Mr Bishnu Mishra1, Pitambar Pati, Muduru Dora
1Indian Institute Of Technology Roorkee, Roorkee, India
Sulfide mineralization in Betul belt (BB) in the central India tectonic zone (CITZ) is one of the critical zinc-enriched polymetallic sulfide mineralization in India. Stratiform ore bodies hosted within the volcano-sedimentary units were moderately conceptualized to be a volcanic-hosted massive sulfide (VHMS) type deposit by earlier workers. As it is not yet wholly realized whether the deposit is genetically less fertile or underexplored, uncertainty remains in its future course of exploration. In this study an effort has been made to provide insights into various genetic aspects of mineralization, including major elements content, the enrichment of trace elements, and consequently, their broad exploration significance. Therefore, sphalerite trace element geochemistry has been studied using electron probe microanalyzer (EPMA) to obtain total major elements and laser ablation inductively coupled mass spectroscopy (LA-ICP-MS) to measure trace elements concentration. The trace elements such as Pb, Mn, Co, Cu, Ga, Ge, Ag, Cd, In, Sn, Sb, Bi, along with Fe in bulk sphalerite specimens have been analyzed using LA-ICP-MS technique. Thereafter, the dataset has been investigated using a multivariate statistical procedure called principal component analysis (PCA). This study shows that sphalerite in the BB are relatively abundant in Fe content ranging from 4.58 wt% to 11.10 wt% with mean 7.54 wt%. Trace elements like Mn and In show comparatively high concentration with a mean value of 3533.31 ppm and 33.73 ppm respectively. On the other hand, Ga, Ge and Ag content are depleted in the sphalerite with a mean value of 0.58 ppm, 0.36 ppm and 0.90 ppm respectively. Subsequently, the ore-forming temperature is conservatively and separately estimated using the geothermometers devised by Kullerud, 1953 and Frenzel et al., 2016, which range from 3190C to 5560C and 374.100C to 402.250C respectively. This study suggests the sulfide mineralization in the BB is high temperature, magmatic-hydrothermal origin. The enrichment of elements is predominantly controlled by the ore-forming temperature and host lithology. We observed the effect of metamorphism and recrystallization of the BB sphalerite. We encouraged to target basement exposed areas for further exploration activities. Pre to syn mineralization deformation structures are considered to be useful to locate the mineralization. This study also significantly added the degree of confidence to the growing consensus and typified BB sulfide mineralization as a VHMS type of deposit.
Keywords: Sphalerite, LA-ICP-MS, trace element geochemistry, Sulfide Mineralization, VHMS, Betul Belt.
Bishnu Prasad Mishra completed his B.Sc. from Utkal University, Odisha in Geology, and M.Sc. from Indian Institute of Technology Roorkee, Roorkee. At present, he is pursuing a Ph.D. with MHRD Fellowship with the supervision of Dr. Pitambar Pati in the Department of Earth Sciences, IIT Roorkee.