T24A-01 INVITED
Mountain ranges and the deformation of continents
Mountain ranges are the most spectacular manifestation of continental dynamics and a primary locus of geo- hazards. Their geological imprint is ubiquitous since all continents consist of cratonic cores that grew with time through collisions with accreting terrains. Understanding how mountain range form and evolve as a result of the interaction between deep seated tectonic processes, and climate driven surface processes is thus a major issue in earth science. The Himalaya is probably the best place on earth where orogenic processes can be observed at work today and where the geological history of a mountain belt can be compared with its current tectonic processes. We now have a reasonably solid understanding of the structure of the range, of its petro-metamorphic history, and of the kinematics of its active deformation and seismicity. The long-term geological history of the range – from several millions to a few tens of millions of years – has been documented by structural, thermobarometric and thermochronological studies. Morphotectonic investigations have revealed its evolution over the past several thousands or tens of thousands of years. And, finally, geodetic measurements and seismological monitoring have revealed the pattern of strain and stress build-up over several years, or due to single large earthquakes. The presentation will show how the results of these investigations can be assembled into a simple, coherent picture of the structure and evolution of the range. The Himalayan model will be compared to other case examples of active orogeny and some implications regarding continental deformation and the influence of surface processes will be drawn.