陕西省柞水—山阳矿集区冷水沟铜钼矿床地质特征及找矿预测

发布时间：2018-08-25 19:04

【摘要】：柞水-山阳矿集区燕山期中酸性小岩体出露广泛,且围绕这些中酸性小岩体普遍发育有斑岩-矽卡岩型Cu-Mo矿化,如池沟Cu-Mo矿、小河口Cu矿、冷水沟Cu-Mo矿等。近年来对于该矿集区地质矿产方面的研究多集中在地层、构造环境的划分,岩体的地球化学和同位素特征、形成时代、岩浆源区等,而对于典型矿床(点)的系统研究不够。本次选取冷水沟铜钼矿床进行深入研究,通过细致的野外地质调查、显微鉴定、岩石地球化学测试分析、Nd-Sr同位素测试、流体包裹体测试等工作,总结地质与蚀变特征,划分成矿阶段,探讨冷水沟小斑岩体成岩构造背景和岩石成因,建立本区及周围找矿模式,进行找矿预测并提出找矿标志。取得主要成果如下:①冷水沟铜钼金矿床矿化类型可分为斑岩型、矽卡岩型和构造蚀变岩型,从冷水沟斑岩体到外围表现为斑岩型铜钼矿(洞子沟和孔雀垭矿段)、矽卡岩型铜矿(双龙寨和银洞垭矿段)、构造蚀变岩型金银矿(南沟和徐家湾矿段),构成了完整的斑岩成矿系统。②冷水沟斑岩体富硅、富钾、准铝质,属I或I→A型过渡型的高钾钙碱-钾玄性系列,具壳幔混合的特征,这与典型的成矿斑岩体类似。该岩体及围岩蚀变较强,具有较好的空间分带性,但对称性不明显,自斑岩体向外蚀变类型依次为钾化-绢英岩化-矽卡岩化、角岩化。根据冷水沟铜钼矿床矿物包裹关系和脉体穿插特征,认为成矿期分为四个阶段,分别为磁铁矿阶段、早期热液阶段、中期热液阶段和晚期热液阶段。铜矿主要形成于早中热液期。③流体包裹体研究表明,本区斑岩型、矽卡岩型矿石包裹体主要为气液两相包裹体,偶见含NaCl晶体的包裹体,成矿流体属中温、中盐度,成矿过程中流体发生了沸腾作用。氢氧同位素组成表明成矿流体主要来自于岩浆热液,有少量大气降水的参与,黄铁矿中硫同位素组成显示,以幔源硫为主。④根据岩体的岩石地球化学和Nd-Sr同位素特征,判断成岩成矿构造背景为燕山早中期陆内碰撞挤压背景下的局部伸展环境。斑岩体在形成时经历了部分熔融,轻微同化混染和结晶分异作用,且其地球化学特征显示为壳幔混合源。⑤根据矿石特征、蚀变特征、成矿机制等建立了冷水沟铜钼矿的成矿模式、总结了找矿标志。指出区内在找矿过程中应注重小斑岩体、断裂交汇部位、蚀变强烈地段和Cu-Mo-Ag-Au-As元素组合异常。根据冷水沟斑岩型铜钼矿床的研究,结合区内和区域的地物化遥资料,进行了找矿预测,认为在区内找矿应该将重点放在Cu-Mo异常和激电异常组合较好的银洞垭和Cu-Mo异常范围较大的洞子沟一带。
[Abstract]:The intermediate acid small rock masses of Yanshanian are widely exposed in the Zhashui-Shanyang ore concentration area, and the porphyry skarn type Cu-Mo mineralization is generally developed around these intermediate acid small rock bodies, such as the Cu-Mo deposit in Zhigou, the Cu deposit in Xiaohekou and the Cu-Mo ore in Lengshuigou. In recent years, the research on geological and mineral resources in this ore concentration area is mainly focused on stratigraphy, division of tectonic environment, geochemistry and isotopic characteristics of rock mass, age of formation, source of magma and so on, but the systematic study of typical deposits (points) is not enough. Through detailed field geological investigation, microscopic identification, rock geochemistry analysis, Nd-Sr isotopic test, fluid inclusion testing and so on, the geological and alteration characteristics are summarized. The diagenetic tectonic setting and petrogenesis of the Lianggou small porphyry are discussed, the prospecting model in this area and its surrounding is established, the prospecting prediction is carried out and the prospecting criteria are put forward. The main results obtained are as follows: the mineralization types of the Shuanggou Cu-Mo gold deposit can be divided into porphyry type, skarn type and structural alteration type. The porphyry copper-molybdenum deposits (Dongzigou and Kongqiya sections), skarn copper deposits (Shuanglongzhai and Yindongya sections) and structural altered rock type gold and silver deposits (Nangou and Xujiawan sections) are formed from the Lengguogou porphyry to the periphery. The integrated porphyry ore-forming system .2 chilled gully porphyry is rich in silicon, Kalium-rich, quasi-aluminous, belongs to I or I A type transition type high potassium calcium alkali-potassium metaphysical series, with the characteristics of crust and mantle mixing, which is similar to typical ore-forming porphyry. The alteration of the rock mass and surrounding rock is stronger and has better spatial zonation, but the symmetry is not obvious. The outward alteration types of the porphyry are potash, sericite, skarn and hornstone. According to the mineral encapsulation relationship and the intercalation characteristics of veins in the Lianggou Cu-Mo deposit, the metallogenic period is divided into four stages: magnetite stage, early hydrothermal stage, middle hydrothermal stage and late hydrothermal stage. The ore inclusions of porphyry type and skarn type in this area are mainly gas-liquid two-phase inclusions, the inclusions containing NaCl crystals are occasionally found, and the ore-forming fluids belong to medium temperature and medium salinity, and the ore inclusions are mainly formed in the early and middle hydrothermal stage of the ore inclusions, and the ore inclusions of skarn type and skarn type in this area are mainly gas-liquid two-phase inclusions. Fluid boiling occurs during mineralization. The composition of hydrogen and oxygen isotopes indicates that the ore-forming fluids are mainly derived from magmatic hydrothermal fluids, with the participation of a small amount of atmospheric precipitation. The sulfur isotopic composition in pyrite shows that mantle sulfur is the main source of sulfur according to the petrogeochemical and Nd-Sr isotopic characteristics of the rock mass. It is concluded that the diagenetic and metallogenic tectonic setting is a local extensional environment in the early and middle Yanshanian intracontinental collision and compression setting. The porphyry body experienced partial melting, slight assimilation and differentiation during its formation, and its geochemical characteristics showed that the crust and mantle mixed source .5 was altered according to the ore characteristics. The ore-forming model of Lenggou copper-molybdenum deposit is established and the prospecting criteria are summarized. It is pointed out that attention should be paid to small porphyry bodies, fault intersections, strong alteration areas and Cu-Mo-Ag-Au-As element assemblage anomalies in the prospecting process. Based on the study of the Lianggou porphyry copper-molybdenum deposit and the geophysical and chemical remote data of the area and the region, the prospecting prediction is carried out. It is considered that the ore prospecting in this area should focus on the areas of Yindongya and Dongzigou where the combination of Cu-Mo anomaly and IP anomaly is better than that of Yindongya and Dongzigou where the range of Cu-Mo anomaly is large.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.41;P618.65

【相似文献】