PhD: Mesozoic biogeomorphology: how life sculpted continental habitats and the sedimentary rock record

Interactions between life and non-marine Earth surface processes create crucial interdependencies in modern environments that sculpt landscapes and habitats. In deep time, these interactions also led to the creation of distinct sedimentary facies and rock products that have elucidated the deep roots of this interaction in the Palaeozoic: this project will fill a knowledge gap by investigating how they manifested during the Mesozoic, providing the theatre of evolution for angiosperms, grasses, dinosaurs, birds and mammals.

Importance of the area of research concerned:
The interaction between physical alluvial processes and vegetation plays a major role in sedimentation, geomorphology, channel patterns and ecosystem functioning in rivers. The awareness of this importance has been used to construct non-actualistic conceptual models of alluvial processes and habitats that operated in the Palaeozoic and Precambrian, yet the Mesozoic – the time of the first flowering plants, the first grasses, a huge variety of terrestrial ecosystems that provided the theatre for dinosaur, bird and mammal evolution – remains unstudied from this perspective.

Project summary :
The sedimentary and geomorphological importance of plants with advanced ecological adaptations in modern rivers is clear. Angiosperms and grasses, aquatic life-habits and C4 carbon fixation are critical aspects of vegetation in modern rivers and yet none appeared on Earth until the Mesozoic. This project will assess how the evolution of these traits affected physical sedimentation, as revealed by the sedimentological facies record. The results will enable us to more fully answer fundamental questions surrounding the co-evolution of life and physical environments, the evolutionary context of present-day river habitat functioning and the stratigraphic distribution of distinct sedimentary facies.

What will the student do?:
The primary task of the student on this project will be the construction (through literature survey and meta-analysis of recurring facie properties) of a comprehensive global database of alluvial facies properties and their stratigraphic ranges throughout the Mesozoic Era. From this, field-sites will be identified (e.g., the extensive alluvial basin fills of Alberta, Wyoming and Colorado) from which ground-truthing of observed trends and characteristics will be analysed in detail, primarily using a variety of sedimentary geology field techniques including logging, architectural analysis and ichnology. In selecting sites, special emphasis will be placed on known vertebrate fossil localities, permitting the recognition of how novel or time-specific biogeomorphic environments provided the theatre for the evolution of terrestrial Mesozoic vertebrates. Statistical analysis of rock properties recorded in the database and field observations will provide a robust assessment of the effects of evolving vegetation on both habitats and geological materials at scales ranging from the local to global.