Kadavur Layered Anorthosite-Gabbro Complex, Tamil Nadu

Autor(en)

Debaleena Sarkar, Jyotisankar Ray, Suresh C. Patel, Moumita Chowdhury, Christian Koeberl, Soumili Sahoo, Pratik Mukherjee

Abstrakt

The Kadavur anorthosite-gabbro complex (10°35'N: 78°11'E), Tamil Nadu, consists of the three distinct rock units which are layered anorthosite-gabbro, schistose anorthosite-gabbro, and sporadic pegmatoidal variant. Based on texture, the layered-type can again be divided into a mesocumulate unit (MCU) and a non-cumulate unit (NCU). Several major oxides and oxide ratios indicate, from Harker variation diagrams that the mesocumulate unit (MCU) and schistose unit (SU) are geochemically similar. The plots for non-cumulate unit (NCU) show a compositional spread in those variation diagrams, suggesting fractionation (involving clinopyroxene and plagioclase) from the supernatant magma on separation of the MCU. Variations in the compositions of TiO₂ vs P₂ O₅, Ba vs SiO₂, La vs Zr, and Yb vs Zr also indicate that NCU has a compositional spectrum, whereas plots for MCU and SU are distinctly different. The geochemical behaviour of the pegmatoidal unit (PU) shows affinity for both the NCU and MCU. The normalized rare earth element (REE) ratios as well as the Zr and Ni concentrations, strongly favour an “Archean basalt” parent magma having tholeiitic or calc-alkaline/ (or transitional) affinity. The present study strongly indicates that the Kadavur anorthosite-gabbro complex was influenced by deformation during intrusion.

Organisation(en)

Department für Lithosphärenforschung

Externe Organisation(en)

University of Calcutta, Amity University Punjab, Indian Institute of Technology Bombay

Journal

JOURNAL OF THE GEOLOGICAL SOCIETY OF INDIA

Band

100

Seiten

1511-1520

Anzahl der Seiten

10

ISSN

0016-7622

DOI

https://doi.org/10.17491/jgsi/2024/174011

Publikationsdatum

11-2024

Peer-reviewed

Ja

ÖFOS 2012

105105 Geochemie

Schlagwörter

ASJC Scopus Sachgebiete

Geology

Link zum Portal

https://ucrisportal.univie.ac.at/de/publications/80dd31b1-6f00-47ff-a6e8-6ece6e2b661d