Rb-Sr age of the Sivamalai alkaline complex, Tamil Nadu

Subba Rao, T. V. ; Narayana, B. L. ; Gopalan, K. (1994) Rb-Sr age of the Sivamalai alkaline complex, Tamil Nadu Proceedings of the Indian Academy of Sciences - Earth and Planetary Sciences, 103 (3). pp. 425-437. ISSN 0253-4126

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Official URL: http://www.ias.ac.in/j_archive/epsci/103/3/425-437...

Related URL: http://dx.doi.org/10.1007/BF02841531


The Sivamalai alkaline complex comprises ferro-, pyroxene-hornblende- and nepheline-syenites. Field relations show that the nepheline syenites followed the emplacement of non-feldspathoidal syenites. Mineralogical data on the syenite suite have been reviewed. The Sivamalai alkaline rocks are not strongly enriched in rare-earth elements like most miaskites. Rb-Sr isotopic analyses of a suite of six samples from the various members of the complex define an isochron corresponding to an age of 623 ±21 Ma (2σ) and initial Sr ratio of 0.70376 ±14 (2σ). This is consistent with a model of fractional crystallization of a parent magma derived from an upper mantle source with apparently no isotopic evidence for more than one magma source for the complex. The Sivamalai alkaline complex represents a Pan-African alkaline magmatic event in the southern granulite terrane of Peninsular India.

Item Type:Article
Source:Copyright of this article belongs to Indian Academy of Sciences.
Keywords:Sivamalai Alkaline Complex; Rb-Sr Whole-rock Isochron; Initial Strontium Ratio; Fractional Crystallization; Rare-earth Element Abundances
ID Code:13578
Deposited On:12 Nov 2010 15:18
Last Modified:16 May 2016 22:43

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