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Upstream versus downstream controls on a natural sediment routing system from source-to-sink

Author Nikhil SHARMA
Director of thesis Prof. Sebastien Castelltort
Co-director of thesis Prof. Thierry Adatte
Summary of thesis

The Middle Eocene Climatic Optimum (MECO) represents an episode of widespread warming about 40 million years ago. It is characterised by gradual warming over a period of 500,000 years and rise in ocean temperatures of about 5 C in the mid and high-latitudes (Sluijs et al., 2013). Contrary to the traditional understanding of downstream factors controlling fluvial successions, we propose to test our hypothesis that upstream factors rather than downstream factors control fluvial architecture through changes in the sediment supply and water discharge with paleoslope as a measurable proxy to quantify these changes. We test this hypothesis in a natural system, the Escanilla sediment routing system which corresponds to the Middle Eocene Climatic Optimum. The Escanilla formation is an overall prograding succession consisting of 1000 m thick alluvial and fluvial deposits at the southern-margin of the Tremp-Graus Basin in Spain. Multiple sections will be sampled close to the source, and at intermediate and distal part of the system for paleohydraulics (grain size and cross-set measurements, flow direction, channel geometry) and for paleoclimatic reconstructions from fine-grained floodplain samples (XRD, XRF, clay mineral separation, stable isotopes).

Status middle
Administrative delay for the defence 2023
URL https://sites.google.com/view/earthsurfacedynamics/home/nikhil-sharma
Twitter @nik_sharma38