甘肃玛曲大水金矿矿体地质数据中蕴涵的成矿信息   总被引：3，自引：0，他引：3  

何进忠  姚书振  龚全胜  陈耀宇 《地质学报》2008,82(8):1142-1151

大水金矿是著名的超大型矿床,对于其地质地球化学特征已有许多较深入的研究,本文通过单因素直方图统计、关联分析、分形统计、曲线拟合等方法研究了矿体地质数据之间的关系。规模最大的主矿体与其他矿体相比,在顶板围岩、底板围岩、品位、矿体倾向、长度、延深等6个要素上均体现出奇异性,可见主矿体是在十分特殊的地质环境中形成的。控矿变量中,矿体长度、厚度、延深和倾向等变量之间具有相关性,倾向在20°~320°内变化,倾角、品位与其他变量之间的相关性不显著;由此推测,成矿作用的发生并不直接受控于浅层的构造因素,而与岩浆侵入及热液活动诱发的似环状、似锥状局部构造裂隙有关。矿体资源量具有明显的多重分形分布特征,而矿体的长度总体上呈简单分形分布,与前人的研究结果联系起来看,大吨位矿体的围岩以构造角砾岩或蚀变角砾岩为特征,属于充填成因;而中等规模的矿体则属于热液交代成因,一些小规模矿体可能与沉积作用有关;在成矿空间上,不同期次的成矿作用遵循了同位成矿规律。矿床的吨品位关系对幂律分布并不能很好地拟合,而是服从指数分布。  相似文献   

中国铁矿床品位-吨位模型   总被引：1，自引：0，他引：1  

阴江宁  肖克炎  邹伟  丁建华  娄德波 《矿床地质》2008,27(6):782-790

文章以2005年国家有关部门公布的铁矿储量数据为依据,在拥有翔实和权威的铁矿数据材料的基础上,经过分析整理和统计计算,以铁矿的6种矿床类型(沉积变质型、沉积型、矽卡岩型、岩浆岩型、火山岩型和风化型)为划分依据,建立了中国铁矿及其伴生矿种的品位和吨位模型,并对其品位-吨位联合分布的模型进行了研究。通过研究得出结论,中国铁矿的资源量不服从正态分布,经过对数变换后服从正态分布,品位除了矽卡岩之外都直接服从正态分布。由于铁矿的品位和吨位之间相关性较差,因而不具备分形特征。最后通过建立吨位和品位的直方图来构造正态分布函数,从而实现累计概率曲线的拟合。在取得了远景区的矿床类型、矿床数分布以及矿床的品位和吨位的累计概率曲线后,可以使用计算机通过蒙特卡洛模拟的方法来实现远景区资源量的预测和模拟。  相似文献   

河南省前河构造蚀变岩型金矿的矽卡岩化及其找矿意义     

汪在聪  李胜荣  申俊峰 《矿床地质》2008,27(6):751-761

前河金矿床位于秦岭造山带内,矿体赋存于低绿片岩相变质的中元古界熊耳群安山质火山岩地层中,严格受断裂控制。通过对前河金矿深部和外围找矿工作发现,石家岭矿段发育有矽卡岩化岩石,主要发育于合峪花岗岩体北部赋存金矿体的F4断裂附近,围岩是低绿片岩相的安山质火山岩,并且在前河大桥附近有石榴子石脉产出;岩相学特征及电子探针成分分析表明,该矽卡岩化岩石由钙铁石榴子石、透辉石-钙铁辉石、绿帘石、绿泥石、阳起石、石英和方解石等矿物组成,经历了干矽卡岩阶段、湿矽卡岩阶段以及石英硫化物阶段这一典型演化过程;褐帘石电子探针成分和穆磁铁矿具赤铁矿的假象表明,湿矽卡岩阶段具有还原性特征。因此,前河金矿矽卡岩化可能由附近合峪花岗岩岩浆热液交代形成。  相似文献   

阿尔泰造山带南缘和准噶尔板块北缘晚古生代构造演化及多金属成矿作用   总被引：8，自引：2，他引：6  

张海祥  牛贺才  沈晓明  马林  于学元 《矿床地质》2008,27(5):596-604

研究表明,阿尔泰南缘和准噶尔北缘晚古生代大地构造演化及成矿作用均受古亚洲洋形成与演化的控制。晚古生代该地区经历了3个不同性质的构造演化阶段,同时伴有不同的多金属成矿作用。早泥盆世,由于古亚洲洋板块的俯冲,在阿尔泰南缘形成了一系列陆缘断陷盆地,并伴随以铅、锌、铜、铁多金属为主的矿化;同时,俯冲的古亚洲洋板块发生部分熔融,形成了埃达克岩及与其有关的铜矿床。随着板块俯冲的继续,中泥盆世出现了前弧盆地,并形成了铜-铅-锌多金属矿床。至石炭纪,西伯利亚板块与哈萨克斯坦-准噶尔板块发生碰撞,在额尔齐斯缝合带附近出现了由于挤压作用而形成的金矿床,同时,在缝合带北侧(阿尔泰地区),由于壳型花岗岩的广泛发育,形成了稀有金属矿床。早二叠世,在额尔齐斯缝合带附近又发生了碰撞后的板内拉张作用,从而诱发了一系列与地幔作用有关的岩浆活动,形成了以喀拉通克为代表的铜-镍矿化。因此,阿尔泰南缘和准噶尔北缘晚古生代多金属找矿远景区包括:阿勒泰南缘早泥盆世火山-沉积盆地内铅、锌、铜及铁多金属矿床和准噶尔北缘早泥盆世与埃达克岩有关的铜矿床;中泥盆世前弧盆地内的铜多金属矿床;石炭纪额尔齐斯缝合带内与碰撞有关的金矿床及稀有金属矿床;早二叠世与板内拉张有关的铜-镍多金属矿床。  相似文献   

证据权重法在张家口地区铅锌银富集区定量评价中的应用     

李随民  姚书振  韩玉丑  郝华金  陈树清 《矿床地质》2008,27(5):647-654

文章以张家口铅锌银多金属富集区为例,在前人研究的基础上,运用GIS平台提取了与成矿关系密切的赋矿层位、岩体5km缓冲区、深大断裂3km和次级断裂1km的复合缓冲区及化探、物探异常等证据图层,选用证据权重法模型对研究区进行了成矿远景区分析和评价,取得了较好效果,并讨论了预测过程中信息提取时应注意的问题。  相似文献   

内蒙古突泉县莲花山银铜矿床成矿地质背景探讨   总被引：2，自引：0，他引：2  

肖丙建  王伟德  张强  李宪栋  王真亮  刘同  胡来龙 《地质与勘探》2008,44(1):26-30

文章通过对莲花山银铜矿床与成矿关系较密切的次火山岩的岩石化学、微量元素、稀土元素和同位素分析,对该矿床的成矿地质背景进行了探讨;认为莲花山银铜矿床是在太平洋板块向亚洲大陆板块俯冲下产生的弧后引张区,由来源于上地幔或下地壳的深源钙碱性岩浆多次上侵,在相对封闭的还原环境下形成的中高温热液矿床.  相似文献   

内蒙古正蓝旗羊蹄子山-磨石山钛矿区两种不同成因类型的锐钛矿富矿体   总被引：1，自引：0，他引：1  

赵一鸣  李大新  吴良士  马润  陈文明  王佩华  高学东 《矿床地质》2008,27(4):459-465

内蒙古正蓝旗羊蹄子山-磨石山钛矿床有两种不同类型的锐钛矿富矿体,即产于北部磨石山矿带的沉积变质型锐钛矿富矿体和产于南部羊蹄子山矿段的热液改造型锐钛矿富矿体。两类富矿体在矿体规模、形态、矿石结构构造特征、矿石矿物共生组合、矿石化学成分、锐钛矿粒度和成矿时代及成矿机理等方面,都存在较明显的差异。沉积变质型锐钛矿富矿体呈层状、似层状产出,矿石具有明显的细条纹状构造;由以石英为主的条纹和以锐钛矿、金红石、钛铁矿、直闪石(±黑云母、石榴子石)为主的条纹互层组成;矿石品位(TiO2)为5.0%～15.46%,平均值为8.64%,Fe2O3 FeO含量中等(6.99%～15.61%),锐钛矿颗粒细小(0.01～0.1mm);形成于元古宙〔(1751±8)Ma〕二道凹群变质岩系中。热液改造型锐钛矿富矿体呈透镜状,规模相对较小;矿石具有块状、网脉状、细脉浸染状构造;共生矿物除锐钛矿、金红石、钛铁矿、石英外,常有较多的叶片状赤铁矿,局部有直闪石、黑云母和石榴子石;锐钛矿粒度较大(0.05～0.2mm,少数可达0.5mm),且分布不均匀;是在元古宙沉积变质富锐钛矿变质石英砂岩的基础上,经燕山晚期〔(118±3)Ma〕花岗岩侵入,遭受热液改造而成。  相似文献   

Liquefaction potential of Quaternary alluvium in Bolu settlement area,Turkey   总被引：1，自引：0，他引：1  

Koray Ulamis  Recep Kilic 《Environmental Geology》2008,55(5):1029-1038

Groundwater bearing alluvial units in the seismically active settlement areas may bring out probable damage on the urban and built environment due to liquefaction. Bolu settlement area and surroundings are located in the North Anatolian Fault Zone. Geotechnical boreholes were drilled in order to determine the distribution of the geological units, to obtain representative soil samples and to measure groundwater level. Quaternary aged alluvium is the main geological unit in the South of study area. Stiffness and consistency of the soils were determined by Standart penetration test. P and S wave velocities of soil have been measured along the seismic profiles. The index and physical properties of the samples have also been tested in the laboratory. Liquefaction potential and safety factor of the sandy levels in Quaternary aged alluvium were investigated by different methods based on SPT and V _s. Liquefaction seems to be a significant risk in case of an earthquake with a _max = 0.48 g and M _w = 7.5 at different levels of the boreholes. This situation may bring out environmental problems in the future.  相似文献   

Source parameters of March 10 and September 13, 2007, United Arab Emirates earthquakes     

Y. Al Marzooqi  K.M. Abou Elenean  A.S. Megahed  I. El-Hussain  A.J. Rodgers  E. Al Khatibi   《Tectonophysics》2008,460(1-4):237-247

On March 10 and September 13, 2007 two earthquakes with moment magnitudes 3.66 and 3.94, respectively, occurred in the eastern part of the United Arab Emirates (UAE). The two events were widely felt in the northern Emirates and Oman and were accompanied by a few aftershocks. Ground motions from these events were well recorded by the broadband stations of Dubai (UAE) and Oman seismological networks and provide an excellent opportunity to study the tectonic process and present day stress field acting in this area. In this study, we report the focal mechanisms of the two main shocks by two methods: first motion polarities and regional waveform moment tensor inversion. Our results indicate nearly pure normal faulting mechanisms with a slight strike slip component. We associated the fault plane trending NNE–SSW with a suggested fault along the extension of the faults bounded Bani Hamid area. The seismicity distribution between two earthquake sequences reveals a noticeable gap that may be a site of a future event. The source parameters (seismic moment, moment magnitude, fault radius, stress drop and displacement across the fault) were also estimated from displacement spectra. The moment magnitudes were very consistent with waveform inversion. The recent deployment of seismic networks in Dubai and Oman reveals tectonic activity in the northern Oman Mountains that was previously unknown. Continued observation and analysis will allow for characterization of seismicity and assessment of seismic hazard in the region.  相似文献   

Regional geoid determination in Antarctica utilizing airborne gravity and topography data   总被引：2，自引：2，他引：0  

Mirko Scheinert  Jan Müller  Reinhard Dietrich  Detlef Damaske  Volkmar Damm 《Journal of Geodesy》2008,82(7):403-414

Antarctica is the only continent that suffers major gaps in terrestrial gravity data coverage. To overcome this problem and to close these gaps as well as to densify the global satellite gravity field solutions, the International Association of Geodesy (IAG) Commission Project 2.4 “Antarctic Geoid” was set into action. This paper reviews the current situation concerning the gravity field in Antarctica. It is shown that airborne geophysical surveys are the most promising tools to gain new gravity data in Antarctica. In this context, a number of projects to be carried out during the International Polar Year 2007/2008 will contribute to this goal. To demonstrate the feasibility of the regional geoid improvement in Antarctica, we present a case study using gravity and topography data of the southern Prince Charles Mountains, East Antarctica. During the processing, the remove–compute– restore (RCR) technique and least-squares collocation (LSC) were applied. Adding signal parts of up to 6 m to the global gravity field model that was used as a basis, the calculated regional quasigeoid reveals the dominant features of bedrock topography in that region, namely the graben structure of the Lambert glacier system. The accuracy of the improved regional quasigeoid is estimated to be at the level of 15 cm.  相似文献