Age,composition, and source of continental arc- and syn-collision granites of the Neoproterozoic Sergipano Belt,Southern Borborema Province,Brazil |
| |
| Institution: | 1. Department of Geology and Natural Resources, Institute of Geosciences, P.O. Box 6152, State University of Campinas – UNICAMP, 13083-970 Campinas, SP, Brazil;2. John de Laeter Centre of Mass Spectrometry, School of Applied Physics, Curtin University of Technology, Perth, WA 6845, Australia;3. Department of Geology, Federal University of Pernambuco, 50740-530 Recife, PE, Brazil;4. Faculty of Geology, Geosciences Institute, Federal University of Para, Belém 66075-110, Brazil;1. Instituto de Geociências, Universidade Estadual de Campinas, 13081-970 Campinas, SP, Brazil;2. Instituto de Ciência e Tecnologia, Universidade Federal de Alfenas, 37715-400 Poços de Caldas, MG, Brazil;3. Instituto de Geociências, Universidade de Brasília, 70910-900 Brasília, DF, Brazil;1. Departamento de Geologia, Programa de Pós-Graduação em Geodinâmica e Geofísica, Universidade Federal do Rio Grande do Norte, Natal, RN, Brazil;2. CPRM – Serviço Geológico do Brasil, Núcleo de Apoio de Natal (NANA/CPRM), Caixa Postal, CEP 59.078-970 Natal, RN, Brazil;1. Instituto de Ciência e Tecnologia, Universidade Federal de Alfenas, Poços de Caldas, MG, Brasil;2. Instituto de Geociências, Universidade Estadual de Campinas, SP, Brasil;3. Instituto de Geociências, Universidade de Brasília, DF, Brasil;1. Instituto de Geociências, Universidade de São Paulo, 05508-080 São Paulo, SP, Brazil;2. Departamento de Geologia, Universidade Federal de Pernambuco, 50740-530 Recife, PE, Brazil;3. AIRIE Program, Department of Geosciences, Colorado State University, Fort Collins, CO, USA;4. CEED - Centre for Earth Evolution and Dynamics, University of Oslo, Norway;1. Departamento de Geologia, Universidade Federal de Pernambuco, Recife 50740-530, Brazil;2. CPRM – Serviço Geológico do Brasil, Brazil |
| |
| Abstract: | The Sergipano belt is the outcome of collision between the Pernambuco-Alagoas Domain (Massif) and the São Francisco Craton during Neoproterozoic assembly of West Gondwana. Although the understanding of the Sergipano belt evolution has improved significantly, the timing of emplacement, geochemistry and tectonic setting of granitic bodies in the belt is poorly known. We recognized two granite age groups: 630–618 Ma granites in the Canindé, Poço Redondo and Macururé domains, and 590–570 Ma granites in the Macururé metasedimentary domain. U–Pb SHRIMP zircon ages for granites of first age group indicated ages of 631 ± 4 Ma for the Sítios Novos granite, 623 ± 7 Ma for the Poço Redondo granite, 619 ± 3.3 Ma for the Lajedinho monzodiorite, and 618 ± 3 Ma for the Queimada Grande granodiorite. These granitoids are dominantly high-K calc-alkaline, magnesian, metaluminous, mafic enclave-rich (Queimada Grande and Lajedinho), or with abundant inherited zircon grains (Poço Redondo and Sitios Novos). Geochemical and isotope data allow us to propose that Sítios Novos and Poço Redondo granites are product of partial melting of Poço Redondo migmatites. Sr-Nd isotopes of the Queimada Grande granodiorite and Lajedinho monzodiorite suggest that their parental magma may have originated by mixing between a juvenile mafic source and a crustal component that could be the Poço Redondo migmatites or the Macururé metasediments. Other 630–618 Ma granites in the belt are the mafic enclave-rich Coronel João Sá granodiorite and the Camará tonalite in the Macururé sedimentary domain. These granites have similar geochemical and isotopic characteristics as the Lajedinho and Queimada Grande granitoids. We infer for the Camará tonalite and Coronel João Sá granodiorite that their parental magmas have had contributions from mafic lower crust and felsic upper crust, most probably from underthrust São Francisco Craton, or Pernambuco-Alagoas Domain. The younger 590–570 Ma granite group is confined to the Macururé metasedimentary domain. Although these granites do not show typical features of S-type granites, their U–Pb age, field relationships, geochemical and Sr-Nd data suggest that their parental magmas have originated from high degree melting of the Macururé micaschists. Field observations support a model in which the Macururé domain, limited by the Belo Monte-Jeremoabo and São Miguel do Aleixo shear zones, behaved as a ductile channel flow for magma migration and emplacement during the Neoproterozoic, very much like the channel flow model proposed for emplacement of leucogranites in the Himalayas. |
| |
| Keywords: | Sergipano belt Granites Geochemistry U–Pb geochronology Sr–Nd isotopes West Gondwana |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
