Hostname: page-component-586b7cd67f-gb8f7 Total loading time: 0 Render date: 2024-11-28T16:58:54.420Z Has data issue: false hasContentIssue false

Petrology of the alkali syenites of the Mundwara magmatic suite, Sirohi, Rajasthan, India

Published online by Cambridge University Press:  01 May 2009

M. K. Bose
Affiliation:
Department of Geology, Presidency College, Calcutta-12, India
D. K. Das Gupta
Affiliation:
Department of Geology, Presidency College, Calcutta-12, India

Summary

The alkali syenites of the Mundwara magmatic suite, Sirohi district, Rajasthan, in north-western India, are chiefly developed in the Musala hill of the complex. They comprise three principal varieties representing different stages of crystallization, viz. nepheline-sodalite syenite, nepheline-barkevikite microsyenite, and nepheline poor leucosyenite. The dominant constituent of these hypersolvus syenites is alkali feldspar, an orthoclase microperthite showing a variable degree of exsolution. The chief mafic mineral is a distinctly green and zoned sodic pyroxene, close to aegirine-augite in composition. A brown calciferous amphibole, identified as a barkevikite, is developed in addition in the microsyenites. Reddish brown biotite of the phlogopite-annite series is common to all the syenites. The petrography and mineralogy of the syenites are discussed, and a comparative study of the Mundwara syenites with similar rocks of the Deccan volcanic province is presented. Chemistry and mineralogy of the syenites of the Mundwara suite suggest that they are related to those associated with the Deccan volcanic province.

Type
Articles
Copyright
Copyright © Cambridge University Press 1973

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Bose, M. K. 1963. Calciferous brown amphibole in alkalic gabbro of Koraput, Orissa, India. Am. Miner. 48, 1405–9.Google Scholar
Bose, M. K. 1971. Petrology of the nepheline syenite of Mount Girnar, India. Lithos 4, 357–66.CrossRefGoogle Scholar
Bose, M. K. 1972. Deccan basalts. Lithos 5, 131–45.CrossRefGoogle Scholar
Coulson, A. L. 1933. The geology of Sirohi state, Rajputana. Mem. geol. Surv. India 63, Pt. I., 8394.Google Scholar
Deer, W. A., Howie, R. A. & Zussman, J. 1963. Rock forming minerals, 2. Longmans.Google Scholar
Hallimond, A. F. 1943. On the graphical representation of the calciferous amphiboles. Am. Miner. 28, 6589.Google Scholar
Hamilton, D. L. & Mackenzie, W. S. 1965. Phase equilibrium studies in the system nepheline-kalsilite-SiO2-H2O. Mineralog. Mag. 34, 214–31.Google Scholar
Heron, A. M. 1924. The soda-bearing rocks of Kishangarh. Rec. geol. Surv. India 56, Pt. 2, 179–97.Google Scholar
Jhingran, A. G. 1954. Petrographic studies of rocks from Girnar hills. Rec. geol. Surv. India 83, 501–15.Google Scholar
Krishnan, M. S. 1926. Petrography of the rocks from Girnar and Osham hills. Rec. geol. Surv. India 58, 380424.Google Scholar
Mathur, K. K., Dubey, V. S., & Sharma, N. L. 1926. Magmatic differentiation in Mount Girnar. J. Geol. 34, 289307.CrossRefGoogle Scholar
Nockolds, S. R. 1947. The relation between chemical composition and paragenesis in the biotite micas of igneous rocks. Am. J. Sci. 245, 401–20.CrossRefGoogle Scholar
Nockolds, S. R. 1954. Average chemical compositions of some igneous rocks. Bull. geol. Soc. Am. 65, 1007–32.CrossRefGoogle Scholar
Ringwood, A. E. 1959. Genesis of basalt trachyte association. Beitr. Miner. Petrogt. 6, 346–51.Google Scholar
Sabine, P. A. 1950. The optical properties and composition of acmitic pyroxenes. Mineralog. Mag. 29, 113–25.Google Scholar
Sharma, T. R. 1969. Magmatic differentiation in the Mundwara igneous complex, Sirohi dist., Rajasthan. J. Ind. Geosci. Ass. 11, 7994.Google Scholar
Subbarao, S. 1964. The geology of the igneous complex of the Girnar hills. Gujarat. Int. geol. Congr. 22nd Session 7, 4260.Google Scholar
Sukheswala, R. N. & Avasia, R. K. 1966. Nepheline syenite in the Deccan Traps of Jawhar, Bombay, J. geol. Soc. India 7, 8691.Google Scholar
Sukheswala, R. N., Avasia, R. K. & Master, D. J. 1970. Dyke cluster of Phenai Mata region, Chhota Udaipur, Gujarat. West Commemoration Volume, 608–16.Google Scholar
Sukheswala, R. N. & Udas, G. R. 1964. Carbonatite of Amba Dongar, India. Some structural considerations. Abs Int. geol. Congr. 22nd Session, India, 109.Google Scholar
West, W. D. 1958. The petrography and petrogenesis of forty-eight flows of Deccan Trap penetrated by boring in Western India. Trans. natn. Inst. Sci. India 4, No. 1, 156.Google Scholar
Wilkinson, J. F. G. 1961. Some aspects of calciferous amphiboles, oxyhornblende, kaersuitite and barkevikite. Am. Miner. 46, 340–54.Google Scholar
Yellur, D. D. 1968. Carbonatite complexes as related to the structure of Narbada valley, J. geol. Soc. India 9, 118–23.Google Scholar