Fluid Inclusion Petrography and Microthermometry of Barren/Mineralized Quartz Veins-Reef of Malanjkhand Cu Deposit, Central India: Implication on Ore and Non-Ore Forming Environment

Abstract

Quartz reefs and veins of variable thickness have been intruded in host Paleoproterozoic Malanjkhand granites in the mine area and are primarily restricted to phyllic as well as potassic alteration zones. They are mainly of two types: mineralized and barren. Fluid inclusion petrography depicts mainly five types of inclusion which are aqueous biphase, monophase, monocarbonic, H2O-CO2 and polyphase (L+V+H). They are called here Type I, Type II, Type III, Type IV, and Type V, respectively, and are present in both mineralized and barren quartz veins/reefs. All types of inclusion are common except type V, which appears rare in both. However, the sizes of type II and IV are unexpectedly small. The micro thermometry results imply a relatively high temperature (209.4-376.4oC) of fluid entrapment in the mineralized counterpart. However, it is considerably lower (133.9-182.2oC) for the barren counterpart. Although the salinity of fluid appears low for mineralized quartz veins/reef (0.63-0.87 wt.% NaCl equivalent), while for barren counterpart, it is considerably higher (0.92-0.98 wt.% NaCl equivalent). The observed textural and microthermometry results advocate that the Malanjkhand hydrothermal system has resemblances with the porphyry system and indicates probable genetic linkage between barren and mineralized quartz veins/reef. Keywords: Fluid Inclusions, Quartz Veins/Reef, Aqueous Inclusions