complex
• Riacho Seco Nucleus
• Fulgencio Orthogneiss

The Western Pernambuco-Alagoas Domain is a complex tectonic domain of the Southern part of the Neoproterozoic Borborema Province. It borders the Northern margin of Sao Francisco Craton. U-Pb and Sm-Nd data discussed in this work show that, in the Western Pernambuco-Alagoas Domain, large volumes of granitic rocks of various ages related to different tectonic events are recognized. The Cariris Velhos Event is represented by Lobo (974 +/- 8 Ma) and Rocinha (956 +/- 2 Ma) orthogneisses; whereas Paleoproterozoic and Archean basement rocks are represented by Fulgencio Orthogneiss (1,996 +/- 8 Ma), Riacho Seco Gneissic-migmatitic Complex (1,992 +/- 27 Ma), and orthogneisses of Entremontes Complex (2,734 +/- 11 Ma). Six groups of granitoids are recognized: Brasiliano granitoids (Ediacaran-Cryogenian), with Meso-to Paleoproterozoic model ages; Cariris Velhos granitoids (Tonian) yielding Mesoproterozoic model ages; Paleoproterozoic granitoids from Pernambuco-Alagoas Domain, with Neoarchean to Paleoproterozoic Nd model ages; Paleoproterozoic granitoids from Riacho Seco Nucleus, represented by Riacho Seco Gneissic-migmatitic Complex, with Archean model ages; Archean granitoids represented by the rocks of Entremontes Complex; and granitoids emplaced in the Sao Francisco Craton displaying Paleoproterozoic to Archean model ages. Prominent among the new data obtained is the Paleoproterozoic age of Riacho Seco Gneissic-migmatitic Complex, which is formed by Archean basement reworking. The new data reveal the presence of Paleoproterozoic and Archean basement inliers and a large volume of Cariris Velhos granitoids in the Western Pernambuco-Alagoas Domain. The orogen, therefore, involved extensive reworking of older blocks, possibly including parts of Sao Francisco-Congo Craton.

• 出版日期2014-12