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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Insights on the origin of the Graciosa A-type granites and syenites (Southern Brazil) from zircon U-Pb geochronology, chemistry, and Hf and O isotope compositions

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Author(s):
Jobim Vilalva, Frederico Castro [1] ; Simonetti, Antonio [2] ; Farias Vlach, Silvio Roberto [3]
Total Authors: 3
Affiliation:
[1] Univ Fed Rio Grande do Norte, Ctr Ciencias Exatas & Terra, Dept Geol, BR-59078970 Natal, RN - Brazil
[2] Univ Notre Dame, Dept Civil & Environm Engn & Earth Sci, Notre Dame, IN 46556 - USA
[3] Univ Sao Paulo, Inst Geociencias, Dept Mineral & Geotecton, BR-05508080 Sao Paulo, SP - Brazil
Total Affiliations: 3
Document type: Journal article
Source: LITHOS; v. 340, p. 20-33, SEP 2019.
Web of Science Citations: 1
Abstract

The Neoproterozoic, post-collisional, Graciosa Province (southern Brazil) comprises several A-type intrusions and related volcanics of alkaline and subalkaline (or aluminous) petrographic associations. U-Pb age determinations, trace element, and Hf and O isotopic compositions were obtained for zircons from six distinct A-type granitic and syenitic plutons from both alkaline and subalkaline associations from the province. Geochronological results indicate that their emplacement, petrogenetic evolution and crystallization spanned over a similar to 9 million years interval, with peak magmatism at similar to 580 Ma. Plutons were emplaced in a post-collisional extensional regime related to the geodynamic evolution of the south-southeastern part of the Gondwana supercontinent. Hf isotopic compositions are highly variable, with epsilon Hf(t) values between +1.4 to -31, whereas delta(18)0 signatures are mainly between +4.7 and +6.0 parts per thousand. These features, along with trace element signatures, especially for Hf, U, Nb, and rare-earth elements, suggest that generation of the Graciosa rocks occurred via partial melting of a lithospheric mantle previously metasomatized by slab-derived fluids, followed by variable degrees of crustal contamination at depth. (C) 2019 Elsevier B.V. All rights reserved. (AU)

FAPESP's process: 08/00562-0 - Mantle-crust interaction and the genesis and evolution of the A-type: post-collisional magmatism: geochemical and isotopic records from the Graciosa Province, S-SE Brazil
Grantee:Silvio Roberto Farias Vlach
Support Opportunities: Regular Research Grants