论文部分内容阅读
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。
Nanling Scientific Drill (SP-NLSD-1) is located at the intersection of Nanling metallogenic belt and Wuyishan metallogenic belt - silver pit mine in southern Jiangxi. The drilling footage is 2967.83 m in total, drilling four types of magmatic rocks such as rhyolite, granite porphyry, granodiorite porphyry and gabbro diorite. The rhyolite is a new type of rock exposed in the Yinkeng orefield. The LA-ICP-MS zircon U-Pb dating indicates that it formed at (381.0 ± 3.1) Ma, which complements the record of the Hercynian magmatism in this area. The diagenetic ages of granitic dioritic porphyrite, granodiorite porphyrite and diorite diorite porphyrite are 101.3 ~ 161.0 Ma, which are the products of magmatism in Yanshan Period. Rhyolite and granite porphyry have similar geochemical characteristics. The normalized rare earth element distribution curve of chondrite is a seagull with two flanks and a flat flank. It has obvious Eu negative anomalies, enriched in large ion lithophile elements and slightly enriched The εHf (t) values of high field strength elements and zircons are -10.8 ~ -7.1 and -23.4 ~ -8.7, respectively. The geochemical characteristics of granodiorite porphyry feldspar and diorite porphyrite are similar. Chondrite meteorites standardized rare earth The elemental distribution curve is right-leaning and the Eu negative anomaly is not obvious. It is enriched in LILE and slightly enriched in high-field-strength elements. The εHf (t) value of zircon from granodiorite porphyry is -17.9 ~ -1.9 . The results of petrography, geochronology and geochemistry show that rhyolite, granite porphyry, granodiorite porphyry and gabbro diorite should all be crustal magma formed by remelting of Paleoproterozoic crustal materials The rocks, granodiorite porphyry and gabbro diorite porphyry may inherit the mantle source during their formation. There is no direct relationship between rhyolite and the known mineralization in the Yinkeng orefield. The granite porphyry is related to the mineralization of tungsten, bismuth and uranium. The granodiorite porphyry is related to the mineralization of Cu, Pb, Zn and Ag. The Yinkeng orefield is in a special tectonic part, that is, the junction of the Nanling metallogenic belt and the Wuyishan metallogenic belt. The linear faults in the deep reach of the mantle and the grid-like faults cut into the crust develop here at the same time. Different tectonic settings lead to In the Yanshanian period, granodiorite porphyry and granite porphyry are formed, corresponding to Cu, Pb, Zn and Au mineralization and tungsten polymetallic mineralization, respectively, forming two relatively independent metallogenic series.