四川攀西地区稀土资源成矿规律及找矿靶区

以牦牛坪稀土矿为代表的攀西地区是我国重要的稀土资源成矿带,攀西稀土矿包括岩浆热液型、伟晶岩型、第四系砂矿型、火山岩型和离子吸附型等类型。重点针对牦牛坪矿床的成矿地质背景、矿化特征及成矿条件等成矿机制进行分析,研究控矿与成矿要素、成矿规律; 完善了岩浆热液型轻稀土矿床成矿模型; 厘清了区域上不同类型矿床的产出特点及各类型矿床的内在成因联系,并科学分析区域稀土资源,圈定稀土找矿靶区,进一步缩小找矿范围。     

熊耳山—外方山矿集区中生代Au-Mo成矿系统

熊耳山—外方山矿集区位于秦岭造山带之华北板块南缘,经历了复杂的碰撞造山过程,成矿时间跨度大,成矿强度高,成矿作用多样。复合造山过程和相应的成矿作用已被深入研究,但成矿系统的划分和叠加成矿作用尚需研究。本文将熊耳山—外方山矿集区发育的Au-Mo矿床划分为造山型Mo矿床、斑岩型Mo矿床、岩浆热液脉型Mo矿床、造山型Au矿床和岩浆热液型Au矿床5个类型,对应5种成矿系统：(1)造山型Mo矿床形成于250~227 Ma的同碰撞环境和227~194 Ma的后碰撞环境,为变质热液萃取壳源Mo成矿;(2)斑岩型Mo矿床形成于163~135 Ma的洋陆俯冲环境和135~116 Ma的岩石圈减薄环境,为岩浆热液携带幔源或壳源Mo成矿;(3)岩浆热液脉型Mo矿床形成于227~194 Ma的后碰撞环境,为岩浆热液携带幔源Mo成矿;(4)造山型Au矿床在三叠纪发生了预富集作用,主要形成于163~135 Ma的洋陆俯冲环境和135~103 Ma的岩石圈减薄环境,为变质热液萃取壳源Au成矿;(5)岩浆热液型Au矿床仅形成于135~103 Ma的岩石圈减薄环境,为岩浆热液携带壳源Au成矿。矿集区主要存在两种叠加成矿作用,即不同构造背景下多种成矿系统的叠加和同一构造背景下不同成矿系统的叠加。     

再论紫金山矿田成矿系列与成矿模式

紫金山矿田是由我国大陆发现的首例高硫型浅成低温热液矿床-紫金山铜金矿床为主要组成部分,该矿床深部和边部相继发现了斑岩型铜(钼)矿、中低温热液型铜矿和低硫浅成热液型银(金、铜)矿、火山岩型铀矿及高温热液型钨锡矿异常等。自晚侏罗世开始,矿田内经历了多期次的构造作用、岩浆活动及其热液蚀变,致使紫金山矿田形成多期次的成矿作用,它们相互叠加、富集以及空间上侧向排列的特点,构成“构造的构造”、“体中体”、“蚀变的蚀变”、“矿化的矿化”等特征的复杂多样构造-流体-成矿系统,并具有显著的自上而下“U、Ag→Au→Au、Cu→Cu→Cu、Mo→W、Sn”矿化垂直分带特征和“多层楼”成矿模式。在空间上不同成因类型矿床又显现出侧列分布的格局,构成了独特的“紫金山式”成矿系列与成矿模式。通过对比研究表明：在紫金山铜金矿床深部仍存在着斑岩型铜（钼）矿床以及边部可能具有的高温热液型钨锡矿床等,展现出矿田内具有广阔的找矿新领域,为配合进一步地质勘查找矿工作提供科学依据。     

新疆北部大地构造演化阶段与斑岩－浅成低温热液矿床的构造环境类型

本文系统总结了新疆北部斑岩-浅成低温热液矿床的成矿时代,按构造环境将该类矿床归为三大类型:洋-陆俯冲型、碰撞造山型、板内型,其中碰撞造山型又可分为碰撞型和后碰撞型。4类矿床的差别主要在于矿床金属元素组合,以及同期相伴出现的矿床类型不同:俯冲型斑岩矿床以斑岩Cu-Au矿-浅成低温热液Au矿组合为主,以伴有海相火山岩有关的VMS矿床和铁矿为特征;碰撞型和后碰撞型矿床以斑岩Cu-Mo-Au组合为主,伴有构造蚀变岩型复合/叠加的浅成低温热液型Au矿出现;板内型矿床以斑岩型单Mo(或Mo-Re)组合为主。斑岩矿床与浅成低温热液矿床虽为同一成矿系统,但二者基本不共生,且后者成矿时代一般晚于前者10～20 Ma。斑岩-浅成低温热液矿床的含矿岩石和成矿特征并不随构造环境类型不同而出现特征性差别。不同时期的斑岩矿床在分布上具有继承性和"同位成矿"特点,并表现出一定的分带性,从早到晚逐渐由靠近缝合带向外扩展、由线型分布逐渐趋于面型分布。     

萤石矿自然重砂矿物组合规律及其找矿意义

为探究不同类型的萤石矿所反映的自然重砂矿物组合所携带的对各类型萤石矿的指示特征,统计了浙江、湖南、湖北、青海、广西、福建、安徽、新疆、甘肃、河北共计10个地区23个典型萤石矿床的自然重砂矿物报出情况,计算各重砂矿物报出率,分析得出热液型矿、后期热液型及热液充填型3种类型萤石矿床各自对应的自然重砂矿物组合和标型矿物组合。结果显示,各类型矿床自然重砂矿物组合既有相同之处也有显示各自的特点。因此,按照矿床类型建立的自然重砂矿物组合及其含量变化,对于新一轮的矿产资源勘查具有重要的意义。     

西藏叶噶玉弄铅多金属矿地质特征及找矿远景

西藏叶噶玉弄铅多金属矿为南冈底斯—念青唐古拉Cu、Au、Fe、Pb、Zn、Sb成矿带-蒙亚啊Pb、Zn矿集区新发现的又一铅多金属矿点。通过对矿区成矿地质条件、矿床特征、成矿要素等的综合分析,确定了该矿床成因类型为热水沉积—热液叠加改造型矿床。通过与邻区典型矿床成矿要素的对比,总结了研究区的成矿规律,并对研究区找矿远景及区域找矿模式进行了探讨。     

西准噶尔萨吾尔地区主要矿床类型及成矿规律

本文基于萨吾尔地区目前发育的主要矿床(点)吐尔库班套铜镍矿点、阔尔真阔腊金铜矿床、布尔克斯岱金矿床、罕哲尕能铜矿床、塔斯特金矿床、黑山头金矿点、那林卡拉铜钼矿点等的研究,分析了区域矿化类型及成矿规律。认为萨吾尔地区矿床成因类型可分为三类,岩浆Cu-Ni硫化物矿床、斑岩型-浅成低温热液型Au-Cu-Mo矿床、与中酸性侵入岩有关的构造蚀变岩型Au矿床。矿化以Au、Cu矿化为主,Cu-Ni、Mo矿化次之。成矿时代分布在中泥盆世、早石炭世、晚石炭世,集中于早石炭世(354~336Ma)。空间上,岩浆Cu-Ni硫化物矿床分布于萨吾尔北部科克森套地区,斑岩型-浅成低温热液型Au-Cu-Mo矿床、与中酸性侵入岩有关的构造蚀变岩型Au矿床主要分布于萨吾尔山南部。成矿构造背景分别对应于区域中泥盆世岛弧环境、早石炭世岛弧环境、晚石炭世碰撞造山后环境。区域成矿规律显示了进一步的找矿潜力:萨吾尔北部科克森套地区发育的镁铁-超镁铁岩体的岩浆Cu-Ni硫化物矿床的找矿潜力;阔尔真阔腊-布尔克斯岱地区斑岩型-浅成低温热液型金铜矿床的找矿潜力;区域晚石炭世-早二叠世斑岩型Cu-Mo矿床的找矿潜力;萨吾尔断裂及其次级断裂控制范围内的Au-Cu找矿潜力。     

兴蒙造山带成矿规律及若干科学问题

兴蒙造山带位于中亚造山带东段,形成于古生代,在中生代遭受了西北部蒙古-鄂霍茨克洋构造域和东部古太平洋构造域的强烈改造。该造山带也是中国北方地区一个重要的金属成矿带,因此对该造山带成矿规律的总结和研究,无论是在理论上还是在找矿勘查实践中都具有十分重要的意义。笔者对该地区的研究成果进行了收集和整理。根据已有的年代学数据,该区已发现的绝大多数矿床形成于侏罗纪—白垩纪,与古生代古亚洲洋构造体系关系不大。根据兴蒙造山带内的成矿与不同构造体系演化之间的关系,将研究区内的矿床分为4类:(1)与古亚洲洋构造体系有关的矿床,形成于500~210 Ma,矿床类型主要是斑岩型Cu-Mo、Mo和Au矿床、浅成低温热液型Au矿床和矽卡岩型Pb-Zn矿床,矿床形成环境主要为岛弧及古亚洲洋闭合后的碰撞与伸展阶段;(2)与蒙古-鄂霍茨克洋构造体系有关的矿床,形成时间240~110 Ma,矿床类型主要是斑岩型Cu-Mo和Mo多金属矿床、浅成低温热液型Au矿床、中低温热液脉型Pb-Zn-Ag矿床和热液脉型Ag多金属矿床,形成环境主要为陆缘弧、蒙古-鄂霍茨克洋闭合后的碰撞造山-后碰撞,以及造山后的伸展崩塌阶段;(3)与古太平洋构造体系有关的矿床,成矿作用发生于210~100 Ma,矿床类型主要有斑岩型Mo(W、Cu)矿床、矽卡岩型多金属矿床和浅成低温热液型Au矿床,形成于与古太平洋板块俯冲有关的活动大陆边缘环境;(4)与蒙古-鄂霍茨克洋和古太平洋构造体系叠加有关的矿床,矿床主要形成于150~120 Ma,矿床类型主要有斑岩型Mo(Cu、W)矿床、热液脉型Pb-Zn-Ag和Cu多金属矿床、高温岩浆热液型稀有稀土元素、W(Sn)、Sn矿床和矽卡岩型Fe多金属矿床,矿床形成环境处于蒙古-鄂霍茨克洋和古太平洋这两大构造体系的叠加区域,总体属于一个伸展的构造背景。不同构造体系下的成矿特点是不同的,而所富集的主要金属元素也有差别。根据所产出的不同金属的资源量大小对比,Cu主要产在与古亚洲洋构造体系和蒙古-鄂霍茨克洋构造体系,Mo主要产在蒙古-鄂霍茨克洋构造体系和古太平洋构造体系,Pb-Zn主要产在蒙古-鄂霍茨克洋和古太平洋构造体系叠加区和古亚洲洋构造体系,Au主要产在古太平洋构造体系,Ag和Sn主要产在蒙古-鄂霍茨克洋和古太平洋构造体系叠加区,W主要产在蒙古-鄂霍茨克洋和古太平洋构造体系叠加区域和古太平洋构造体系。     

内蒙古大兴安岭中北段铜铅锌金银多金属矿床成矿规律与找矿方向

本文根据内蒙古大兴安岭中北段地质构造演化、成矿特征、中俄蒙邻近地区矿产分布和近年来的地质和找矿工作进展,划分了地质构造单元和成矿区带,总结了该地区主要矿床类型和成矿时代分布规律,提出了多金属矿的找矿方向。本文将大兴安岭中北段可以划分为额尔古纳地块、鄂伦春晚华力西褶皱带和东乌旗早华力西褶皱带三个Ⅲ级构造单元,细分为满洲里-新右旗中生代火山-深成岩隆起区等14个Ⅳ级构造单元。工作区主要矿床类型有矽卡岩型、斑岩型、热液型,其次为海相沉积型、岩浆熔离型、砂矿型和云英岩型,其中斑岩型和热液型矿床是主要矿床类型,热液型矿床可以细分为6个子类型。矿床的分布总体上具有北东呈带、北西向成行特点,根据矿床的分布和区域构造特征可以分为德尔布干和东乌旗-兴安两个北东向Ⅲ级成矿带,13个Ⅳ级成矿区。从成矿时代上看,矿床的形成经历了从早古生代至晚中生代的很长时间,而已晚中生代为主。但不同类型矿床的成矿时代分布有很大差异。单一的斑岩型铜（钼金）矿从早古生代延续至燕山期,而其他类型矿床均形成于燕山期。提示在大兴安岭今后的找矿工作中对于矽卡岩型和热液型矿床主要集中于燕山期构造岩浆活动区,而斑岩型矿床找矿则应同时注意古生代和中生代等构造岩浆活动区。     

青海锡铁山块状硫化物矿床的类型及地质特征

锡铁山铅锌矿床是我国大型块状硫化物矿床之一。本文系统地阐述了锡铁山矿床成矿的区域地质背景、含矿绿岩系和矿床地质特征,以及矿床的成因与类型。通过对柴达木北缘绿岩系区域构造、火山岩地质及成矿活动的研究,认为该矿床形成于晚奥陶世古裂谷海槽或称裂谷型优地槽环境中。同时,通过对矿体宏观特征、矿石矿物组成和组构、矿石主元素 Zn、Pb、S的变化和伴生 Au、Ag 的赋存状况与分布、稳定同位素、围岩与其蚀变以及成矿时的物理化学条件的综合研究,确定锡铁山矿床属加里东期火山喷气沉积、热液叠加改造型块状硫化物多金属矿床。从而,初步建立了“锡铁山式”矿床的成矿模式。     

阴极发光在翡翠研究中的应用

通过对多个翡翠及其他玉石标本进行阴极发光实验,观察不同品种的翡翠、处理翡翠制品以及翡翠的相似玉石品种在阴极发光镜下的荧光颜色、发光强度、环带特点、颗粒形态和裂隙状况等的不同特征,来有效鉴别翡翠、处理翡翠及翡翠的相似品。同时依据不同类型翡翠在阴极发光下的特征,对翡翠的品质、颜色等的划分提供依据。     

Morphotectonic study of Hispaniola

Geomorphological analysis; aerial photographs; and geomorphologic, geological, geophysical, topographical, and field studies show that the morphology of Hispaniola can be linked to lateral variations in the geometry and tectonism of the Caribbean-North American Plate Boundary Zone. Three main categories of the relief were established: territorial units (1 megablock, 2 macroblocks, 14 mesoblocks, 209 blocks, 401 microblocks, and 527 nanoblocks), morphostructural alignments (4 first-, 1 second-, 12 third-, and 30 fourth-rank), and 16 knots between morphostructural alignments (second-to fourth-rank). The main seismic activity is concentrated on the first-and second-rank lineaments, and some important epicenters are located in the vicinity of the lineament intersections. The origin of the earthquakes in the vicinity of such knots can be explained by the forcing/pushing of macroblocks northeastward. The existence of earthquakes along the main lineaments may be explained by tension or compression in a restraining bend zone. From the current study, it appears that earthquake occurrence in Hispaniola is related with the stress concentrations in the vicinity of morphotectonic zones. A seismotectonic interpretation of Hispaniola is shown where three zones exist, each of them with a different active level and dimensions. The text was submitted by the authors in English.     

土壤地质单位的建立与研究--以浙江省为例

土壤地质单位是地学工作者根据地质资料、结合成土特征提出的一种新型土壤分类方法,其实质就是在充分考虑气候、生物、地形、时间等成土因素的同时,抓住母岩-母质-土壤三者之间的成生联系,找出成土母岩岩性、矿物成分、结构构造、地球化学特征对土壤结构、质地、厚度、微量营养元素的制约关系,为农业区划和农业种植结构调整提供科学的依据.笔者据浙江省农业地质背景调查项目实践,在从地学角度对浙江省成土母质进行分类的基础上,结合土壤亚类建立了土壤地质单位,并提出研究内容和研究方法.     

Experimental study of stick-slip behaviour

Simple axi-symmetric uni-axial compression tests have been realized on dry loose samples of glass beads (diameters d: d=0.2 ± 0.05 mm, 0.75 ± 0.1 mm, or 3 mm) and on Hostun sand under small lateral confinement, σ₃<60 kPa, using different sample sizes. The experiments with the two smallest spheres (d=0.2 and 0.75 mm) exhibit stick-slips, which are characterized by (i) a rapid release Δq of the deviatoric stress q and by (ii) the strain Δε₁ separating two events. The samples which exhibit stick-slip also present a weakening of strength q(ε₁) as the rate of deformation dε₁/dt is increased. No stick-slip is generated during the first part of the q−ε₁ curve, i.e. when q grows fast with ε₁. Four different parameters helped us determine the statistics of Δq and Δε: the lateral pressure σ₃′, the rate of deformation dε₁/dt, the sample height H, and the diameter D. The statistics do not depend on rate history. They look like exponentials in small samples and/or in (large sample+fast dε₁/dt), and they look like Poissonian or Gaussian in (Large sample+small dε₁/dt). This change in statistics is attributed to a varying of triggering process starting from a single random event in small samples to multiple random events. We have interpreted this change of statistics as due to some finite size effect so that the representative elementary volume shall contain at least (200)³ grains. Localization of deformation is visible at the end of compression but cannot be detected from stick-slip statistics nor from q vs ε curve. Copyright © 2004 John Wiley & Sons, Ltd.     

岩体强度的各向异性研究

本文运用断裂力学理论推导了含节理岩体的初裂强度公式,定量地讨论了节理方向、长度对岩石强度的影响,阐明了节理岩体强度各向异性的实质。通过证实,本文所建立的公式具有很强的适用性和较高的可靠性,可用于实际的工程岩体稳定性评价。     

土体各向异性研究进展

综合论述了土体各向异性在土体本构理论发展的不同阶段的研究进展：详细介绍了国内外在各向异性研究中所采用的试验手段、研究方法、理论成果和应用情况：对具代表意义的重要成果作了比较详细的描述和分析。分析了原生各向异性和应力各向异性的区别与联系，认为土体材料的颗粒结构性是各向异性产生的根本原因，复杂的应力状态是各向异性产生的客观条件：强调了各向异性，尤其是应力各向异性在土体本构理论研究中的重要性，对以后各向异性研究方法提出自己的观点。     

Aeromagnetic study of peninsular India

The degree sheet Aeromagnetic maps up to 17‡N, acquired from the Geological Survey of India, have been manually redigitised at 6 minute intervals to study the long wavelength anomalies over peninsular India. These data have been collected at different survey altitude, epochs, flight line directions, etc. Great care has been taken to correct the total field map and remove the contribution due to the core field and prepare an accurate crustal anomaly map. For the first time, a regional map, depicting the NW-SE structural features north of the orthopyroxene isograd with the essentially E-W features to the south of it and revealing several well known structures, is presented. The analytical signal is calculated to delineate the source fields of these anomalies. It dramatically maps the charnockites and is able to delineate the orthopyroxene isograd. In the Dharwar region the magnetic signatures are associated with the intrusives/ iron ore bodies. Thus, we find that the source rocks of the aeromagnetic anomalies are the host province of charnockites in the SGT and the intrusives/iron ore bodies in the Dharwar belt. Gravity residuals are calculated and a tectonic map of the region is presented from the combined geopotential data.     

石香肠构造研究综述

石香肠构造是一种传统的线状构造，由于其在区域构造应力场方面的研究意义及其所包含的流变学信息和控矿意义等一直吸引着研究者的关注。简述了近几十年来石香肠构造在形态学研究上的进展，分析了其在理论研究上的成果，概括了其在应用研究方面的现状，并对当前及今后石香肠构造的研究方向提出了建议。     

High-pressure structural study of muscovite

The compressibility and structural variations of two 2M₁ muscovites having compositions (Na_0.07K_0.90 Ba_0.01□_0.02)(Al_1.84Ti_0.04Fe_0.07Mg_0.04)(Si_3.02Al_0.98) O₁₀ (OH)₂ (7 mole % paragonite) and (Na_0.37K_0.60□_0.03)(Al_1.84Ti_0.02 Fe_0.10Mg_0.06)(Si_3.03Al_0.97) O₁₀(OH)₂ (37 mole % paragonite) were determined at pressures between 1 bar and 35 kbar, by single-crystal X-ray diffraction using a Merrill-Bassett diamond anvil cell. Isothermal bulk moduli, setting K′ = 4, were 490 and 540 (± 30) kbar for the Na-poor and Na-rich samples respectively. Both samples show highly anisotropic compressibility patterns, with β _a ∶β _b ∶β _c = 1∶1.15∶3.95 for the Na-poor sample and β _a ∶β _b ∶β _c = 1∶1.19∶3.46 for the Na-rich one. HP structural refinements showed that the different compressibility was largely due to the partial substitution of Na for K in the interlayer region. Moreover, the different compressibility of the tetrahedral and octahedral layers, observed in both micas, increased the a rotation of the tetrahedral layer by about 2° in 28 kbar, as also indicated by the evolution of interlayer cation bond lengths. This increases the repulsion of oxygens of the basal layers and between the high-charged cations of the tetrahedral layer. As a consequence, phengitic substitution, reducing α rotation, would increase the baric stability of mica. Comparison between the HP structures of muscovite and phlogopite indicated the lower compressibility of the latter, mainly due to the greater compressibility of the dioctahedral layer with respect to that of the trioctahedral layer. The HT and HP behaviour of di- and trioctahedral micas showed an anisotropy in the compressional pattern which was markedly greater than that observed in the dilatation pattern. This unexpected result was explained by the different evolution with P and T of alkaliO bond lengths. By combining HP and HT data, a tentative equation of state of muscovite is proposed.     

A thermochemical study of monohydrocalcite

The thermodynamic properties of monohydrocalcite, CaCO₃ · H₂O, have been obtained using a well-characterized natural specimen. Equilibration of the solid with water at 25°C under 0.97 atm CO₂ led to an activity product [Ca²⁺][CO₃^2?] = 10^?7.60±0.03 and a free energy of formation ΔG_f^o = ?325,430 ± 270 calmol^?. The enthalpy of solution of monohydrocalcite in 0.1 N HCl at 25°C led to a standard enthalpy of formation ΔH_f^o = ?358,100 ± 280 cal mol^?1. Estimates of the variation of ΔG_f with temperature and pressure showed monohydrocalcite to be metastable with respect to calcite and aragonite.