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MENUVolume : 3, Issue : 3, March - 2014
Characterisation of Manganese Ores of Shimoga Schist Belt, Dharwar Craton, Southern India
Chinnaiah
Abstract :
Shimoga pre bodies are oadly classified based on their mode of occurrence and genesis. The Dharwar group in the Shimoga schist belt is represented by narrow belts of steeply dipping metasedimentary formation and volcanic rocks, including stratiform manganese iron formation, phyllite/argillite, quartzite, greywacke, metabasalt, basic and ultrabasic intrusive.
The late Archaean manganiferous formation in Shimoga area is spatially associated with carbonates (stromatolitic limestone and dolomite) and oxide facies banded iron formation. In the study area, the supracrustal rocks have been subjected to green schist to lower amphibolite facies metamorphism. manganiferous formation and the spatially associated BIF and phyllite in the study areas have been subjected to varying degrees of supergene alteration.
Presence of manganese minerals like pyrolusite, cryptomelane, hollandite, nsutite, ramsdellite, lithiophorite and goethite. Pyrolusite and cryptomelane are different generations. Lithiophorite is encountered as dissolution cavity-fillings in colloform variety of the infiltration type manganese ores. The cavities probably developed after the formation of botryoidal manganese ores by the processes of dissolution and have been subsequently filled by lithiophorite.
Faics of different ore minerals observed indicate metasedimentary, infiltration types of manganese ore, more than one generation of pyrolusite and cryptomelane are recognized. Mineral association of manganese and textural characteristics attest a low-temperature formation of metasedimentary ore bodies later subjected to oxidation solution process during weathering in the zone of lateritisation.
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Cite This Article:
Chinnaiah Characterisation of Manganese Ores of Shimoga Schist Belt, Dharwar Craton, Southern India GLOBAL JOURNAL FOR RESEARCH ANALYSIS, Vol.III, Issue.III, March-2014
