Marcoux, Éric and Breillat, Noémie and Guerrot, Catherine and Négrel, Philippe and Hmima, Samia Berrada and Selby, David (2019) 'Multi-isotopic tracing (Mo, S, Pb, Re Os) and genesis of the Mo W Azegour skarn deposit (High-Atlas, Morocco).', Journal of African earth sciences., 155 . pp. 109-117.
The MoCuW Azegour skarn, located in the High-Atlas in Morocco, is associated with a Late Hercynian alkaline granitic intrusion. Here the origin of the mineralisation via ReOs geochronology and using Mo, S and Pb isotopes is discussed. The age of mineralisation defined by ReOs molybdenite geochronology is 276 ± 1.2 Ma for the Azegour mine, and 267 ± 1.2 for the Tizgui deposit suggesting for multiple mineralisation events associated with the Hercynian alkaline granitic intrusion. The δ98MoNIST of molybdenite range from −0.60‰ to 0.42‰ (n = 26) for the Azegour mine and from 0.08‰ to 0.40‰ (n = 2) for the Tizgui mine. Variations of the δ98MoNIST occur either at the deposit scale with a difference of about 0.72‰, and at the sample scale (few cm), which exhibits a difference of up to 0.40‰. A multi-phased mineralisation is proposed as the main processes explaining the variation in the δ98MoNIST values although the influence of a Rayleigh fractionation process cannot be precluded. The high δ34S values determined from molybdenite, pyrrhotite, and chalcopyrite (8–14.7‰) suggest a sedimentary origin for sulphur from the Cambrian sedimentary country rocks. Whereas, the initial 206Pb/204Pb compositions of common lead (18.08–18.30) for chalcopyrite and pyrrhotite imply a strong contribution of lead from the host volcano-sedimentary units.
|Full text:||(AM) Accepted Manuscript|
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|Publisher Web site:||https://doi.org/10.1016/j.jafrearsci.2019.04.007|
|Publisher statement:||© 2019 This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/|
|Date accepted:||08 April 2019|
|Date deposited:||12 April 2019|
|Date of first online publication:||11 April 2019|
|Date first made open access:||11 April 2020|
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