Quantifying the response of rapidly eroding landscapes to climate change with cosmogenic nuclides

• Applicant: Professor Dr. Dirk Scherler
• Subject Area: Palaeontology ; Mineralogy, Petrology and Geochemistry
• Term: from 2015 to 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 280477818

In many regions on Earth, Global Warming and the associated changes in the hydrological cycle affect total river runoff and the frequency and magnitude of floods. Changes in discharge are likely to immediately affect the transport capacity of rivers, but how climatic changes affect the supply of sediments from hilllopes is not well understood. In this project, we want to measure cosmogenic nuclide concentrations in fill terraces of the Yamuna River, India, to determine the temporal variability of hillslope erosion rates and to unravel how a rapidly eroding landscape in the Himalaya has responded to climatic changes in the past. We will supplement our geochemical approach with a reconstruction of the geometry and volume of the valley fill, based on field mapping and topographic modeling. The geometrical reconstruction allows us to assess the spatial distribution of sediment storage and temporal changes in the longitudinal channel profile, which affects the sediment transport capacity. Furthermore, we will use different geochronological methods to obtain an accurate chronology of the aggradation-and-incision cycle, and combine these data with sedimentological observations for inferring the source and origin of the sediments, and with paleo-hydrologic reconstructions based on stable isotopes in leaf waxes. These data, combined with our volume estimate and the erosional history of hillslopes, allow us to reconstruct the sediment budget through time and draw a comprehensive picture of the environmental conditions during the period of valley aggradation and to test existing models of how Himalayan landscapes respond to climate change. The expected results of this project will help assessing the impacts of present-day climate change, and evaluating the consequences of Quaternary climate fluctuations for erosion in the Himalaya and the postulated feedbacks on Late Cenozoic climate change.

• DFG Programme: Research Grants
• International Connection: India
• Co-Investigator: Professor Dr. Dirk Sachse
• Cooperation Partner: Professor Vikrant Jain, Ph.D.