【作者】 周铸；

【导师】 杨立强；

【作者基本信息】 中国地质大学(北京) ， 矿物学、岩石学、矿床学， 2012， 硕士

【摘要】 胶西北望儿山金矿床是焦家式和玲珑式金矿的过渡类型,发育石英脉和蚀变岩两种矿化样式。论文以构造-流体-成矿系统思想为指导,综合运用现代矿床学、矿田构造学和计算机模拟等多学科方法技术,对望儿山金矿床控矿构造应力场进行了系统研究,探讨了其构造控矿模式,获得如下主要认识。1、金矿体的产出严格受NE向望儿山断裂带及其派生的NE向与近SN向次级断裂联合控制。断裂面附近主要赋存含金石英脉,其两侧往往发育蚀变岩型金矿化；在断裂产状由缓变陡处和不同方向断裂交汇部位,矿化强度大,富矿体一般产于断裂由近SN向变为NE向的转弯部位。2、多数矿体在其控矿断裂带内的延伸方向与其走向相同,只有少数较小矿体与倾向一致。矿体生长的这种不一致性除了受控矿构造应力场性质的制约外,成矿流体流动方式与流体通道的变化也是重要原因。单个金矿体的生长经历了个由管状到扁平状的变化过程,其走向上的延长远大于倾向上的延深。3、主控矿断裂带经历了从成矿初期左旋→成矿主期右旋→成矿晚期左旋的运动学性质变化,相应的力学性质经历了从扭性→张扭性→扭性→压扭性的变化过程。控矿构造应力场最大主压应力方位发生了大角度的顺时钟旋转：从成矿初期的NWW向转为NNE向,经成矿主期的NE向,到成矿晚期的NW向。4、成矿过程经历了多次不同温度、不同性质的构造-热液活动,其中至少有一期韧性活动、一期脆性活动,以及至少一期较高温的热液活动(450℃-600℃)和一期较低温的热液活动(300℃左右)。5、金矿床是构造-流体耦合成矿的产物。成矿前NNW向的挤压构造应力场促使在不同地质体的接触部位形成断裂,使之成为成矿流体上升的有利通道,并在下盘围岩中形成SW向侧伏的容矿空间。主成矿期至少经历了左行和右行两期不同的张性构造活动,变形温度为300℃-400℃左右；控矿断裂的韧性变形与脆性变形构造叠加／转换是金大量沉淀富集的最重要构造环境。成矿后期构造环境体现出高强度挤压特征,且变形温度较高,约450℃-600℃更多还原

【Abstract】 The Wangershan gold deposit, situated in the Jiaodong area, is the transition onethat between Jiaojia and Linglong type, and the mineralization is characterized byquartz vein and alternation types. Using the mineral deposit, structural andmathematical simulation methods, the dissertation done the systematic ore-controllingtectonic stress filed research, discussed the ore-controlling structural model. Theresults are as following:1. The occurrence of the ore bodies are mainly controlled by the NE-trendingWangershan shear zone and its secondary faults, and the nearly N-S-trending faults.The mineralization that occurred in the faults are characterized by the quartz veintypes, while in wall rock, it turns to be alternation type. The occurrence change parts,and the intersections between different trending faults are the favorable locations ofmineralization.2. Most of the ore bodies that occurred in the faults are characterized by samestriking to the ore-hosting faults, while few are different which indicate the growth ofthe ore bodies is controlled by the combination of ore-controlling stress field,ore-forming fluid flow pattern, and the occurrence change of faults. The growprogress of ore bodies are characterized by early tubular and late flat which lengthgreater than depth.3. The major ore-controlling share zone have experienced the sinistral, dextral,and sinistral shear movements, from early to late mineralization stage, correspondingto the mechanical properties changed from twisting to transtensional and back totwisting then transpressional. The orientation of maximum principal stress havechanged from the NWW of early mineralization stage, to NNE or NE of the mainstage, and last to the NW of the late stage.4. The EBSD analysis of quartz showed that the mineralization have experiencedseveral hydrothermal tectonic events that including at least one stage of ductile shearand brittle shear, and at least one stage of high temperature hydrothermal activity(450600) and another lower temperature hydrothermal activity (300).5. The NNW direction compressive tectonic stress field lead to the formation offaults that at the connection parts of different geological bodies which are thefavorable hydrothermal pathways and mineralization positions. The ore-controllingfaults have experienced early sinistral and late dextral shear deformation. Numericalsimulations showed that the translation/superimposition of tectonic regime from"ductile shear" to “brittle shear” was the most important tectonic environment for thegold enrichment. The tectonic environment in the late mineralization stage showedhighly compressional with high deformation temperature (450600).更多还原