【摘要】 金山金矿床位于赣东北矿集区内,是与韧性剪切带有关的超大型金矿床。黄铁矿是该矿床最主要的载金矿物。文章利用含金黄铁矿的稀土元素组成示踪了金山金矿床的成矿物质及成矿流体的来源和性质。研究结果表明,金山金矿床黄铁矿稀土元素总量较高,∑REE平均为171.664×10-6,富集轻稀土元素,LREE平均为159.556×10-6,HREE平均为12.108×10-6,轻重稀土元素比∑LREE/∑HREE平均为12.612,(La/Yb)N值平均为11.765,为轻稀土元素富集型;轻稀土元素有较明显的分馏,而重稀土元素的分馏不明显,(La/Sm)N值平均为3.758,(Gd/Yb)N值平均为1.695;Eu负异常明显,δEu值平均为0.664;基本无Ce异常,δCe值平均为1.044。黄铁矿的稀土元素特征与该矿床的围岩(蚀变变形的变质岩)、区域地层具有相似的地球化学特点,而与邻近的花岗闪长斑岩稀土元素特征不同,所以金山金矿床的成矿物质来源于变质岩围岩,成矿流体主要为变质水。黄铁矿中的Co/Ni比值显示金山金矿床为中低温矿床;成矿经历了沉积成岩、区域变质、韧性剪切带的动力变质作用及表生氧化作用的演化过程。从黄铁矿的Y/Ho比值推断金山金矿床含金黄铁矿的成矿流体为变质流体。黄铁矿中微量元素与矿区变质岩也有相似的组成,亏损HFSE。从黄铁矿的REE、LREE、HFSE、Hf/Sm、Nb/La、Th/La、Co/Ni、Y/Ho等特征,可推断金山金矿床的成矿流体是Cl多于F的变质流体。更多还原

【Abstract】 Located in the northeast Jiangxi ore-concentration area, the Jinshan gold deposit is a superlarge gold deposit related to the ductile shear zone. Pyrite is the main gold-bearing mineral. Based on REE composition of Au-bearing pyrite, the present paper traced the sources of ore-forming materials and the sources and characteristics of ore-forming fluids in the Jinshan gold deposit. The ∑REE of gold-bearing pyrite is as high as 171.664×10 -6 on average, with relatively high LREE (159.556×10 -6) and low HREE (12.108×10 -6). The ∑LREE/ ∑HREE ratio 12.612 and the (La/Yb)-N ratio 11.765 indicate that the gold-bearing pyrite belongs to the LREE-rich type. (La/Sm)-N is 3.758 and (Gd/Yb)-N is 1.695, showing an obvious LREE fractionation. The REE distribution patterns show obvious Eu anomaly with average values of δEu 0.664 and δCe 1.044. REE characteristics are similar to those of wall rocks (altered and deformed metamorphic rocks) and regional strata, but differ from those of the granodiorite porphyry nearby. All this indicates that the ore-forming materials of the Jinshan gold deposit were derived from the wall rocks, and that ore-forming fluids were metamorphic water. The Co/Ni ratio of pyrite suggests that the Jinshan gold deposit is a medium-low temperature deposit. The mineralization of the Jinshan gold deposit has undergone such evolutionary process as sedimentation-diagenesis, regional metamorphism, dynamic metamorphism of the ductile shear belt, and supergene oxidation. It is also shown that the ore-forming fluids of the Jinshan gold deposit were composed mainly of metamorphic water. Other features of trace elements in the pyrite are also similar to those of metamorphic rocks, such as the depletion of HFSE. Such features as REE, LREE, HFSE, Hf/Sm, Nb/La and Th/La, together with Co/Ni and Y/Ho ratios of gold-bearing pyrite, reveal that the ore-forming fluid of the Jinshan gold deposit originated from the Cl-rich deep metamorphic water.更多还原