冀东峪耳崖金矿床成因研究

发布时间：2018-06-09 01:21

  本文选题：峪耳崖金矿 + 矿床地质　； 参考：《中国地质大学(北京)》2017年硕士论文

【摘要】：峪耳崖金矿位于冀东地区,大地构造上属于华北克拉通北缘中段,燕山褶皱带东部与山海关隆起相交的位置,马兰峪复式背斜的北侧区域。矿区内的地层大致可以分为两个部分,下部为太古宇变质岩系,上部以中元古界碳酸盐岩为主的沉积地层;构造发育,控矿断裂主要呈北东、北北东向;岩浆岩主要以燕山期峪耳崖花岗岩为主,并构成其主要赋矿岩石。矿石以石英-多金属硫化物脉型、石英细脉浸染型为主。矿石矿物主要包括黄铁矿、黄铜矿、闪锌矿、方铅矿、镍黄铁矿等,脉石矿物主要有石英、长石、绢云母、绿泥石、方解石等。金主要以裂隙金、包裹金的状态赋存于硫化物(主要为黄铁矿)中,少量分布于石英的裂隙中。近矿蚀变主要为硅化、黄铁矿化、绿泥石化、绢云母化。成矿阶段从早到晚依次划分为乳白色石英-黄铁矿阶段、烟灰色石英-多金属硫化物阶段、细粒石英-黄铁矿阶段、脉状方解石阶段;其中第二、三为主要的金成矿阶段。主成矿期矿脉包裹体水δD值范围为-66‰~-112‰,计算的包裹体水δ18O值范围为5.4‰~7.2‰,花岗岩包裹体水δD值范围为-63‰~-104‰,计算的包裹体水δ18O值范围为3.3‰~5.8‰;主成矿期方解石δ13CPDB值介于-3.7‰~-6.8‰,δ18OSMOW值介于9.6‰~18.8‰;矿石黄铁矿δ34S的值在2.5‰~4.5‰之间。以上同位素特征指示成矿流体、物质均来自岩浆体系。Pb同位素特征指示成矿物质主要来自下地壳。矿石稀土元素特征显示成矿与花岗岩密切相关。峪耳崖花岗岩的SiO2含量的变化范围为74.34%~75.78%,平均含量75.17%。Al2O3含量为13.22%~14.68%,平均为13.60%;A/CNK值位于0.98~1.06之间,平均1.02;表现出过铝质的特征。w(TFe2O3)/w(MgO)值位于3.26~7.36之间,平均5.66,值较低;P2O5含量很低;总碱(Na2O+K2O)含量较高,平均8.70%。富集Rb、Th、U、K、La、Ce等元素,亏损P、Ti等元素;δEu值在0.42~0.63之间,平均为0.51;岩体稀土球粒陨石配分图呈现出轻、重稀土分馏明显,右倾的特征。综合这些特征判断,峪耳崖花岗岩可能主要来自于下地壳的重熔。金矿形成于下地壳的重熔作用产生的酸性岩浆的演化晚期。矿床为典型的岩浆热液型金矿床。
[Abstract]:The Yuerya gold deposit is located in the eastern part of Hebei Province, and belongs to the middle segment of the northern margin of North China Craton, the position of intersection between the eastern Yanshan fold belt and Shanhaiguan uplift, and the northern side of the Malanyu complex anticline. The strata in the mining area can be roughly divided into two parts, the lower part is the Archean metamorphic series, the upper part is the sedimentary stratum of the middle Proterozoic carbonate rock, the structure is developed, the ore-controlling fault is mainly NNE, NNE; The magmatic rocks are mainly Yanshanian Yuerya granite and the main ore-hosting rocks. The ore is quartz-polymetallic sulphide vein type, quartz vein disseminated type. Ore minerals mainly include pyrite chalcopyrite sphalerite galena nickel pyrite etc. Gangue minerals mainly include quartz feldspar sericite chlorite calcite and so on. Gold is mainly fissured gold, the state of wrapped gold occurs in sulfides (mainly pyrite), and a small amount of gold is distributed in the fissures of quartz. Near-ore alteration is mainly silicification, pyrite, green mud petrifaction, sericite. The metallogenic stage is divided into the milky quartz-pyrite stage, the smoke gray quartz-polymetallic sulfide stage, the fine grain quartz-pyrite stage and the vein calcite stage from early to late, the second and third of which are the main gold metallogenic stage. The range of 未 D value of ore-vein inclusions is -66 鈥，

本文编号：1998143