【作者】 董树义；

【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， 2008， 博士

【摘要】 沂南金矿床位于华北板块东南缘沂沭断裂带(郯庐断裂带的中段)西侧的鲁西地区,辖相距6km的铜井和金场两个矿区,是一个典型的Au、Cu、Fe矽卡岩型矿床。近年来,沂南金矿接替资源严重匮乏,亟需基础理论的指导和成矿规律的系统研究。本文在大量野外工作基础上,综合运用构造地质学、岩石学、矿物学、矿床学、地球化学、流体包裹体地质学、同位素地质学和成矿预测学等多学科的理论和方法,在对沂南金矿床成因和控矿因素研究的基础上,总结了成矿规律,圈定了两个新的找矿靶区,并经工程验证取得了很好的找矿效果。矿床产于燕山期中酸性～酸性杂岩体的接触带及其外侧的新元古界-寒武系围岩中,受岩浆岩、地层岩性、构造和围岩蚀变的共同控制。成矿岩浆为深成的幔源岩浆,在上侵演化过程中受到地壳物质不同程度的混染,形成以玢岩和斑岩为主的钙碱性岩杂岩体,在化学成分上具有埃达克质岩的特征。以碳酸盐岩为主的赋矿地层良好的物理性质和活泼的化学性质为成矿提供了有利的围岩条件。NW与NE、NEE向断裂构造的交汇部位控制了成矿岩体的就位,而控矿和容矿的构造则主要为接触带构造、捕虏体构造、层间破碎带构造以及不整合面构造等。以矽卡岩化为主的围岩蚀变控制了矿化的强度、矿体的厚度以及矿石类型的空间展布。硫、碳、铅、氢、氧同位素研究表明,矿石中的硫和碳主要来自于幔源岩浆;矿石铅具有含过剩放射性成因铅的异常铅特征,放射性成因铅很可能来自于晚太古代结晶基底;成矿热流体主要为岩浆热液,在成矿晚期则有不同程度的大气降水混入。流体包裹体研究结果显示,由早期成矿阶段至晚期成矿阶段,成矿流体的均一温度和盐度依次下降,成矿作用发生于1.7~0.6km的浅成条件下。在主要矿石矿物沉淀的氧化物阶段和石英硫化物阶段,成矿流体曾发生过广泛的不混溶(沸腾)作用,这一作用很可能是导致矿床中Au、Cu、Fe等矿质沉淀富集的主要原因。综合研究认为,沂南金矿床在含矿岩浆岩、赋矿地层、控矿构造、围岩蚀变及分带、矿化类型及其空间组合、成矿深度与剥蚀深度等方面存在一定的规律。在此基础上,确定了岩浆岩、地层岩性、构造、地球物理及地名与采矿遗迹等方面的预测标志,并应用于矿区外围的成矿预测中,分别于金场矿区外围的两泉庄和铜井矿区外围的西朝阳圈定了两个找矿靶区,经钻探工程验证,均成功见矿,从而为沂南金矿的进一步找矿展示了广阔的前景。更多还原

【Abstract】 As a typical skarn deposit in the western Shandong Provinc, the Yinan gold deposit is located on the west side of the Yishu fault zone (the middle segment of the Tanlu fault zone) at the southeastern margin of the North China plate. It includes the Tongjing and Jinchang ore districts which are 6 km away from each other. In the recent years, the shortage of succeeding resources is becoming a serious problem in the mine, and thus the guidance of basic theories and the systematic study on the metallogenetic laws are urgently needed. Based on comprehensive field investingations and synthetic studies on metallogenesis and ore-controlling factors by applying multiple disciplines and methods such as tectonic geology, petrology, geochemistry, fluid inclusions, isotope geology and metallogenic prediction, the metallogenic laws of the deposit are summarized in this paper. Through project attestation, good effects on ore exploration were obtained from two new prospecting targets delimited during this study.The deposit occurs at the contact zone between the intermediate-acidic complexs of the Yanshanian and their surrounding wall rocks of the Neoproterozoic to Cambrian. The mineralization is jointly controlled by magma, strata lithology, structure and wall rock alterationr. Ore-forming magmas were drived from the deep mantle and were contaminated by the crust to some degree during their ascending process. The calc-alkali complexs are typically porphyrite or porphyry and show characteristics of adakite-like rocks in chemical composition. The ore-bearing strata are mainly carbonate rocks, and their sound physical and chemical characters provided favorable wall rock conditions for mineralization. The location of the ore-forming intrusions were controlled by the intersecting places between the NW and NE or the NW and NEE trending fault structures. The ore-controlling and ore-bearing structures mainly include contact zone, xenoliths structure, interlayer fractured zone and unconformity structure, etc. The mineralization intensity, the orebody thickness and the spatial distribution of different ore types were mainly controlled by skarnization of the wall rocks.Sulfur, carbon, lead, hydrogen and oxygen isotopic studies indicated that S and C in the ore were mainly derived from the mantle magma and Pb was characterized by anomalous lead containing superfluous radioactive lead. The radioactive lead may come from crystalline basement of the late Archean. The ore-forming fluids were mainly magmatic hydrothermal fluids, though some meteoric water might be added during later mineralization stage. Detailed study on fluid inclusions indicated that the homogenization temperature and salinity of the ore-forming fluids declined from the early to late mineralization stage, and the mineralization occurred under the epithermal conditions of 1.7~0.6 km. During the oxide and the quartz-sulfide stages when the main ore minerals were precipitated, the ore-forming fluids had gone through an immiscible process (boiling) that may have caused the precipitation and concentration of Au, Cu, and.The integrated study suggested that the Yinan gold deposit presented some metallogenic laws on the aspects of ore-concerning magmas, strata, ore-controlling structures, wall rock alteration and zonation, mineralization types and their spatial combination, ore-forming and denudation depth, etc. Some prediction indicators of magmatic rocks, strata lithology, structures, geophysics, place names and mining relics were confirmed and applied to the metallogenic prediction on the entourage of the mine. Two new targets are delimited in the Liangquanzhuang and Xichaoyang areas around the mine. Ores were found by drilling project attestation in both areas, which exhibited a nice future for the further ore exploration of the Yinan gold deposit.更多还原