[1] UFZ Helmholtz Ctr Environm Res, Dept Monitoring & Explorat Technol, D-04318 Leipzig, Germany
[2] Council Geosci, Geophys Unit, ZA-0001 Pretoria, South Africa
[3] CSIR, ZA-0001 Pretoria, South Africa
[4] Univ Halle Wittenberg, Inst Geosci & Geog, D-06120 Halle, Germany
[5] Univ Pretoria, Nat Hazard Ctr, ZA-0028 Pretoria, South Africa
[6] Beak Consultants GmbH, D-09599 Freiberg, Germany
[7] UFZ Helmholtz Ctr Environm Res, Dept Landscape Ecol, D-04318 Leipzig, Germany
[8] Fed Inst Geosci & Nat Resources, D-30655 Hannover, Germany
[9] Afrika Gold AG, CH-8835 Feusisberg, Switzerland
[10] Univ Witwatersrand, Sch Geosci, ZA-2050 Johannesburg, South Africa