The fingerprint of environmental change in the aeolian sedimentary record: a field-based study in the south-western United States

http://www.nercdtp.leeds.ac.uk/projects/index.php?id=806

Desert aeolian sedimentary systems are sensitive to changes in a wide range of environmental variables, including climate, sea level, sediment supply and tectonic factors. As such, the preserved sedimentary deposits of ancient desert dune fields record a fingerprint of past environmental change. This research project will use a field-led approach to characterise a variety of different types of aeolian sedimentary system, and will develop a suite models that will enable regional palaeoenvironmental reconstruction for desert systems that evolved during different periods in earth history in response to dramatically changing conditions. Developed models will be used as predictors of sediment system response to future environmental change, especially desertification arising from on-going climate change.

The aim of this research project is to develop a model to account for the response of preserved desert aeolian sedimentary systems to global drivers of environmental change, including climate, sea level, sediment supply and tectonics. Work will involve field-based data collection from world-class outcrops in the Colorado Plateau region of the South-western United States.

Specific research objectives of this research are as follows: (i) to collect a field-derived data set describing a range of sedimentary architectural styles from a world-class outcropping example of a major aeolian succession for which external controls can be shown to have played a key role in determining the preserved system state; (ii) to demonstrate evidence to show that primary allogenic and autogenic controls on preserved aeolian sedimentary successions are interdependent and interrelated via a series of complex feedback mechanisms; (iii) to develop a novel and innovative “next-generation” sequence stratigraphic model with which to explain how a range of interlinked environmental factors act to govern the nature of the preserved sedimentary record; (iv) to show how the model can be applied more generally to account for the sedimentology of a range of aeolian successions.

This research project will involve three principal research methods: (i) field-based data collection from a well-exposed aeolian study succession located in the Colorado Plateau region of the south-western United States, involving sedimentary lithofacies analysis to reconstruct aeolian dune type and the nature of autogenic bed-form behaviour (e.g. migration style), architectural-element analysis to reconstruct how the aeolian dunes accumulated and became preserved, and sequence stratigraphic analysis to determine how the aeolian succession is divided into separate sequences, each representing a distinct phase of dune-field accumulation under a specific set of palaeoenvironmental conditions; (ii) establishment of a database to account for the global distribution of preserved aeolian desert successions through geologic time. This aspect of the project will relate different types of aeolian succession to a range of global environmental controls that are known to have operated at certain times in Earth history; (iii) the application of forward numerical modelling software (already developed by FRG-ERG at Leeds) to show how different configurations of environmental controls can give rise to aeolian dune-field successions with predictable sedimentary features. These three research strands will serve as the basis for the development of the next generation of sequence stratigraphic models for non-marine successions developed in arid continental settings.

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.

The project will involve field-based data collection over three field seasons. Training in field-based sedimentology data acquisition techniques will be provided. There will be opportunities for the appointed applicant to spend time in the offices of our chosen project partner, Petrotechnical Data Systems (PDS), and one or more of our partner companies. Training will be provided in advanced 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 academia or industry. The successful applicant will join a team of 20+ academic staff, PDRAs and PhD research students who collectively form the Fluvial & Eolian Research Group at Leeds. The group has been undertaking world-leading sedimentary research for 20 years and is supported by a large consortium of sponsor companies.