Relations between tectonics, climate and erosion in an active orogen: case study of the eastern Himalaya in Bhutan and India

The collision between the Indian and Eurasian continents about 55 Ma ago resulted in the uplift of the Himalaya, the largest and highest mountain belt on Earth. This range creates a physical barrier that has a profound effect on climate by forcing moist winds derived from the Indian Ocean to condense along its southern rampart and deliver heavy rainfalls. At short timescales (year), this phenomenon called the monsoon has impact on human populations by generating landslides and dramatic floods. At geological timescales (thousands to millions of years), the monsoon influences the erosion of the Himalaya, modifying its topography and making it the most important source of sediment input to the world's oceans. Importantly, the erosion history of the Himalaya has major consequences for global climate change by modulating CO2 levels in the atmosphere through rock weathering and organic carbon burial in the oceanic sediments. The erosion of the range results from the complex interactions between accretion and deformation of the rocks (tectonic processes) and climatically modulated surface processes. The purpose of my research program is to decipher and quantify these interrelations. This basic scientific issue with a special emphasis on the Himalayan orogen was recently identified as one of the four most important current research topics in tectonics. I will focus on key parts of the eastern Himalayan orogen and its foreland basin in Bhutan and India. I will adopt a multidisciplinary approach involving field mapping (to identify the rock units and the structures), thermochronology (to measure erosion), stable isotope geochemistry, palynology, magnetostratigraphy (to decipher climatic changes), and numerical modelling to investigate dynamic relations between climatic and tectonic factors and their impact on the landscape evolution of this mountain over the last 10 million years. Benefits for Canada include specialized yet multidisciplinary training to students in the high-profile context of Himalayan research, and further understanding of the processes responsible for the Earth's evolution that will inform into policy development initiatives regarding geohazard, environmental protection and climate change.