东秦岭造山带河南段金成矿规律及其形成机理研究

【作者】 杨群周；

【导师】 彭省临；

【作者基本信息】 中南大学 ， 矿产普查与勘探， 2002， 博士

【摘要】 论文结合河南省有色地矿局科研项目，以壳体成矿学为理论指导，用常规地质和连续介质物理研究方法，研究东秦岭造山带河南段造山带特征、金成矿规律及其控制因素，探讨金的成矿机理，建立其数学模型，进行数值模拟，确定金矿找矿的方向和有利区段，具有重要理论和实践意义。 论文较系统总结了在造山带、地球动力学、成矿流体、成矿作用动力学、地洼学说成矿理论等领域的研究现状及发展趋势，以及研究区内前人在这些领域的研究现状和存在的不足。运用壳体成矿学理论对区内造山带的空间结构、时间结构进行研究，将其划分为2个Ⅰ级、3个Ⅱ级、6个Ⅲ级、45个Ⅳ级大地构造单元，认为其为地洼型造山带，属挤压-拉张型，对金成矿有重要控制作用。 研究了区内金成矿的统—性和多样性，前者表现为其时空分布主要受“空间过渡际成矿”和“时间过渡际成矿”控制，后者主要表现为工业类型、赋矿地层、成矿时代、赋矿构造等方面的多样性。论证了区内金成矿的“多因复成”特征，提出了区内金矿是在前地槽、地槽阶段金初步富集的基础上叠加了地洼阶段流体成矿作用的“沉积-变质-流体叠加改造矿床”的新观点。首次对区内金矿床进行了地球动力学分类，将其划分为三个类型，七个亚类型。 探讨了区内金矿床与深部构造的关系，提出了幔向斜陡坡带和航磁异常联合控制金矿床分布的新认识并探讨其机理；讨论了区域、矿田、矿床和矿体构造的控矿作用；将区内金矿床和国内外微细浸染型金矿床进行对比研究并总结其特点。 探讨了区内造山带演化、金成矿及其动力学机理，提出了热应力是影响变质作用、构造形成演化及成矿地球动力学环境的主控因素的新认识；对多孔均匀介质中流体对流的临界条件进行探讨，首次提出了除岩石物理性质外，构造层厚度和温度梯度是影响流体对流乃至矿质输运的主要因素。据此对区内造山带演化、金成矿的某些机理进行了定性的解释。 推导出成矿流体压力场分布方程，对熊耳山地穹金的成矿流体压力场进行计算机数值模拟。更多还原

【Abstract】 Conbined with the scientific research projects of Henan Non-ferrous Geological Exploration Bureau , guided by the cyustobody metallogeny, by means of traditional methods of geological research and continuum physics, characteristics of the erogenic zone,gold ore-forming laws and its controlling factors in the region are summarized, dynamical environments and mechanism of gold ore-formation are studied,mathematical models are set up,computer numerical simulations are perfomed and the direction and favorable area for gold exploration are pointed out in the dissertation.So it has important significance in the theory and practice.The research actuality and developing tendency of the fields of orogeny,geodynamics,ore-forming fluids,dynamics of ore-forming processes,Diwa theory metallogeny and so on are summarized in the dissertation. The research actuality in these fields and lack of gold metallogeny research in the region are pointed out.Based on the crustobody metallogeny,the space structure and time structure of Henan area in East Qinling orogenic zone are studied.And the region is divided into 2 I -class,3 II-class,6 III-class,45IV -class tectonic units and considered as the Diwa -type orogenic zone, which belongs to compressive -tensile type and control ore-formations of gold and non-ferrous metals seriously in the region.Oneness and variety of gold ore-formation in the region are studied. The former means that the distributions of space and time of gold deposits are controlled by "space transition ore-formation" and "time transition ore-formation". The latter embodies mainly industrial type,ore-existing stratum,ore-forming time,ore-existing structure and so on. Characteristics of gold polygenetic compound deposits in the region are demonstrated. The new viewpoint is put forward that the gold deposits in the region belong to "sediment- metamorphism-fluid superposition reconstruction" deposits which are formed by fluid superposition reconstruction in the Diwa stage’ on the basis of preliminary enrichment in the fore-geosyncline,geosyncline stage.The classification of gold deposits in the region is performed on geodynamic environment first.The gold deposits in the region are divided into three types,seven sub-types.Relationship between abysmal structures and gold deposits in the region is discussed and new viewpoint is put forward that the steep slope belt in the mantle syncline and areomagnetic abnormals gradient belt jointly control the distribution of the deposits,with mechanism studied. Ore controlling of structure of region,ore field,deposit,and ore body is discussed .The contrast of gold deposits in the region and fine disseminated gold deposits home and overseas are studies and their characteristicses are summarized.The evolution of orogenic zone,gold ore-formation and its dynamic mechanism are studied and the new viewpoint is put forward that thermal stress is a main controlling factor in metamorphism,formation ,evolution of structure and ore-forming geodynamic environment. The critical condition of fluid convection in porous equal medium and the new conclusion is reached first that the thickness of structural layer and temperature gradient are main factors influencing fluid convection andtransport of ore-forming matters in additional to physical properties of rocks. According to the conclusion some mechanisms such as the transform from compressive type to tensile one of erogenic zone,transport and accumulation of ore-forming matters such as gold and so on and many ore-forming temperature values are interpreted qualitatively.The distribution equation of ore-formation fluid pressure field is deduced. Numerical simulation of ore-formation fluid pressure field in Xiongershan geodome are performed.更多还原