Can periodic sediment input signals make it through to the sedimentary archive?

Introduction: “How can we accurately decode a sedimentary succession for periodic input sediment supply signals if we have gaps in the succession and signals are shredded?” A common assumption in stratigraphic analysis is the stratigraphic record presents us with an unbiased record of past landscapes & climate. However, whilst the stratigraphic record does contain the most complete record of Earth history a direct link between fluvial dynamics, fluvial successions, sediment supply signals related to climate and tectonics is complicated by: a) the presence of significant time gaps in stratigraphy; and b) the modification and ‘shredding’ of sediment supply signals, generated by climate, by sediment transport, prior to their transfer to the fluvial stratigraphic record (Fig.1). We have successfully developed a new theoretical framework that defines critical thresholds of sediment supply that must be surpassed in order for these signals to be stored in the fluvial sedimentary record, and not shredded by autogenic processes (Toby et al., in review). The aim of this research project is to provide the first application of this theory to field and subsurface datasets where we have good age control and laterally extensive correlation. This work is a fundamental leap forward in how field scientists examine and interpret the clastic sedimentary, with particular relevance to past climate and tectonic sediment supply signals. This knowledge affords us the ability to unlock paleo-environmental records (e.g. Foreman and Straub, 2017) and predict the architecture of clastic sedimentary successions that can hold natural resources (Burgess et al. accepted).

Project Summary: The student will focus on two main sites in the Spanish Pyrenees (Fig. 2) and the USA. This field data will be supplemented by data collection on a subsurface data set where well, core and seismic data is available. There is a good possibility that the student will spend 4-5 weeks undertaking reduced-scale laboratory experiments at Tulane University (USA) under the supervision of Dr Straub. The outcome will be a robust sedimentary tool that will allow us to discriminate between noise and signal in fluvial successions, and therefore accurately identify those sediment patterns that relate to climate & tectonic signals. The results of the PhD will be published in high-impact journals and the student will have the opportunity to present key findings at international research conferences. The student will receive training in a range of qualitative and quantitative sedimentary techniques, and accompanying software (e.g. MATLAB, Delft3D). It will be expected that the student will participate in workshops that provide additional training in research skills and experimental design. The School of Environmental Sciences requires that the student participate in a comprehensive postgraduate research programme.