Syntectonic granite emplacement at different structural levels: The Closepet granite, South India

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Moyen, J.F. and Ne ́de ́lec, A. and Martin, H. and Jayananda, M. (2003) Syntectonic granite emplacement at different structural levels: The Closepet granite, South India. Journal of Structural Geology, 25 (4). pp. 611-631. ISSN 0191-8141

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Official URL: https://dx.doi.org/10.1016/S0191-8141(02)00046-9

Abstract

The Closepet granite, in South India, is a large (400 km long but only 30 km wide), elongate, Late Archaean granitic body. Structural levels from deep crust to upper levels crop out, as evidenced by a shallowing of paleo-depths from north to south all along the Closepet granite. This allows the study of the emplacement of the same granitic body at various crustal levels. Four zones have been identified: a root zone, where magmas are collected in active shear zones; a transfer zone, featuring large-scale magma ascent and crystal-liquid partitioning in the granitic 'mush'; a 'gap', where the mush was filtered, allowing only the liquids to rise; shallow intrusions, filled with this liquid. The Closepet granite was emplaced syntectonically. Field work and anisotropy of magnetic susceptibility allowed documentation of steep foliations with subhorizontal lineations, both in the root and transfer zones and in the shallow intrusions. Remote sensing evidenced a network of shear zones bounding the Closepet granite. In the porphyritic root and transfer zones, magmas cooled slowly, thus developing strong fabrics during large-scale dextral shearing. Ascent of residual liquids amidst the crystallizing solid framework was not recorded in the fabrics. However, these liquids were channelised through the gap and infilled the homogeneous shallow intrusions, where rapid cooling only permitted the development of feint, although wholly consistent, fabrics. © 2002 Elsevier Science Ltd. All rights reserved.

Item Type: Article
Additional Information: cited By 45
Uncontrolled Keywords: Structural levels, Anisotropy; Crystal structure; Fabrics; Filtration; Shearing; Syntactics, Granite, Archean; crustal structure; emplacement; granite; magnetic susceptibility; microstructure; remote sensing; tectonic setting, 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: 10 Feb 2016 09:33
Last Modified: 10 Feb 2016 09:33
URI: http://eprints-bangaloreuniversity.in/id/eprint/970

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