1 ESS Division, Department of Science and Technology, Ministry of Science and Technology,
Government of India, New Delhi - 110 016, India

2 Department of Earth Sciences, Indian Institute of Technology Roorkee, Roorkee - 247 667, India

The Himalayan Mountain is unique and classical example of Continental Collision Tectonics and links up the present day geodynamic processes with those of Late Mesozoic and Cenozoic. These processes are essentially responsible for the evolution of the Himalaya during the Late Mesozoic subduction and accretion, followed by the collision of continents attached to the Indian and Eurasian Plates and ensuing extension, sedimentation and present-day seismo-tectonics.

As a sequel to the Solid Earth Programme of the DST and the data generated by numerous agencies, need for integrated multi-disciplinary Geotransects in the Himalayan region was projected at a number of scientific fora. Considering that Northwest Himalayan region provides unique coverage of almost all tectonic units from the lndo-Gangetic Plains to the loftiest Ladakh and Karakoram ranges, it was considered appropriate to launch an integrated programme on a priority basis. Accordingly, NW Himalayan Geotransect Programme (HIMPROBE) was conceived as a long-term multidisciplinary- multi-institutional research endeavor under Deep Continental Studies (DCS) Programme of the Department of Science and Technology.

The main focus of the HIMPROBE programme is to investigate the geodynamic processes in the youngest mountain belt across the Himalaya in a 100 km wide corridore along Hoshiarpur- Mandi-Leh-Karakoram transect (Fig. 1). The corridor encompasses the following major tectonic units from south to north:

• Outer-Himalayan Cenozoic Foothill Belt of the Panjab Re-entrant
• Frontal outermost para-autochthonous Lesser Himalayan Shali-Krol Belt of Proterozoic metavoicanics-quartz-dolomite sequence and its exposure within the Larji-Kulu-Rampur windows.
• Allochthonous Himalayan Metamorphic Belt (HMB) of the Bajura-Kulu and Jutogh Nappe in the Lesser Himalaya and the Higher Himlayan Crystallines.
• Higher Himalayan Crystallines (HHC) as a remobilized basement.
• Tethyan Sedimentary Zone (TSZ) containing the Ph-3nerozoic covers from Cambrian to Eocene with Permian rift-related Panjal voicanics.
• Tso-Morari Crystallines (TMC).
• Trans-Himalayan Indus-Tsangpo Suture Zone (ITSZ), Ladakh Satholith, Shyok Suture Zone (SSZ) and Karakoram Metamorphic Complex (KMC).
  

The programme .envisaged carrying out integrated geological and geophysicail studies to improve our understanding of the tectonic evolution of the Himalayan crust and mantle, and the dynamic processes which controlled the evolution through time. The efforts have been made through various projects to evaluate surface observations with deep geophysical and geochemical probing; applying ind adapting latest technology to obtain an integrated image of the NW-Himalayan lithosphere. Recently acquired geophysical data sets particularly seismic tomography, MT (Magnetotelluric) and LMT ( Long period Magnetotelluric) are being integrated with geological, geochernical. and geochronological data to understand the geodynamic processes.

The experience gained in the HIMPROBE Programme will provide impetus to launch similIar multidisciplinary integrated programmes in other sectors of the Himalaya with a view to understand geodynamic processes of this complex mountain belt.