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福建省金矿成矿地质条件与成矿远景 总被引:1,自引:1,他引:0
福建省金矿与地层、构造、岩浆岩等成矿地质条件关系密切,金矿赋矿层位有8个,其中以前寒武纪麻源群、龙北溪组和中生代火山岩、火山碎屑岩层位为最主要。金矿主要分布在区域性断裂、火山构造、北东向与北西向两组断裂复合部位及火山基底起部位,韧性剪切带、推覆(剥离)构造发育地段,是金矿重要成矿部位。金矿成矿时代主要有前寒武纪和燕山期两个成矿期,两者在成矿时间上显示继承性,在空间上具有相关性。金矿化在前寒武纪与中 相似文献
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辽西中生代火山岩建造中的金矿 总被引:2,自引:0,他引:2
辽西中生代火山岩建造中金矿床的形成与火山活动密切相关。根据金矿化所处的构造位置、金矿化特征及岩石建造,区内金矿床(点)可划分为(1)与3次火山岩有关,(2)与古火山构造有关;(3)与喷出岩有关三个类型。在火山岩建造中,中酸性-酸性次火山岩体边缘构造破碎带,火山构造发育地带及火山喷发岩带对金成矿有利。 相似文献
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吉林二密复式火山机构及成矿控制作用 总被引:1,自引:1,他引:0
以松顶山为中心的二密复式火山机构,受东西向基底断裂与近南北向壳断裂叠加部位控制.中心(松顶山一带)为先期闪长质次火山岩侵入,闪长质岩体边缘接触带附近发育寄生火山口(次一级),并充填花岗质次火山小岩株,构成破火山机构环状构造(内环).二密铜金矿床各矿段主要铜矿体集中于花岗质岩体内及其附近,总体分布和方向又受接触带构造控制.结合区域成矿规律,通过成岩成矿关系研究表明,本矿床除铜矿外,还具有金的找矿前景,并给出了该矿床的成矿模式. 相似文献
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大兴安岭北段金、多金属矿床区域成矿特征 总被引:13,自引:2,他引:13
大兴安岭北段是我国重要的金、铜、铅、锌等多金属成矿区之一。矿床具有北东成带、北西成行的分布特征。成矿作用主要集中在燕山晚期,与燕山晚期火山岩、次火山岩具有内在的成因联系。东西向、北东-北北东向断裂构造是主要的容矿构造,多组断裂构造的交汇部位是矿化的有利部位。成矿物质以深源为主,有部分地壳物质的加入。根据区域成矿特点及成矿条件划分2种成矿类型、3个成矿带,建立了多金属矿床的成矿模型。 相似文献
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内蒙古巴彦哈尔-昌特敖包地区金矿地质特征及找矿潜力初探 总被引:1,自引:0,他引:1
阐述了晚元古代温都尔庙群是区内金成矿有利的矿源层,其分布地带发现了金矿(化)集中区,金矿(化)体主要分布于该岩群与加里东期、华力西期花岗岩,石英闪长岩接触部位,并受控于糜棱岩带,后又叠加了燕山期花岗岩及次火山岩成矿活动,形成构造破碎蚀变岩型、石英脉型及次火山热液型金矿。指出该地区只要有温都尔庙岩群分布,加之叠加有不同期次的岩浆岩及有利的构造,就有可能找到新的金矿床。 相似文献
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内蒙古西口子-八道卡地区岩金成矿特征 总被引:1,自引:1,他引:1
西口子-八道卡地区大地构造位置处于额尔古纳地块北部.区内出露变质岩系为古元古界新华渡口群和新元古界震旦系加疙瘩群.侏罗纪中-酸性岩浆岩活动强烈.基底断裂构造呈近东西向,在侏罗纪形成一系列左行的压扭性北东向断裂构造及伴随的北西向、近南北向张性断裂.金矿化体呈脉状、透镜体状发育在变质岩系、黑云二长花岗岩体的破碎蚀变带内或变质岩系与石英闪长岩的接触部位,受左行压扭性北东向断裂构造与北西向、近南北向张性断裂构造的联合控制.金矿化类型为蚀变岩型和石英脉型,金矿化与硅化、黄铁矿化、绢英岩化关系密切.地球化学研究表明金矿化与黑云二长花岗岩、石英闪长岩关系密切,成矿物质主要来源于地壳深部或地幔,成矿热液属富碱质的、具有弱还原性质的岩浆热液.依据区内金矿成矿作用特点,总结了金矿找矿标志. 相似文献
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考虑核电厂地基-基础的动力相互作用,应用显式动力有限差分法分析了地震作用下极软岩、较软岩、坚硬岩上核电厂建筑结构基础的地震响应特征,比较了岩石坚硬程度对基础加速度反应谱的影响。研究表明:随着岩石坚硬程度的提高,核电厂建筑物结构基础的地震响应有增加的趋势;在周期轴上,基础处的加速度反应谱曲线会随着岩石坚硬程度的提高逐渐向短周期(高频段)方向移动。在高频段,建造于较坚硬岩石上基础结构的加速度反应谱值偏大;在中等频段,建造于较软岩石上基础结构的加速度反应谱值偏大;在低频段,岩石坚硬程度对加速度反应谱的影响不显著。 相似文献
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Ivan V. BRAGIN Georgy A. CHELNOKOV Oleg V. CHUDAEV Natalia A. KHARITONOVA Sergey V. VYSOTSKIY 《《地质学报》英文版》2016,90(1):276-284
Studied waters belong to warm(T=30-50℃),alkaline(pH=8.9-9.3),low mineralized(TDS235 mg/1)Na-HCO_3 or Na-SO_4-HCO_3 thermal waters with high content of SiO_2(up to 81 mg/l)and F(up to 3.9 mg/1),occur on modern volcano-tectonic rejuvenated areas of Eastern Sikhote-Alin orogenic belt.Low~3He concentration as well as N_2/O_2 and N_2/Ar ratios exclude influence of deep mantle fluid.New rare earth element data constrain our understandmg of water-rock interaction occurring in the water source region.Meteoric origin of waters is proved by stable isotope values varying from-71‰to-136.1‰and from-10.8‰to-18.8‰forδ~2U andδ~(18)O respectively.REE patterns reflect high pH,resultfing from water-rock interaction and oxidative conditions.Calculations of deep aquifer temperature using Na-K and quartz geothermometers show 116.8-131.1°C and 82.2-125.8℃respectively.Presence of deep faults both with abnormal thermal gradient(~45-50 K/km)define unique geochemical shape of thermal waters of Sikhote-Alin,area,where no present volcanic activity is registered. 相似文献
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M. D. Sharma 《Journal of Earth System Science》2004,113(2):247-257
Three dimensional scattering of near-field is studied for dilatation and rotation in the time domain. The perturbation method
is applied to solve the equation of motion for the first order scattering from a weak inhomogeneity in an otherwise homogeneous
medium. The inhomogeneity is assumed close enough to the point source so that the near-field intermediate wave is dominating
over the far-field sphericalP andS pulses. The integral expressions are derived to relate dilatation and rotation of scattering to the radial fluctuations of
velocities and density in the inhomogeneity. These integrals are solved to calculate the strains of scattering from (a part
of) an inhomogeneous spherical shell of arbitrary curvature. Variable curvature may allow the shape of inhomogeneity volume
element to change uniformly from spherical to rectangular. Rotation of scattering from a spherical shell is independent ofP wave velocity inhomogeneity. Dilatation of scattering does not involveS wave velocity inhomogeneity but its gradient. The back scattering results are obtained as a special case. Strains are computed
numerically, for hypothetical models to study the effects of various parameters viz., velocity inhomogeneity, distance of
source from inhomogeneity and from receiver, and thickness of inhomogeneity. The curvature of the spherical shell is varied
to study the effects of the shape of inhomogeneous volume element on scattering. 相似文献
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地震次生地质灾害风险评估集对态势分析 总被引:2,自引:0,他引:2
5.12四川汶川8级强震引发了大量次生地质灾害,加剧了灾情并严重影响抗震救灾。地震次生地质灾害受多重因素制约,其孕育与致灾过程具有不确定性。利用集对分析原理与方法,对地震次生地质灾害进行同异反态势分析,拟定了风险评估的集对分析同一度、差异度、对立度等指标体系的构建原则与赋值标准,对承灾体系统的不确定性及其作用作了刻画与分析,建立了不同风险分区代表性的集对分析联系度表达式,为地震灾害研究提供了可资借鉴的新思路和技术方法。 相似文献
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下扬子区三叠纪古地理演化 总被引:2,自引:2,他引:0
下扬子区在三叠纪期间接受了早-中三叠世海相碳酸盐沉积、中-晚三叠世海陆交互相和陆相湖沼沉积.沉积相带的空间分布和古地理格局的变迁明显地受到区域构造的控制.区内盆地发育与演化是在华南板块与扬子板块、扬子板块与华北板块相互作用的背景下进行的.早-中三叠世末期的印支运动是下扬子区构造-古地理格局改变的决定性因素,使下扬子海盆闭合,沉积类型由海相沉积变为陆相沉积.下扬子区三叠纪古地理的演化特征也为板块碰撞提供了沉积证据. 相似文献
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Isothermal thermogravimetric experiments have been carried out to determine the reaction kinetics of the dehydration processes
in fuller's earth, a natural Ca-montmorillonite. Dehydration in swelling clays is a complex reaction, and analysis of the
thermogravimetric data using empirical rate equations and time-transformation analysis reveals that the nature of the rate
controlling mechanism is dependent upon both the temperature regime of the sample as well as the extent of reaction. For fuller's
earth, we find that the dehydration kinetics are dominated by a nucleation and growth mechanism at low temperatures and fractions
transformed (stage I), but above 90 °C the last stages of the reaction are diffusion controlled (stage II). The activation
energy for dehydration during stage I is around 35 kJ · mol−1, whereas the removal of water during stage II requires an activation energy of around 50 kJ · mol−1. These two stages of dehydration are associated with primary collapse of the interlayer (stage I) and movement of water that
is hydrated to cations within the interlayer (stage II).
Received: 28 August 1998 / Revised, accepted: 27 January 1999 相似文献