位于西秦岭文县弧形构造带的阳山金矿，是勉略缝合带内已探明金资源最大的独立金矿，且金矿形成后经历多期次构造活动，因此阳山金矿是研究矿床热演化、变化与保存的理想选区，其研究成果可用来约束金成矿时限，同时定量的隆升剥蚀数据可为深部找矿及矿床储藏提供远景潜力评价依据。本文采集钻孔矿化接触带中英云闪长斑岩脉，利用LA- ICP- MS技术进行裂变径迹测年。3件样品磷灰石裂变径迹年龄中心值为124. 3±6. 4 Ma、146. 4±6. 3 Ma和117±13 Ma，其中一件样品磷灰石裂变径迹平均长度为12. 11 μm。热历史反演的时间- 温度曲线表明，在146 Ma阳山金矿带内英云闪长斑岩脉体温度下降到磷灰石裂变径迹封闭温度区间（60～120℃），即在侏罗纪晚期或白垩纪早期之后，研究区几乎没有大规模岩浆活动或热液活动，缺乏与燕山期同时期区域性岩浆活动相对应的热事件。磷灰石裂变径迹年龄数据分析认为，即使金矿带在喜马拉雅期可能存在微弱的热事件扰动，但岩浆热液活动规模较小且对金成矿作用贡献微乎其微。结合磷灰石热历史时间- 温度曲线，阳山金矿带大规模成矿事件的时间集中在210～195 Ma区间，且热历史反演曲线未显示有后期成矿叠加。通过与阳山金矿带三个矿段热历史对比，证实阳山金矿带与区域相比存在差异化隆升剥蚀，且安坝矿段相较于葛条湾、泥山矿段剥蚀程度弱，是成矿与储矿的理想地段，推测剥蚀少的复背斜核部有较大的找矿潜力。
The Yangshan gold ore belt is located in the arc- shaped structural belt of the Wenxian County in the West Qinling, which is an independent gold deposit belt with the largest proven gold resources in the Mianlue suture zone. After the formation of the gold deposit, the area has experienced multiple stages of tectonic activities. Therefore, the Yangshan gold ore belt is an ideal selection area for studying the thermal history evolution, change and preservation of the deposit. The research results can indirectly limit the time of gold mineralization, and the quantitative uplift and denudation data can provide prospective potential evaluation for deep ore prospecting and deposit storage.After systematically analyzing the data, in this paper, samples of the tonalite porphyry dike in the mineralized contact zone of the borehole were collected, and the LA- ICP- MS fission track dating technology was used to obtain the dating data and track information. The central values of apatite fission track ages of ZK6001- 001, ZK0110- 001 and ZK1820- 001 are 124.3 ± 6.4 Ma (1σ), 146.4 ± 6.3 Ma (1σ) and 117 ± 13 Ma (1σ), respectively. In addition to ZK0110- 001, 22 apatite fission track lengths (mean 12.11 μm, Dpar mean 2.27 ± 0.28 μm) are obtained. The time- temperature curve of thermal history inversion shows that the temperature of the tonalite porphyry vein body in the Yangshan gold ore belt had dropped to the closed temperature range of the apatite fission track (120~60℃) at 146 Ma, that is, in the late Jurassic or after the early Cretaceous. There was almost no large- scale magmatic fluid or hydrothermal activity in the study area, and there is no record of thermal events corresponding to the regional Yanshanian magmatic activity in the same period. Analysis of apatite fission track dating data shows that although there may be a weak thermal event disturbance in the Himalayan period of the gold ore belt, the magmatic hydrothermal activity was small scale and had little contribution to the gold mineralization. Combined with the thermal history time- temperature curve of apatite, the metallogenic time of large- scale mineralization in the Yangshan gold ore belt was concentrated in the range of 210~195 Ma, and the thermal history inversion curve does not show superimposition of mineralization. The comparison with the thermal history of the three ore sections of the Yangshan gold ore belt shows that the Yangshan gold ore belt has differential uplift and denudation, and the Anba ore section is weaker in denudation than the Getiaowan and Nishan ore sections. It is inferred that the ideal location for orebody formation and preservation is the core of the compound anticline with less denudation and greater prospecting potential.
杨忠虎,熊韬,勾宗洋,李虎,王亮.2022.西秦岭南缘阳山金矿带磷灰石LA- ICP- MS裂变径迹热年代学研究[J].地质学报,96(11):3849-3866.
Yang Zhonghu, Xiong Tao, Gou Zongyang, Li Hu, Wang Liang.2022. LA- ICP- MS fission track thermochronology of apatite in the Yangshan gold ore belt, southern margin of West Qinling[J]. Acta Geologica Sinica,96(11):3849-3866.