Granites from the Mantle – the xenolith perspective

This is a self-funded, 3 year full-time or 6 year part-time PhD studentship, to commence in October or February.

The project is supervised by Dr Mike Fowler, Prof James Darling and Prof Craig Storey.

The origins of granitic magmas through time is key to our understanding of crustal evolution on Earth. High Ba-Sr granites have geochemical characteristics traceable through related mafic magmas to enriched sources in the Sub-Continental Lithospheric Mantle (SCLM, e.g. Fowler et al., 2008).

Fowler and Rollinson (2012) argue that they are Phanerozoic equivalents of sanukitoids, which first appeared in the Neoarchaean as a result of evolving plate tectonic regime (e.g. steepening of the down-going slab). High Ba-Sr granites could, therefore, represent the continued expression of juvenile granite genesis that originated nearly 3 Ga ago.

On this project, you'll test their proposed mantle origin by defining and interpreting the distribution of the characteristic lithophile trace elements within xenoliths of the SCLM. The discovery of zircon in SCLM xenoliths from China (Liu et al., 2010), and silicate inclusions armoured in ophiolitic chromites (e.g. Robinson et al., 2015) increase the likelihood that there's still a lot to be discovered.

The SCLM beneath the Caledonian orogen has been sampled by numerous alkali basalt magmas; the xenoliths have been studied in great detail for many years.

Recent publications have demonstrated significant isotopic (Bonadiman et al., 2008) and chemical (Hughes et al., 2015) overlap with the proposed source of the Caledonian high Ba-Sr granites (Fowler et al., 2008).

It seems possible, then, that members of the xenolith suite represent source materials of the mafic parents to the granites – a hypothesis that can be tested with further study of the Streap and Rinibar xenoliths using modern micro-beam instrumentation, such as electron microscopy and laser ablation ICP-MS.

If confirmed, genuinely juvenile granites will need to be accounted for in global crustal growth models.

Fees and funding

Visit the research subject area page for fees and funding information for this project.

Funding availability: Self-funded PhD students only. 

PhD full-time and part-time courses are eligible for the UK Government Doctoral Loan (UK and EU students only).

Bench fees

Some PhD projects may include additional fees – known as bench fees – for equipment and other consumables, and these will be added to your standard tuition fee. Speak to the supervisory team during your interview about any additional fees you may have to pay. Please note, bench fees are not eligible for discounts and are non-refundable.

Make an Enquiry

For administrative and admissions enquiries please contact tech-enquiries@port.ac.uk.

How to apply

To start your application, or enquire further about the process involved, please contact Dr Mike Fowler (mike.fowler@port.ac.uk), Prof James Darling (james.darling@port.ac.uk) and Prof Craig Storey (craig.storey@port.ac.uk) quoting both the project code (SEES4461018) and the project title.