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TitreMetavolcanic host rocks, mineralization, and gossans of the Shaib al Tair and Rabathan volcanogenic massive sulfide deposits of the Wadi Bidah Mineral District, Saudi Arabia
AuteurVolesky, J C; Leybourne, M I; Stern, R J; Peter, J M; Layton-Matthews, D; Rice, S; Johnson, P R
SourceInternational Geology Review vol. 59, issue 16, 2017 p. 1975-2002, https://doi.org/10.1080/00206814.2017.1307789
Année2017
Séries alt.Secteur des sciences de la Terre, Contribution externe 20150441
ÉditeurTaylor and Francis
Documentpublication en série
Lang.anglais
DOIhttps://doi.org/10.1080/00206814.2017.1307789
Mediapapier; en ligne; numérique
Formatspdf
Lat/Long OENS 30.0000 46.0000 28.0000 16.0000
Sujetsgîtes sulfureux; gîtes volcanogènes; gisements minéraux hydrothermaux; altération hydrothermale; exploration; prospection minière; analyses de la roche, éléments de terres rares; chapeaux ferrugineux; minéraux métalliques; minéralogie
Illustrationslocation maps; satellite images; cross-sections; photographs; diagrams; graphs; ternary diagrams
ProgrammeÉtude des gîtes de sulfures massifs volcaniques, Initiative géoscientifique ciblée (IGC-4)
Résumé(disponible en anglais seulement)
The Wadi Bidah Mineral District of Saudi Arabia contains more than 16 small outcropping stratabound volcanogenic Cu-Zn-(Pb) ± Au-bearing massive sulphide deposits and associated zones of hydrothermal alteration. Here, we use major and trace element analyses of massive sulphides, gossans, and hydrothermally altered and least altered metamorphosed host rock (schist) from two of the deposits (Shaib al Tair and Rabathan) to interpret the geochemical and petrological evolution of the host rocks and gossanization of the mineralization. Tectonic interpretations utilize high-field-strength elements, including the rare earth elements (REE), because they are relatively immobile during hydrothermal alteration, low-grade metamorphism, and supergene weathering and therefore are useful in constraining the source, composition, and physicochemical parameters of the primary igneous rocks, the mineralizing hydrothermal fluid and subsequent supergene weathering processes. Positive Eu anomalies in some of the massive sulphide samples are consistent with a high temperature (>250°C) hydrothermal origin, consistent with the Cu contents (up to 2 wt.%) of the massive sulphides. The REE profiles of the gossans are topologically similar to nearby hydrothermally altered felsic schists (light REE (LREE)-enriched to concave-up REE profiles, with or without positive Eu anomalies) suggesting that the REE experienced little fractionation during metamorphism or supergene weathering. Hydrothermally altered rocks (now schists) close to the massive sulphide deposits have high base metals and Ba contents and have concave-up REE patterns, in contrast to the least altered host rocks, consistent with greater mobility of the middle REE compared to the light and heavy REE during hydrothermal alteration. The gossans are interpreted to represent relict massive sulphides that have undergone supergene weathering; 'chert' beds within these massive sulphide deposits may be leached wall-rock gossans that experienced silicification and Pb-Ba-Fe enrichment from acidic groundwaters generated during gossan formation.
Résumé(Résumé en langage clair et simple, non publié)
Le présent document s'appuie sur des données géochimiques sur roche totale pour la minéralisation, ainsi que sur des roches encaissantes non altérées et altérées de gisements de métaux communs de type sulfures massifs volcanogènes en Arabie saoudite afin de déterminer où et comment les gisements se sont formés. Il décrit également les méthodes d'exploration qui pourraient guider la recherche vers des minéralisations cachées dans la région et ailleurs dans le monde.
GEOSCAN ID297655