A Comparative Study of the Gondwana Sequences of Peninsular India and Nepal (extra-peninsular India)

Gondwana sequences are well-preserved in peninsular and extra-peninsular India. Although these Gondwana units have similar provenance, there are marked differences in their lithology, thickness and depositional environments.

In Nepal, the extra-peninsular Gondwana sequences are found along the Lesser Himalaya in Surkhet, Dang, Palpa and Barahachhetra. Sedimentation continued from the Carboniferous through early Miocene with major unconformities in the Surkhet, Dang, and Palpa areas (western Nepal) that also record a shift in sediment provenance from cratonic India to the Himalayan orogenic belt. The sequence in Barahachhetra (eastern Nepal) however is thin and records only Permo-Carboniferous deposition. The Tansen Group (2400 m) in Palpa consists of Sisne Formation (Lower Gondwana), Taltung and Amile formations (Upper Gondwana), Bhainskati and Dumri formations (Post Gondwana) with lithologies ranging from diamictite, sandstone, shale to quartz-arenites. The Barahachhetra Formation (Lower Gondwana) of eastern Nepal is thin (350 m), outcrops north of the Main Boundary Thrust, and consists of five lithostratigraphic units having lithologies ranging from volcanic clasts, shale, dolomite, to sandstone. Upper Gondwana sequence in eastern Nepal is not well documented.

The Damodar basin of peninsular India, located close to extra-peninsular India, has a quite complete Gondwana sequence consisting of the following formations: Talchir, Barkar, Barren Measures, Raniganj (Lower Gondwana), Panchet, and Mahadev (Upper Gondwana) ranging in lithology from glacial boulders, sandstones, shale, to coal beds. Total thickness of the Damodar basin is about 3200 m.

With some variation in lithology, the extra-peninsular Gondwana sequences are thinner and tectonically more disturbed than the peninsular Gondwana sequences. We plan to compare and contrast the Gondwana sequences from these two areas through petrofacies analysis and heavy mineral study.