Abigail Rooney

PhD Project:

Nitrogen isotopes as indicators of climate change; an investigation of late Devonian - early Carboniferous black shales in the USA

Supervisors: Geoff Clayton, Chris Nicholas, Robbie Goodhue

Co-supervisor: Dr Cortland Eble (Kentucky Geological Survey)

Global climate change alters ocean chemistry by significantly affecting the productivity of planktonic life. These chemical changes are recorded in nitrogen preserved in the tissues of plants and animals in sedimentary rocks. The proposed project will establish if nitrogen isotopes can be used to recognise climate changes that affected the earth 350 million years ago. ¹⁵N/¹⁴N ratios will be determined from late Devonian – early Carboniferous marine rocks and chemostratigraphic profiles will be constructed. The stratigraphic interval selected spans glaciation and deglaciation around the palaeo-south pole and in the USA it is represented mostly by marine black shales. A novel aspect of the project will be the analysis of separated organic constituents such as the palynomorph Tasmanites and woody land plants tissues, rather than the crude ‘whole-rock’ approach used in previous investigations.