Abstract
The Singhbhum Shear Zone (SSZ) in eastern India is one of the major uranium repositories of the country. Some of the important uranium deposits viz., Bagjata, Jaduguda, Bhatin, Narwapahar and Banadungri-Singridungri are juxtaposed in the central part of SSZ. The uranium mineralization in central SSZ is mainly hosted by tourmaline-apatite-magnetite bearing sericite quartz chlorite schist with uraninite being the main radioactive mineral phase. A close spatial relationship exists between uraniferous minerals and chlorite occurrences in central SSZ. Three different types of chlorite assemblages were recognized and their relationship with uranium mineralization was studied in detail to unravel the physico-chemical conditions for precipitation of uranium vis-a-vis chlorite geothermometry and constrains on the chlorite chemistry. Detailed petrographic studies and mineral chemical studies of the host rocks indicate three distinct chlorite type viz. (1) metamorphic chlorite, forming a typical metamorphic assemblage with quartz, muscovite, sericite, biotite and K-feldspar, (2) hydrothermal alteration product of biotite and (3) hydrothermal vein chlorite. The three chlorite types were characterized based on: (1) the range of XFe and AlIV, (2) correlation between Si (apfu) and XFe and (3) compositional diagram between XFe vs. AlIV. Based on the mineral chemistry and thermometry of chlorite 3, the co-genetic uranium mineralization has been suggested to be precipitated from a hydrothermal fluid rich in Fe, Mg and Ti in a reducing environment within a temperature window of about 312 °C–355 °C. A fluid mixing model for the remobilization and reconstitution of this hydrothermal uranium mineralization vis-a-vis chlorite occurrence is postulated and its geothermometry suggest an epithermal mineralization in the study area. A comparative study of chlorites from four important uranium provinces of the world i.e. Jabiluka of Australia, Rozna of Czech Republic, Beaverlodge of Canada and central SSZ of India reveals a similarity in the mineral chemistry of the chlorites associated with uranium mineralization. Thus, textural study of chlorites corroborated with their mineral chemistry and geothermometry is a useful reconnoitre tool for uranium exploration.
| Original language | English |
|---|---|
| Article number | 102997 |
| Journal | Ore Geology Reviews |
| Volume | 112 |
| DOIs | |
| State | Published - Sep 2019 |
| Externally published | Yes |
Bibliographical note
Publisher Copyright:© 2019 Elsevier B.V.
Funding
The authors are thankful to Director, AMD for according permission to publish this research paper. The authors are also thankful to all the Additional Directors, AMD, Hyderabad for their encouragement and support in publishing this research work. Authors are grateful to Regional Director and Dy. Regional Director, AMD, Eastern Region, Jamshedpur for their continuous guidance during this research work. The authors are thankful to the Director, Indian Institute of Technology (Indian School of Mines), Dhanbad for the facilities from IIT (ISM) Central Research Facility, for Electron Probe Analysis. Authors are highly grateful to Dr Franck Bourdelle, Maître de Conférences, Université de Lille – Sciences et Technologies for his valuable suggestions. Authors are sincerely thankful to the anonymous reviewers of this paper, whose comments have greatly helped in enhancing the quality of this paper.
| Funders | Funder number |
|---|---|
| Indian School of Mines | |
| Université Lille 1 - Sciences et Technologies |
Keywords
- Chlorite thermometry
- Reducing environment and hydrothermal mineralization
- Singhbhum Shear Zone
- Uranium