1. School of Geography, Earth & Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
2. Present address: Saudi Aramco, Box 782, Dhahran Mail Center, Abqaiq 31311, Saudi Arabia
3. School of Earth, Ocean & Planetary Sciences, Cardiff University, Main Building, Park Place, Cardiff, CF10 3YE, UK
4. Present address: ‘Brithdir’, Bethania Road, Acrefair, Wrexham, LL14 3TT, UK
5. Present address: School of Geography, Earth & Environmental Sciences, University of Plymouth, Drake Circus, Plymouth, PL4 8AA, UK
6. Present address: Brigantia Resources Ltd, 7 Carlton Croft, Streetly, Sutton Coldfield, West Midlands, B74 3 JT, UK