Gold deposits associated with the gabbroic rocks at Tirek area, western Hoggar, Algeria

fluid inclusion study

Warda Saad, Djamal Eddine Aissa, Koichiro Watanabe, Sachihiro Taguchi

Research output: Contribution to journalArticle

Abstract

The Tirek gold deposit hosted in the Archean shield is one of the richest sources of mined gold for Algeria. The deposit is controlled by the East Ouzzal shear zone (EOSZ), a transcurrent N–S lithospheric fault. The EOSZ is a late Pan-African dextral-ductile shear zone separating two contrasting Precambrian domains: the Archean In Ouzzal block to the west (Orthogenesis with subordinate metasediments reworked and granulitized during the ca. 2 Ga Eburnean event) and a middle Proterozoic block to the east involved in the ca. 600 Ma Pan-African event. The auriferous quartz veins are mainly oriented in two directions, N–S veins hosted in mylonitic rocks and NE–SW veins hosted in gabbroic or gneissic bands. The NE–SW veins contain the richest ore. Gold ore is found in a system of veins and lenticular quartz veinlets arranged in anastomosing networks. The hydrothermal alteration associated with these veins is characteristically a carbonate-sericite-albite-pyrite assemblage. Gold is the main metal of economic importance; it is disseminated in the quartz as grains or fibers along microcracks and as microscopic grains in the host rocks. Microthermometric results and Raman laser data from fluid inclusions demonstrate that the ore-forming fluids contained H2O-CO2±CH4 and were low salinity. Homogenization temperatures are commonly 250–310 °C. In the Tirek deposit, the role of the shear zone that hosts the mineralization was to drain the hydrothermal fluid. Interactions between the fluid and the mafic host rocks and CO2 also contributed to the formation of the hydrothermal gold deposit at Tirek.

Original languageEnglish
Article number26
JournalArabian Journal of Geosciences
Volume11
Issue number2
DOIs
Publication statusPublished - Jan 1 2018

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fluid inclusion
gold
shear zone
rock
host rock
Archean
quartz
ore-forming fluid
microcrack
metasediment
quartz vein
hydrothermal alteration
mafic rock
albite
hydrothermal fluid
drain
shield
Precambrian
Proterozoic
pyrite

All Science Journal Classification (ASJC) codes

  • Environmental Science(all)
  • Earth and Planetary Sciences(all)

Cite this

Gold deposits associated with the gabbroic rocks at Tirek area, western Hoggar, Algeria : fluid inclusion study. / Saad, Warda; Aissa, Djamal Eddine; Watanabe, Koichiro; Taguchi, Sachihiro.

In: Arabian Journal of Geosciences, Vol. 11, No. 2, 26, 01.01.2018.

Research output: Contribution to journalArticle

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