Journal of Geological Society of India (Online archive from Vol 1 to Vol 78)

G. N. Jadhav ¹, N. Sharma ², Priyanka Sen ¹

Affiliations
1 Department of Earth Sciences, IIT Bombay, Powai, Mumbai - 400 076, IN
2 Department of Geology, M.S.University of Baroda, Vadodara - 390 002, IN

Abstract

The bauxites deposits of Kachchh area in Gujarat are investigated to characterize them based on mineralogical and petrographic studies. The major bauxitic mineral in these occurrences is gibbsite, with minor concentration of boehmite and diaspore. Apart from the bauxitic minerals, the other associate minerals are kaolin, calcite, alunite and the iron ore minerals such as hematite and goethite and titanium rich anatase. The iron ore minerals (hematite and goethite) are 10-50microns in size and are disseminated throughout the oolitic and pisolitic bauxitic minerals. At places the goethite exhibits colloform texture. The preservation of basaltic texture in some of the samples indicate that the insitu nature of these bauxites, which are formed by the alteration of calcic plagioclase from the parent basalt. Although, the basalt occurs as the main parent rock for these bauxites, the presence of calcite in some of the samples represent the possibility of having a limestone parent rock at least in some of the bauxite occurrences.

Keywords

Gibbsite, Boehmite, Diaspore, Alunite, Oolite, Pisolite, Colloform Texture, Kachchh, Gujarat.

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