金瓜石地區硫化鐵礦物與河川重礦物之探勘地球化學

Exploration Geochemistry of Iron Sulfides and Heavy Concentrates of Stream Sediments in the Chinkuashih Area

余炳盛(B. S. Yu)

《鑛冶：中國鑛冶工程學會會刊》 35卷2期 (1991/06) Pp. 34-42

https://doi.org/10.30069/MM.199106_35(2).0003

摘要

硫化鐵礦物與河川重礦物之探勘地球化學對金瓜石及其附近地區之金銅礦探勘為方便而有效的方法。此地的硫化鐵礦物有黃鐵礦及白鐵礦。白鐵礦為腎狀，產在礦體的頂部。往礦體方向，其晶體大小由＜5增至＞10mm，金、銀、銅、錳、鉛等微量元素含量也明顯增加。黃鐵礦分布極廣，其微量元素含量可反映出不同的礦型。在金銅礦與含銅金礦帶，黃鐵礦的特性為含有高量的銅，最高可達1.5%，平均約4000 ppm，含砷量因硫砷銅礦包裹體之有無而呈極度不規則，可由（300至4000 ppm），富金帶之黄鐵礦則以高金（6-30ppm）與高銀（60-100 ppm）含量為其特性。而富金帶及其附近之黃鐵礦的鋇、鉛與鋅含量均非常不規則，主要和重晶石、方鉛礦與閃鋅礦的包裹體有關。黃鐵礦晶型與大小對此區探礦亦有助益：由金礦帶、含銅金礦帶至金銅礦帶，黃鐵礦的晶體由＜1 mm漸增至＞40 mm，晶型也由正方體變為五角十二面及八面體。河川重礦物主要為黃鐵礦，出微量元素異常顯示本地仍有許多值得進一步探勘的地區。根據土壤汞氣及本文研究的結果，最近由經濟部與台大地質系合作的研究計劃發現了含金量很高的礦體。

並列摘要

The iron sulfide minerals found in the Chinkuashih are marcasite and pyrite. Colloform marcasite occurs on the top of ore bodies. when approaching an ore body, the crystal size increases from ＜5 to＞ 10 mm, and Au, Ag, Cu, Mn and Pb contents increase as well. Pyrite is widely distributed in this area. In gold-copper and copper-bearing gold zones, the pyrite is high in Cu content, up to 1.5%, averaging 4,000 ppm. Arsenic contents vary wilh the amount of enargite inclusions. In bonanzas, pyrite is typically high in Au, 6-30 ppm, and Ag, 60-100 ppm. The Ba, Pb, and Zn contents of pyrite in or near bonanzas are irregular. The size and crystal forms of pyrite are also useful for prospecting. From a goldzone through a copper-bearing gold zone to a gold-copper zone, the sizes increase from ＜1 to＞ 40 mm, while the form varies from cube through pyritohedron, to octahedron. Heavy concentrates of stream sediments are composed of ＞90% of pyrite. In several unexplored areas near Chinkuashih, the trace elements anomalies in some of these concentrates may indicate mineralizations. According to the mercury anomaly in soil together with results from this study has led to discovery of a highgrade ore body.