Nature, age, and tectonic setting of granitoid-hosted, orogenic gold deposits of the Jiaodong Peninsula, eastern North China craton, China
Nature, age, and tectonic setting of granitoid-hosted, orogenic gold deposits of the Jiaodong Peninsula, eastern North China craton, China
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DOI：
10.1007/s00126-001-0238-3
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发表时间：
2002-04
影响因子：
4.8
通讯作者：
Y. Qiu;D. Groves;N. McNaughton;Liang-gen Wang;Taihe Zhou
中科院分区：
文献类型：
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作者：
Y. Qiu;D. Groves;N. McNaughton;Liang-gen Wang;Taihe Zhou
胶东黄金省位于华北克拉通东南边缘，黄金产量和资源量合计超过 900 吨。该省95%以上的金矿赋存于中生代花岗岩中，这些花岗岩在大约1950年左右时不时地侵入晚太古代变质基岩。 160–150 和 130–126 Ma。胶东半岛的矿床是世界上最大的花岗岩类金矿床省之一。胶东金矿以二级或三级附属断层中的块状含金石英脉形式出现，以及沿主要区域性断层的蚀变带中呈浸染状和网状矿化形式出现。矿化发生在先前存在的 D2 韧性剪切带的脆性再激活 (D3) 过程中。围岩蚀变主要是钾长石和绢云母，还有硫化物矿物和最靠近矿体的广泛硅化物。这种变化伴随着挥发物、铁、镁、钾、铷、银、砷、金、铋和锑的引入。金矿脉中基本金属的富集度普遍较低，但局部显着。大多数金矿床的金沉积发生在 250 至 350 °C 的温度下，矿石流体含有 CO2，计算出的盐度为 6-13 wt% NaCl 当量。昭冶矿带、西峡矿床和牟平乳山矿床具有相似的构造控制、蚀变模式、矿石矿物组合和稳定同位素特征。铅同位素数据表明，矿石阶段的铅受到其母岩的缓冲。昭冶带花岗岩类金矿床的放射性成因最强，西峡带绿岩类金矿床的放射性成因最少，牟平乳山带花岗岩类金矿床的放射性成因居于中间。胶东金矿省赵-冶、西峡和牟平-乳山带的金矿化似乎大致是同时发生的。 130–120 Ma，受到主岩和后金岩脉上的 SHRIMP U-Pb 锆石测年以及热液蚀变矿物和矿石的 Ar-Ar、Rb-Sr 和 K-Ar 测年的限制。这个早白垩世年龄比华北克拉通和扬子克拉通之间的秦岭-大别-苏鲁造山带超高压变质作用高峰期早约1亿年，位于黄金省以南约500公里处。然而，它与碰撞造山运动的伸展和折返阶段以及太平洋板块俯冲到欧亚大陆地壳之下重叠。胶东金矿床大部分赋存于华北克拉通边缘，也有部分赋存于两克拉通缝合带。与全球典型的造山矿脉金矿床相比，它们相对于太平洋板块的俯冲带明显向陆地倾斜。约的矿脉金矿床。 130-120Ma发生在郯庐断裂带两侧。现有数据支持金矿化与太平洋板块俯冲之间的时间联系。
The Jiaodong gold province, along the southeastern margin of the North China craton, has combined production and resources of >900 tonnes of gold. More than 95% of the gold in this province is hosted in Mesozoic granitoids, which intruded Late Archean metamorphic basement rocks episodically at ca. 160–150 and 130–126 Ma. The deposits of the Jiaodong Peninsula form one of the largest provinces of granitoid-hosted lode-gold deposits in the world. The Jiaodong gold deposits occur as massive auriferous quartz veins hosted in subsidiary second- or third-order faults, and as disseminated- and stockwork-style mineralization hosted in alteration zones along major regional-scale faults. Mineralization took place during brittle reactivation (D3) of pre-existing D2 ductile shear zones. Wall rock alteration is dominated by K-feldspar and sericite, with also sulfide minerals and extensive silicification closest to the orebodies. The alteration was accompanied by the introduction of volatiles, Fe, Mg, K, Rb, Ag, As, Au, Bi, and Sb. Enrichment of base metals in the gold lodes is generally low, although locally significant. Gold deposition took place at temperatures of 250 to 350 °C for most gold deposits, and the ore fluids are CO2-bearing and have calculated salinities of 6–13 wt% NaCl equiv. Deposits from the Zhao–Ye, Xixia, and Muping–Rushan belts have similar, if not identical, structural controls, alteration patterns, ore mineral assemblages, and stable isotope signatures. Lead isotope data indicate that the ore-stage leads were buffered by their host rocks. The granitoid-hosted gold deposits in the Zhao–Ye belt are most radiogenic, the greenstone-hosted deposits in the Xixia belt is the least radiogenic and the granitoid-hosted deposits in the Muping–Rushan belt have intermediate compositions. Gold mineralization in the Zhao–Ye, Xixia, and Muping–Rushan belts in the Jiaodong gold province appears to be broadly contemporaneously at ca. 130–120 Ma, as constrained by SHRIMP U–Pb zircon dating on host rocks and a post-gold dike, as well as by Ar–Ar, Rb–Sr, and K–Ar dating of hydrothermal alteration minerals and ores. This Early Cretaceous age is about 100 million years younger than the peak of ultra-high pressure metamorphism in the Qinling–Dabie–Sulu orogen between the North China and Yangtze cratons, and about 500 km south of the gold province. However, it overlaps with the extension and exhumation stage of the collisional orogeny, and the subduction of the Pacific plate beneath the Eurasian continental crust. Whereas the majority of the Jiaodong gold deposits occur on the margin of the North China craton, some also occur in the suture zone between the two cratons. They are significantly landward relative to the subduction zone of the Pacific Plate compared with typical orogenic lode-gold deposits globally. Lode-gold deposits of ca. 130–120 Ma occurred on both sides of the Tan-Lu fault zone. Available data favor a temporal link of gold mineralization with Pacific Plate subduction.