Geochemistry and Geochronology : Implications on Mantle versus Crustal Signature of Syenitic Magma

The Soarinho Alkaline Intrusion, southeastern Brazil, makes up part of the Serra do Mar Igneous Province, and it is composed of alkali feldspar syenite, alkali feldspar trachyte, quartz syenite, and monzonite. Geochemical and geochronological analyses of the Soarinho were compared with data from its...

Full description

Saved in:
Bibliographic Details
Published in:Minerals (Basel) 2023-07, Vol.13 (7)
Main Authors: da Silva, Daniel Adelino, Potratz, Guilherme Loriato, Geraldes, Mauro Cesar
Format: Article
Language:English
Subjects:
Crust
Earth
Geochronology
Porphyry
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The Soarinho Alkaline Intrusion, southeastern Brazil, makes up part of the Serra do Mar Igneous Province, and it is composed of alkali feldspar syenite, alkali feldspar trachyte, quartz syenite, and monzonite. Geochemical and geochronological analyses of the Soarinho were compared with data from its neighbors, Rio Bonito and Tanguá. Zircon U-Pb Laser Ablation ages show that Soarinho is younger than Rio Bonito and Tanguá. Ages obtained from the monzonite (60 ± 2 Ma), alkali feldspar syenite (58 ± 2 Ma), and quartz syenite (58 ± 2 Ma) are indistinguishable within error. One nepheline syenite sample from Tanguá gives an age equal to those of Rio Bonito already published (65 ± 1 Ma). Petrographic and geochemical data show a clear contrast among Soarinho, Rio Bonito, and Tanguá. Lu-Hf isotopic data for the three alkaline intrusions (all negative) point to some similarities in their sources. The data suggest an enriched mantle source for Soarinho; however, an older continental crust contribution cannot be discarded.
ISSN:2075-163X
2075-163X
DOI:10.3390/min13070904