| 南岭科学钻中与两种岩浆岩有关的矿床成矿系列——年代学、地球化学、Hf同位素证据 |
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| 引用本文：郭娜欣,陈毓川,赵正,吕晓强,刘珍,陈郑辉,曾载淋,李江东,张凤荣.2015.南岭科学钻中与两种岩浆岩有关的矿床成矿系列——年代学、地球化学、Hf同位素证据[J].地球学报,36(6):742-754. |
| DOI：10.3975/cagsb.2015.06.06 |
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| 基金项目:深部探测实验研究“南岭于都-赣县矿集区立体探测技术与深部成矿预测示范”(编号: SinoProbe-03-03);“南岭于都-赣县矿集区科学钻探选址预研究”(编号: 201011064-3/4/5);国家科技支撑计划课题(编号: 2011BAB04B07);国家自然科学基金项目(编号: 41372092)和中央公益性科研院所基金项目(编号: K1303) |
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| 中文摘要:南岭科学钻(SP-NLSD-1)位于南岭成矿带与武夷山成矿带的交汇部位——赣南银坑矿田。该钻孔总进尺2967.83 m, 钻遇了流纹岩、花岗斑岩、花岗闪长斑岩、辉长闪长玢岩等四种岩浆岩。流纹岩为银坑矿田新揭露的岩石类型, LA-ICP-MS锆石U-Pb定年表明其形成于(381.0±3.1) Ma, 补充完善了本区海西期岩浆活动的记录; 花岗斑岩、花岗闪长斑岩、辉长闪长玢岩的成岩时代为101.3~161.0 Ma, 为燕山期岩浆活动的产物。流纹岩与花岗斑岩具有相似的地球化学特征, 球粒陨石标准化稀土元素配分曲线为两翼近平坦的海鸥型, 有明显的Eu负异常, 显著富集大离子亲石元素, 轻微富集高场强元素, 锆石εHf(t)值分别为–10.8 ~ –7.1、–23.4 ~ –8.7; 花岗闪长斑岩与辉长闪长玢岩的地球化学特征相似, 球粒陨石标准化稀土元素配分曲线为右倾型, Eu负异常不明显, 显著富集大离子亲石元素, 轻微富集高场强元素, 花岗闪长斑岩的锆石εHf(t)值为–17.9 ~ –1.9。岩相学、年代学和地球化学研究结果表明, 流纹岩、花岗斑岩、花岗闪长斑岩、辉长闪长玢岩应该均为古元古代地壳物质重熔形成的壳源岩浆岩, 花岗闪长斑岩和辉长闪长玢岩在形成过程中可能继承了幔源物质。流纹岩与银坑矿田内已知的成矿作用无直接关系, 花岗斑岩与钨铋铀矿化有关, 花岗闪长斑岩与铜铅锌金银矿化有关。银坑矿田处于特殊的构造部位, 即南岭成矿带与武夷山成矿带交汇部位, 深达地幔的线型断裂和切入地壳的网格状断裂同时在此处发育, 不同的构造环境导致在燕山期形成花岗闪长斑岩和花岗斑岩, 分别对应铜铅锌金银矿化和钨多金属矿化, 形成两个相对独立的成矿系列。 |
| 中文关键词:南岭科学钻 岩浆岩 成矿系列 银坑矿田 |
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| Metallogenic Series Related to Two Types of Granitoid Exposed inthe Nanling Scientific Drill Hole: Evidence from Geochronology,Geochemistry and Hf Isotope |
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| Abstract:The Nanling Scientific Drilling-1 (NLSD-1), a subproject of the Sinoprobe Program called “Deep Exploration Technology and Experimentation”, is situated at the Yinkeng orefield in the junction of Nanling and Wuyi Mountains metallogenic belts. The drilling project, with footage of 2967.83 meters, revealed rhyolite, granite porphyry, granodiorite porphyry and pyroxene diorite porphyry. The rhyolite, a new type of granite occurring in the Yinkeng orefield, has a weighted mean age of (381.0±3.1) Ma, obtained by LA-ICP-MS zircon U-Pb dating, which fills the gap in Hercynian magmatism. The ages of granite, granodiorite porphyry and pyroxene diorite porphyry are (151.7±1.1) Ma, (160.3±0.8) Ma, (101.3±0.8) Ma and (161.0±4.1) Ma, respectively. Rhyolite and granite porphyry displayed similar geochemical characteristics. The chondrite-normalized REE patterns of rhyolite and granite porphyry exhibit the seagull form with obvious negative Eu anomaly, while primitive mantle-normalized patterns show enrichment of incompatible elements. Granodiorite and pyroxene diorite porphyry have similar geochemical characteristics and assume right-oblique chondrite-normalized and primitive mantle-normalized patterns. Zircon εHf(t) values of rhyolite, granite and granodiorite porphyry are in the range of –10.8 to –7.1, –23.4 to –8.7, –17.9 to –1.9, respectively. Petrographical, geochronological and geochemical studies indicate that all of the four types of magmatic rocks were derived from Paleoproterozoic crust. Evolving mantle-derived material took part in the formation of granodiorite and pyroxene diorite porphyry. Rhyolite is not directly related to mineralization known in the Yinkeng orefield; granite porphyry is related to W-Bi-U minerali-zation, and granodiorite porphyry has relationship with Cu-Pb-Zn-Au-Ag metallogeny. The Yinkeng orefield lies at a special tectonic position, i.e., at the junction of the Nanling metallogenic belt and the Wuyishan ore-forming belt, where linear fractures that cut deeply into the mantle and network faults that cut into the the crust are developed together. Different tectonic mechanisms resulted in the formation of two independent metallogenic series of granite-W-polymetallic mineralization and granodiorite-Au-Ag-Cu-Pb-Zn mineralization in Yanshanian period. |
| keywords:Nanling Scientific Drilling magmatic rocks metallogenic series Yinkeng ore field |
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