熊耳山地区内生金矿床成矿系列

按容矿空间和控矿因素,可将熊耳山地区内生金矿床划分为角砾岩型、构造破碎带蚀变岩型、石英脉型及由不同控矿因素复合控制的复合类型等。空间上不同类型之间具有密切的共生过渡关系。太华群原岩中的金在变质热液作用下被活化迁移至有利的构造部位,发生局部富集,形成"矿胚"或"矿胚"的发展,并为后期岩浆热液再次搬运,参与成矿。燕山中晚期钙碱性岩浆岩具较大的成矿能力,是本区金矿床的主要矿源。不同类型矿床稳定同位素及包裹体特征具相似的变化特点,分析表明,成矿流体主要源自岩浆,在成矿早期和晚期,不同地区可能有不同程度的变质水或大气水加入。作者认为,区内不同类型的金矿床是在统一的大地构造环境和成矿背景中形成的,有统一的矿质和介质来源,具相同或相似的成因,以发育角砾岩型金矿床为特点,以构造破碎带蚀变岩和角砾岩型为主要矿床类型,形成一个特定的矿床组合,即熊耳山地区内生金矿床系列。     

秦岭地区黄铁矿特征与金矿关系的研究

根据秦岭地区金矿床中黄铁矿特征,总结出典型的微细浸染型和含金石英脉型两种类型矿床特征。黄铁矿与金矿关系密切,含金黄铁矿多产于成矿的富集地段。通过对该区黄铁矿标型特征(晶形、粒级与热电性和微量元素)的系统研究,认为黄铁矿标型特征的研究,对深部找金矿与远景评价具有指导意义。     

河南灵宝枪马金矿床成矿特征研究

本文对枪马金矿成矿特征进行了初步探讨,认为该矿形成同晚燕山期花岗质岩浆活动,太华群变质地层有关,矿床属中温混合热液成因类型。断裂构造严格控制了含金石英脉的产出,并决定了矿脉内工业矿体的规模及其空间定位,为矿山生产及进一步探矿找矿工作提供了依据。     

东天山康古尔金矿床石英位错构造及其动力学意义

康古尔金矿床形成于脆韧性—脆性剪切变形构造演化过程中。应用透射电镜超微技术分析水热成矿期石英位错构造、位错密度及差应力值有助于加深认识剪切构造条件下的成矿动力学机制。石英位错构造特征反映成矿期构造变形环境为中温—中低温、高差异应力、高应变速率。成矿期构造差应力演化呈明显的脉动性,这种脉动性所形成的“应力地震泵吸”机制对金矿成矿至关重要。     

豫陕晋金三角金矿成矿探讨

豫陕晋金三角是我国重要的黄金生产基地。该金三角的成矿条件极为优越,处于多构造体系复龠 我间,地层出露齐全、岩浆活动强烈、控金断裂系统网络交织、金源层（体）广布,所以金的成矿类型繁多,金矿床星罗棋布,文章对该区金矿成矿作专题探讨。     

Metamorphic charnockite in contact aureoles around intrusive enderbite from Natal, South Africa

In the Port Edward area of southern Kwa-Zulu Natal, South Africa, charnockitic aureoles up to 10 m in width in the normally garnetiferous Nicholson's Point Granite, are developed adjacent to intrusive contacts with the Port Edward Enderbite and anhydrous pegmatitic veins. Mineralogical differences between the country rock and charnockitic aureole suggest that the dehydration reaction Bt + Qtz → Opx + Kfs + H₂O and the reaction of Grt + Qtz → Opx + Pl were responsible for the charnockitization. The compositions of fluid inclusions show systematic variation with: (1) the Port Edward Enderbite being dominated by CO₂ and N₂ fluid inclusions; (2) the non-charnockitized granite by saline aqueous inclusions with 18–23 EqWt% NaCl; (3) the charnockitic aureoles by low-salinity and pure water inclusions (<7 EqWt% NaCl); (4) the pegmatites by aqueous inclusions of various salinity with minor CO₂. As a result of the thermal event the homogenization temperatures of the inclusions in charnockite show a much larger range (up to 390 °C) compared to the fluid inclusions in granite (mostly <250 °C). Contrary to fluid-controlled charnockitization (brines, CO₂) which may have taken place along shear zones away from the intrusive body, the present “proximal” charnockitized granite formed directly at the contact with enderbite. The inclusions indicate contact metamorphism induced by the intrusion of “dry” enderbitic magma into “wet” granite resulting in local dehydration. This was confirmed by cathodoluminescence microscopy showing textures indicative for the local reduction of structural water in the charnockite quartz. Two-pyroxene thermometry on the Port Edward Enderbite suggests intrusion at temperatures of ∼1000–1050 °C into country rock with temperature of <700 °C. The temperature of aureole formation must have been between ∼700 °C (breakdown of pyrite to form pyrrhotite) and ∼1000 °C. Charnockitization was probably controlled largely by heat related to anhydrous intrusions causing dehydration reactions and resulting in the release and subsequent trapping of dehydration fluids. The salinity of the metamorphic fluid in the contact zones is supposed to have been higher at an early stage of contact metamorphism, but it has lost its salt content by K-metasomatic reactions and/or the preferential migration of the saline fluids out of the contact zones towards the enderbite. The low water activity inhibited the localized melting of the granite. Mineral thermobarometry suggests that after charnockite aureole genesis, an isobaric cooling path was followed during which reequilibration of most of the aqueous inclusions occurred. Received: 8 November 1998 / Accepted: 21 June 1999     

新疆西昆仑造山带北缘中元古代帕什托克闪长岩侵入序列及其地质意义

位于塔里木地块西南缘、西昆仑造山带北缘的帕什托克侵入序列由石英闪长岩-石英二长闪长岩组成,类似TTG组合,形成于中元古代晚期。本文从帕什托克侵入序列的地球化学分析出发,通过对该侵入序列两期侵入岩的主量元素和微量元素的研究,讨论了该侵入序列的成因、构造环境和与其相关的板块间地球动力学模式,认为该侵入序列为I型准铝质高钾钙碱性花岗闪长岩系列,属活动板块边缘碰撞前大陆弧花岗岩类,两期侵入岩为同源岩浆演化,母岩浆属壳幔混合源,且岩浆向酸性演化。根据岩浆演化的物理环境和构造环境,推测早古生代库地洋的完全闭合与库地洋壳向塔里木古陆块俯冲消减有关,是塔里木古陆块和柴达木古陆块在Rodinia超级大陆汇聚过程中的产物。     

晋北煅烧高岭土用煤矸石的应用矿物学特征

为了给晋北煅烧高岭土用煤矸石的评价和开发利用提供科学依据,采用XRD、XRF、SEM和白度计等现代分析测试技术,研究了晋北煅烧高岭土用煤矸石的应用矿物学特征。结果表明:1)根据造纸和涂料用煅烧高岭土的国家标准,晋北煤矸石主要可分为3种类型:合格原料、基本合格原料和不合格原料。2)与合格和基本合格原料相比,不合格原料煅烧产物的化学成分中SiO2、Al2O3、Fe2O3含量以及碱金属与碱土金属总含量都与前者有较大差异。3)合格和基本合格原料主要由高岭石(85%~94%)组成,不合格煤矸石矿物组合为高岭石(30%~60%)+石英(23%~38%)+伊利石(14%~26%),并含少量黄铁矿和白云石等杂质矿物,石英等杂质矿物和含铁矿物是分别导致煅烧产物化学成分和白度不合格的主要原因。4)合格原料中高岭石结晶度较好,主要为不规则片状、书册状和弯曲片状,片表面光滑,片径大小范围较大,为0.05~51.22μm,平均2.80μm,径厚比41.24。     

Relationship Between Electrical Properties and Sedimentary Environment of the Longmaxi Formation Shale, Southern Sichuan

The Lower Silurian Longmaxi Formation in the south of Sichuan is a key player in the exploration and development of shale gas in China. Due to a highly complex topographic area, electromagnetic methods (EM) become important exploration means in this area. Many studies have been conducted on the shale mineral composition and electrical properties of shale, however, the correlation between sedimentary environments and the electrical properties of shale remain poorly understood. The electrical properties and sedimentary environment of the organic-rich shale of the Longmaxi Formation have been studied by means of X-ray diffraction, organic geochemistry, scanning electron microscopy and complex resistivity measurements. The discovered high quartz content of the Longmaxi Formation shale results in low resistivity. Deep-water shelf biogenic quartz contributes lower resistivity more than that of shallow-water terrigenous quartz. The deep-water anoxic and organic sedimentary environment led to major enrichment of pyrite, leading to a high polarization effect in shale. We present the correlation between the lithofacies types and electrical properties of Longmaxi Formation. The mixed siliceous shale lithofacies is the most favorable among the three lithofacies, which is characterized by high total organic carbon (TOC) content, high brittleness mineral content, high polarization and low resistivity (“three high and one low”). This feature is an effective identification of shale gas reservoirs by electromagnetic prospecting. Our study can provide constraints on electrical parameters of rocks for electromagnetic “sweet spot” exploration of shale gas, and so this has important geological significance to shale gas exploration and development.     

溶剂萃取原子吸收光谱法测定高纯石英砂中痕量铁

高纯石英砂用HF等溶剂溶解并蒸干后,在微酸性介质中用抗坏血酸还原Fe^3＋为Fe^2＋,与1,10-二氮杂菲形成Fe2＋3络合物,加入适量ClO4^-阴离子与之形成离子缔合物,用硝基苯萃取,原子吸收测定有机相,本法检出限1.1μg/g,样品分析结果的RSD%为：4.52～10.3.