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

  • T. V. Subba Rao
  • B. L. Narayana
  • K. Gopalan


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 () 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.


Sivamalai alkaline complex Rb-Sr whole-rock isochron initial strontium ratio fractional crystallization rare-earth element abundances 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Balaram V and Saxena V K 1988 Determination of Rare Earth Elements (REE) in Standard Geological Reference Samples by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) using Indium as Internal Standard;First International conference on plasma source mass spectrometry, Durham University, UK, 44Google Scholar
  2. Bhaskar Rao B 1982 Petrology of the Alkaline Rocks around Sivamalai, Coimbatore District, Tamil Nadu, India;Geol. Rundsch. 71 263–279CrossRefGoogle Scholar
  3. Bose M K 1968a Mineralogical study of striped pyroxene in syenitic rocks of Sivamalai, S. India;Am. Mineral. 53 464–471Google Scholar
  4. Bose M K 1968b On the leucocratic syenites of Sivamalai, Coimbatore, Madaras;Bull Geochem. Soc. India. 3 17–23Google Scholar
  5. Bose M K 1971 Petrology of the alkaline suite of Sivamalai, Coimbatore, Tamil Nadu;J. Geol. Soc. India. 12 241–261Google Scholar
  6. Bese M K 1972 Petrology of the alkaline rocks from Precambrian Eastern Ghats Orogenic Belt of India;Proc. 24th Indian Geol. Congr. 14 18–25Google Scholar
  7. Bose M K and Basu A R 1970 Structure of the alkaline intrusive of Sivamalai, Tamil Nadu;J. Geol. Min. Metall. Soc. India 42 221–223Google Scholar
  8. Clark G S and Subba Rao K V1971 Rb-Sr isotopic age of Kunavaram Series;Can. J. Earth. Sci. 8 1597–1602Google Scholar
  9. Czawford A R 1969 Reconnaisance Rb Sr dating of the Precambrian rocks of southern peninsular India;J. Geol. Soc. India 16 117–166Google Scholar
  10. Czygan W and Goldenberg G 1989 Petrography and geochemistry of the Alkaline complexes of Sivamalai, Elchuru and Uppalapadu, India.Mem. Geol. Soc. India 15 225–240Google Scholar
  11. Drury S A, Harris N B W, Holt R W, Reeves-Smith G J and Wightman R T 1984 Precambrian tectonics and crustal evolution in south India;J. Geol. 92 3–20CrossRefGoogle Scholar
  12. Gerasimovski V I 1974 Trace elements in selected groups of alkaline rocks. In:The alkaline rocks (ed) H Sorensen (New York: John Wiley) pp 291–308Google Scholar
  13. Henderson C M B, Pendlebury K and Foland K A 1989 Mineralogy and petrology of the Red Hill alkaline igneous complex, New Hampshire, U.S.A.;J. Petrol. 30 627–666Google Scholar
  14. Henderson P 1984Rare earth element geochemistry, (Amsterdam: Elsevier) p. 295Google Scholar
  15. Holland T H 1901 The Sivamalai series of elaeolite syenites and corundum syenites in Coimbatore District, Madras.Mem. Geol. Surv. India,30 III 169–217Google Scholar
  16. Kuno H 1968 Differentiation of basaltic magmas;Bull Volcanol. Series 2. 32 141–176CrossRefGoogle Scholar
  17. Leake B E 1978 Nomenclature of amphiboles;American Mineralogist 63 1023–1052Google Scholar
  18. Leelanandam C 1993a Eulitic and ferrosilitic orthopyroxenes from fefrosyenites of south India: evidences for a high temperature crystallization and tholeiitic parentage.Curr. Sci. 64 729–735Google Scholar
  19. Leelanandam C 1993b Alkaline Magmatism in the Eastern Ghat Belt -A Critique.J. Geol. Soc. India 42 435–447Google Scholar
  20. Nagpal M K, Nagpaul K K. and Bose M K 1974 Fission track ages of some alkaline rocks of India;J. Geol. Soc. India 15 306–313Google Scholar
  21. Narayana B L, Rameshwar Rao D, Rama Rao P, Gopalan K, Balaram V, Natarajan R, and Gnaneshar Rao T 1988 Geochemistry and petrogenesis of the Dindigal granite, Tamil Nadu -A Pan-African magmatic event.Workshop on Proterozoic rocks of India, Calcutta, Nov. 14–15 60–61Google Scholar
  22. Sorensen H 1974The alkaline rocks (London: Wiley-Interscience) pp. 622Google Scholar
  23. Subba Rao T V, Bhaskar Rao Y J, Sivaraman T V and Gopalan K 1989 Rb-Sr age and petrology of the Elchuru alkaline complex: Implications to alkaline magmatism in the Eastern Ghat Mobile Belt;Mem. Geol. Soc. India 15 207–223Google Scholar
  24. Subramaniam A P 1949 A petrographic study of the alkaline rocks of Sivamalai;Proc. Indian Acad. Sci. 30 69–94Google Scholar
  25. Thornton C P and Tuttle O F 1960 Chemistry of igneous rock I. Differentiation Index;Am. J. Sci. 258 664–684CrossRefGoogle Scholar
  26. Williamson J H 1968 Least square fitting of a straight Une;Can J. Phys. 46 1845–1847Google Scholar

Copyright information

© Indian Academy of Sciences 1994

Authors and Affiliations

  • T. V. Subba Rao
    • 1
  • B. L. Narayana
    • 1
  • K. Gopalan
    • 1
  1. 1.National Geophysical Research InstituteHyderabadIndia

Personalised recommendations