柴胡栏子金矿目前保有储量已不能满足金矿持续生产的需要,应开展进一步深边部找矿工作.基于成因矿物学理论,采用矿物地球化学方法对矿区内黄铁矿化学成分标型特征进行了研究.结果表明:(1)黄铁矿中Co/Ni元素比值和As-Co-Ni元素三角图解显示,柴胡栏子金矿黄铁矿成因较复杂,受建平群、区域变质和岩浆热液活动等诸多因素的制约;(2)黄铁矿中Au/Ag和S/Se等特征值显示出岩浆热液特征,表明成矿流体的形成主要与矿区岩浆活动有关;(3)黄铁矿晶体中的金以纳米微粒金存在,因纳米金具有较强的迁移性以及被碳质吸附的特性,因此矿区含碳质较高的绢云母化含石墨斜长片麻岩是最有利的赋矿围岩.依据矿区黄铁矿成分特征,结合区域地质、矿区地质及蚀变带特征,得出柴胡栏子金矿形成受诸多因素的联合控制,矿区基性岩脉侵入活动是重要的因素,基性岩脉不仅带来部分矿源,而且其携带的岩浆热液使建平群中的金(这部分金已在区域变质过程中得到活化)进一步活化而进入成矿流体中,在NNE向挤压构造带和NWW向张性裂隙构造带的交会部位,成矿流体与围岩广泛交代形成以蚀变岩型为主的金矿床,矿区东南部深部建平群老变质岩地层具有较好的找矿前景,尤其是绢云母化含石墨斜长片麻岩中的构造发育部位.

Based on the physical parameters of the rocks (ores) and the genetic types of ore deposits, the geophysical exploration models have met issues of multiple solutions for deep prospecting prediction. It is necessary to find recognizable geological targets with high precision by geophysical methods. The ore prospecting practice over past years has demonstrated that the ore field tectonic deformation lithofacies belt is an outstanding target and significant prospecting results have been achieved. At present, the geophysical exploration work of large-scale mining area is heavy, while that of medium-scale ore field is limited, and both of them lack the strategic guidance at different levels. In order to establish the geophysical identification mark of the tectonic deformation lithofacies belt in ore field, it is necessary to clarify the complex time-space relationship between geology and geophysics, and strengthen the connection between geomechanics and geophysical exploration methods. In this paper, a method of processing and interpreting geophysical information at different levels is proposed. According to the "✳-shaped" structural features of the tectonic traces in the study area and the characteristics of the periodic development of the tectonic system, the geophysical exploration data of different scales and dimensions are analyzed from the two levels of ore field and deposit, and the information of tectonic deformation lithofacies belts is extracted. The specific operation procedures are as follows: (1) Making an area geophysical exploration within the scope of the ore field, interpreting the "✳-shaped" fault structure system, and then selecting the tensional and tension-torsional ore-bearing fault structures and predicting the prospecting direction; (2) Laying out large-deep geophysical profiles in the ore-bearing fault zone, analyzing the denudation degree and burial depth, and delineating the location of prospecting targets based on the geochemical exploration information. The application results of this method in the Chaihulanzi gold field in Chifeng, Inner Mongolia is introduced. The "✳-shaped" distribution of structural traces of the Neocathaysian tectonic system are interpreted from the geophysical data of the ore field, and then it is confirmed that the NNW and NWW trending tectonic deformation lithofacies belts are the main ore-bearing structural belts and there is a spatio-temporal sequential relationship between them in the two mining areas. These findings, provides a basis for deep ore prospecting and prediction.

基于岩(矿)石物性参数和矿床成因类型建立的地球物理勘查模型,在深部找矿预测中出现了多解性的问题,急需找到地球物理方法能够高精度识别的地质体目标.多年的找矿实践表明,矿田构造变形岩相带就是一个重要的选项,业已取得显著的找矿效果.目前,大比例尺的矿区地球物理勘查工作较多,而中比例尺的矿田地球物理研究比较薄弱,且两者均缺乏分层次的战略指导.为了建立矿田构造变形岩相带的地球物理判别标志,需要厘清地质与地球物理的复杂时间-空间关系,加强地质力学与地球物理勘探方法的联系.文章提出分层次处理和解释地球物理信息的思路,即根据研究区构造形迹的"米字型"结构特征和构造体系阶段性发展的特点,从矿田、 矿床2个层次解析不同尺度-维度的地球物理勘查资料,提取构造变形岩相带信息.具体操作流程为先在矿田范围内布置面积性物探,解译"米字型"断裂构造系统,选定张性和张扭性含矿断裂构造,预测找矿方向;再在含矿断裂带布置大深度物探剖面,分析剥蚀程度和埋藏深度,结合化探信息圈定找矿靶区位置.文中以内蒙古赤峰柴胡栏子金矿田为例,介绍该方法的找矿应用效果.首先从矿田地球物理资料中解译出新华夏构造体系"米字型"分布的构造形迹,然后在2个矿区内确认了北北西和北西西走向的构造变形岩相带是主要的含矿构造带,且两者之间存在时空上的先后关系,为深部找矿预测提供了依据.

华北克拉通北缘大规模金成矿作用集中发生在印支期和燕山期,有关更早期的金成矿作用研究较少.柴胡栏子金矿是赤峰-朝阳金矿集区西部典型的热液型金矿床,为探讨其成矿时代,本文对矿区内与矿体时空关系密切的中性脉岩进行了LA-ICP-MS锆石U-Pb同位素定年,得到矿区成矿前闪长玢岩的年龄为(332.4±1.7)Ma,成矿后闪长玢岩的年龄为(257.1±1.6)Ma,闪长岩脉的年龄为(266.1±0.6)Ma.结合前人所测矿区截断矿体的闪长玢岩年龄(290.9±4.3)Ma,将柴胡栏子金矿的成矿时代限定在(332.0±1.7)～(290.9±4.3)Ma,金矿化发生在中石炭世-早二叠世,是华北克拉通北缘少见的晚古生代金成矿事件,推测该金矿的形成与华北克拉通北缘陆-弧碰撞后构造体制由挤压向拉张的环境转换有关.

柴胡栏子金矿位于中国东部大兴安岭北北东向构造带与华北地块北缘近东西向构造带的交汇部位.该交汇区经历了多期构造-岩浆活动,产出了柴胡栏子、莲花山、红花沟等多个大-中型金矿床.航磁和遥感资料解译结果表明,矿田内发育北北西向、北西西向、北北东向和北东东向共4个方向的构造形迹,呈现"米字型"结构的展布特点,分别控制了晚古生代岩浆岩(脉岩)和主要金矿床的展布.在柴胡栏子金矿区,4个方向的构造形迹也组成了"米字型"结构,控制了矿体(矿化带)和化探异常的展布.矿田和矿区级别的构造形迹均呈现"米字型"分布特点,是新华夏构造体系分级控岩控矿规律的具体表现.上述认识为矿床成因研究和矿田成矿预测提供了重要的依据.