甘肃小铁山隐伏多金属矿床地球化学预测指标

GEOCHEMICAL PROGNOSTIC INDICATORS FOR THE XIAOTIESHAN CONCEALED POLYMETALLIC DEPOSIT IN GANSU PROVINCE

小铁山隐伏多金属矿床是海底火山喷发—沉积建造成因的矿床。赋矿地层、岩性具有较高含量的Cu-Zn-Ba-Ag-Co组合。在矿田和矿床范围内,这些元素形成清晰的原生异常,异常相互交替叠置于矿化地段。在矿体延伸方向上,元素的原生异常分布组合具有轴向分带现象,前缘元素I、Na2O、Li,与矿体密切相关元素为Cu、Zn,Hg、Au、Pb、Ag、Bi、Sb、As,尾部元素Cd、Mo、Co、Sn。多元素累乘比值[w(Na2O)×w(Li)]/[w(K2O)×w(Rb)]从矿上向尾部具有规律的下降,矿体上、下盘的元素组合明显不同,矿体上盘富集亲铁元素,矿体下盘富集亲硫元素。这些指标对评价异常远景和矿化剥蚀程度具有一定的意义。

The Xiaotieshan concealed polymetallic deposit is genetically a submarine volcanic eruptive -sedimentary deposit. Its orehosting strata contain fairly abundant Cu, Zn, Ba, Ag and Co. Within the ore field and the ore deposit, these elements form distinct primary anomalies, which are superimposed on the mineralization sector. In the extending direction of the ore body, the distribution and association of the primary anomalies assume axial zoning, with the frontal elements being I, Na2 O, Li, the elements closely associated with the ore body being Cu, Zn, Hg, Au, Pb, Ag, Bi, Sb, As, and the rear elements being Cd, Mo, Co, Sn. From the upper part of the ore body to the rear part, [ （ w （ Na2 O） × w （Li） ] / [ w （ K2 O） × w （Rb） ] decreases regularly. The element association in the hanging wall is obviously different from that in the lying wall： the hanging wall is enriched with siderophile elements, while the lying wall has abundant thiophile elements. These indicators are surely of some significance in the evaluation of anomaly prospects and mineralization-denudation extent.