Contrasted granite emplacement modes within an oblique crustal section: The closepet granite, South India

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Moyen, J.-F. and Nédélec, A. and Martin, H. and Jayananda, M. (2001) Contrasted granite emplacement modes within an oblique crustal section: The closepet granite, South India. Physics and Chemistry of the Earth, Part A: Solid Earth and Geodesy, 26 (4-5). pp. 295-301. ISSN 1464-1895

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Official URL: https://dx.doi.org/10.1016/S1464-1895(01)00059-X

Abstract

TThe Closepet Granite, in South India, is a large, syntectonic Archaean granitic complex. Differential erosion has exposed it from the lower (25 km) to upper crust (5 km). Four main parts are recognized from bottom to top: (i) A root zone, where magmas formed, collected and rose within active shear zones, leaving schlieren behind. The surrounding crust was highly ductile, leading to diffuse deformation. (ii) A transfer zone, where the magma was progressively enriched in K-feldspar phenocrysts during its ascent. In this part, the granite rose as a mush moving as a whole within a less ductile crust. Slow cooling was responsible for a long magma residence time under conditions favoring to fabric enhancement and strain partitioning, leading to horizontal and vertical melt migration. (iii) A gap<sub/>(dyke complex that acted as a filter zone), were the ascent of the mush was stopped. Probably due to high phenocryst load and high viscosity contrast with the wall rocks. Only crystal-poor melts could continue their ascent through the dykes. (iv) A zone of shallow intrusions, where the liquids extracted from the mush filled small, elliptical plutons, cooling quickly and developing only very weak fabrics. © 2001 Elsevier Science Ltd. All rights reserved.

Item Type: Article
Additional Information: cited By 8
Uncontrolled Keywords: Cooling; Erosion; Viscosity; Wall rock, Granite emplacement modes, Granite, emplacement; granite; magmatism, India
Subjects: Faculty of Science > Earth Sciences > Geology
Divisions: Jnana Bharathi / Central College Campus > Department of Geology
Depositing User: Mr. Kirana Kumar D
Date Deposited: 09 Feb 2016 07:13
Last Modified: 01 Mar 2016 10:27
URI: http://eprints-bangaloreuniversity.in/id/eprint/886

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