Origin of the Paleoproterozoic “Giant Quartz Reef” System in the Bundelkhand Craton, India: Constraints from Fluid Inclusion Microthermometry, Raman Spectroscopy, and Geochemical Modelling

Abstract The Bundelkhand “giant quartz reef” (BGQR) system comprises 20 major reefs which run for tens of km in strike length average width 40 m and occurs spatial intervals 12–19 the craton, North Central India. BGQR is distinct from vein systems originating crustal scale shearing observed ancient as well modern convergent tectonic settings. Fluid inclusions studied are intriguingly diverse although dominated by aqueous fluid exhibit a broad range salinity ~0 to 28.9 wt% NaCl equivalent temperature homogenization 58 385°C. Primary pseudosecondary assemblages grain interiors growth zones vary randomly their Th—salinity characteristics that preclude identification discrete events. Aqueous evolved through mixing two sources fluids—a meteoric moderate temperature—moderate was possibly derived granodiorite based on an important clue provided hydrous mineral bearing detected Raman microspectrometry. results modeling with PHREEQC indicate fluids could be suitable mechanism formation these giant reefs. available 1-dimensional diffusive transport model deposition silica helps putting constraints time span context system. possible result shallow-crustal visualized “Paleoproterozoic geothermal system” granitic terrane.