【作者】 张文钊；

【导师】 顾雪祥；

【作者基本信息】 中国地质大学（北京） ， 矿物学　岩石学　矿床学， 2010， 博士

【摘要】 华北板块北缘我国重要的金-多金属成矿带之一,该区经历了古生代多期板块俯冲和陆缘增生过程,构造-岩浆活动强烈,成矿地质条件优越。内蒙古毕力赫金矿床位于华北板块北缘古生代增生带内,是一个资源严重危机、濒临倒闭的国营矿山。通过对区域成矿地质条件综合分析,在矿山资源潜力评价和矿床地质特征详细研究基础上,认为矿床是形成于早古生代古亚洲洋俯冲碰撞,华北陆块北缘增生带之后,叠加晚古生代(二叠纪)陆缘火山-岩浆带背景的浅成低温-斑岩型金矿床。提出以针对性的地质科研引路,以斑岩型矿床成矿模型为指导,以有效的勘查方法技术组合配套使用为手段,适时并大胆设计验证工程,分期、分阶段有重点地加以实施的危机矿山找矿勘查增储的基本思路。通过工作,首次在毕力赫矿区外围新发现大型隐伏的独立斑岩型金矿床。矿床具有矿体规模大(单个矿体资源量超过20 t)、品位高(最高52.75×10-6)、变化小、埋深浅、金属矿物含量低(小于3%)、矿石简单、易采、易选等特点。研究表明,矿床形成于(271.3±1.7)Ma(MSWD=1.06),受NE和NW 2组构造交会部位及花岗闪长斑岩体控制,具有以斑岩体为中心,从深部到浅部、从中心到边部,由钾硅酸盐蚀变带→钾硅酸盐蚀变带+石英-绢云母化叠合带→石英-绢云母化带+中级泥化带→高岭土化带、蛋白石化带的环带特征。石英包裹体均一温度包括550℃和小于380℃的2个区间,盐度变化在0.88%～8.68%之间,H、O同位素组成指示主成矿期成矿热液为岩浆水与大气降水混合物。建立了矿床形成的描述型模型。该矿床的发现具有如下重意义:一是全国危机矿山接替资源勘查项目成功实施提供了典型示范;二是破解了本区作为典型的弧构造-岩浆环境却没有典型的大型斑岩型矿床发现这一长期困扰人们的科学谜题;三是对区域基础地质问题的重新认识提供了新线索;四是根据斑岩型矿床成群成带分布特点,为在本区及相似的环境内斑岩型矿床勘查提供了科学导向;五是基于本矿床发现的科学过程所总结出的找矿勘查思路和模型将对本区下一步找矿具有推广意义。更多还原

【Abstract】 The north edge of North-China Plate is one of important gold-polymetal metallogenic belts. It undergone poly-periods plate subduction and continental-margin accretion of Paleozoic era, had strong structure-magmatic activity and ascendant metallogenic geological condition. The Bilihe gold deposit locates in the Paleozoic accretion zones of north edge of North-China Plate, is a state-operated mine at resource conjuncture and close to bankrupt. Based on analysis of regional metallogenic geological condition, evaluation of mine resource potential and research of field geological character, the deposit was a epithermal-porphyry type gold deposit that formed after paleo-Asia ocean subducting collision and accretion of north-margin of North-China in Early Paleozoic, superimposed continental-margin volcanic-magmatic setting of Later Paleozoic (Permian Period). This paper took pertinency geological research as guidance, porphyry type model as direction, general technique methods as means, and prospecting exploration as basic way, discovered a large concealed porphyry type gold deposit around Bilihe mine firstly. The Bilihe gold deposit had character of large scale(more than 20 t per orebody), high grade(top to 52.75×10-6), small change, shallow embedding, low content of metallic mineral(less than 3%), simple ore, and easy mine and dressing. The mineralization age of the Bilihe deposit was (271.3±1.7)Ma(MSWD=1.06). The deposit was controlled by combined part of NE and NW strike structure and granodioritic porphyry units. The zoning character of the deposit from depth to shallow, from center to border was kali-silicate alteralization zone→kali-silicate alteralization zone+quartz-sericitization congruence zone→quartz-sericitization + intermediate argilization→kaolinization and opalizztion. The homogenization temperatures of quartz had two zones of 550℃and 380℃. The salinity was 0.88%~8.68%. The character of H, O isotope indicated that the mineralizing fluid was the mixture of magmatic water and meteroric water. The describing model was established in this paper. The discovery of the Bilihe deposit had important significances as follows: 1)provided a typical example for triumphant actualizing conjuncture mine succeed resources item; 2) explained a science topic that this area as a typical arc-structure-magma setting but no typical porphyry deposit; 3)provided new clew for regional fundamental geological study; 4)offered scientific lead for porphyry deposit founding in similar setting; 5)supplied new model for forecasting prospect in this area.更多还原