Reconstructing the evolution of the Bengal Fan with physical properties (ReconFan)

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The Project ReconFan relies on my previous work and publications on different environments of the Bengal Fan and the resulting gaps in knowledge. The focus lies on sediment physical and optical property data collected during IODP Expedition 354. General objectives are to (i) unravel the history of turbiditic and hemipelagic deposition on the lower fan as a result of the interplay of Himalayan erosion and Asian monsoon development, (ii) provide high-resolution age control through orbital tuning, biomagnetostratigraphy, and ash identification, and (iii) study the response to climate and monsoon forcing on different time scales. These objectives have partially been fulfilled with the current funding, and three manuscripts have been compiled: one of which is under review, the second one is ready for submission, and the third one is near completion. During the renewal period, ongoing investigations shall be concluded and new, so far not used methods shall be employed. At least two more papers as first author shall be published. For the Pleistocene sections, age models based on orbital tuning and spectral analysis were constructed for all Expedition 354 sites, with the aid of paleomagnetic and biostratigraphic constraints. Also, Fourier Transform Infrared Spectroscopy has been used to determine bulk geochemistry. Both of these methods shall now be expanded to Plio-Miocene sections. Specifically, sediment physical (wet-bulk density, compressional-wave velocity, and magnetic susceptibility) and optical (LaCie L*, a*, b* reflectance color) properties shall be processed to assign sediment facies, i. e. determine, through geochemical calibration, the relative proportions of the three major sediment components detritus, biogenic opal, and biogenic carbonate. A novel color reflectance method, the so-called Q4/7 analysis shall be employed to test if facies variations can be discriminated based on geochemical properties. Relative proportions of sand, silt, and clay shall be determined for the detrital fraction, based on grain-size determinations, to provide highly-resolved sediment budgets for turbidites. The ultimate goals of the investigations are to obtain vital information to unravel the erosional history and the associated amount of fluvial transport via the Ganges Brahmaputra river systems, the depocenter migration with respect to sea-level changes, and the long-term changes in monsoon and climate as documented on the Lower Bengal Fan.