My Research: "Carbon Cycling and Mass Extinctions"
I have recently submitted my PhD thesis entitled Carbon Cycling and Mass Extinctions: The Permo-Triassic of the Arabian Margin. My work involves trying to understand how the global carbon cycle responded and recovered from a major perturbation, namely the Permian-Triassic Mass Extinction. Occurring ~250 Ma and resulting in the loss of 90% of marine life the extinction event involved a large disruption of the carbon cycle. Biodiversity and the carbon isotope record for the Early Triassic fail to return to 'normal' for around 5 Myrs after the extinction itself. The Early Triassic is characterised by numerous secondary extinctions, turnover events, major positive and negative carbon isotope excursions.The principle aim of my thesis is to understand the role of the carbon cycle in the end-Permian extinction and recovery, both in terms of extinction and feedback mechanisms. This requires analysis of environmental change to try to explain the δ13C record for the PTB and Early Triassic, and to link these changes to biotic events. This thesis focuses on reconstructing two environmental variables: 1) water column redox conditions and 2) surface water pH. These reconstructions were undertaken for the Arabian Margin that represents a unique shelf-to-basin transect for the Late Permian and Early Triassic. It is a mixed carbonate and clastic setting that, makes it possible to apply a diverse suite of proxies including Fe-speciation (for redox reconstruction), and boron isotopes preserved in carbonate (for pH reconstructions).