胶东新立金矿控矿构造特征和矿化强度分布

发布时间：2018-05-27 05:05

本文选题：构造 + 矿化强度　；参考：《中国地质大学(北京)》2015年硕士论文

【摘要】：胶东半岛以焦家型金矿为主,其形成于120 Ma左右。焦家型金矿由于区域断裂下盘水岩反应而形成广泛的蚀变和矿化。研究认为这些金矿的连续矿化带和贫矿带受区域断裂倾向、倾角改变形成的膨胀区所控制,而在连续的矿化带内发生强烈的水岩反应。但是,对连续矿化带内构造特征和水岩反应如何影响矿化强度的研究较为局限。本次对胶东新立金矿进行详细的野外观察,查明三山岛-仓上断裂(F1)在大尺度控制新立金矿矿体分布。对主断裂(F1)、次级断裂(F2)断层泥进行X射线粉晶衍射分析得出,F1断层泥主要由高岭石和石英组成,含少量黄铁矿、伊利石和石膏,F2断层泥含有大量的石英和绢云母以及少量高岭石和伊蒙混层。根据矿物共生关系和相图,高岭石是绢云母反应形成的,伊利石由高岭石转化所致,伊蒙混层是高岭石转化为伊利石的中间产物,矿物之间的转化反映了aK+或aK+/aH+连续减小。F1断层泥的粒度分析得出其分布曲线呈单峰型、复式双峰和三峰型,其粒度分布分维值为2.61-2.82,而F2断层泥仅呈简单双峰型,分维值为2.46-2.52,表明F1断层泥组份经历颗粒旋转磨蚀阶段,F2断层泥组份处于约束碾磨阶段。F1断层泥中大量的黏土矿物、高度分化的颗粒粒度以及定向的显微构造导致低的横向渗透性,导致矿体只产出在F1下盘,F2为成矿后构造。通过新立金矿矿体参数的分布及矿化样式统计,应用分形模型和间隙度方式量化金浓度空间分布特征,进而查明矿化强度分布及控制因素。在连续矿化带内,各穿脉具有以下特征,(1)F1倾向、倾角改变与矿体厚度和线金属量无关;(2)穿脉内强烈矿化区域通常是远离主断裂面(通常靠近主断裂面处裂隙发育);(3)蚀变带内含金硫化物团块和脉通常具有一定的不规则和溶蚀边;(4)阈值(分割低金浓度、低分维值和高金浓度、高分维值的浓度)和间隙度(评估金浓度空间分布均匀性的参数)分别与矿体厚度和线金属量呈正相关和负相关。综合以上现象,我们认为连续矿化带内水岩反应是影响矿化强度的重要因素。随着矿化等级增加,阈值增加,间隙度减小表明控制金沉淀的水岩反应被增强且空间更加均匀分布。这些现象表明连续矿化带控制金沉淀的水岩反应具有空间自组织机制特征,这种机制已经被广泛的应用到不同地质作用过程。
[Abstract]:Jiaodong Peninsula is dominated by Jiaojia type gold deposit, which was formed at about 120 Ma. Jiaojia-type gold deposits are widely altered and mineralized due to the reaction of regional faults. It is considered that the continuous mineralization zones and the ore-poor zones of these gold deposits are controlled by the regional fault tendency and the swelling zone formed by the change of dip angle, while the strong water-rock reaction occurs in the continuous mineralization zone. However, the study of the structural characteristics in the continuous mineralization zone and how the water-rock reaction affects the mineralization intensity is limited. The detailed field observation of Xinli gold deposit in Jiaodong shows that Sanshando-Cangshang fault F1) controls the distribution of Xinli gold ore body on a large scale. The X-ray powder diffraction analysis of fault gouges from main faults and secondary faults shows that the fault gouges are mainly composed of kaolinite and quartz, and contain a small amount of pyrite. Illite and gypsum F 2 fault gouges contain a large amount of quartz and sericite, and a small amount of kaolinite and immonitic mixes. According to the mineral symbiosis relationship and phase diagram, kaolinite is formed by sericite reaction, Illite is caused by kaolinite transformation, and the immonitic layer is the intermediate product of kaolinite conversion to Illite. The transformation between minerals reflects the grain size analysis of fault gouge with continuous decrease of AK or AK / AH. The distribution curve is of single peak type, double peak type and three peak type. The fractal dimension of grain size distribution is 2.61-2.82, while that of F2 fault gouge is simple double peak type. The fractal dimension is 2.46-2.52, which indicates that the gouge components of F1 fault gouge are in the confined grinding stage and a large number of clay minerals are found in the gouge of F _ 1 fault. Highly differentiated particle size and directional microstructures lead to low transversal permeability, resulting in orebodies occurring only in F1 footwall and F2 as post-metallogenic structures. Based on the distribution of orebody parameters and mineralization patterns of Xinli gold deposit, the spatial distribution characteristics of gold concentration were quantified by fractal model and gap degree, and the distribution of mineralization intensity and the controlling factors were found out. In the continuous mineralization zone, each perforating vein has the following characteristics: 1. The change of inclination angle is not related to the thickness of orebody and the amount of line metal) the strong mineralization area in the vein is usually far away from the main fault surface (usually near the main fault surface where the fissures are developed) and the au sulphide masses and veins in the alteration zone usually have a certain amount of gold sulfides and veins. Irregular and corroded edges / 4) threshold (partition of low gold concentration, The low fractal dimension and high gold concentration and the concentration of high fractal dimension are positively and negatively correlated with the thickness of ore body and the linear metal content, respectively, and the gap degree (the parameter to evaluate the uniformity of gold concentration spatial distribution). In view of the above phenomena, we think that the water-rock reaction in the continuous mineralization zone is an important factor affecting the mineralization intensity. With the increase of mineralization grade and the increase of threshold value, the decrease of gap degree indicates that the water-rock reaction controlling gold precipitation is enhanced and the spatial distribution is more uniform. These phenomena indicate that the water-rock reaction controlled by gold deposits in the continuous mineralization zone has the characteristics of spatial self-organization mechanism which has been widely used in different geological processes.
【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】：2015
【分类号】：P618.51

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