The Wassa deposit: a poly-deformed orogenic gold system in southwest Ghana - implications for regional exploration

Stephane Perrouty, Mark W Jessell, Yan Bourassa, John Miller, Daniel Apau, Luc Siebenaller, German Velasquez, Lenka Baratoux, Laurent Ailleres, Didier Beziat, Stefano Salvi

Research output: Contribution to journalArticleResearchpeer-review

24 Citations (Scopus)

Abstract

The Ashanti greenstone belt in southwest Ghana hosts many gold deposits distinguished by different timing and structural contexts. This study investigates the evolution of the Wassa system by integrating field and geophysical observations. This 4 million ounces (past production and current resources) gold deposit is interpreted to represent the oldest gold mineralization event in West Africa with gold-bearing pyrites aligned and stretched within the S1 ductile fabric. Mineralized quartz-carbonate veins were strongly deformed during the D1 deformation event. Three additional folding events are characterized by hectometer-scale tight to isoclinal folds, by a kilometer-scale synform fold centered on the mine and by a late recumbent metric-scale folds. Because of its early timing, the Wassa system represents a new poly-deformed deposit type in West Africa and highlights a potential for new discoveries in the underexplored meta-volcanic and meta-sedimentary Sefwi Group. Timing of the gold mineralization at the Wassa mine makes this deposit type a possible candidate for the source of the gold contained in the Tarkwa paleoplacer.
Original languageEnglish
Pages (from-to)536-547
Number of pages12
JournalJournal of African Earth Sciences
Volume112
DOIs
Publication statusPublished - 2015

Keywords

  • Ashanti Belt
  • Birimian
  • Eburnean
  • Eoeburnean
  • Tarkwaian
  • Wassa

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