Magmas, fluids, faults and metals – re-assessing the controls on magmatic-hydrothermal W-Sn-Cu-As-Zn-Pb mineralisation and zonation associated with the Cornubian Batholith, SW England, NERC GW4+ , PhD in Geology studentship. Ref: 3347

About the award

Supervisors

Lead Supervisor

Dr Robin Shail Camborne School of Mines, College of Engineering, Mathematics and Physical Sciences, University of Exeter.

Additional Supervisors

Dr Jamie Wilkinson Department of Earth Sciences , National History Museum.

Dr Clara Wilkinson, Natural History Museum, Department of Earth Sciences

Dr Jens Andersen, Camborne School of Mines, College of Engineering, Mathematics and Physical Sciences, University of Exeter.

Location:

University of Exeter, Penryn Campus, Penryn, Cornwall TR10 9FE

This project is one of a number that are in competition for funding from the NERC Great Western Four+ Doctoral Training Partnership (GW4+ DTP).  The GW4+ DTP consists of the Great Western Four alliance of the University of Bath, University of Bristol, Cardiff University and the University of Exeter plus five Research Organisation partners:  British Antarctic Survey, British Geological Survey, Centre for Ecology and Hydrology, the Natural History Museum and Plymouth Marine Laboratory.  The partnership aims to provide a broad training in earth and environmental sciences, designed to train tomorrow’s leaders in earth and environmental science. For further details about the programme please see http://nercgw4plus.ac.uk/

For eligible successful applicants, the studentships comprises:

  • An index-linked stipend for 3.5 years (currently £14,777 p.a. for 2018/19);
  • Payment of university tuition fees;
  • A research budget of £11,000 for an international conference, lab, field and research expenses;
  • A training budget of £4,000 for specialist training courses and expenses.

Up to 30 fully-funded studentships will be available across the partnership.

Eligibility
Students from EU countries who do not meet the residency requirements may still be eligible for a fees-only award but no stipend.  Applicants who are classed as International for tuition fee purposes are not eligible for funding.
 

Project Background

The W-Sn-Cu-As-Zn-Pb ore field, centred upon the Early Permian Cornubian Batholith, is a global exemplar of magmatic-hydrothermal mineralisation associated with peraluminous granites and mineral zonation, where there is often a progressive change in dominant mineral assemblage with distance from the granite (W-Sn ± As proximal and Cu, Zn and Pb distal). The heterogeneous distribution of metals and mineralisation styles around “emanative centres”, including the anomalous occurrence of substantial Cu with peraluminous granite, indicates a complex relationship between magmatism, separation of magmatic volatile phases, faulting and fluid mixing. Changes in source melting and differentiation control the broad distribution of granite types and metal prospectivity (Simons et al., 2017). The focus of this project is to characterise the fluid types involved in mineralisation and how their structurally-controlled migration and mixing has controlled variations in the distribution of mineral assemblages and metals. 

Project Aims and Methods

The project is focussed upon the systematic analysis of melt and fluid inclusions in different granite types and mineralisation styles from across the SW England orefield. These will be used to determine: (1) the compositional variability of primary exsolved magmatic-hydrothermal fluids and their control by evolving melt compositions, and (2) the parameters controlling precipitation of ore metals from these solutions (e.g. cooling, phase separation, wall-rock reaction). Careful sample mineralogy and petrography, including SEM, QEMSCAN and cathodoluminescence techniques, will underpin the fluid inclusion microanalysis using microthermometry and laser ablation ICP-MS. Isotopic analysis of minerals will be used to evaluate alternative models for the source and evolution of fluids. These data will be combined with the distribution of syn-magmatic fault systems and historical metal production, to provide a re-evaluation of the controls on mineralisation, mineral zonation and the origin of “emanative centres”. The project will utilise material from collections at the Natural History Museum, Imperial College London and Camborne School of Mines but will require fieldwork to collect samples from areas where cross-cutting relationships between intrusions and vein sets can be documented in detail. Current and recent exploration by the CASE partners has provides an unparalleled opportunity to sample from diamond drill core samples.

Training

The student will spend 90% of their time at the University of Exeter (UoE) where they will be based for their fieldwork and receive training in GIS / sample collection / preparation, transmitted / reflected microscopy, SEM / QEMSCAN (automated SEM), cathodluminescence, electron probe microanalysis and preliminary microthermometric evaluation of inclusion fluids. The student will spend 10% of their time at the NHM (CASE partner institution) where they will receive training in laser ablation ICP-MS analysis of granite melt inclusions and inclusion fluids in granite-hosted magmatic quartz and inclusion fluids in representative hydrothermal vein parageneses.

CASE or Collaborative partner
The three CASE partners, all working across SW England, will provide the student with a unique insight into contemporary mineral exploration and access to diamond drill cores for sampling and relevant assay and historical production data showing distribution of metals within fault-controlled vein systems (lodes).

 

NERC

Fig 1: SW England granites (Simons et al. 2016, 2017)

 NERC
Fig.2 QEMSCAN image of polymetallic magmatic-hydrothermal mineralisation at Dolcoath Mine
 

References / Background reading list

Simons, B.J., Shail, R.K. & Andersen, J. 2016. The petrogenesis of the Early Permian Variscan granites of the Cornubian Batholith: Lower plate post-collisional peraluminous magmatism in the Rhenohercynian Zone of SW England. Lithos, 260, 76-94.

Simons, B.J., Andersen, J.C.Ø., Shail, R.K. & Jenner, F.E. 2017. Fractionation of Li, Be, Ga, Nb, Ta, In, Sn, Sb, W and Bi in the peraluminous Early Permian Variscan granites of the Cornubian Batholith: precursor processes to magmatic-hydrothermal mineralisation. Lithos, 278-281, 491-512. https://doi.org/10.1016/j.lithos.2017.02.007

Wilkinson, J.J., Stoffell, B., Wilkinson, C.C., Jeffries, T.E. & Appold, M.S. 2009. Anomalously metal-rich fluids form hydrothermal ore deposits. Science, 323, 764-767. http://doi.org/10.1126/science.1164436 

Entry requirements

Applicants should have obtained, or be about to obtain, a First or Upper Second Class UK Honours degree, or the equivalent qualifications gained outside the UK.   Applicants with a Lower Second Class degree will be considered if they also have Master’s degree.  Applicants with a minimum of Upper Second Class degree and significant relevant non-academic experience are encouraged to apply.

Candidate Requirements
We are looking for a well-qualified and highly motivated Earth Sciences/Geology graduate who wishes to carry out a PhD in mineralogy/petrology and economic geology. Excellence in geochemistry and mineralogy are essential; experience of microanalytical techniques and statistical data evaluation are desirable.

All applicants would need to meet our English language requirements by the start of the  project http://www.exeter.ac.uk/postgraduate/apply/english/.

 

How to apply

In the application process you will be asked to upload several documents.  Please note our preferred format is PDF, each file named with your surname and the name of the document, eg. “Smith – CV.pdf”, “Smith – Cover Letter.pdf”, “Smith – Transcript.pdf”.

  • CV
  • Letter of application outlining your academic interests, prior research experience and reasons for wishing to undertake the project.
  • Transcript(s) giving full details of subjects studied and grades/marks obtained.  This should be an interim transcript if you are still studying.
  • If you are not a national of a majority English-speaking country you will need to submit evidence of your current proficiency in English.
  • Two References (applicants are recommended to have a third academic referee, if the two academic referees are within the same department/school).

Reference information
You will be asked to name two referees as part of the application process.  It is your responsibility to ensure that your two referees email their references to pgrenquiries@exeter.ac.uk, as we will not make requests for references directly; you must arrange for them to be submitted by 7 January 2019

References should be submitted to us directly in the form of a letter. Referees must email their references to us from their institutional email accounts. We cannot accept references from personal/private email accounts, unless it is a scanned document on institutional headed paper and signed by the referee.

All application documents must be submitted in English. Certified translated copies of academic qualifications must also be provided.

The closing date for applications is midnight on 7 January 2019.  Interviews will be held between 4 and 15 February 2019.

If you have any general enquiries about the application process please email pgrenquiries@exeter.ac.uk.  Project-specific queries should be directed to the supervisor.

Data Sharing
During the application process, the University may need to make certain disclosures of your personal data to third parties to be able to administer your application, carry out interviews and select candidates.  These are not limited to, but may include disclosures to:

  • the selection panel and/or management board or equivalent of the relevant programme, which is likely to include staff from one or more other HEIs;
  • administrative staff at one or more other HEIs participating in the relevant programme.

Such disclosures will always be kept to the minimum amount of personal data required for the specific purpose. Your sensitive personal data (relating to disability and race/ethnicity) will not be disclosed without your explicit consent.

Summary

Application deadline:7th January 2019
Value:£14,777 per annum for 2018-19
Duration of award:per year
Contact: PGR Enquiries pgrenquiries@exeter.ac.uk