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首页> 外文期刊>Ore Geology Reviews: Journal for Comprehensive Studies of Ore Genesis and Ore Exploration >Geology, geochronology, and tectonic setting of the Jiapigou gold deposits, southern Jilin Province, China
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Geology, geochronology, and tectonic setting of the Jiapigou gold deposits, southern Jilin Province, China

机译：吉林省南部佳pi沟金矿床的地质，年代学和构造背景

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摘要

The Jiapigou area, at the northeastern corner of the North China Craton (NCC), is one of the most important gold-producing areas in China. It was responsible for nearly half of China's gold production in the 1960s and at present has >100 t Au reserves. Although numerous studies, mostly not published in international literature, have been undertaken on these deposits, their genesis, age, and tectonic setting are still controversial, mainly because of the lack of reliable geochronological data. Gold deposits at Jiapigou are hosted by several ductile shear zones within late Archean gneissic tonalite, trondhjemite, and granodiorite (TTG) and amphibolite (2523 + - 6 Ma), which have been retrogressed to greenschist facies. The deposits occur as massive auriferous quartz veins that contain sulfides (<10 vol. percent) and less common disseminated- and stockwork-style mineralization. The lodes are characterized by high Au/Ag ratios and relatively higher Cu (up to 1.3 percent) and Pb (as much as 10.3 percent) contents than most other gold deposits in the NCC. Although phyllic alteration is most common, potassic and chloritic alterations characterize felsic and mafic host rocks, respectively. Compiled stable isotope and fluid inclusion data show delta~(34)S, delta~(13)C, delta~(18)O and delta D values ranging from -0.2 per thousand to 12.6 per thousand, -4.2 per thousand to -5.0 per thousand, 5 per thousand to 12 per thousand, and -70 per thousand to -94 per thousand, respectively. These data likely indicate consistent sources of sulfur, carbon, and hydrothermal fluids, but do not actually indicate any specific reservoir. Fluid inclusions from the deposits show variable homogenization teniperatures between 150 and 350 deg C, and are characterized by low salinity (0.7 to 6.5 wt. percent NaCl equiv.) and H_2O-CO_2 + - CH_4, N_2 solutions. The initial lead isotope compositions of the deposits have considerable variations, even within individual deposits, possibly indicating multiple lead sources for the deposits. In the Jiapigou gold orefield, there are no major intrusions, but felsic, alkaline, and mafic dikes are common. These dikes usually occupy the same fault system as the gold lodes, with dikes locally hosting gold mineralization. Zircon SHRIMP U-Pb dates on pre-ore dikes yield ages of ca. 220 Ma, which constrains the maximum age of gold mineralization, whereas ~(40)Ar/~(39)Ar dates on hydrothermal sericite give an age of ca. 204 Ma. The timing of major gold mineralization in the Jiapigou area is therefore constrained between 220 and 204 Ma; this suggests a late Triassic gold-forming event. This episode of gold mineralization is coeval with, or slightly later than, the post-orogenic magmatism that followed the final orogenesis of the Inner Mongolian-Daxinganling erogenic belt (IMDOB), suggesting that a post-orogenic tectonic setting is appropriate for the late Trjassic gold mineralization. Zircon SHRIMP dating of a granitic batholith adjacent to the Jiapigou region and also hosting gold lodes that have been previously constrained-by Ai-Ar geoehronology between 144 and 120 Ma yielded an age of 166 + - 2 Ma, indicating that a mid-Jurassic (Yanshanian) gold-forming episode occurred at Jiapigou and in neighboring regions. This Yanshanian gold mineralization was contemporaneous "with subduction of the Pacific plate. On the basis of the nature, timing, and tectonic setting, we favor a classification of 'erogenic gold' for the Jiapigou deposits.
机译：位于华北克拉通（NCC）东北角的加皮沟地区，是中国最重要的黄金产区之一。在1960年代，它占了中国黄金产量的近一半，目前金储量> 100吨。尽管已对这些矿床进行了许多研究，但大多数都未在国际文献中发表，但其成因，年龄和构造背景仍存在争议，这主要是由于缺乏可靠的年代学数据。贾皮沟的金矿床由晚太古代的片麻岩斜长石，长白云母，花岗闪长岩（TTG）和角闪石（2523 +-6 Ma）内的几个韧性剪切带所控制，这些区域已经退回了绿片岩相。矿床为巨大的含石英的脉，含有硫化物（<10％（体积）），且不常见的散布式和储层式矿化。矿床的特征是高的金/银比和相对较高的金矿中其他大多数金矿的铜（高达1.3％）和铅（高达10.3％）含量。尽管页岩蚀变是最常见的，但钾质和绿泥质蚀变分别是长英质和镁铁质寄主岩的特征。编译后的稳定同位素和流体包裹体数据显示δ〜（34）S，δ〜（13）C，δ〜（18）O和δD值范围为-0.2 /千至12.6 /千，-4.2 /千至-5.0千分之五，千分之五至十二，千分之七十至-94千分这些数据可能表明硫，碳和水热流体的来源一致，但实际上并未表明任何特定的储层。沉积物中的流体夹杂物在150到350摄氏度之间显示出均质的可变温度，并且具有低盐度（NaCl当量为0.7至6.5 wt。％）和H_2O-CO_2 +-CH_4，N_2溶液的特征。沉积物的初始铅同位素组成即使在单个沉积物中也有相当大的变化，可能表明该沉积物有多种铅源。在甲皮沟金矿田中，没有大的侵入，但长石，碱性和黑手性堤坝很常见。这些堤防通常具有与金矿相同的断层系统，堤防在当地托管着金矿化作用。锆石SHRIMP U-Pb的年代为前矿石堤防的产生年龄。 220 Ma限制了金矿化的最大年龄，而在热液绢云母上的〜（40）Ar /〜（39）Ar日期给出的年龄约为。 204马。因此，甲皮沟地区主要金矿化的时间被限制在220至204 Ma之间。这表明晚于三叠纪的成金事件。金矿化的这一时期与内蒙古-大兴安岭造山带（IMDOB）最终造山运动发生后的造山后岩浆活动同期或稍晚，这表明造山后的构造环境适合于晚Trjassic金矿化。锆石SHRIMP测年与嘉皮沟地区相邻的花岗岩基岩，也拥有先前受144-120 Ma的Ai-Ar地质年代学约束的金矿，其年龄为166 +-2 Ma，表明侏罗纪中期（燕山期成金事件发生在甲皮沟及附近地区。燕山期的金矿化与太平洋板块俯冲是同期的。根据自然，时间和构造背景，我们赞成对贾皮沟矿床进行“生金”的分类。

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