Geochronology and thermochronology of the gneisses of the Brasiliano/Pan-African Araguaia Belt: Records of exhumation of West Gondwana and Pangea break up
| Autor: | Candido Augusto Veloso Moura, J. M. Milhomem Neto, Tiago Jonatan Girelli, A.N.C. Dias, Farid Chemale, K. M. Masuyama |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
education.field_of_study
010504 meteorology & atmospheric sciences Paleozoic Archean Population Geology Orogeny 010502 geochemistry & geophysics Fission track dating 01 natural sciences Thermochronology Gondwana Paleontology Geochronology education 0105 earth and related environmental sciences Earth-Surface Processes |
| Zdroj: | Journal of South American Earth Sciences. 80:174-191 |
| ISSN: | 0895-9811 |
| DOI: | 10.1016/j.jsames.2017.09.027 |
| Popis: | The 1200 km long Araguaia Belt, central-north Brazil, was formed as a result of the Neoproterozoic (Ediacaran) to Early Cambrian collage of West Gondwana and has several dome structures in whose nuclei crop out basement inliers of Archean and Paleoproterozoic orthogneisses. Thus, the orthogneisses from Lontra, Cocalândia, Colmeia and Cantao dome structures were selected for fission-track thermochronology and U-Pb double dating. Three Archean magmatic episodes ranging from 2830.9 ± 6.9 Ma (Colmeia dome) to 2905 ± 5.1 Ma (Lontra dome) and one Paleoproterozoic magmatic event at 1835 ± 31 Ma (Cantao dome) are recognized by U-Pb LA-MC-ICP-MS zircon dating. Fission-track thermochronology in zircon permitted to identify three well-defined age populations, which correspond to major regional geological events. The older population (489 ± 15 Ma to 498±8Ma) records the exhumation process and the orogenetic collapse of the Araguaia Belt. The intermediate population (331 ± 8 Ma to 345 ± 13 Ma) is related to the Gondwanides orogeny which affected the western margin of Gondwana and therefore the interior of South American. Finally, the younger fission track ages (197 ± 3 Ma, 197 ± 4 Ma, 198 ± 2 Ma and 208 ± 10 Ma) reflect crustal heating around 200 Ma, which is associated with the Lower Jurassic Mosquito tholeiitic magmatism and extended the influence of the Central Atlantic Magmatic Province to the Araguaia Belt. This mafic magmatism has been recognized in different regions of the South American and was an important source of heat for hydrocarbon generation in some Paleozoic intracratonic basins. |
| Databáze: | OpenAIRE |
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