1. Department of Earth Sciences, University of Stellenbosch, Matieland, 7602, Stellenbosch, South Africa Sasol Mining (Pty) Ltd, Private Bag X1034, Secunda, 2302, South Africa e-mail address: acoetzee90@gmail.com
2. Department of Earth Sciences, University of Stellenbosch, Matieland, 7602, Stellenbosch, South Africa e-mail address: akisters@sun.ac.za