Submarine conduits are long term sediment routing systems - so how and when do they fill? A field-based study of deep-marine canyon fills, Baja California, Mexico.

Supervisors: Kane, I.A.1, Flint, S.S.1, Hodgson, D.M.2, McArthur, A.2 Hubbard, S.3

1 Stratigraphy Group, School of Earth and Environmental Sciences, University of Manchester, Manchester M13 9PL, UK
2 Stratigraphy Group, School of Earth and Environment, University of Leeds, Leeds LS29JT, UK
3 Department of Geoscience, University of Calgary, Alberta, T2N 1N4, Canada

Submarine canyons are incisional features that indent continental shelves and act as conduits for large volumes of sediment transferred from continents to oceans. For most of their lives canyons are dominated by erosion and bypass of sediment to deep-water channels and lobes. Canyons are filled with sediment in response to changes in the sediment flux to the canyon head, which may be driven by tectonics, sea-level change, or lateral shift of the sedimentary feeder system. The fill therefore does not necessarily reflect the processes that operated through most of the canyon's lifecycle, particularly during canyon initiation. The fill of canyons is of interest as they can form reservoirs when the canyon is partially to fully filled with sand, which may occur during a relatively slow shutdown of sediment supply to the canyon head; in contrast, canyons may form seals when they are mud-filled, which may be indicative of more abrupt cessation of sand supply.

This study will investigate ancient submarine canyon fills of the Peninsular Ranges forearc basin, uplifted and cropping out on the Pacific Coast of Baja California, Mexico. The canyon margins are reasonably well-constrained and their position and orientation have been linked to basin tectonics (Kane et al. in review). The influence of tectonics in submarine canyon formation is important as it can determine the location and spacing of canyons, dictate their geometry and orientation with respect to the regional slope, and influence connection to fluvial sediment input. The fills of the canyons are diverse, with mass-transport deposits, thin-bedded overbank deposits and coarse grained channel-fills and bedforms. The study will seek to document facies distributions and architectural element mapping within canyons and reconstruct the behaviour of turbidity currents through the life cycles of the canyons (e.g. subcritical vs supercritical flows and their products) with comparison to modern submarine canyons on the seafloor.

This studentship is focused on a topic of international importance and will form part of the Slope5 project, which is an Industry-funded research programme. We expect you to submit manuscripts to international scientific journals during the course of the studentship and to present the results of your research at relevant UK and International conferences. The project will provide excellent training in field mapping, process and experimental sedimentology, data analysis, and development of geological models. You will join one of the largest groups in the world working on earth surface processes and sedimentary basins, having access to excellent facilities and the support of supervisors with leading expertise in process sedimentology and the physical modelling of deep-marine sedimentary processes.

Application deadline is 13th September, and interviews will be held on 10th October in Edale, UK. For more information please contact Dr Ian Kane (ian.kane@manchester.ac.uk; +44 161 275 3949) and complete the online application form indicating the project title and primary supervisor at: http://www.manchester.ac.uk/study/postgraduate-research/admissions/how-to-apply/

posted: 02 August 2019     Please mention EARTHWORKS when responding to this advertisement.