Abstract
The present paper for the first times gives details of pyroxenesövites of Amba Dongar and discusses significance of these pyroxenes in evolution of carbonatite magma in Amba Dongar. Calciocarbonatite (sövite) forms the major mass of carbonatite in Amba Dongar complex. It shows large variation in texture and mineral composition and has complex evolutionary history. Three types of compositional variations are observed in sövite samples, (1) monomineralic sövites are coarse grained with 99% calcite, (2) sövites with abundant apatite, barite, pyrochlore, magnetite and zirconolite and (3) silico-sövite with of clinopyroxene and phlogopite. In the crystallization history of various sövite types, silico-sövite seems to have crystallized as an earlier phase and was later caught up in major sövite mass. Both, phlogopite-sövite and pyroxene-sövite are coarse grained and exhibit hypidiomorphic texture. Phlogopite is strongly zoned with Mg-rich core to Fe-rich rims. Pyroxenes also exhibit zoning with decrease in Ca and Mg and increase in Fe and Na from core to rim. In general composition of clinopyroxene varies from diopsidic to aegirine-augite. Pyroxenesövites show good concentration of Ba, Sr, Nb and LREE. Elevated concentrations of LREE are found in two aegirine-sövites.
Article PDF
Similar content being viewed by others
Avoid common mistakes on your manuscript.
References
Andersen, T. (1988) Evolution of peralkaline calcite carbonatite magma in the Fen complex, southeast Norway. Lithos, v.22, pp.99–112.
Barker, D.S. (2001) Calculated silica activities in carbonatitic liquids. Contrib. Mineral. Petrol., v.141, pp.704–709
Brögger, W.C. (1921) Die Eruptivgesteine des Kristianiagebietes. IV. Das Fengebiet in Telemark, Norwegen. Norsk. Vidensk. Selsk. Skr. I, Mat. Naturv. KL No9, Oslo.
Chakhmouradian, A.R. and Mitchell, R. H. (2003) The role of assimilated silica in the evolution of carbonatites. 4th EuroCarb Workshop, Canary Islands, Spain
Chakhmouradian, A.R., Zaitsev, A.N. (2002) Calcite-amphibole-clinopyroxene rock from the Afrikanda complex, Kola Peninsula, Russia: mineralogy and a possible link to carbonatites. III. Silicate minerals. The Canadian Mineralogist, v.40, pp.1347–1374.
Chakrabarty, A., Sen, A.K., Ghosh, T.K. (2009) Amphibole–a key indicator mineral for petrogenesis of the Purilia carbonatite, West Bengal, India. Mineral. Petrol., v.95, pp.105–112.
Eckermann (von) H (1948) The alkaline district of Alnö island. Geol. Surv. Sweden (SGU), Uppsala. (176)
Gittins, J.R.E. Harmer and D.S. Barker (2005) The bimodal composition of carbonatites, Reality or misconception? Lithos, v.85, pp.129–139
Heinrich, E. Wm (1966) The geology of carbonatites. Rand McNally and Co, Chicago
Hogarth, D.D. (1989) Pyrochlore, apatite and amphibole: distinctive minerals in carbonatite. In: Bell, K. (Ed.), Carbonatites: Genesis and Evolution. Unwin Hyman, London, pp.105–148.
Kresten, P. (1979) The Alnö complex, Nordic Carbonatite Symposium, Alnö
Pecora, W.T. (1962) Carbonatite problem in Bearpaw Mountains, Montana. Geol. Soc. Amer., Buddington vol, pp.83–104
Reguir, E.P., Chakhmouradian, A.R., Halden, N.M., Malkovets, V.G., Yang, P. (2009) Major-and trace-element compositional variation of phlogopite from Kimberlites and carbonatites as a petrogenetic indicator. Lithos v.112S, pp.372–384.
Reguir, E.P., Chakhmouradian, A.R., Pisiak, L., Halden, N.M., Yang, P., Cheng Xu, Kynicki, J. and Couëslan, C.G. (2012) Trace-element composition and zoning in clinopyroxene-and amphibole-group minerals: Implications for element partitioning and evolution of carbonatites. Lithos, v.128-131, pp.27–45.
Saether, E. (1957) The Alkaline rock province of the Fen area in southern Norway. Kgl Norske Vidensk Selsk. Skr No.1
Viladkar, S.G. and Wimmenauer, W. (1992) Geochemical and petrological studies on the Amba Dongar carbonatites (Gujarat, India). Chemie der Erde, v.52, pp.277–291
Viladkar, S.G. (2000) Phlogopite as an indicator of magmatic differentiation in the Amba Dongar carbonatite, Gujarat, India. N.Jb. Miner. Mh. 7, 302–314.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Viladkar, S.G. Pyroxene-sövite in Amba Dongar carbonatite-alkalic complex, Gujarat. J Geol Soc India 90, 591–594 (2017). https://doi.org/10.1007/s12594-017-0756-y
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s12594-017-0756-y