U-Pb SHRIMP and 40Ar/39Ar constraints on the timing of mineralization in the Paleoproterozoic Caxias orogenic gold deposit, São Luís cratonic fragment, Brazil

Klein, Evandro Luiz, Tassinari, Colombo Celso Gaeta and Vasconcelos, Paulo Marcos (2014) U-Pb SHRIMP and 40Ar/39Ar constraints on the timing of mineralization in the Paleoproterozoic Caxias orogenic gold deposit, São Luís cratonic fragment, Brazil. Brazilian Journal of Geology, 44 2: 277-288. doi:10.5327/Z2317-4889201400020008


Author Klein, Evandro Luiz
Tassinari, Colombo Celso Gaeta
Vasconcelos, Paulo Marcos
Title U-Pb SHRIMP and 40Ar/39Ar constraints on the timing of mineralization in the Paleoproterozoic Caxias orogenic gold deposit, São Luís cratonic fragment, Brazil
Journal name Brazilian Journal of Geology
ISSN 2317-4889
2317-4692
Publication date 2014-01-01
Year available 2014
Sub-type Article (original research)
DOI 10.5327/Z2317-4889201400020008
Volume 44
Issue 2
Start page 277
End page 288
Total pages 12
Place of publication Sao Paulo, Brazil
Publisher Sociedade Brasileira de Geologia
Language eng
Formatted abstract
Caxias is an orogenic gold deposit in the São Luís cratonic fragment, which is correlated with the Rhyacian terranes of the West-African Craton. The deposit postdates peak metamorphism (estimated at 2100 ± 15 Ma) and is hosted in a shear zone that cuts across schists of the Aurizona Group (2240 ± 5 Ma) and the Caxias Microtonalite. The emplacement age of the microtonalite, as determined in this work by SHRIMP U-Pb zircon dating, is 2009 ± 11 Ma and represents a late-stage magmatic event in the São Luís cratonic fragment. Older zircon age of 2139 ± 10 Ma is interpreted as due to inheritance from the older granitoid or volcanic suites (magmatic sources?) or to contamination during emplacement. Lead isotope compositions indicate that the Pb incorporated in ore-related pyrite was probably sourced from regional, orogenic calc-alkaline granitoids of ca. 2160 Ma. Hydrothermal sericite from Caxias yielded a 40Ar/39Ar plateau age of 1990 ± 30 Ma, which combined with the emplacement age of the Caxias Microtonalite brackets the age of gold mineralization between 2009 ± 11 and 1990 ± 30 Ma.
Keyword Geochronology
Isotope geochemistry
Orogenic gold
Q-Index Code C1
Q-Index Status Confirmed Code
Institutional Status UQ

Document type: Journal Article
Sub-type: Article (original research)
Collections: School of Earth Sciences Publications
Official 2015 Collection
 
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