- Fieldwork to the Karoo Province, South Africa, as part of a large international team of experts
- Lab geochemistry to quantify the geochemistry of Karoo province ‘host rock’
- Climate modelling to explore the effects of Karoo-Ferrar emissions
Many of the most severe climate ‘events’ and carbon cycle perturbations of the Meso-Cenozoic coincide with major episodes of volcanism linked to Large Igneous Provinces (LIPs). One of the most extreme examples is the end-Toarcian oceanic anoxic event, a global climate change event which roughly coincides with the emplacement of the Karoo and Ferrar large igneous provinces (located today in South Africa and Antarctica, respectively). LIPs like Karoo and Ferrar supply carbon-based greenhouse gases to the atmosphere by two main mechanisms: 1) Carbon dioxide, released from both intruded and erupted magma and 2) Thermogenic methane, formed when shallow igneous sills intrude organic matter-rich sedimentary rock, and emitted via hydrothermal vents. But the quantity, relative timing, and rates of carbon emissions from the Karoo-Ferrar province are poorly known because we lack information both about the intrusive volcanism itself and the chemical composition of the host rock into which it intruded. Was this volcanism truly sufficient to drive the dramatic climate perturbation of the Toarcian OAE? Or was the volcanic carbon release relatively minor or simply too slow to explain Toarcian climate observations?
This PhD project will combine fieldwork, lab geochemistry, and literature/database assimilation to constrain the carbon emissions from the Karoo-Ferrar province. This will include traditional field geology and collection of structural information on the ground in Karoo, as well as seismic and/or satellite interpretation of sill dimensions for Karoo and/or Ferrar provinces.
This PhD project will combine fieldwork, lab work and the compilation of large databases. The fieldwork to South Africa will likely be split over two field seasons and will include collecting information about the dimensions and geological relationships between intrusive igneous bodies of the Karoo LIP as well as collecting samples of the ‘host rock’ into which it intruded for later geochemical analysis (including organic carbon content and stable isotope analysis). For a geologically or geophysically-orientated student, a database of sill dimensions will be constructed by interpreting seismic and/or satellite images of sills from the Karoo and Ferrar regions. For a quantitatively-orientated applicant, Earth System Modelling could be used to explore the climate and carbon cycle consequences of the Karoo-Ferrar carbon emissions.
Training and Skills
This project will suit a highly motivated, well-rounded student who excels in synthesising data across a wide array of interdisciplinary fields. A numerate student in any branch of earth sciences or physical geography is highly desirable, but a background in field geology is key. Although full training in interpreting seismic/satellite data and in numerical modelling is provided, previous experience with coding and/or computational techniques will be highly advantageous.
Year 1: Begin literature review of Karoo LIP and collation of a database of the dimensions of known sills from satellite images. Fall: field season in South Africa.
Year 2: Analyse samples collected in Karoo, finalise database of Karoo sill dimensions. Spring: second field season in South Africa
Year 3: Construct database of Ferrar instrusive igneous bodies from seismic data. Modelling of carbon emissions from Karoo-Ferrar LIP.
Partners and collaboration (including CASE)
The project will include one or more field trips to the Karoo province in South Africa as part of a large team of international collaborators. In addition to supervisors Greene and Jones, the team will include leading international experts on Mesozoic sedimentology, stratigraphy, and geochronology Prof. Aisha Al-Suwaidi (Khalifa University, United Arab Emirates) and Prof. Micha Ruhl (Trinity College Dublin). Further collaborations with the British Antarctic Survey will explore the nature of the Ferrar LIP from seismic data.
Please contact Dr Sarah Greene (firstname.lastname@example.org) or Steve Jones (S.Jones.email@example.com) for further information or to discuss the project in greater detail.