Determining the palaeodrainage history of the Nile River: investigating rift tectonics and land-ocean-atmosphere interactions.

Aim: The aim of the project is to determine the time of initiation, and paleodrainage history, of the Nile River. Although unpublished oil company data show Nile delta sediments as old as Oligocene, debate exists as to the source of such sediment. Many workers consider that these older deposits are locally derived from the Red Sea Hills, and that initiation of an extensive Nile drainage network, extending as far south as Ethiopia and Uganda, did not occur until later, with estimates ranging from Miocene to Quaternary. Environmental and economic impact of the research: Determination of the Nile's palaeodrainage is critical to better understanding of land-ocean-atmosphere interactions since the river's hydrology is directly forced by large-scale oceanographic and climatic changes. Additionally, the river's drainage has the potential to allow discrimination between plume versus isostatic control on rift-related uplift, and its drainage is also thought to have influenced hominid dispersal and ancient civilisations. Economically, the study will contribute to a better understanding of how large rivers influence the development of ocean anoxia and development of sapropels which are important oil source rocks. Specific to Nile delta hydrocarbon potential, documentation of variation in the core's composition allows evaluation of 1) temporal variability of resultant changes in porosity/permeability and hence hydrocarbon prospectivity, 2) spatial variability, related to sediment distribution, with implications for well correlation and distribution of reservoir systems. Approach: Nile delta sediments locally sourced from the Neoproterozoic Red Sea Hills island arc rocks have a different petrographic, isotopic and geochemical signature from those derived from the Nile's headwaters of the Oligocene Ethiopian Flood Basalts (drained by the Blue Nile) and Archaean-Neoproterozoic Saharan Craton (drained by the White Nile). Modern river sediment collected from the White Nile, Blue Nile and rivers draining the Red Sea Hills will be subject to petrographic, isotopic and geochemical techniques (see Table 1; Case for Support) to characterise the signature of these potential source regions. Data will then be compared with analyses conducted on Nile delta core samples of Eocene to Recent age and the provenance of the detritus determined. Thus the time of initiation of input to the delta from the sources which are today at the Nile's headwaters can be deduced, and changes in input documented through time. These data will be coupled with subsurface well and seismic data to produce a regional temporal and spatial understanding of sediment input and distribution. Training: The student will be trained in 1) subsurface data analysis, and core description, interpretation and sampling, 2) geochemical, isotopic and petrographic techniques, 3) field sampling techniques during modern river sediment collection and 4) generic 'transferable' skills. Training details are provided in a separate section. The student will be trained by experienced supervisors and analysts. Lead supervisor Najman (Lancaster) has more than 20 years experience in the integration and interpretation of multi-technique provenance studies. Co-supervisors Butterworth (BP Egypt) and Kneller (Aberdeen) both have more than 20 years experience working on subsurface data and deepwater systems including the Nile delta. NIGL, where the isotopic analyses will be undertaken, is a world class research institute with emphasis on training. Manchester and Edinburgh, where geochemical analyses will be undertaken, provides state of the art facilities run by dedicated lab managers. Petrography will be carried out under the guidance of Garzanti (University of Milano-Bicocca) who has substantial experience in the study of sands from the Nile River and from rivers draining the Red Sea Hills.