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Cambridge NERC Doctoral Training Partnerships

Graduate Research Opportunities
 
Brief summary: 
The project aims to make significant progress in understanding the YTT eruption and the nature and extent of its impacts via detailed investigations of the tephra record. It will begin with new multidisciplinary laboratory investigations of available samples from terrestrial, marine and lacustrine records, aimed at elucidating details of the eruption characteristics and plume dispersal and identifying, if present, proxy evidence for abrupt environmental change associated with the eruption. Particular attention will be paid to disentangling effects related to environmental disturbance caused by tephra fallout and those due to climate forcing by volcanic aerosol. We anticipate new fieldwork at sites in India where high-resolution stratigraphic sequences have been found. A parallel strand will consider modelling hydrological and ecological disturbances caused by large-scale tephra blankets.
Importance of the area of research concerned: 
The Toba ‘super eruption’ 74,000 years ago – more correctly known as the Youngest Toba Tuff (YTT) is a signature volcanic event for understanding the storage and eruption of very large volumes of magma, and the global climatic effects of explosive volcanism. Some have considered it had substantial impacts on the biosphere including human populations and at the very least it offers an exceptionally valuable chronostratigraphic horizon in the form of ash layers found in marine, terrestrial, lacustrine and archaeological contexts many thousands of kilometres form source. Numerous modelling efforts have attempted to constrain its possible climatic consequences, but these have been limited by uncertainties, notably in the magnitude of the co-eruptive sulphur release to the atmosphere. Attempts to attribute climatic changes to the eruption based on interpretation of sedimentological records has also been hampered by low temporal resolution and the substantial climatic variation in the Late Pleistocene. Despite the size and importance of the YTT, surprisingly little systematic work has been done to bring together the proximal, medial and distal tephra records associated with the eruption.
Project summary : 
The project aims to make significant progress in understanding the YTT eruption and the nature and extent of its impacts via detailed investigations of the tephra record. It will begin with new multidisciplinary laboratory investigations of available samples from terrestrial, marine and lacustrine records, aimed at elucidating details of the eruption characteristics and plume dispersal and identifying, if present, proxy evidence for abrupt environmental change associated with the eruption. Particular attention will be paid to disentangling effects related to environmental disturbance caused by tephra fallout and those due to climate forcing by volcanic aerosol. We anticipate new fieldwork at sites in India where high-resolution stratigraphic sequences have been found. A parallel strand will consider modelling hydrological and ecological disturbances caused by large-scale tephra blankets.
What will the student do?: 
The student will undertake a thorough review of available literature including sediment core reports to identify suitable materials for laboratory investigation. These will include sediments sampled at terrestrial, lacustrine and marine sites, some of which are already held in Cambridge. Laboratory work will include detailed characterisation of tephra and micromorphological investigation of sediments. Substrates below YTT horizons will be studied in addition to sediments above the YTT. We expect the student to undertake fieldwork at promising sites in India, to include detailed stratigraphic and sedimentological analysis both on site and subsequently in the laboratory. Lastly, the student will have the opportunity to apply a suitable ecological model to probe the impacts of tephra fallout on terrestrial habitats. Depending on the course the project takes, other very large eruptions might also be examined along similar lines, such as the circa 40 ka Campanian Ignimbrite eruption, which is also important in archaeological contexts.
References - references should provide further reading about the project: 
Lane, C.S., Chorn, B.T. and Johnson, T.C., 2013. Ash from the Toba supereruption in Lake Malawi shows no volcanic winter in East Africa at 75 ka. Proceedings of the National Academy of Sciences, 110(20), pp.8025-8029.
Ge, Y. and Gao, X., 2020. Understanding the overestimated impact of the Toba volcanic super-eruption on global environments and ancient hominins. Quaternary International. https://doi.org/10.1016/j.quaint.2020.06.021
Williams, M., 2012. Did the 73 ka Toba super-eruption have an enduring effect? Insights from genetics, prehistoric archaeology, pollen analysis, stable isotope geochemistry, geomorphology, ice cores, and climate models. Quaternary International, 269, pp.87-93.
Applying
You can find out about applying for this project on the Department of Geography page.
Professor Christine Lane
Department of Geography Graduate Administrator
Professor Clive Oppenheimer