矿床形成深度与深部成矿预测

摘要：阐述了不同类型内生矿床的成矿深度和金属沉淀的垂直范围。热液成矿作用的深度下限可以下降到10000～12000m。不同类型矿床的成矿深度范围与成矿时的具体地质构造特征有关,且有很大的变化空间。金属矿床的形成深度受成矿母岩岩浆侵位深度的约束,而岩浆侵位的深度又与岩浆中挥发组分的数量、流体释放的时间、成矿元素的矿物/熔体和溶液/熔体分配系数等因素有关。据此可以解释斑岩铜－（钼）、斑岩钼-(铜)和斑岩钨矿床形成深度的差异。地温梯度和多孔岩石的渗透率也与成矿深度有关。CO2等挥发组分的溶解度对压力非常敏感,因此流体包裹体地质压力计对于成矿深度的确定有重要的应用价值。在开展深部成矿预测和找矿时,探寻隐伏岩体顶上带或岩钟是寻找深部与花岗岩有关的多金属矿床的捷径之一。     

矿床形成深度与深部成矿预测

阐述了不同类型内生矿床的成矿深度和金属沉淀的垂直范围。热液成矿作用的深度下限可以下降到10000～12000m。不同类型矿床的成矿深度范围与成矿时的具体地质构造特征有关,且有很大的变化空间。金属矿床的形成深度受成矿母岩岩浆侵位深度的约束,而岩浆侵位的深度又与岩浆中挥发组分的数量、流体释放的时间、成矿元素的矿物/熔体和溶液/熔体分配系数等因素有关。据此可以解释斑岩铜-(钼)、斑岩钼-(铜)和斑岩钨矿床形成深度的差异。地温梯度和多孔岩石的渗透率也与成矿深度有关。CO2等挥发组分的溶解度对压力非常敏感,因此流体包裹体地质压力计对于成矿深度的确定有重要的应用价值。在开展深部成矿预测和找矿时,探寻隐伏岩体顶上带或岩钟是寻找深部与花岗岩有关的多金属矿床的捷径之一。     

银山矿田九区铅锌矿床深部成矿地球化学及预测

通过对银山矿田九区铅锌矿床－60m--150m9－11和9－25矿体垂向上成矿元素及伴生的指示元素特征研究，推测在－150m以下九区铅锌矿床矿体仍将延伸。     

河南光山县千鹅冲铜钼多金属矿床地质特征及成因浅析

河南光山县千鹅冲铜钼多金属矿床是新发生的一个隐伏矿床。通过对区域地质背景矿区地质特征以及矿床特征等分析与研究,认为铜钼矿床为深部隐伏岩钟斑岩体。外接触带铜钼多金属矿床。矿体主要赋存于隐伏岩体顶上带中,矿床规模与隐伏（斑）岩体或隐伏（斑）岩体上方岩钟（成矿母岩）、隐伏岩体顶上带（赋矿围岩）及区域性断裂构造等密切相关。该矿床的发现对该成矿区带找矿隐伏有现实指导意义。     

隐伏岩体顶上带与深部成矿预测

岩浆侵入的流体流动模拟表明,侵入体上方是流体聚焦流动的位置,流体通量远大于旁侧围岩,流体在此产生沸腾作用。随温度降低,侵入体上方渗透率逐渐增大,最大渗透率出现在侵入体的顶部。含水岩浆侵位后在其顶上带发生二次沸腾和减压过程,释放出的巨大机械能远大于围岩的抗张强度,足以引起围岩发生脆性破坏。岩浆岩顶上带的水饱和外壳及其围岩发生破裂形成陡倾裂隙和水力破裂。直立长椭球状岩浆体的侵入会在岩浆岩顶上带产生放射状和同心圆状裂隙,同时产生爆破角砾岩筒。因此侵入体顶上带的岩钟、岩枝、岩脉,放射状、同心圆状裂隙和角砾岩筒均为构造弱化带,是热液矿脉密集发育的部位。矿床地质学研究已充分证明,岩浆岩顶上带确是容纳与中酸性岩浆有关的热液矿床的最佳部位。在开展深部成矿预测和找矿的过程中,探寻隐伏岩体顶上带和/或岩钟,是寻找深部与花岗岩类有关的多金属矿床的捷径。     

铜矿峪变斑岩型含钼铜矿床成矿作用及找矿预测

通过对铜矿峪矿床在含铜建造、矿床地质特征、地球化学特征等方面的综合论述,探讨其成矿物质来源、矿床富集机制及成矿模式,并对找矿远景进行预测。     

Manganese deposits: Communication 1. Genetic models of manganese ore formation

Major regularities in the formation of manganese rocks and ores have been established on the basis of available published and original data. The proposed genetic classification of main manganese deposits (with model examples) is as follows: sedimentary-diagenetic (Nikopol, Bol’she-Tokmak; Ukraine), (volcanogenic) hydrothermal-sedimentary (deposits of the Atasui area, Kazakhstan; Magnitogorsk Trough, South Urals), epigenetic (catagenetic) (deposits of the Kalahari manganese ore field, South Africa; Usinsk deposit, Kuznetsk Alatau), and supergene (residual, infiltrational, cavern filling, and pisolitic deposits in India, Brazil, South Africa, and Australia). The results suggest the following conclusions: (1) all primary manganese rocks and ores at the known deposits are hydrothermal- and diagenetic-sedimentary formations of marine environments; (2) manganese concentrations achieve the size of deposits at postsedimentary stages of the initial manganiferous sediment and manganese rock transformation (diagenesis, catagenesis, and retrograde diagenesis); (3) indispensable participation of the isotopically light carbon dioxide related to the destruction of organic matter (OM) is a characteristic feature of manganese carbonate formation during diagenesis; and (4) the role of organic carbon in manganese ore formation becomes notable since early stages of Mn accumulation in the Precambrian sedimentary basins (terminal Archean-initial Early Proterozoic).     

黑龙江宝兴沟金矿床构造叠加晕特征及深部预测

宝兴沟矿区位于黑龙江省塔河县,2002年由1∶10万水系沉积物测量异常圈定,2007年通过1∶1万和1∶2万土壤测量进一步圈定了异常范围,并利用槽探工程进行揭露,首次发现了Au矿体,矿体主要为蚀变砂岩、蚀变闪长岩、蚀变闪长玢岩等,少量为含金石英脉,以中-低温蚀变为主。本文在充分收集矿区已有资料的基础上,结合矿区最新的钻孔采样数据,对矿床地球化学特征进行了研究;分析了矿床构造叠加晕分布特征,矿床前缘晕特征指示元素为Sb、As,近矿晕特征指示元素为Pb、Ag、Au、Zn、Cu,尾晕特征指示元素为W、Mo、Bi,初步确定了宝兴沟金矿床串珠状矿体、不同深部矿体组合的构造叠加晕模式;并依据已知矿体及矿床构造叠加晕,对深部有利成矿部位进行了预测,指出I-1-1号矿体向下应有很大的延伸或I-1-3号矿体深部应有盲矿存在,I-2-1号矿体深部可能有盲矿体存在。     

Geochemical signatures of possible deep-seated ore deposits in Tertiary volcanic centers, Arizona and New Mexico, U.S.A.

A reconnaissance geochemical survey of stream drainages within 21,000 km² of southeastern Arizona and southwestern New Mexico shows broad zones of low-level to moderate contrast anomalies, many associated with mid-Tertiary eruptive centers and Tertiary fault zones. Of these eruptive centers, few are known to contain metallic deposits, and most of those known are minor. This, however, may be more a function of shallow erosion level than an indication of the absence of mineralization, since hydrothermal alteration and Fe-Mn-oxide staining are widespread, and geochemical anomalies are pervasive over a larger part of the region than outcrop observations would predict. Accordingly, interpretations of the geochemical data use considerations of relative erosion levels, and inferred element zonalities, to focus on possible undiscovered deposits in the subsurface of base-, precious-, and rare-metal deposits of plutonic-volcanic association. In order to enhance the identification of specific deep targets, we use the empirically determined ratio: This ratio is based on reported metal contents of nonmagnetic heavy-mineral samples from the drainage sediment, determined by emission spectrographic analysis. Before the ratio was computed for each sample site, the data were normalized to a previously estimated regional threshold value. A regional isopleth map was then prepared, using a cell-averaging computer routine, with contours drawn at the 25th, 50th, 75th, 80th, 90th, 95th and 99th percentiles of the computed data.     

The Witwatersrand deposit and the problem of the ore formation

The problem of the origin of the Witwatersrand gold-uranium deposit is considered. The fluvial and explosion hydrothermal origin of pyrite spheroids and Au-bearing pseudoconglomerate is denied. Evidence for the primary character of spheroids and the autochthonous crystallization of pyrite under endogenic conditions is furnished. The association of gold with carbonaceous rocks is interpreted in terms of the nuclear magnetic physicochemical phenomena. It is concluded that the Witwatersrand deposit is a hydrothermal metasomatic deposit.     

小秦岭东闯金矿Au/Ag值特征及深部找矿预测

小秦岭地区不同矿化类型的含Au石英脉Au/Ag值有不同的特点，多金属硫化物型一般小于0.8，黄铁矿型介于0.8-2.0之间，少黄铁矿型一般大于2.0。利用Au/Ag值可以大致确定矿脉的矿化类型，判断矿脉的水平，垂向分带和剥蚀深度，预测深部矿脉的矿化类型，东闯金矿床深部Au/Ag值为1.39，预示其深部有可能出现黄铁矿型矿化，深部探矿仍有前景。