The mineralogy and geochemistry of the Mundwara carbonatite dykes, Sirohi District, Rajasthan, India

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Authors:Le-Bas, M. J.; Srivastava, R. K.
Author Affiliations:Primary:
Univ. Leicester, Dep. Geol., GB-Leicester LE1 7RH, United Kingdom
Volume Title:Neues Jahrbuch für Mineralogie. Abhandlungen
Source:Neues Jahrbuch für Mineralogie. Abhandlungen, 2, p.207-227. Publisher: E. Schweizerbart'sche Verlagsbuchhandlung, Stuttgart, Federal Republic of Germany. ISSN: 0077-7757
Publication Date:1989
Note:In English. 43 refs.; illus. incl. 49 anal., 7 tables
Summary:Using these three calcite carbonatite dykes as an example, it is shown that the mica in stable equilibrium with the carbonatite magma is a phlogopite and that the amphibole is a magnesio- arfvedsonite. The pure albite in these carbonatites is in reaction relation with carbonatite and clearly is relict from an earlier stage of fenitization, but almost pure K-feldspar crystallized within the carbonatite dykes as well as in the adjacent fenites. The carbonatites in the dykes have low Na and K contents, but the mineralogical relations are interpreted to show that the primitive carbonatite magma emplaced in these dykes contained Na and K as well as Ca, and that the Na and K were mostly lost to the fenites, producing the calcite carbonatite. The sequence of reactions suggests that Na had already been lost from the carbonatite at the time when it was precipitating K-rich minerals. [R.E.S.]
Subjects:Alkali feldspar; Amphibole group; Arfvedsonite; Carbonatites; Chain silicates; Chemical composition; Clinoamphibole; Dikes; Feldspar group; Fenite; Framework silicates; Geochemistry; Igneous rocks; Intrusions; K-feldspar; Metamorphic rocks; Metasomatic rocks; Mica group; Mineral composition; Petrology; Phlogopite; Sheet silicates; Silicates; Asia; India; Indian Peninsula; Rajasthan India; Sirohi India; Mundwara
Coordinates:N245000 N245000 E0723300 E0723300
Abstract Numbers:89M/4951
Record ID:1991032403
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom, Reference includes data from Geoline, Bundesanstalt fur Geowissenschaften und Rohstoffe
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