Epithermal gold mineralization at Wadi Abu Khushayba, southwestern Jordan

摘要: Abstract The Wadi Abu Khushayba area in southwestern Jordan hosts an auriferous, quartz-veined shear zone with features of epithermal low-sulfidation gold system. quartz-lode and quartz-carbonate mineralization is characterized by open-space textures, typically sharp-walled veins multi-stage brecciation the late Neoproterozoic (~ 560 Ma) rhyolitic granophyric host rocks. Silicic alteration cryptocrystalline quartz abundant; potassic expressed muscovite K-feldspar blastesis, commonly dispersed hematite laths. Sulfide content low. Relict pyrite chalcopyrite occur comb cockade quartz. Gold occurs disseminated volcanic subvolcanic wall rocks as vein infill. coexistence vapor-rich liquid-rich fluid inclusions quartz, presence adularia calcite mineralogy suggest boiling concomitant deposition a structural setting favoring high flow. Fluid define temperature range 350–380 °C low salinity (~ 1.5–7 wt.% NaC1 equiv.) for ore Pressure estimated at 200–250 bars, indicating maximum paleo-depth 2500 m (hydrostatic). It appears likely that system represents near-surface expression larger unexposed mesothermal Such systems are typical elsewhere Arabian–Nubian Shield, but not exposed where present-day erosional level close to unconformity transgressive Early Cambrian platform sedimentation.