豫西南高庄金矿床Re-Os定年及S-Pb同位素和REE示踪

高庄金矿床是豫西南一处重要金矿，成矿时代、物质来源以及矿床成因类型尚不清楚。本文对高庄金矿石中载金矿物磁黄铁矿进行Re-Os测年，获得(137±2) Ma成矿年龄，表明金矿床为燕山晚期成矿。分别对载金矿物磁黄铁矿、容矿地层(二郎坪群火神庙组)和侵入岩体(堂坪岩体)进行了S、Pb和REE组成分析。矿石硫化物δ34SCDT值为-3.0‰～-1.5‰，平均值为-2.24‰，深源S特征明显，矿石S可能来源于容矿的二郎坪群火神庙组基性火山岩地层。矿石硫化物206Pb/204Pb、207Pb/204Pb、208Pb/204Pb的变化范围分别为17.106～17.505、15.469～15.602、37.835～38.194。堂坪岩体206Pb/204Pb、207Pb/204Pb、208Pb/204Pb的变化范围分别为18.244 3～19.238 2、15.594 8～15.693 5、38.504 2～39.616 3，二郎坪群火山岩206Pb/204Pb、207Pb/204Pb、208Pb/204Pb变化范围分别为18.176 8～18.669 2、15.607 1～15.801 9、38.375 9～39.080 9。矿石铅同位素组成与地层和岩体的岩石铅组成相近，表明岩体和地层都提供了成矿物质。矿石与二郎坪群火神庙组地层的REE球粒陨石标准化配分曲线都为平坦型。可见，豫西南高庄金矿形成于秦岭碰撞造山之后的燕山晚期陆内构造岩浆热液过程，成矿物质主要来源于矿体周围火山岩地层。

Re-Os dating and S-Pb isotopic and rare earth elements analyses of the Gaozhuang gold deposit in southwestern Henan,China

The Gaozhuang gold deposit is an important gold deposit in southwestern Henan Province and has been studied by other researchers. However, the metallogenic province and epoch as well as ore types of the gold deposit are still poorly understood. In this paper, we performed Re-Os dating of pyrrhotite in the Gaozhuang gold deposit. The determined Re-Os age was 137±2 Ma, indicating the deposit was formed in the Late Yanshan Epoch. We also analyzed S and Pb isotopic and REE compositions of the gold-bearing mineral (pyrrhotite), the host strata (the Huoshenmiao Formation of the Erlangping Group) and the intrusive rock (the pluton rock mass). The δ34SCDT value of ore sulphide was between -3.0‰ and -1.5‰ with an average value of -2.24‰, which suggests that sulfur may come from the deep source since its δ34SCDT value was close to that of the original mantle sulfur (0±3‰), and that the sulfur ore may originate from the surrounding volcanic rock strata. Ratios of 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb for ore sulfides ranged in 17.10617.505, 15.46915.602 and 37.83538.194, respectively. The 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb ratios for the Tangping intrusion ranged in 18.244319.2382, 15.594815.6935 and 38.504239.6163, respectively. And the 206Pb/204Pb, 207Pb/204Pb and 208Pb/204Pb ratios for the host strata were of 18.176818.6692, 15.607115.8019 and 38.375939.0809, respectively. The above almost indistinguishable Pb isotopic ratios and their variation trend for the ore-lead, host strata and intrusion suggest that the ore-forming material is provided by both the host strata and the intrusion. The chondrite normalized REE distribution curves of the ore minerals were very similar to those of the Huoshenmiao Formation of the Erlangping Group, and they were all flat. The above results allow us to propose that the Gaozhuang gold deposit was formed in the Late Yanshan Epoch in the intracontinental metallogenic stage after the Qinling collisional orogeny. And the ore-forming material of the Gaozhuang gold deposit mainly comes from the host strata.