1. Bureau of Economic Geology, The University of Texas at Austin, 10100 Burnet Road, Austin, TX 78758, USA
2. Department of Geoscience and Engineering, Delft University of Technology, Stevinweg 1, Delft 2628CN, the Netherlands. E-mail: R.Weijermars@tudelft.nl
3. Alboran Energy Strategy Consultants, Delft, the Netherlands
4. Department of Applied Mathematics, Delft University of Technology, Mekelweg 4, Delft 2628CD, the Netherlands