黑龙江省完达山地区先锋北山金矿床地质特征及成因研究

发布时间：2018-09-08 20:42

【摘要】：黑龙江省先锋北山金矿床位于完达山地块西南端，地处环太平洋成矿带，属于锡霍特—阿林超地体增生部分。完达山地块位于兴凯地块以北，佳木斯地块以东地区。该区域主要经历了印支期-燕山期强烈的构造岩浆活动，这两期构造岩浆演化作用为区内成矿作用提供了有利的地质条件。本文大量收集、分析整理区域及矿区地质资料基础上，对先锋北山金矿区进行野外地质调查，对采集样品进行室内综合分析，以此深入研究矿床地质特征、矿床成因类型及成矿构造环境。 先锋北山金矿床矿体主要赋存在皮克山组上段酸性火山岩中，受EW向弧形断裂带控制，在已发现的三条矿化带中共探明19条矿体，矿体多呈脉状、透镜状产出，矿石具有脉状、网脉状、细脉浸染状构造。根据矿石矿物生成顺序可划分热液期和表生氧化物期，其中热液期可划分为石英-黄铁矿，石英-自然金两个成矿阶段。围岩蚀变主要有硅化、绢云母化、碳酸盐化及青磐岩化等。 主成矿阶段包裹体类型主要为气液两相包裹体，属NaCl-H2O流体体系，均一温度范围为105.5～277.8℃，盐度范围为0.7～5.4wt％NaCleqv,密度范围为0.76～0.94g/cm3，成矿压力在8.92～19.30MPa之间，成矿深度为0.89～1.41km。说明主成矿阶段的流体具中低盐度、低温、成矿压力较低的特点，综合分析认为，先锋北山金矿床属于浅成低温热液型金矿床。 先锋北山赋矿流纹岩、流纹质角砾岩和岩屑晶屑凝灰岩属于碱性系列岩石，LREE相对富集，HREE相对亏损，轻重稀土元素分异明显，具有明显的负铕异常，富集大离子亲石元素（LILE），亏损高场强元素（HFSE），Rb和Sr，Ti和Zr、Nb和Ta等比值显示出壳源特征。矿区内花岗闪长岩属于过铝质高钾钙碱I型花岗岩，LREE相对富集，HREE相对亏损，铕异常不明显，富集大离子亲石元素（LILE）Rb、Th、K，亏损高场强元素（HFSE）Nb、Ta、P、Ti等；石英闪长玢岩LREE相对富集，HREE相对亏损，无铕异常；富集大离子亲石元素（LILE）Rb、Th，K等，亏损高场强元素（HFSE）Nb、Ta、P、Ti等地球化学特征显示其属于准铝质高钾钙碱性岩石。 矿区内发育的花岗闪长岩的锆石U-Pb年龄为128.3±2.6M，石英闪长玢岩的锆石U-Pb年龄为108.48±0.99Ma，，赋矿流纹岩及流纹质角砾岩锆石U-Pb年龄分别为为116.98±0.47Ma和116.98±0.42Ma，结合矿区侵入接触关系，限定先锋北山金矿形成于早白垩世晚期116.98±0.47Ma和108.48Ma之间。 根据对矿区赋矿围岩及脉岩的岩石地球化学特征，运用火山岩构造判别图解，确认先锋北山金矿形成于碰撞后构造环境，结合成岩成矿时代，认为先锋北山金矿床的形与太平洋板块俯冲和完达山地块与佳木斯地块的拼合有着密切的关系，系古太平洋构造体制由挤压变为伸展背景下的产物。
[Abstract]:Xianfeng Beishan gold deposit in Heilongjiang Province is located at the southwest end of the Wandashan massif, located in the Pacific Rim metallogenic belt, and belongs to the accretive part of the Sihott-Arin superterrane. The Wandashan block is located north of Xingkai block and east of Jiamusi block. The tectonic magma activity in this area mainly experienced from Indosinian to Yanshanian epoch, and the evolution of tectonic magma in these two periods provided favorable geological conditions for mineralization in the region. On the basis of collecting, analyzing and arranging the geological data of the area and mining area, this paper makes a field geological survey on Xianfeng Beishan Gold Mine area, and carries out an indoor comprehensive analysis of the collected samples in order to further study the geological characteristics of the deposit. Genetic types of ore deposits and metallogenic tectonic environment. The ore bodies of Xianfeng Beishan gold deposit mainly occur in the acid volcanic rocks of the upper Pikeshan formation, controlled by the EW arc fault zone. 19 ore bodies have been discovered in the three discovered mineralization zones. The orebodies are mostly vein-like, lenticular and veinlike. Reticular veins, vein-like structures. According to the ore mineral formation sequence, the hydrothermal stage and the superoxide stage can be divided into two metallogenic stages: quartz pyrite and quartz natural gold. The main alteration of surrounding rock is silicification, sericite, carbonization and Qingwanglianlitization. The main types of inclusions in the main metallogenic stage are gas-liquid two-phase inclusions, which belong to NaCl-H2O fluid system. The homogenization temperature ranges from 105.5 鈩

本文编号：2231643