Active tectonics in the Sutlej Valley (NW-Himalaya, India)

Research project P 14129 Active tectonics in the Sutlej Valley (NW-Himalaya, India) Bernhard GRASEMANN 06.03.2000 It is suggested to investigate the mechanics of an active extruding metamophic massif between a thrust at the base and a normal fault on the top of a tectonic wedge in the Sutlej Valley (NW-Himalaya in India). Results of the planned project are expected to contribute to the growing appreciation of the importance of surficial processes and their impact on subsurface dynamics and the evolution of mountain belts. The present tectonic situation in the Sutlej Valley is dominated by a still an-going extrusion of a metamorphic massif between a thrust at the base and a normal fault on the top of a tectonic wedge. Seismicity, deformed quarternary deposits and numerous hot springs manifest active tectonics in the Sutlej Valley. Although tectonic wedge models represent attractive solutions for important tectonic questions like shortening parallel, extensional deformation within a convergent orogen, inverted metamorphism or exhumation of high grade metamorphic rocks, little is known about the brittle and ductile internal deformation and the kinematics of the extrusion path of tectonic wedges. Recent models explaining the exhumation of tectonic wedges stress the feedback between erosion and tectonics, and even postulate that in some places strain is first order driven by erosion, e.g. in the Himalayan syntaxis areas as well as the Sutlej Valley are characterised by high tectonic activity and spectacular high erosion and exhumation rates. Furthermore these are the only three locations along the strike of the whole Himalayan orogen, where the big rivers originating to the North, near Mount Kailash in Tibet (Indus, Sutlej and Brahmaputra) transact the entire orogen. The Sutlej Valley represents an exceptional field laboratory for this kind of questions. The planned combination of structural, geochronological, sedimentological, geomorphological and remote sensing techniques will improve the understanding of the interaction of endogenic and exogenic process in the Sutlej area with global implications on comparable mountain belts. Additionally, the result of the planned investigations will provide a new approach in the geo-risk management of this earthquake- and landslide-sticken area.