Sethumadhav, M.S. and Gunnell, Yanni and Ahmed, Mohamed Muzamil and Chinnaiah, . (2010) Late Archean manganese mineralization and younger supergene manganese ores in the Anmod–Bisgod region, Western Dharwar Craton, southern India: Geological characterization, palaeoenvironmental history, and geomorphological setting. Ore Geology Reviews, 38 (1). 70 - 89. ISSN 0169-1368
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The field setting, mineralogical, geochemical, genetic and depositional features of Late Archean metasedimentary manganese, as well as Cenozoic supergene manganese and ferromanganese ores, along the ~75km long linear tract of the Anmod–Bisgod region in the Western Dharwar Craton, southern India, are described. The 2700Ma metasedimentary manganiferous formation is underlain by stromatolitic limestone/dolomite and quartzite/arenite and also occurs within the former. The older quartzite/arenite, which contains redox-sensitive detrital pyrite and uraninite as well as thucolite, indicates sedimentation under anoxic to oxic transitional palaeoenvironmental condition, whereas the younger stromatolitic limestone/dolomite indicates development of oxygen in the depositional environment. The manganese ore types have been classified into three categories, one of which is a Mn-rich duricrust once capping the Late Archean manganiferous formation. It formed during a Cenozoic lateritic weathering event and was eroded in response to crustal uplift. Perhaps uniquely, clastic deposits of the eroded Mn-duricrust occur in mineable quantities in the form of fluvial palaeochannel fills. These cryptomelane-rich supergene ores are also suitable for radiometric dating. Knowing their age would help to constrain the timing of Mn-duricrust formation and, indirectly, the regional weathering event responsible for the extensive laterite occurrences of southern India.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | Late Archean palaeoenvironment, Manganiferous formation, Lateritic manganese ores, Palaeochannel, Cenozoic weathering, India |
| Subjects: | F Earth Science > Geology |
| Divisions: | Department of > Earth Science |
| Depositing User: | LA manjunath user |
| Date Deposited: | 08 Jul 2019 10:35 |
| Last Modified: | 14 Jul 2022 05:48 |
| URI: | http://eprints.uni-mysore.ac.in/id/eprint/4908 |
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