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Fully funded PhD scholarship
From: Davies Siwan. <Siwan.Davies@xxxxxxxxxxxxx>Fully funded PhD scholarship
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Dear all,
I would be grateful if you can inform students at your institutions of this fully-funded PhD opportunity at Swansea University. This scholarship is open to UK/EU students only. For further details on how to apply please follow the link http://www.swansea.ac.uk/geography/postgraduate/phdopportunitiesandresearchtopics/swanseauniversityphdscholarshipvolcanicashdeposition/
Deciphering the processes affecting volcanic ash deposition within sedimentary environments using X-ray microtomography and u-XRF techniques
Supervisors:
Prof. Siwan Davies (Swansea University)
Dr Richard Johnston (Swansea University)
Dr Sabine Wulf (GFZ, Potsdam, Germany)
Application deadline: 9 June 2014
Project summary
Volcanic ash horizons or tephras are critical dating tools to advance our understanding of the timing and mechanisms of past climatic changes. Following a volcanic event, ash is deposited instantaneously over the land surface, oceans and ice and is preserved as distinct horizons within geological archives. As each tephra has a distinct geochemical fingerprint, common horizons traced between different archives (e.g. ice-cores, marine records and lake sequences) represent fix-points in time (isochrons) allowing an unprecedented insight into the associated climatic signals preserved within each sequence. This depends entirely on the premise that the stratigraphic position of a tephra relates to the exact time of the eruption and associated tephra fallout and is unaffected by post-depositional processes. Within marine and lake records, it has become increasingly apparent that some tephra horizons have been displaced by secondary processes e.g. bioturbation, vertical migration of particles through soft-sediment, sediment loading and bottom-current reworking. This represents a key challenge for optimising the use of tephra horizons in studies of past climate. Identifying the operation and affect of such processes, however, is limited by the current techniques e.g. simple core descriptions/logging, tephra concentration profiles.
This project will employ a suite of new analytical techniques (X-ray microtomography, thin-section analysis and u-XRF techniques) to determine how the distribution of tephra particles is affected within different environments and to develop a protocol for interpreting the competing influence of sedimentary and depositional processes. Calcareous, organic-rich and clastic-rich sediments from North Atlantic marine records and lake records (e.g. Lago Grande di Monticchio) will be explored to investigate three-dimensional micro-sedimentological features. A focus on lake as well as marine sediments will provide an insight into the full-range of sedimentary processes in contrasting depositional realms.
X-ray microtomography work will be undertaken at the XICHAL unit at Swansea University (Engineering http://johnstonlab.wordpress.com) and the u-XRF analyses will be performed at Potsdam.
Siwan Davies
Athro | Professor
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Daearyddiaeth | Geography
Coleg Gwyddoniaeth | College of Science
Prifysgol Abertawe | Swansea University
Abertawe| Swansea
Cymru| Wales
SA2 8PP
Ffôn | Phone: 01792 295233
Ffacs | Fax: 01792 295955
Ebost | Email: siwan.davies@xxxxxxxxxxxxx
http://www.swansea.ac.uk/staff/science/geography/siwan.davies/
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