About the Project
The Antrim lavas were erupted during continental rifting that led to the opening of the North Atlantic ca. 56 Ma and now form a basalt plateau in NE Ireland including the iconic UNESCO World Heritage site the Giant’s Causeway. Much work to date has focused on the petrology and geochemistry of the basalt, resulting in a sophisticated understanding of the genesis and evolution of the basalt magma. However, relatively little is known about the internal stratigraphy of the lava sequence. This project aims to determine the stratigraphy of the Antrim Lavas from 20 cores drilled across the plateau that penetrate the basalt sequence, plus 14 more logged boreholes (5 with geophysical logs), complemented by field sampling, logging, mapping and a suite of laboratory analyses and modelling. In addition to stratigraphic analysis based on textural, petrological and geochemical characteristics, the project will use magnetic analyses to aid stratigraphic interpretation, including anisotropy of magnetic susceptibility (AMS) and palaeomagnetism. This will enable us to develop the most detailed model for the stratigraphy and emplacement of the Antrim lavas to date, developing our understanding of the volcanism that accompanied the rifting of the N. Atlantic, and one of the most detailed datasets worldwide that can be used to explore how magma productivity and effusive eruption frequency vary during rifting on kiloyear timescales.
The principal aim of the project is to develop a detailed stratigraphic model for the Antrim Lava sucession. The project objectives involve a combination of field work, core logging and laboratory analyses (including petrology, geochemistry and rock magnetism). The main objectives are therefore:
Establish basalt and interbasalt facies: Examination of core and detaled logging of texture, composition, colour, structures, sediments, zeolites, veins, etc. This will be supported by magnetic analyses (establish magnetostratigraphy using magnetic properties)
Correlation of facies between cores: quantitative analysis of basalt texture and composition. This can be supported by field work and logging sections in quarries and coastal cliffs.
Generation of stratigraphc model: facies correlations used to establish a sequence and develop 3D framework using Move modelling software.
Eruption sequence for Antrim lavas: this will include the newely established stratigraphic framework and examination of eruption vents and lava emplacemnt directions. Emplacement directions will use facies and stratigraphy as well as textures that record lava flow (vesicles, AMS fabrics).
Stratigraphic analysis of cores including establishing correlations between basalt facies, magnetostratography and petrological analyses.
Texture and fabric analyses achieved through AMS measurements of split cores and oriented outcrop samples.
Petrological analyses using quantitative petrological techniques and scanning electron microscopy.
3D modelling of the internal stratigraphy using correlated facies to establish facies architecture and structure using geological modelling software MoveTM
Funding Notes
In addition to completing an online application form, you will also need to complete and submit the CENTA studentship application form available from www.centa.org.uk.
CENTA studentships are for 3.5 years and are funded by the Natural Environment Research Council (NERC). In addition to the full payment of their tuition fees, successful candidates will received the following financial support.
Annual stipend, set as £14,553 for 2017/18
Research training support grant (RTSG) of £8,000
CENTA students are required to undertake 45 days training throughout their PhD including a 10 day placement.
References
Cooper, M. R., Walsh, J. J., van Dam, C. L., Young, M. E., Earls, G., Anderson, H. & Walker A. (in prep). Palaeogene Alpine tectonics and Icelandic plume-related magmatism and deformation in Ireland.
Mitchell, W. I., Meighan, I. G., Cooper, M. R., Ture, M. D., Ellam, R. M., Noble, S. R., Knox, R. W. O’B., Hards, V. L., McGinn, C. & Walker, G. P. L. (deceased) 2010. A Palaeogene, Pre-Flood Basalts Supervolcano in Co. Antrim?: Evidence from the ‘Clay with Flints.’ IGRM abstract volume, p. 52-53.
Gamble, J. A., Wysoczanski, R. J. & Meighan, I. G. 1999. Constraints on the age of the British Tertiary Volcanic Province from ion microprobe U-Pb (SHRIMP) ages for acid igneous rocks from Northern Ireland. J. Geol. Soc. Lond. 156, 291-299 (1999).
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