1 févr. 2013

Bourse doctorale (PhD) : South Pacific beach ridges: sedimentology and genesis

L'université d'Ulster à Coleraine propose une bourse doctorale (PhD) pour l'étude des cordons littoraux dans le Pacifique Sud, et plus particulièrement en Polynésie française.

PhD Project title: South Pacific beach ridges: sedimentology and genesis
Supervisors: Prof Andrew Cooper, Prof. Derek Jackson (University of Ulster)
Contact details: jag.cooper@ulster.ac.uk; d.jackson@ulster.ac.uk
External advisor: Prof Samuel Etienne (EPHE)

Tropical coasts are characterised by long periods of low wave energy, punctuated by periodic storms (hurricanes, typhoons and tropical cyclones; Figure 1).  These storms have a variety of impacts on tropical coasts ranging from erosion  to deposition of ridges of reef-derived rubble (Morton et al., 2008) and/or sand (Forsyth et al.,  2010). Storms are the most important factor in the cycling of sediment through topical coast systems (Hubbard, 2005).  
The deposits of tropical storms therefore contain a proxy record of past storminess which has been used in a few instances to extend the documentary record (e.g.  Nott & Hayne, 2001; Hayne & Chappell, 2001; Forsyth et al., 2010)  but this can only be properly interpreted if the mechanisms of deposition are known (Scheffers, 2005). Morton et al. (2008) for example speculated that the coarse coral rubble beaches of the Caribbean might originate from individual large storms or a succession of smaller ones and hence their role as past climate proxies remains uncertain. In several Caribbean islands, boulder and unsorted debris fields have also been attributed to tsunami, although none of the  work rules out a storm origin.  Identifying storm and tsunami deposits can be problematic 
(Morton et al., 2007).  Tropical storms and hurricanes are an annual occurrence in the Caribbean, North and South  Pacific and Indian Ocean; every year hurricanes affect the shores of at least a few islands. The susceptibility of an individual shoreline to hurricane impact is, however, dependent on the hurricane track and consequently, at any given location, hurricane impacts are a relatively infrequent occurrence.

Project objectives
The aim of this project is to investigate the origin and palaeoenvironmental significance of sand beach ridges and related deposits (lagoonal scour pits, rubble ridges etc) at selected sites in islands of French Polynesia.

Specific objectives are:
• To measure and map the geomorphology of the selected deposits (sand ridges and rubble ridges)
• To investigate the sedimentology (texture, composition, bedding) of the deposits and surrounding area
• To evaluate the various depositional modes for ridge emplacement (via field measurement and modelling).
• To assess the potential of the assemblage of landforms as palaeo-storm/tsunami proxies

The project will require the student to:
• Review the state of knowledge of coastal and nearshore storm deposits in the tropics
• Review the nearshore dynamics of various storm types and categories
• Conduct fieldwork to map, measure and sample storm deposits and surrounding areas
• Assess the historical record of storm occurrence and impact at the study sites
• Evaluate potential depositional models for storm deposits

Skills required of the applicant
The project will be suitable for a student with an Oceanography, Earth Sciences, Environmental Sciences or Marine Science background.   Good field mapping skills, a willingness to spend several weeks mapping in tropical islands, practical survey skills and an MSc in sedimentology would be advantageous.

Note: non-UK and non-EU applicants are also very welcome to apply but please first
read funding information at:

The closing date for applications is 8th March 2013.

Full application details can be found at:

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