Variation of strain pattern and its influence on the geometry of the uranium mineralized body in Bangurdih area, western part of the Singhbhum shear zone, eastern India

Timing of shear deformation in the Singhbhum Shear Zone, India: implications for shear zone-hosted polymetallic mineralization

“…The overlapping and younger age (1.59−1.56 Ga) of this metamorphism compared to the shear deformation (1.64−1.59 Ga) reported in the present study is in accordance with the understanding that metamorphism outlasted shear deformation in the SSZ (Sengupta et al 2005). The new age data in conjunction with (a) the micro-textural and micro-structural relationships of the ore minerals with the host-rock fabric suggesting pre-/early-shearing growth of some generations of ore minerals (Pal, et al 2009; Ghosh et al 2013; Chowdhury et al 2020), (b) the morphology of the ore bodies with overprints of ductile deformation (Samanta et al 2021) and (c) previously published ages of mineralization (see Section 1; Johnson et al 1993; Pal et al 2011 a , 2021; Pal & Rhede, 2013) and metamorphism (Mahato et al 2008; Rekha et al 2011) collectively suggest that the polymetallic mineralization in the SSZ initiated much before the onset of ductile shearing and concomitant metamorphism. The rocks in the NSMB are interpreted to have been originally deposited diachronously over a protracted period in an intracontinental extensional setting (Bhattacharya & Mahapatra, 2008; Bhattacharya et al 2015; De et al 2015; Mazumder et al 2015; Olierook et al 2019).…”

“…Regional crustal shortening and progressive ductile shearing associated with this southward crustal movement resulted in the development of pervasive mylonitic foliation that dips towards the north (in the central part of the SSZ near Jamshedpur) or the NE (in the eastern segment of the SSZ, including the study area), and formation of down-dip mineral/stretching lineation (Ghosh & Sengupta, 1987). The mylonitic foliation represents the C-fabric of the mylonites (Roy & Matin, 2020; Samanta et al 2021). The down-dip lineation is roughly parallel to the striations on slickenside surfaces occasionally seen on syn-shearing quartz veins that are emplaced parallel to the mylonitic foliations (Ghosh & Sengupta, 1987).…”

“…Recent studies suggest that the mineralization in the SSZ has many characters akin to Fe-oxide-Cu-Au (IOCG)-type mineralization (Pal et al 2009(Pal et al , 2010(Pal et al , 2011a(Pal et al ,b, 2022Pal & Bhowmick, 2015). The polymetallic ores are hosted in deformed, metamorphosed and metasomatized rocks where both the ore bodies and ore minerals show signatures of post-mineralization shear deformation (Pal et al 2009(Pal et al , 2011bGhosh et al 2013;Chowdhury et al 2020;Samanta et al 2021). In situ dating of ore minerals suggests four major events of mineralization and mobilization at c. 1.88 Ga (light rare earth element (LREE)-mineralization; laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) U-Pb dating of allanite and monazite), c. ≥1.82−1.80 Ga (U-LREE-mineralization; LA-ICP-MS U-Pb dating of monazite and electron microprobe analysis (EMPA) U-Th-Pb Total dating of uraninite), c. 1.66−1.64 Ga (Y þ heavy rare earth element (HREE) ± U mineralization; LA-ICP-MS U-Pb dating of allanite and EMPA U-Th-Pb Total dating of uraninite) and 950 ± 50 Ma (primarily remobilization/redistribution; LA-ICP-MS U-Pb dating of epidote, monazite, florencite and EMPA U-Th-Pb Total dating of uraninite) (Pal et al 2011a(Pal et al , 2021Pal & Rhede, 2013).…”

“…Recent studies suggest that the mineralization in the SSZ has many characters akin to Fe-oxide–Cu–Au (IOCG)-type mineralization (Pal et al 2009, 2010, 2011 a , b , 2022; Pal & Bhowmick, 2015). The polymetallic ores are hosted in deformed, metamorphosed and metasomatized rocks where both the ore bodies and ore minerals show signatures of post-mineralization shear deformation (Pal et al 2009, 2011 b ; Ghosh et al 2013; Chowdhury et al 2020; Samanta et al 2021). In situ dating of ore minerals suggests four major events of mineralization and mobilization at c .…”