Influence of Rock Foliation on Fracture Permeability: The Case of Precambrian metamorphics (Purulia, Eastern India)

Influence of Rock Foliation on Fracture Permeability: The Case of Precambrian metamorphics(Purulia, Eastern India)

Hydrological influence of foliation in variably fractured Precambrian metamorphic rocks is usually difficult to predict. As an exemplar, the Precambrian metamorphic exposed in and around the Balarampur town of Purulia district, West Bengal (India) were studied to find out the influence of rock foliation on fracture permeability using a hydrostructural domain-based model. These Precambrian metamorphic rocks, characterized by foliated fabric, resulted from the combination of (a) brittle granite gneisses rich in quartz and garnet, (b) an intense brittle-ductile shear zone, and (c) ductile metapelites with micaceous minerals. Pre- and post-monsoon depth-to-groundwater table contour maps, mode, coefficient of variance (Cv) and contour maps of frequencies and apertures of fractures demonstrate inter- and intra-domain variable qualitative fracture permeability’s.