Morphotectonic analysis of petroliferous Barmer rift basin (Rajasthan, India)

Geomorphologic studies can set important constraints on the petroleum geosciences of sedimentary basins. In the western Rajasthan area of Indian shield, constituting Barmer and other basins, rift-related sedimentation took place during Late Neoproterozoic to Cambrian Periods and during Mesozoic to Tertiary time. We analyze the Quaternary geomorphology of the Barmer basin mainly in terms of its watersheds by applying Digital Elevation Model aided by field verifications. In detail, we study aeolian landforms, drainage orientation, pattern, rejuvenation, terraces and abandoned gullies. Small streams display cross-valley anomalies. Gorge-like morphology in the eastern part of the basin near Sarnoo and knick-points in gullies near Lini/Sukri characterize the eastern boundary of the Barmer rift basin and parallel NE–SW river characterizes offset lineaments. Amongst the five delineated watersheds, watersheds-1 and 2 are recognised as the most tectonically active having lower index of active tectonics (IAT). This is also supported by the linear-scale parameters stream length gradient index (SL), sinuosity index (SI) and the long-profiles. Sub-watershed analysis using SL and SI of the watershed-1 disclose the tectonically active region within the basin. Micro-scale basin analysis has also been made applying several quantitative indicators. Watersheds-1 and 2 were found to be tectonically active. Using the normalized difference vegetation index (NDVI), the NW–SE line of vegetation across the Giral coal mine in the northern part of the basin indicates a shallow groundwater level (~7 mbgl), and can indicate presence of blind fractures. Research Highlights Geomorphologic analysis of the Barmer basin. Watersheds 1 and 2 are tectonically active. Sub-surface brittle planes ascertained from watershed-1.