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标题：Geochemical signatures of manganese ores around Barbil, Noamundi-Koira basin, Singhbhum Craton, Eastern India
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作者：Shabber H. Alvi ; Mohd. Shaif
期刊名称：Geology, Ecology, and Landscapes
电子版ISSN：2474-9508
出版年度：2021
卷号：5
期号：4
页码：260-268
DOI：10.1080/24749508.2020.1720489
语种：English
出版社：Taylor & Francis Group
摘要：ABSTRACTPalaeoproterozoic Noamundi – Koira Basin (NKB), on the western margin of the >3.0 Ga old Singhbhum Granitoid Complex, forms a horseshoe-shaped synclinorium. Volcanic rocks belonging to Bonai volcanic suite (BVS) occur outside and all-around the NKB that consists of three distinct but conformable stratigraphic units viz; Lower Shale Formation, Middle Banded Hematite Quartzite (BHQ) and/or Banded Hematite Jasper (BHJ) and Upper Shale Formation. The layered, lensoid, lateritoid, and vein type Mn-ore bodies are associated with the Upper Shale Formation. Compositions of the Mn ores widely variable values, SiO2(1.00%- 16.40%), Al2O3(1.62%-17.20%), Fe2O3(10.55%-63.28%), MnO (31.75% −75.72%), Ni (25–260 ppm), Co (78–350 ppm), Zn (82–509 ppm) and Cr (13–187 ppm) clearly reflect their submarine hydrothermal source. Litho-stratigraphic considerations also lead to suggest that BHJ/BHQ and Mn-ore deposits of NKB are genetically related to the BVS. It is suggested that manganese and iron ores were deposited in a (? Forearc) basin associated with the mature island arc or active continental margin setting. FeO and MnO were added to the basin by hydrothermal solutes produced during the Bonai volcanism. BHQ/BHJ precipitation took place under a low redox potential while Mn-ore deposition is a consequence of the high redox potential.
关键词：KEYWORDSPaleoproterozoicBHQ/BHJMn-ore bodieshydrothermalSinghbhum