Characteristics and control of gold mineralisation of Sindurpur Area, North Singhbhum Mobile Belt, Eastern India: Evidence from petrography and mineral chemistry.
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| Title: | Characteristics and control of gold mineralisation of Sindurpur Area, North Singhbhum Mobile Belt, Eastern India: Evidence from petrography and mineral chemistry. |
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| Authors: | Pal, Supriyo1 (AUTHOR), Chatterjee, Soumava2 (AUTHOR), Kumar, Pankaj1 (AUTHOR) pankajkumargsi@gmail.com |
| Source: | Journal of Earth System Science. Sep2024, Vol. 133 Issue 3, p1-16. 16p. |
| Subjects: | Native element minerals, Petrology, Pyrites, Minerals, Sulfide minerals, Thrust belts (Geology), Gold, Reefs |
| Geographic Terms: | India |
| Abstract: | The Paleo-Mesoproterozoic North Singhbhum Mobile Belt (NSMB) is a fold-thrust belt typically found in a collisional setting and is well known for hosting gold mineralisation. A study carried out in the northern part of NSMB depicts varieties of acid volcanic rocks along with mica schist, ferruginous cherty quartzite, black shale, and sheared granite, which are all ubiquitously traversed by quartz veins/reefs. In the study area, gold mineralisation is mostly restricted to brecciated quartz reef occurring ENE–WSW along S1 foliation, which also depicts syn to late kinematic brittle–ductile shearing. The petrographic studies of mineralised cherty variant of quartzite in quartz reef depict the presence of two generations of the quartz vein. The older one is smoky/bluish, altered, recrystallised and consists of disseminated and stringers of pyrite, chalcopyrite, etc., whereas the younger veins are milky white and lack mineralisation. The presence of pyrite–pyrrhotite and chalcopyrite–pyrrhotite associations and conversion of pyrite to pyrrhotite along fracture depicts prograde metamorphism. Trace elemental mineral chemistry depicts significant Au enrichment in pyrite. A positive correlation between Co and Ni concentrations in pyrite indicates hydrothermal origin. Au–As ratio explains the enrichment of gold in pyrite, where gold occurs as a solid solution in pyrite, which is generally referred to as invisible gold. The presence of gold grains/nuggets at the microscopic level and in pan concentrate as well as considerable analytical value in bulk rock coupled with occurrence in sulphide structure, points towards the bimodal nature of gold mineralisation. Mode of occurrence, nature of mineralisation, and surficial, structural and mineralogical characteristics suggest gold mineralisation of the study area is of orogenic type. [ABSTRACT FROM AUTHOR] |
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| Database: | Engineering Source |
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| Abstract: | The Paleo-Mesoproterozoic North Singhbhum Mobile Belt (NSMB) is a fold-thrust belt typically found in a collisional setting and is well known for hosting gold mineralisation. A study carried out in the northern part of NSMB depicts varieties of acid volcanic rocks along with mica schist, ferruginous cherty quartzite, black shale, and sheared granite, which are all ubiquitously traversed by quartz veins/reefs. In the study area, gold mineralisation is mostly restricted to brecciated quartz reef occurring ENE–WSW along S1 foliation, which also depicts syn to late kinematic brittle–ductile shearing. The petrographic studies of mineralised cherty variant of quartzite in quartz reef depict the presence of two generations of the quartz vein. The older one is smoky/bluish, altered, recrystallised and consists of disseminated and stringers of pyrite, chalcopyrite, etc., whereas the younger veins are milky white and lack mineralisation. The presence of pyrite–pyrrhotite and chalcopyrite–pyrrhotite associations and conversion of pyrite to pyrrhotite along fracture depicts prograde metamorphism. Trace elemental mineral chemistry depicts significant Au enrichment in pyrite. A positive correlation between Co and Ni concentrations in pyrite indicates hydrothermal origin. Au–As ratio explains the enrichment of gold in pyrite, where gold occurs as a solid solution in pyrite, which is generally referred to as invisible gold. The presence of gold grains/nuggets at the microscopic level and in pan concentrate as well as considerable analytical value in bulk rock coupled with occurrence in sulphide structure, points towards the bimodal nature of gold mineralisation. Mode of occurrence, nature of mineralisation, and surficial, structural and mineralogical characteristics suggest gold mineralisation of the study area is of orogenic type. [ABSTRACT FROM AUTHOR] |
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| ISSN: | 02534126 |
| DOI: | 10.1007/s12040-024-02331-1 |
