Composite soil-geochemical halos delineating carbonate-hosted zinc–lead–barium mineralization in the Irankuh district, Isfahan, west-central Iran

摘要: Abstract The Irankuh district in west-central Iran hosts several largely unexposed Lower Cretaceous carbonate-hosted Zn–Pb deposits whose host rocks are overlain by soil cover. This paper documents a detailed soil-geochemical exploration program, comprising 804 residual samples that were treated with microwave acid digestion and analyzed ICP-MS for multi-element package. soils overlying the Zn–Pb–Ba veins mineralized zones have geochemical contrast element enrichments more than two to twenty-one times greater non-mineralized background values. most diagnostic elements Zn, Pb, Ag, Ba, Hg Sb which show multi-point anomalies across entire zone concentration ranges of 282–10,000 ppm 73–10,000 ppm 2.2–71.9 ppm 1500–3400 ppm 0.89–36 ppm 11–164 ppm Sb, respectively. newly proposed composite halos defined Ag*Cd/Pb*Zn, Ag*As/Pb*Zn, Ca*Mg/Pb*Zn, Sb*As/Pb*Zn, Hg*Sb/Pb*Zn, Sb*Ba/Pb*Zn, Ba*Ca/Pb*Zn Ag*As* Sb/Pb*Zn*Bi correlate well anomalous patterns individual elements. coincident main faults fractures, particular Gushfil Rumarmar area. On basis low contents Cu Fe variodiagram log (Pb + Zn) versus Pb/Pb + Zn, composition suggests epigenetic stratabound mineralization Mississippi-Valley-Type (MVT). mode occurrences is likely controlled structural replacement sphalerite, galena, carbonates barite or adsorption iron–manganese oxides clay minerals. Follow-up sampling gossans highly faulted-fractured may indicate concealed mineralization.