首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 62 毫秒
1.
龙湾铅锌矿床赋存于早白垩世正长花岗岩与中奥陶统马家沟组碳酸盐岩接触带附近,围岩蚀变强烈.铅锌矿石微量元素特征与正长花岗岩较为相似,矿石Co/Ni值为2.93~4.32,具有岩浆热液成因矿床的特征.矿石稀土元素配分模式为右傾的轻稀土富集型,自矿石到花岗岩体,其稀土总量73.92×10~(-6)到277.42×10~(-6)逐渐升高.碳氧同位素特征显示成矿热液主要为岩浆水.矿床成矿物质主要来源于花岗岩体,矿床为典型的矽卡岩型矿床.  相似文献   

2.
包尔图铜矿床位于南天山库米什洋盆俯冲变质带的边缘,矿体受断裂构造控制。矿区围岩为一套中深变质岩,其稀土元素组成具有如下特征:∑REE较高,LREE/HREE=2.46~16.86,轻重稀土元素明显分异,且轻稀土相对富集,负铕异常,配分模式曲线向右倾斜。矿石的∑REE相对较低,LREE/HREE=0.06。0.97,轻重稀土元素明显分异,重稀土相对富集,配分曲线向左倾斜,与混合岩脉体的稀土元素配分模式相近。稀土元素组成特征指示矿床的成矿过程可能与混合岩化作用有关。结合矿床地质特征,认为包尔图铜矿床为变质热液型铜矿床。  相似文献   

3.
对拉拉铁氧化物-铜-金(IOCG)矿床中与铜矿化密切相关的变质期方解石(Ⅰ)和热液期方解石(Ⅱ)的稀土元素(REE)及C,O同位素地球化学特征进行研究,以探讨方解石成因及沉淀影响因素、成矿流体来源及性质。研究结果表明:方解石(Ⅰ)具有极低的REE总质量分数(wREE平均75.98×10-6),方解石(Ⅱ)的REE总质量分数相对较高(平均313.85×10~(-6));方解石(Ⅰ)的δ(13CPDB)为-3.84‰~0‰,方解石(Ⅱ)的δ(13CPDB)为-3.98‰~-1.40‰,二者大小接近且相对变化较小;方解石(Ⅰ)的δ(18OSMOW)为9.45‰~12.2‰,方解石(Ⅱ)的δ(18OSMOW)为8.1‰~11.6‰,后者相对低于前者。分析认为:方解石(Ⅰ)不是变质成矿期的主要REE载体,其成矿流体中REE含量很低;方解石(Ⅱ)为热液期REE的主要载体,其成矿流体中REE含量较高。两期方解石均为热液成因,但二者成矿流体不同源;水岩反应及降温作用耦合影响本矿床两期方解石的沉淀。方解石(Ⅰ)的REE配分曲线为平坦型,既有正Eu异常也有负Eu异常,无Ce异常,配分模式受流体中REE络合物稳定性控制,其成矿流体为大量LREE沉淀后的残余高温变质成矿流体,继承了海相喷发的火山围岩部分特征;方解石(Ⅱ)的REE配分曲线为左倾型,显著正Eu异常,无Ce异常,配分模式受方解石晶体化学因素控制,其成矿流体为大气降水与围岩反应形成的低温高氧逸度热卤水。方解石(Ⅰ)的成矿流体中的C由深源C和海水C共同提供;方解石(Ⅱ)的成矿流体中的C来自地幔柱成因的基性辉长岩浆分异释放的CO2,O同位素受大气降水影响发生明显负漂移。  相似文献   

4.
郭家岭型花岗岩主要分布于胶西北北部的上庄、丛家、郭家岭一带,近年在大尹格庄金矿钻孔中发现了斑状花岗岩。本次研究采取大尹格庄斑状花岗岩样品,测试了岩石主量元素、微量元素和稀土元素含量。岩体具有高的Ba(1 187×10~(-6)~1 897×10~(-6))、Sr(931.25×10~(-6)~989.54×10~(-6))、轻稀土(113.17×10~(-6)~167.68×10~(-6))含量,低的Nb(3.81×10~(-6)~6.09×10~(-6))、Ta(0.18×10~(-6)~0.31×10~(-6))和重稀土(4.21×10~(-6)~5.63×10~(-6))含量,轻稀土富集、重稀土亏损(LREE/HREE=26.07~32.04),无明显Eu异常,亏损高场强元素Nb、Ta、P、Ti,与上庄岩体同属郭家岭型花岗岩。岩浆具有壳幔混合特点,成岩背景为活动大陆边缘。大型金矿附近都有郭家岭型花岗岩存在,金矿的形成与郭家岭型花岗岩相依;成岩时间早于金矿成矿时间5~10 Ma,与岩浆期后热液矿床成岩成矿时间差相符;郭家岭型花岗岩为金矿成矿提供了成矿物质、热源和矿化剂,胶东金矿的形成与郭家岭型花岗岩关系密切。  相似文献   

5.
对相山铀矿田山南矿区围岩、矿石稀土元素地球化学特征进行了研究。矿区基底片岩∑REE平均值与火山岩系岩石∑REE平均值大致相当,自围岩、普通矿石到富矿石,∑REE不断增高。围岩稀土元素配分模式均呈轻稀土富集的右倾型,火山岩系岩石稀土元素配分模式彼此平行一致,火山岩系具同源性,是同一岩浆房脉动事件的产物。火山岩系围岩及矿石Eu亏损明显,结合稀土组分比值特征及岩、矿石轻、中、重稀土三角图解和LREE/HREE-(Eu/∑REE)×100图解特征,表明火山岩浆在通向地表途中受到高度分馏结晶作用,U及REE富集于岩浆期后热液,为铀成矿提供了物质基础,矿区火山岩系成岩事件与铀成矿事件均是受制于火山岩浆活动的地质事件。成矿流体富含F,Cl,CO2等挥发分,在还原环境下成矿物质卸载,成矿温度可能不大于250℃,富矿石成因更为复杂,可能经历了多期次成矿叠加。  相似文献   

6.
西藏尼木斑岩铜多金属矿区位于冈底斯铜钼多金属成矿带中段,具典型斑岩型铜矿床矿化特征。区内岩浆岩从酸性到中酸性均有出露,通过对不同类型岩浆岩主量、微量、稀土元素的分析测试结果显示,其SiO_2变化于57.94%~70.12%,平均为67.63%,K_2O+Na_2O变化于6.68×10~(-6)~8.84×10~(-6),平均约7.97×10~(-6),多属高钾钙碱性岩石;各类岩石中W、Pb、Th,Ba、As、Sb、Bi、Ag、Rb、Te、Cs、Hf明显富集,而Ta、V、Hg、Au、Sc、Cr、Co、Ni、Nb、Mo等明显贫化;稀土总量变化于89×10~(-6)~427×10~(-6),稀土配分曲线呈明显的右倾型,轻稀土相对富集,基本无Eu异常。里特曼指数(δ)-戈蒂尼指数(τ )关系图、(Yb+Ta)-Rb、(Y+Nb)-Rb构造环境判别图均显示其形成于岛弧环境造山带环境;A-C-F图解显示为I-S型过渡型,相对偏向于S型。综合分析认为区内岩浆岩应为青藏高原隆升中地壳部分融熔的产物,可能为同源、同构造环境下岩浆分异的结果。  相似文献   

7.
通过对岩体进行野外地质调查、硅酸盐全分析、稀土微量分析以及LA-ICP-MS锆石U-Pb法测定年龄,探讨吉林南部荒沟山地区侏罗纪花岗岩形成的动力学环境。结果表明,荒沟山地区的老秃顶子岩体和草山岩体的LA-ICP-MS锆石U-Pb年龄为178~181 Ma;主要岩石类型为似斑状黑云母花岗岩;岩石具有较高的SiO2含量(质量分数为72.04%~73.68%),为准铝质到过铝质的高钾钙碱性Ⅰ型花岗岩;稀土元素总量(质量分数为94.24×10-6~170.14×10-6),具有右倾的稀土元素配分模式,中等的负铕异常(δEu=0.51~0.69);在原始地幔标准化蛛网图中,富集K、Rb、Th等不相容元素,亏损Ba、Nb、Ta、P、Ti等,具有活动大陆边缘岩浆弧的地球化学特征。其形成与古太平洋板块向华北板块的俯冲有关。  相似文献   

8.
为了研究青海省昆仑河地区的大地构造环境及岩石年代学意义,对昆仑河两侧的晚三叠世花岗岩的主量元素、微量元素及LA-ICP-MS锆石U-Pb同位素定年进行研究和探讨。结果表明:该岩石为高钾钙碱性过铝质岩石,主量元素具有高K_2O(5.36%~5.92%),低P_2O_5(0.07%~0.08%),FeO(0.27%~1.6%),TiO_2(0.18%~0.24%)的特征,大离子亲石元素Rb,Th相对富集,而高场强元素Nb,Hf,Zr则明显亏损,稀土元素含量高,ΣREE为(433.67~590.00)×10~(-6),稀土元素配分模式呈轻稀土强烈富集的右倾斜型,(La/Yb)N值为9.74~16.86,岩石具明显的负铕异常(δEu=0.15~0.19),说明岩浆物质来源于地壳上部,可能有少量地幔物质混入。锆石LA-ICP-MSU-Pb同位素定年结果表明,该地区花岗岩的成岩年龄为(200.9±1.1)Ma(MSWD=3.2),为晚印支期岩浆活动产物。结合地球化学图解、区域地质背景及年代学证据,认为该花岗岩应为后碰撞构造环境的产物。  相似文献   

9.
湖南锡田钨锡多金属矿田成矿分带样式及机理   总被引:1,自引:0,他引:1  
为了探索锡田矿田内矿床分布规律及其成矿热液系统内在联系,对区内燕山期14个岩浆热液矿床野外特征进行调查和显微矿相学观察,采用将矿化类型、矿石矿物组合和成矿均一温度相结合的方法对区域矿化规律进行研究。研究结果表明:矿田内存在南、北2个成矿区域,各自拥有独立成矿热液中心,并且存在明显的钨锡—铅锌—萤石矿床分带规律;流体包裹体均一温度的空间分布与矿化分带相一致,从钨锡矿带(215~384℃)到萤石矿带(136~194℃)连续分布;南、北2个成矿区域白钨矿稀土元素特征均为轻、重稀土元素富集,中稀土亏损,正Eu异常明显(δw(Eu)=7.93~43.58),稀土配分模式均为典型"W"型,反映成矿物质来源相似;其成矿热液来源为同一燕山期成矿热液系统,其矿化分带的原因可能与燕山期岩浆热液系统温度梯度格局有关。  相似文献   

10.
通过分析西凹铜-锡多金属矿床蚀变岩的稀土元素特征,研究该矿的成矿物质、成矿流体来源及成矿环境等。研究结果表明:蚀变花岗岩的稀土元素配分模式与未蚀变花岗岩类似,但也存在一定的差异。相对于未蚀变花岗岩,钾化花岗岩稀土总量增高,重稀土元素(HREE)的富集程度比轻稀土元素(LREE)的大,轻稀土元素中的La,Ce的富集程度比Pr和Nd的大,次生钾长石继承了蚀变流体的稀土元素特征,可能与蚀变流体温度较高有关,且富含F,Cl和CO2有关,成矿流体来源于岩浆期后热液。绿帘石-绿泥石化花岗岩稀土总量略有降低,LREE亏损而HREE略微富集,由流体蚀变、云母类矿物的吸附作用及早期钾化蚀变共同造成。Eu异常和Ce异常,表明钾化处于相对高温氧化条件下,而绿帘石-绿泥石化则处于相对低温和还原的环境中。蚀变花岗岩中REE与成矿元素关系密切,对岩体内部找矿具有一定的指示意义。  相似文献   

11.
The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3~4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰~ -7.8‰, PDB) and matrix dolomites (-6.6‰~ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084~0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078~0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.  相似文献   

12.
AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…  相似文献   

13.
本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。  相似文献   

14.
Various applications relevant to the exciton dynamics,such as the organic solar cell,the large-area organic light-emitting diodes and the thermoelectricity,are operating under temperature gradient.The potential abnormal behavior of the exicton dynamics driven by the temperature difference may affect the efficiency and performance of the corresponding devices.In the above situations,the exciton dynamics under temperature difference is mixed with  相似文献   

15.
The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to  相似文献   

16.
17.
The explosive growth of the Internet and database applications has driven database to be more scalable and available, and able to support on-line scaling without interrupting service. To support more client's queries without downtime and degrading the response time, more nodes have to be scaled up while the database is running. This paper presents the overview of scalable and available database that satisfies the above characteristics. And we propose a novel on-line scaling method. Our method improves the existing on-line scaling method for fast response time and higher throughputs. Our proposed method reduces unnecessary network use, i.e. , we decrease the number of data copy by reusing the backup data. Also, our on-line scaling operation can be processed parallel by selecting adequate nodes as new node. Our performance study shows that our method results in significant reduction in data copy time.  相似文献   

18.
R-Tree is a good structure for spatial searching. But in this indexing structure,either the sequence of nodes in the same level or sequence of traveling these nodes when queries are made is random. Since the possibility that the object appears in different MBR which have the same parents node is different, if we make the subnode who has the most possibility be traveled first, the time cost will be decreased in most of the cases. In some case, the possibility of a point belong to a rectangle will shows direct proportion with the size of the rectangle. But this conclusion is based on an assumption that the objects are symmetrically distributing in the area and this assumption is not always coming into existence. Now we found a more direct parameter to scale the possibility and made a little change on the structure of R-tree, to increase the possibility of founding the satisfying answer in the front sub trees. We names this structure probability based arranged R-tree (PBAR-tree).  相似文献   

19.
There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.  相似文献   

20.
The geographic information service is enabled by the advancements in general Web service technology and the focused efforts of the OGC in defining XML-based Web GIS service. Based on these models, this paper addresses the issue of services chaining,the process of combining or pipelining results from several interoperable GIS Web Services to create a customized solution. This paper presents a mediated chaining architecture in which a specific service takes responsibility for performing the process that describes a service chain. We designed the Spatial Information Process Language (SIPL) for dynamic modeling and describing the service chain, also a prototype of the Spatial Information Process Execution Engine (SIPEE) is implemented for executing processes written in SIPL. Discussion of measures to improve the functionality and performance of such system will be included.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号