Provenance and tectonic setting of greywacke and siltstone of the Nampala gold deposit, Southern Mali

Sory I.M. Konate, Anthony T. Bolarinwa, Daniel Kwayisi, Raymond Webrah Kazapoe, Elhadji Mory Traore, N'Dah N'Tcha Daniel Kouagou, Mamadou L. Bouare

Research output: Contribution to journalArticlepeer-review

Abstract

The petrographical and geochemical analyses of greywacke and siltstone samples from the Nampala gold deposit of the Paleoproterozoic Birimian supergroup, Southern Mali, have been carried out to make inferences on the provenance, tectonic settings, and weathering history of the sediments. Petrographical investigations revealed that greywackes can be classified as feldspathic wackes, with immature to moderately mature sediments, with the siltstones being immature. Geochemically, greywackes show features that resemble typical wacke sedimentary rocks, whereas the siltstones are arkose to litharenite. Overall, Nampala sedimentary rocks experienced low intensity of paleoweathering with <70 CIA and <90 CIW values and have not undergone significant sediment recycling having >1 CIV values. Their quartz and feldspar contents, together with the ratio of Al2O3/TiO2 and La/Sc, suggest the derivation of sediments from felsic igneous rocks, with a possible minor contribution from mafic proto-source rock. The petrographic and geochemical features of the greywackes and siltstones are consistent with siliciclastic rocks formed in an active continental margin, similar to other sedimentary rocks of the Paleoproterozoic Birimian terrane. These findings put positive constraints on the subduction-accretion geodynamic model proposed for the evolution of the Birimian terrane of the West African Craton.

Original languageEnglish
Pages (from-to)129-147
Number of pages19
JournalApplied Earth Science: Transactions of the Institute of Mining and Metallurgy
Volume133
Issue number2
DOIs
Publication statusPublished - Jun 2024

Keywords

  • Baoulé–Mossi Domain
  • Mali
  • Metasediments
  • gold mineralisation
  • provenance

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