Sediment production in large river basins throughout the Quarternary

• Applicant: Dr. Hella Wittmann-Oelze
• Subject Area: Palaeontology
• Term: from 2012 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 210713946

Late‐Cenozoic global cooling has been suggested to be associated with a global increase in sedimentation rates, which is interpreted to be due to an increase in mountain erosion rates. Both enhanced mountain building and changes in climate are associated with increased erosion and silicate weathering that consumes atmospheric CO2. However, it has been hypothesized recently that an increase in global continental erosion in the last 10 million years did not take place at all. Rather, the observed worldwide increase in sedimentation rates is suspected to be a measurement artifact introduced by the different time scales over which sedimentation was measured, and the incomplete preservation of the sediment record.Here, it will be tested whether erosion rates have increased over the late Neogene by analyzing preserved sedimentary records and modern river sediment for their cosmogenic nuclide concentrations. Quartz in buried river sediment carries a memory of the rivers´ basin‐wide denudation rate, in the form of in situ‐produced cosmogenic nuclides (10Be, 26Al). Thus denudation rates, being the sum of erosion and weathering, can be reconstructed throughout the past several million years. Samples from sedimentary records and modern sediment from the largest river basins on all continents (e.g. the Amazon, Mississippi, Ganges, Congo, Murray‐Darling, Danube), covering > 33×106 km2 of Earth´s surface, will be measured for their cosmogenic nuclide concentrations, thereby obtaining a statistically significant coverage of global erosion in several time slices. Analyzing this record at coarse time resolution will provide average, long‐term sediment production rates that will allow to decipher the feedbacks between weathering, erosion and atmospheric CO2 levels.

• DFG Programme: Research Grants
• International Connection: France, Israel, Switzerland
• Participating Persons: Dr. Ahuva Almogi-Labin; Professor Serge Berné; Professor Dr. Friedhelm von Blanckenburg; Dr. Peter W. Kubik