When the levee breaks: crevasse-splay evolution, geomorphology and sedimentary record

Background
Crevasse splays are lenticular sediment accumulations deposited by river floods that breach channel levees. They are prominent features of river landscapes and of the sedimentary record of fluvial successions, and have considerable environmental and applied importance.
In coastal areas and subsiding wetlands, for example, crevasse-splay formation is a primary agent of land building. On cultivated floodplains, crevasse channels can cause undesired sand accumulation, rendering agricultural soils sterile. Yet in dryland settings, they provide a lifeline to agriculture where they drain into arid floodbasins. Elsewhere, the deposits of crevasse splays act as sites for the concentration of natural pollutants or anthropogenic contaminants, including microplastics.
In subsurface fluvial successions, crevasse splays have considerable economic significance. They control the volumes and connectivity of aquifers and hydrocarbon reservoirs. They act as hosts for minerals such as uranium. They are targets for heat exploitation in geothermal reservoirs. They are potential repositories for the safe, short-term underground storage of hydrogen as a fuel source. They can form underground repositories for carbon capture and storage (CCS).
This project seeks to improve our understanding of environmental controls on the formation and on the geomorphological and sedimentary characteristics of fluvial crevasse splays. Advances in the field will contribute to both fundamental and applied science, for example to predictions of landscape evolution, to the characterization of subsurface clastic successions, and to interpretations of environmental change from the stratigraphic record.

Aim and objectives
The overall aim of the PhD project is to improve our understanding of the controls on crevasse-splay formation, evolution and abandonment, and of how these translate to variable landforms and sedimentary deposits. This will be achieved through an interdisciplinary study, conducted using multiple lines of investigation, whose balance can be tailored to the specific interests of the appointed research student.
Research objectives are as follows: (i) to quantify the influence of controlling factors (e.g., river hydrology, floodplain physiography) on crevasse-splay genesis, evolution and characteristics; (ii) to generate outputs that serve as predictive tools and as guides to geological interpretation, for use in fundamental and applied geosciences (e.g., qualitative facies models, quantitative empirical characterization); (iii) to demonstrate the applied benefits of the research through case studies in environmental or subsurface geoscience.

Methodology
The research will integrate results from the following approaches: (i) analyses of remote-sensing datasets (satellite images, LiDAR data) of several modern rivers, conducted with consideration of river and catchment characteristics (hydrology, climate, vegetation, etc.); (ii) meta-analysis of published literature datasets on the Quaternary and ancient sedimentary record of crevasse-splay deposits; (iii) field-based data acquisition and analysis from ancient (outcrop) or Quaternary (surface or shallow-subsurface) overbank successions; (iv) laboratory-based flume experiments to investigate controls on crevasse-channel development and the morphology of resultant splays; (v) numerical modelling of overbank sedimentation for prediction of stratigraphic architecture of overbank deposits. The appointed student will be able to focus on study methods of interest to them.
There will be scope for assessing the value of the fundamental findings for predictive purposes, in contexts of applied subsurface geology or environmental change.

Eligibility
Applicants should have a BSc degree (or equivalent) in geology, geology-geography, earth sciences, geophysics or a similar discipline. An MSc or MGeol in sedimentology or geoscience (or similar) is desirable. Skills in field-based geological data collection and field sedimentology and stratigraphy are desirable. Experience of using GIS software would be useful, though is not essential.

Training
The project will likely involve field-based data collection over a series of field seasons. Training in field-based sedimentology data acquisition techniques will be provided. There will be opportunities for the appointed applicant to spend time working closely with one or more of our partner companies. Training will be provided in advanced concepts and techniques in clastic sedimentology and stratigraphy, in approaches to basin analysis, and in non-marine sequence stratigraphy. The nature of this research project will enable the appointed applicant to consider a future career in either academia or industry. The successful applicant will join a team of 30+ academic staff, PDRAs and PhD research students who collectively form the Sedimentology Group, which is based at Leeds but additionally benefits from a world-wide network of research associates.