黑龙江金厂金矿岩浆作用及矿床成因

发布时间：2018-03-03 23:31

本文选题：金厂矿区　切入点：岩浆演化　出处：《中国地质大学(北京)》2017年硕士论文　论文类型：学位论文

【摘要】：黑龙江金厂金矿处于元古界太平岭隆起与中生代老黑山断陷的交接部位,属于兴凯湖地块南段。该区南邻华北板块北缘,北邻佳木斯、兴凯地块,位于中亚-蒙古构造域和滨西太平洋构造域交接复合区段。本论文在金厂金矿已有地质资料收集整理、野外调研及室内分析测试等基础上,分析区域地质背景和成矿条件,研究了金厂金矿床地质特征、成矿物质富集条件及流体特征,总结矿区岩浆岩演化规律和控矿因素等,探讨了矿床成因。野外及钻孔观测厘定了金厂矿区岩浆岩单位及其相互关系,结合年代学研究表明,金厂矿区与金矿化有关的岩性是燕山晚期的侵入岩,其岩性为闪长岩和花岗斑岩,而花岗斑岩是成矿岩体。两件闪长岩的锆石U-Pb年龄分别为110.59Ma、111.1Ma,一件含矿花岗斑岩年龄为111.1Ma,燕山晚期闪长岩为准铝质钙碱性,花岗斑岩多数为高钾钙碱性过铝质。主微量、稀土元素数据显示,闪长岩亏损Zr、Y、Yb等高场强元素,相对富集Rb、Th、U、K等大离子亲石元素,Eu弱负异常,轻重稀土分馏较弱,La/Yb比值平均7.49;LREE相对富集,HREE相对亏损,其配分模式与安第斯型钙碱性安山岩系列类似,而与岛弧钙碱性系列的平坦曲线区间有较大不同;花岗斑岩富集Rb、K等大离子亲石元素,亏损Nb、Ta、Ti等高场强元素,具有Nd、Hf正异常,稀土元素总量变化较大,轻重稀土分馏较晚期闪长岩强,La/Yb比值平均8.1,LREE相对富集,HREE相对亏损。与闪长岩相比,总体趋势几乎一致,显示两者具有演化关系。燕山晚期岩浆岩形成于安第斯型活动大陆边缘弧火山环境,岩浆可能源于受俯冲板片脱水交代的地幔楔的部分熔融,可能属于伊泽奈崎板块向中国东部大陆的俯冲的结果。流体包裹体数据表明金厂金矿区含矿热液以两个岩体为起始中心,沿两个方向,即北东向J-0至J-I和北西向J-XI至J-I运移,形成各矿(化)体。金厂金矿各类型矿体与岩浆活动具有密不可分的联系,燕山晚期花岗斑岩也是下一步找矿重点。
[Abstract]:Heilongjiang Jinchang gold deposit is located at the junction of the Proterozoic Taiping Ling uplift and the Mesozoic Laoheishan fault depression, belonging to the southern section of the Xingkai Lake block, which is adjacent to the northern margin of the North China plate to the south, Jiamusi to the north, and Xingkai block to the north. In this paper, the geological background and metallogenic conditions of Jinchang Gold Mine are analyzed on the basis of geological data collection, field investigation and laboratory analysis and test. The geological characteristics, ore-forming enrichment conditions and fluid characteristics of Jinchang gold deposit are studied, and the evolution law of magmatic rock and ore-controlling factors are summarized. In this paper, the genesis of the deposit is discussed. The magmatic rock units and their relationships in the Jinchang mining area are determined by field and borehole observations. Combined with the chronological study, it is shown that the lithology related to the gold mineralization in the Jinchang mining area is intrusive rock of the late Yanshanian period. Its lithology is diorite and granitic porphyry, while granitic porphyry is metallogenic. The zircon U-Pb age of the two diorites is 110.59 Ma-111.1 Ma, one ore-bearing granitic porphyry age is 111.1 Ma, and the late Yanshanian diorite is quasi-aluminous calc-alkaline. Most of the granitic porphyry are high potassium calc-alkaline peraluminite. The main trace and rare earth element data show that the diorite is depleted of high field strength elements such as zirconia YYb, and is relatively rich in large ion lithophile elements, such as RbBU, Th, U, K, etc., and the EU is weakly negative anomaly. The average La- / Yb ratio of light and heavy rare earth fractionation is 7.49% LREE relative enrichment and HREE relative depletion, and its partition pattern is similar to that of Andes calc-alkaline andesite series, but is different from the flat curve range of island arc calc-alkaline series. Granitic porphyry is rich in large ion lithophile elements, such as RbPU K, and depleted in high field strength elements such as Nbtadu, Ti and so on. It has a positive NdndHf anomaly, and the total amount of rare earth elements varies greatly. Compared with the diorite, the average La- / Yb ratio of heavy and heavy rare earth fractionation is 8.1% LREE relative enrichment and HREE relative depletion. Compared with diorite, the general trend is almost the same. The late Yanshanian magmatic rocks were formed in the Andes active continental margin arc volcanic environment, and the magma probably originated from the partial melting of the mantle wedge which was dehydrated and replaced by the subduction plate. The data of fluid inclusions indicate that the ore-bearing hydrothermal fluid in the Jinchang gold ore area starts at two rock bodies and migrates along two directions, namely, J-0 to J-I from NE to J-I and J-XI to J-I from NW to NW, which may be the result of subduction of the Isenazaki plate to the eastern Chinese continent. The ore bodies of Jinchang gold deposit are closely related to magmatic activities, and the granitic porphyry of late Yanshanian is the next step.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P618.51

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