Different carbon reservoirs of auriferous fluids in African Archean and Proterozoic gold deposits? Constraints from stable carbon isotopic compositions of quartz-hosted CO2-rich fluid inclusions

Lüders V, Klemd R, Oberthür T, Plessen B (2015)

Publication Language: English

Publication Type: Journal article

Publication year: 2015

Journal

Mineralium Deposita Springer Verlag (Germany)

Book Volume: 50

Pages Range: 449-454

Journal Issue: 4

DOI: 10.1007/s00126-015-0588-x

Abstract

Stable carbon (and when present, nitrogen) isotope ratios of fluid inclusions in quartz from selected gold deposits in Ghana and Zimbabwe have been analyzed using a crushing device interfaced to an isotopic ratio mass spectrometer (IRMS) in order to constrain possible sources of the auriferous fluids. The study revealed a striking difference in stable carbon isotopic compositions of CO₂ in quartz-hosted fluid inclusions from Archean and Paleoproterozoic orogenic gold deposits and points to diverse sources of CO₂ in the studied deposits. Whether this finding can be generalized for other Archean and Proterozoic orogenic gold deposits worldwide remains open. However, a significant CO₂ contribution by mantle degassing can be ruled out for every deposit studied. Devolatilization of greenstone belt rocks is the most likely source for CO₂ in some Archean Au deposits in Zimbabwe, whereas CO₂ in Proterozoic vein-type Au deposits in the West African Craton is most likely derived from C_org-bearing metasedimentary rocks. The δ¹³C_CO2 values of high-density CO₂-rich, water-poor inclusions hosted in quartz pebbles from the world-class Au-bearing conglomerate deposits at Tarkwa (Ghana) differ considerably from the δ¹³C_CO2 values of similar high-density CO₂-rich inclusions in vein quartz from the giant Ashanti deposit (Ghana) and disprove the idea of derivation of the Tarkwaian quartz (and gold?) from an older equivalent to the Ashanti vein-type gold deposit.

Authors with CRIS profile

Reiner Klemd Professur für Geochemie von Lagerstätten

Involved external institutions

Helmholtz-Zentrum Potsdam Deutsches GeoForschungsZentrum - GFZ

Germany (DE) Bundesanstalt für Geowissenschaften und Rohstoffe (BGR)

Germany (DE)

How to cite

APA:

Lüders, V., Klemd, R., Oberthür, T., & Plessen, B. (2015). Different carbon reservoirs of auriferous fluids in African Archean and Proterozoic gold deposits? Constraints from stable carbon isotopic compositions of quartz-hosted CO2-rich fluid inclusions. Mineralium Deposita, 50(4), 449-454. https://doi.org/10.1007/s00126-015-0588-x

MLA:

Lüders, Volker, et al. "Different carbon reservoirs of auriferous fluids in African Archean and Proterozoic gold deposits? Constraints from stable carbon isotopic compositions of quartz-hosted CO2-rich fluid inclusions." Mineralium Deposita 50.4 (2015): 449-454.

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