Stellenbosch University professor Alex Kisters on March 17 presented the third webinar as part of a free-to-attend five-part webinar series on alteration and its linkages to fluids, structures and gold deposits in reference to the Barberton gold deposits in Mpumalanga.

The webinar, which was hosted by the geoscience collective the Overberg Geoscientists Group (OGG), in collaboration with nonprofit organisation the Geological Society of South Africa (GSSA), was titled “Barberton gold deposits as examples of the interplay of structure and alteration”.

In the presentation, Kisters showed that fluid flow, alteration and mineralisation in the area were long-lived, or multiphase/episodic. He said this reflected the evolution of first-order folds or re-folds from flexural slip to fold lock-up.

He noted that the fluid flow, alteration and mineralisation was localised along lithological contacts, preferably with sharp rheological contrasts, and that there appeared to be differing orebody geometries, orientations and controls related to progressively developing first-order host structure.

“The gold is late, but likely to have been introduced throughout, with a late-stage upgrade,” he explained.

The series of webinars hosted by the OGG and the GSSA has been aimed at capitalising on the significant advances at the Barberton gold deposits, under the leadership of Kisters, who was awarded the Draper Memorial Medal in November last year for his work and leadership in greenstone gold mineralisation research.

The webinars takes a look at the intimate relationships between fluids and many crustal processes including partial melting, metamorphism, deformation, alteration and ore formation.

This approach looks at how heat has generated fluid and new minerals, the migration of that fluid through a network of structures, the deformation caused that is driven by high fluid pressures and controlled by rheological contrasts, and how all this crustal activity may include a major gold forming event.

Much of the evidence for all this is contained with alteration mineral assemblages.

The latest presentation by Kisters was the third in a planned weekly series of five. The webinar series, presented on Zoom, is being facilitated by Universities of Melbourne and Stellenbsoch Professor Neil Phillips.

All of the webinars are open to industry, explorationists and the general public and will highlight new research in Barberton and other well-known gold provinces. 

Economic geologist Julian Vearncombe will present the next webinar in the series titled “Optimising the use of structural geology in the gold industry” on March 24 at 10:30.

All the free-to-attend webinars can be accessed at this link:

https://us02web.zoom.us/j/82093178839?pwd=dWs1c2k2RkFuTS9CM2VtZ0lsUHdndz09

For additional information on the webinar series, contact John Bristow at jwbdia@gmail.com or Hennie Greeff at hennie.greeff@gmail.com.