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煎茶岭镍矿是秦岭造山带中至今发现的唯一镍矿床,其成矿特征在铜镍硫化物矿床中具有特殊性。通过对矿床地质、地球化学特征和成矿地质条件的综合研究,发现该矿床严格受韧性剪切带和花岗斑岩的控制,近矿围岩蚀变强烈;矿石以交代结构为特征,细脉状构造发育。矿物生成顺序研究表明,矿石中金属硫化物明显晚于超基性岩,而与其发生蚀变的时间相近,同时由于矿体附近的钠长斑岩发生了强烈的围岩蚀变,因此成矿作用也晚于钠长斑岩。矿石微量元素和稀土元素表现出明显的双重性,在继承超基性岩特征的同时,又与矿区中酸性岩存在密切的联系。在硫同位素组成上,矿石明显地富集重硫,其δ34S无论是变化范围还是平均值均远离镁铁-超镁铁质岩石,而与矿区中酸性岩中黄铁矿的硫同位素具有很好的一致性。说明该矿床应是由热液作用形成的,成因类型属岩浆热液改造型矿床。
The Jianchaling Nickel Mine is the only nickel deposit discovered so far in the Qinling orogenic belt, and its metallogenic characteristics are special in the Cu-Ni sulfide deposit. Through the comprehensive study on the geology, geochemistry characteristics and geological conditions of the deposit, it is found that the deposit is strictly controlled by the ductile shear zone and granite porphyry, and the alteration of the ore wall is intense. The ore is characterized by the structure of metasomatic structure and fine Veins tectonic development. The study on the sequence of mineral formation shows that the metal sulfides in ore are significantly later than that of ultrabasic rocks and are similar to the time of alteration and the ore-forming changes occur due to the strong wall-rock alteration of the albite in the vicinity of the ore body The effect later than the sodium porphyry. Ore trace elements and rare earth elements showed obvious duality, while inheriting the characteristics of ultrabasic rocks, but also with the acidic rock in the mining area there is a close link. On the sulfur isotopic composition, the ore is obviously enriched in heavy sulphide. Its δ34S is far away from the mafic-ultramafic rocks in both the variation range and the average value, and is in good agreement with the sulfur isotopes of pyrite in the intermediate-acidic rocks in the ore district Consistency. It shows that the deposit should be formed by hydrothermal fluid and the genetic type belongs to the magmatic hydrothermal alteration deposit.