Vanadium mineralization at Los Chihuidos sediment-hosted Cu–V deposit, Neuquén Basin, Argentina: An approach to vanadium ore forming processes

• Published in: Di xue qian yuan. Vol. 15; no. 1; pp. 101724 - 252
• Main Authors: Rainoldi, Ana L., Beaufort, Daniel, Franchini, Marta B., Giusiano, Adolfo, Petit, Sabine, Patrier, Patricia, Pons, M. Josefina
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.01.2024; Dpto.de Geología,Universidad Nacional del Sur(UNS),8000 Bahía Blanca,Argentina; Universidad Nacional del Comahue,Facultad de Ingeniería,Departamento de Geología y Petróleo,8300 Neuquén,Argentina%Consultant Geologist,8300 Neuquén,Argentina%Consejo Nacional de Investigaciones Científicasy Técnicas,Centro Patagónico de Estudios Metalogenéticos,Argentina; Consejo Nacional de Investigaciones Científicasy Técnicas,Centro Patagónico de Estudios Metalogenéticos,Argentina%Université de Poitiers,IC2MP,CNRS-UMR 7285,Hydrasa,F-86022 Poitiers Cedex,France%Consejo Nacional de Investigaciones Científicasy Técnicas,Centro Patagónico de Estudios Metalogenéticos,Argentina; Universidad Nacional de Río Negro,Instituto de Investigación en Paleobiología y Geología,Río Negro,Argentina; Elsevier
• Subjects: Bleaching; Clay minerals; Environmental Sciences; Hydrocarbons; Redox front; V-chlorite; Clay minerals; Hydrocarbons; Redox front; V-chlorite; Bleaching; Geoscience Frontiers
• ISSN: 1674-9871
• DOI: 10.1016/j.gsf.2023.101724

[Display omitted] •Redox front system related to the inflow of hydrocarbons into red beds.•Vanadium hypogene ore located at the redox interface.•V-Cu clay minerals indicative of pH-Eh variations through the mineralized redox front. Vanadium mineralization at Los Chihuidos deposit of the Neuquén Basin is linked to the development of a redox front system related to the inflow of hydrocarbons into the red sandstone of the Huincul Formation. Interaction of hydrocarbons with oxidized red beds and connate water generated redox reactions where hematite was dissolved due to iron reduction resulting in the discoloration of the red strata. At the contact between oxidized red sandstone and reduced white sandstone, precipitation of specific mineral phases resulted in the V ore with minor amounts of Cu. With the implementation of the redox interface, abundant V-montmorillonite and V-hematite precipitated at the more oxidizing conditions and Cu-V-corrensite-type at the more reducing conditions of the redox front. As the redox front advanced with fluids constantly migrating into the reservoir, more reducing conditions were stablished, promoting chloritization and minor illitization with V-Cu incorporation and continuous upgrading of the ore. Main ore mineralogy consists of clay minerals including V-bearing montmorillonite, Cu-V-corrensite-type, V-di-trioctahedral chlorite and Cu-tri-trioctahedral chlorite with minor V-illite–smectite mixed-layer minerals and associated secondary V-hematite. Chloritization over illitization was favored due to high amounts of Fe and Mg in detrital clasts and in connate fluids and by low K availability related to low amounts of detrital K-feldspar. The spatial transition of V and /or Cu bearing clay minerals observed through the mineralized redox front at Los Chihuidos deposit (kaolinite → smectite → illite/smectite → corrensite-type → di- trioctahedral -chlorite → tri- trioctahedral -chlorite) and the related variation of V–Cu concentrations in bulk rock are indicative of increasing pH and decreasing Eh of resident solutions from red to white sandstones during the hypogene mineralization process. Late influx of Cu-rich oxidized basinal brines precipitated main copper ore with Cu-sulfides in the white sandstone up to the contact with the redox front in contact with hydrocarbons. During uplift and exhumation, percolation of meteoric water promoted remobilization of V and Cu and the precipitation of oxidized V–Cu ore.