Doris Elise Wendt, University of Birmingham, School of Geography, Earth and Environmental Sciences, College of Life and Environmental Sciences, Birmingham, B15, United Kingdom, Anne Van Loon, University of Birmingham, School of Geography, Earth and Environmental Sciences, College of Life and Environmental Sciences, Birmingham, United Kingdom, Bridget R Scanlon, University of Texas at Austin, Bureau of Economic Geology, Jackson School of Geosciences, Austin, TX, United States and David M Hannah, University of Birmingham, School of Geography, Earth and Environmental Sciences, Birmingham, B15, United Kingdom