微束分析技术在研究伴生金元素赋存状态中的应用   总被引：1，自引：1，他引：0  

戴婕  徐金沙  潘晓东  任静  张茜 《岩矿测试》2011,30(6):655-663

运用微束分析技术扫描电子显微镜(SEM)及其配套的背散射电子像功能,特征X射线线扫描、面扫描功能,能谱仪(EDAX)鉴定功能,观察里伍铜矿矿石中纳米级至微米级的伴生金(超微细金)矿物,获取其形貌照片、能谱图和定性定量分析结果,得到了清晰的金元素及与其共生的元素线、面分布图像,查明了里伍铜矿中的金元素是以类质同象的形式分布于含银的铋矿物和金银矿中,含银的铋矿物和金银矿分布在黄铜矿与磁黄铁矿的裂隙中及含锰的铁闪锌矿中,排除了基体成分的干扰,载金矿物颗粒至少大于20 nm。该方法操作简便,过程简单,分析结果直观、可靠,提高了研究伴生金元素赋存状态的效率。测试的样品为里伍铜矿热液型矿石,经分析形成于燕山中晚期(104～142.2 Ma),为局部构造运动和岩浆期后热液使成矿元素再富集成矿的地质产物,晚于主成矿期——燕山中期。里伍铜矿中Ag和Au的质量比值为1.38～4.59,推测伴生金的成矿温度应小于或等于227℃。里伍铜矿在成矿过程中至少经历了早期的中高温热液阶段和晚期的中低温热液阶段,早期大量硫化物的析出和晚期中低温绿泥石、绢云母矿物的大量出现也证实了这一过程的存在。  相似文献   

Estimation of the evacuation clearance time based on dam-break simulation of the Huaxi dam in Southwestern China     

Cuiyun Cheng  Xin Qian  Yuchao Zhang  Qingeng Wang  Jinbao Sheng 《Natural Hazards》2011,57(2):227-243

It is necessary for China to establish a feasible method to verify whether an emergency evacuation plan (EEP) provides timely evacuation under the threat of flooding as a result of dam failure. Based on simulating the inundation area resulting from failure of the Huaxi Dam, this paper puts forward a quantitative approach to assess the effectiveness of an EEP by estimating the evacuation clearance times. Differences between urban and rural areas are considered, and two transportation modes are selected. Total evacuation clearance times in rural and urban areas are 135 and 80?min, respectively. Results show that total evacuation clearance times are longer than the time it takes for the flood wave to reach some communities in the area. The paper also makes some suggestions on how to decrease the total clearance time and thus enhance the effectiveness of the EEP for the Huaxi Dam.  相似文献   

新矿物南岭石的再研究     

丁奎首  杨主明  林俊  苏文  傅小土  李秋立  唐国强  毛骞 《岩石学报》2011,27(6):1840-1846

本文在原有湿法化学分析结果基础上对南岭石的矿物化学式做了重新计算,纠正了原化学式的错误,并对晶胞参数做了精确测定。经晶体结构测定,确认本矿物不仅是以(AsO₃)阴离子团的氧原子密堆积作为结构框架外,其中还出现了Fe-As成键的新特征,属于一种新结构类型的新矿物。红外光谱及穆斯堡尔谱分析测试显示了本矿物波谱学方面的特征。对矿物新的化学组成除采用电子探针、能谱手段以外,还运用SIMS离子探针证实了锂的确实存在。  相似文献   

福建锦城187Ma花岗岩的发现——对华南沿海早侏罗世构造演化的制约   总被引：7，自引：2，他引：5  

刘潜  于津海  苏斌  王勤  唐红峰  许海  崔翔 《岩石学报》2011,27(12):3575-3589

本文对福建沿海福清地区的锦城花岗岩和牛头尾花岗闪长岩进行了岩石地球化学、锆石U-Pb-Hf同位素分析.LA-ICP-MS锆石U-Pb定年结果显示锦城花岗岩的年龄为187±1Ma,为福建沿海首次发现的早侏罗世岩浆活动;牛头尾花岗岩形成时代为130±1Ma,代表燕山晚期(白垩纪)的一期岩浆活动.锦城花岗岩具有高5iO2、偏碱、高Fe2OT3等特征,为高钾钙碱性系列,岩石相对富集轻稀土,亏损Nb、Ta、Ti等高场强元素,富集Ba、Sr等大离子亲石元素,具高Rb/Sr( 1.31 ～ 1.93)比值及低Rb/Ba(0.26 ～0.29)、Eu/Eu*(0.30 ～0.56)、La/Yb(5.69 ～ 18.39),Sr/Y(2.24 ～2.29)比值,为典型的Ⅰ型花岗岩,且具有火山孤花岗岩的地球化学特征,很可能形成于与俯冲相关的构造背景.牛头尾花岗岩相比锦城花岗岩低SiO2,贫钾,而富镁、钙,属于花岗闪长岩.其更亏损Nb、Ta及富集Ba、Sr,具较低Rb/Sr(0.27)、Rb/Ba(0.09)比值和较高的Eu/Eu*(0.98)、La/Yb( 16.87),Sr/Y( 19.08)比值,同样为具有弧特征的钙碱性Ⅰ型花岗岩,也形成于与大洋俯冲有关的构造背景.锦城花岗岩和年头尾花岗闪长岩具有相似的锆石Hf同位素组成,εHf(t)分别为2.18～4.73和1.25 ～4.15,tDMC均为～ 1.0Ga,表明二者起源于相同的新元古代新生地壳.结合已有的资料,本次研究发现锦城花岗岩与南岭地区同时代岩浆岩( 194 ～ 172Ma)在成因上有密切的联系,暗示古太平洋板决的俯冲很可能自早侏罗世开始.这样,华南古特提斯构造域向古太平洋构造域的转换很可能发生在早侏罗世之前,大致在205 ～ 190Ma期间.  相似文献   

Geological, geochemical characteristics and isotope systematics of the Longqiao iron deposit in the Lu-Zong volcano-sedimentary basin, Middle-Lower Yangtze (Changjiang) River Valley, Eastern China   总被引：8，自引：0，他引：8  

Zhou Taofa  Wu Mingan  Fan Yu  Duan Chao  Yuan Feng  Zhang Lejun  Liu Jun  Qian Bing  Franco Pirajno  David R. Cooke 《Ore Geology Reviews》2011,43(1):154-169

The Middle-Lower Yangtze (Changjiang) River Valley metallogenic belt is located on the northern margin of the Yangtze Craton of eastern China. Most polymetallic deposits in the Changjiang metallogenic belt are clustered in seven districts where magmatism of Mesozoic age (Yanshanian tectono-thermal event) is particularly extensive. From west to east these districts are: E-dong, Jiu-Rui, Anqing-Guichi, Lu-Zong, Tong-Ling, Ning-Wu and Ning-Zhen. World-class iron ore deposits occur in the Lu-Zong and Ning-Wu ore clusters, which are mainly located in continental fault-bound volcanic-sedimentary basins. One of these deposits is the Longqiao iron deposit, discovered in the northern part of the Lu-Zong Basin in 1985. This deposit consists of a single stratabound and stratiform orebody, hosted in sedimentary carbonate rocks of the Triassic Dongma'anshan Formation. A syenite pluton (Longqiao intrusion) is situated below the deposit. The iron ore is massive and disseminated and the ore minerals are mainly magnetite and minor pyrite. Wall rock alteration mostly consists of skarn minerals, such as diopside, garnet, potassic feldspar, quartz, chlorite, phlogopite and anhydrite. Thin sedimentary siderite beds of Triassic age occur as relict laminated ore at the top and the margin of the magnetite orebody. These sideritic laminae are part of Triassic evaporite-bearing carbonate deposits (Dongma'anshan Formation).Sulfur isotopic compositions show that the sulfur in the deposit was derived from a mixture of magmatic hydrothermal fluids and carbonate–evaporite host rocks. Similarly, the C and O isotopic compositions of limestones from the Dongma'anshan Formation indicate that these rocks interacted with magmatic hydrothermal fluids. The O isotopic compositions of the syenitic rocks and minerals from the deposit show that the hydrothermal magnetite and skarn minerals were formed from magmatic fluids. The Pb isotopic compositions of sulfides are similar to those of the Longqiao syenite. Phlogopite coexisting with magnetite in the magnetite ores yielded a plateau age of 130.5 ± 1.1 Ma (2σ), whereas the LA-ICP MS age of the syenite intrusion is 131.1 ± 1.5 Ma, which is slightly older than the age of phlogopite.The Longqiao syenite intrusion may have crystallized from a parental alkaline magma, generated by partial melting of lithospheric mantle, during extensional tectonics. The ore fluids were probably first derived from magma at depth, later emplaced in the sedimentary rocks of the Dongma'anshan Formation, where it interacted with siderite and evaporite-bearing carbonate strata, resulting in the formation of magnetite and skarn minerals. The Longqiao iron deposit is a skarn-type stratabound and stratiform mineral system, genetically and temporally related to the Longqiao syenite intrusion. The Longqiao syenite is part of the widespread Mesozoic intracontinental magmatism (Yanshanian event) in eastern China, which has been linked to lithospheric delamination and asthenospheric upwelling.  相似文献   

海南岛中三叠世正长岩—花岗岩套的地质地球化学特征与构造意义          下载免费PDF全文

周佐民  谢才富  徐倩  高大飞 《地质论评》2011,57(4):515-531

海南岛中三叠世正长岩-花岗岩套分布于陵水-龙滚深断裂两侧及白沙深断裂南东侧.出露总面积516km2.由石英二长岩、石英正长岩及正长花岗岩组成.该岩套SiO2含量变化大,为58.40%-76.14%,富碱富钾,Na2O+K2O为7.10%-11.49%,K2O含量为3.78%-7.91%,属钾玄质碱性系列;A/CNK为0...  相似文献   

塔里木盆地二叠系划分对比与火山岩分布   总被引：3，自引：1，他引：2  

蒲仁海  党晓红  许璟  郭倩  伊红佳 《岩石学报》2011,27(1):166-180

根据全盆地钻井与露头剖面对比和地震剖面追踪解释,探讨了塔里木盆地覆盖区二叠系岩石地层的划分对比。二叠系自下而上由一个自然伽玛曲线加积段、三个自然伽玛曲线退积段组成,加积段为南闸组、退积段分别为库普库兹曼组、开派雷兹克组和沙井子组。南闸组是塔里木盆地最后一次海侵形成的滨浅海灰岩泥岩薄互层为主的沉积。库普库兹曼组和开派雷兹克组是两个基性火山岩-酸性火山岩的旋回或基性火山岩-砂泥岩的旋回。沙井子组是一个与区域构造运动有关的冲积扇、辫状河-曲流河沉积的异旋回。二叠系火山岩在和田河、塔中西部和顺托果勒地区厚度较大,库普库兹曼组火山岩一般0~60m,开派雷兹克组火山岩一般0~200m,局部可超过400m。与库普库兹满组火山岩相比,开派雷兹克组火山岩分布范围由塔西南朝塔东北方向有所迁移。中西部的库普库兹曼组火山岩可能喷发于水下。火山通道多沿着古隆起上的断背斜、断鼻构造分布。火山岩可形成油气藏遮挡,或本身形成储层,但火山活动改造或不同程度地破坏了早期已有油气藏。  相似文献   

CSAMT全区视电阻率电场正演迭代拟合近场校正方法   总被引：2，自引：0，他引：2  

詹少金  钱美平  冯戋戋 《物探与化探》2011,35(5):663-665

利用水平电偶源激发的电磁场,提出了正演迭代拟合电场强度的CSAMT近场校正方法。实验应用表明,在远区该方法的结果等于卡尼亚电阻率,在近区和过渡区则明显改善了卡尼亚电阻率的非波区场畸变。使用该方法能扩大CSAMT的勘探深度,扩展应用领域,更形象地反映地下介质的垂向电性的变化。  相似文献   

Geological characteristics of the Sizhuang gold deposit in the region of Jiaodong, Shandong Province——A study on tectono-geochemical ore prospecting of ore deposits   总被引：1，自引：0，他引：1  

Jianping Qian  Hongyi Chen  Yong Meng 《中国地球化学学报》2011,30(4):539-553

Tectono-geochemical samples were systematically collected from 5 drillcores along the No. 304 explora-tion line and at the -310 m level under the pit in the mining area, totalling 705 samples from the metamorphic rocks, granites, altered rocks and orebodies, and were determined for their contents of 20 kinds of elements including Au, Ag, As, Sb, Hg, Cu,,Pb, Zn, Sn, Bi, Mo, Co, Ni, Mn, Cr, V, Ti, Ba, Rb, Sr, etc. By using the Surfer software the geochemical exploration line profile maps for the 20 kinds of elements and the curves for the element geochemical contents of individual ore vein groups were established. In conbination with the geochemical map analytical method and Gregorian’s zoning index calculation method, the vertical, longitudinal and lateral zonation sequences of the elements were ascertained and the geochemical three-dimentional zonation model of the primary halos was estab-lished on the basis of the analysis of metallogenic structures and alteration zonation. Coupled with the results of analysis of the geology and geochemistry data, it may be concluded that the process of alteration of granites in the mining area is also accompanied with the process of gold enrichment and mineralization. With the intensification of alteration of granites from granite →potash feldspathization granite →sericite-quartz alteration granite, seric-ite-quartz rocks →beresitized granite, pyrite sericite-quartz rock, silicified granite →gold ore, the contents of thio-phile ore-forming elements such as Au, Ag, As, Cu, Bi, Mo, Pb, Sb, Hg, and Sn tended to increase. Factor analysis of trace elements indicated: factor F2 (Au, Ag, Cu, Sn, As) represents the element association brought in at the main stage of hydrothermal metallogenesis; factor F4 (Bi, Sb) and factor F5 (Pb, Zn) represent the ore-forming element association supperposed during the late stage of Au-bearing sulfides. By using the Gregorian’s zoning index and map analysis method we have ascertained the primary halo axial zonation sequence (form frontal halo →tail halo): Pb, Zn, Mn, Ba, Sr, Rb, As, Sb, Ag, Cu, Sn, Mo, Au, Bi, Hg, Ti, Cr, V, Ni, and Co. The geochemical anomalies in the mining area display a tendency of lateral plunging to WS, which is consistent with the lateral plunging of orebodies and mineralization alteration zone. Comprehensive analysis of the results of investigations on ore-controlling structures, mineralization-alteration zonation and geochemical zonation of the primary halos indicates that the gold orebodies in this area are still of greater extension.  相似文献   

江西武山花岗闪长斑岩中黑云母成分特征及其成岩成矿意义   总被引：4，自引：0，他引：4  

东前  杜杨松  曹毅  庞振山  宋林旭  郑震 《矿物岩石》2011,31(2)

江西武山花岗闪长斑岩与矽卡岩铜矿在成因上密切相关,通过对其中的黑云母进行的岩相学观察和详细的矿物化学分析来探讨黑云母的形成条件及其成岩成矿意义。电子探针分析结果表明,武山花岗闪长斑岩中的黑云母富镁贫铁低铝高钛,属镁质黑云母。其AlⅥ为0.03~0.19,w(ΣFeO)/w(ΣFeO+MgO)为0.531~0.567,w(MgO)为12.80%~14.06%,指示武山花岗闪长斑岩属壳幔混源的I型花岗岩。黑云母结晶的温度为720℃~750℃,logfO2为-11.6~-12.5,压力为86 MPa~103 MPa,对应的侵位深度为2.84 km~3.39 km,表明该岩体形成于相对高温较浅环境,具有较大成矿潜力,有利于武山铜矿的形成。  相似文献