Structural Development and Controls to Epigenetic, Mesothermal Gold Mineralization in the Sable-Pilgrim's Rest Goldfield, Eastern Transvaal, South Africa

Exploration & Mining Geology, Vol. 3, No. 3, 1994

MICHAEL HARLEY, Geological Survey of South Africa, Department of Geology, University of the Witwatersrand, Johannesburg, Republic of South Africa. E. GUY CHARLESWORTH, Department of Geology, University of the Witwatersrand, Johannesburg, Republic of South Africa

Bedding-parallel thrust-hosted gold veins are developed in the Sabie-Pilgrim's Rest gold-field, eastern Transvaal, South Africa. The reefs display a complex history characterized by temporally and spatially overlapping events of similar mineralization and deformation. Recognition of the episodic reactivation of these low angle (5° to 10°) thrust faults implicates high fluid pressures (equalling or exceeding lithostatic pressures). Geochemical constraints limit the amount of fluid-rock interaction and the occurrence of transgressive mineralization within the Archaean granitoid basement suggests that the high pressure fluids originated at depth beneath the Transvaal Basin. Similarities exist between gold deposits of Sabie-Pilgrim's Rest and Telfer, Western Australia as well as Passagem de Mariana, Minas Gerais, Brazil. All deposits are sub-parallel to the enclosing bedding which is shallowly inclined. Furthermore, they are also hosted by contractional deformational structures and are clearly epigenetic in origin.