Tourmalinite from Cu-U Belt of Singhbhum, Bihar, India

Tourmalinite occurs as a stratigraphically persistent unit in the Proterozoic Cu-U belt of Singhbhum, Bihar. Internally the tourmalinite is plane laminated with alternations of tourmaline-rich and quartz-rich layers, and is also cross-stratified. Tounnalinite breccia also forms a significant part of the unit. Preserved primary sedimentary features, amidst deformed and metamorphosed rocks, attest to a primary sedimentary origin of the tourmalinite. Close assocication of Cu-Sulphide mineralizations and tourmalinite suggests volcanogenic origin of the Cu-sulphide mineralization and precipitation of the tourmalinite from boron-rich exhalative fluids.