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Cambridge NERC Doctoral Training Partnerships

Graduate Research Opportunities
 

Lead Supervisor: Ed Tipper, Earth Sciences 

Co-Supervisor: Mike Bickle, Earth Sciences

Importance of the area of research concerned: 
The interaction of tectonics, crustal deformation, topography and intense monsoonal climate found in the Himalayan mountains provides an ideal natural laboratory to study the feedback between climate, erosion and tectonics which has been controversial for the past few decades. The eastern most part of the Himalayas is one of the most rapidly eroding on the planet. For example, The Brahmaputra river produces 50% of its sediment load from the Eastern Syntaxis of the Himalaya, only 2% of its drainage area. The neighbouring Irrawaddy River has its headwaters in this region, traversing Myanmar, transporting sediment derived from the mountains on its way to the Indian Ocean. To better understand the evolution and impact of the Himalayan orogen on Earth surface processes, it is critical that a quantitative estimate of the mass removed from the system through physical erosion and sediment is made. The study of the sediments and erosion rates “at the source” is essential to understand shelf sediments offshore Myanmar, i.e. “at the sink”, aiming to reconstruct the Asian monsoon variability and its effect on weathering and erosion in the geological past.
Project summary : 
All landscapes on planet Earth are shaped by the competing forces of uplift and erosion. While they vary extensively in space and time, their mechanistic relationship to global tectonics, climate, and each other, is poorly understood. The Himalaya is the highest and one of the most actively eroding mountain belts in the world. A significant flux of this eroded material is removed by the largely forgotten river, the Irrawaddy River in Myanmar. This project will employ geochemical methods to determine the erosion rates in the Eastern syntaxis of the Himalaya and Indo-Burmese ranges using sediments from the Irrawaddy River in Myanmar. Instantaneous sediment fluxes will be determined using acoustic doppler current profiler measurements in situ in the river and compared to historic records from gauging stations.
What will the student do?: 
We have recently collected a suite of river sand samples as part of a broad study on the Irrawaddy basin. These samples will provide a useful starting point. In the first year, the student will learn how to process sand samples for cosmogenic nuclide analyses such as 10Be (which includes physical and chemical preparation, and mass spectrometric analyses). Such cosmogenic nuclides are sensitive to erosion rates, and the student will generate the first 10Be dataset of the Irrawaddy river basin. In tandem, we have large acoustic data set that will be processed to determine contemporary sediment fluxes. In the second year, additional sand samples will be collected during the dry season in Myanmar to characterise the sub-catchments that feed the Irrawaddy. Together with the existing samples a complete quantification of erosion in the Irrawaddy basin will result.
References: 
Lupker, M., et al., 10Be-derived Himalayan denudation rates and sediment budgets in the Ganga basin. 2012, EPSL vol. 333-334, pp. 146-156
Stewart, R. J., et al., Brahmaputra sediment flux dominated by highly localized rapid erosion from the easternmost Himalaya. Geology, 2008. Vol. 36, pp. 711-714.
Vance, D., et al., Erosion and exhumation in the Himalaya from cosmogenic isotope inventores of river sediments. EPSL, 2003 Vol. 206, pp. 237-288.
Applying
You can find out about applying for this project on the Department of Earth Sciences page.