Article Dans Une Revue Journal of Structural Geology Année : 2024

Refold structures of the Archaean Nyanzaga gold Project, Sukumaland Greenstone Belt, Tanzania: Precursors to the gold-bearing fault system

Résumé

This study presents a complete investigation into the structural-hydrothermal evolution of the Nyanzaga and Kilimani gold deposits within the Neoarchean Sukumaland Greenstone Belt, Tanzania Craton. The first compressional stage, D1a, creates upright E-W folds in response to N-S-oriented shortening. The second stage, D1b, refolds the previously formed structures during ongoing compression/transpression under N-S-oriented shortening. Due to the brittle nature of late deformation, during D1c, a set of faults emerges, with the NW-SE ones exhibit dextral shearing and control the formation of normal N-S vertical faults. A protracted hydrothermal history is recorded, beginning with a disseminated silicate minerals- and pyrite- rich, gold-barren stage associated with the D1a and D1b deformations, followed by the development of a gold- endowed vein system during progressive D1b and D1c stages. Gold was mainly concentrated within vertical NW-SE (Kilimani) and N-S (Nyanzaga) faults. Our findings challenge traditional polyphase deformation models presented in the other gold deposits of the area, by proposing a progressive and continuous deformation- hydrothermal history. In addition, we highlight the influence of refold structures on fault geometry, which is crucial in concentrating gold mineralization under continuous N-S compression and transpression.

Fichier principal
Vignette du fichier
2024-Berthier-tanzanie-gold-JSG24-pre-print.pdf (19.83 Mo) Télécharger le fichier

Dates et versions

hal-04734305 , version 1 (13-10-2024)

Licence

Identifiants

Citer

Célestine Berthier, Alain Chauvet, Julien Feneyrol, Anne-Sylvie André-Mayer, Aurélien Eglinger, et al.. Refold structures of the Archaean Nyanzaga gold Project, Sukumaland Greenstone Belt, Tanzania: Precursors to the gold-bearing fault system. Journal of Structural Geology, 2024, 187, pp.105233. ⟨10.1016/j.jsg.2024.105233⟩. ⟨hal-04734305⟩
183 Consultations
167 Téléchargements

Altmetric

Partager

  • More