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1.
映秀地区花岗岩属龙门山推覆构造带“彭灌杂岩”南段之组成部分,岩石类型以二长花岗岩、英云闪长岩为主,少量花岗闪长岩。按照同源岩浆演化序列的观点,根据岩石学、岩石化学及地球化学、接触关系等特征,将该区花岗岩划分为8个花岗岩单元。其岩石为稀土总量偏低、具负铕右倾型式的钙碱性次铝及过铝型酸性侵入岩,分属造山前陆弧I型花岗岩的成分演化序列及造山晚期S型花岗岩的结构演化序列,其形成时代为中─晚元古代。  相似文献   

2.
根据花岗岩同源岩浆演化序列,将康定县大雪山超单元花岗岩体划分为3个单元,岩石组合特征为石英闪长岩、花岗闪长岩、二长花岗岩,具有明显的成分-结构演化特征。同位素年龄为104~121 Ma,时代属燕山晚期的Ⅰ型花岗岩。通过对岩石化学、稀土元素、微量元素等数据的分析,论述了折多山岩体的物质来源、构造环境及其成因。  相似文献   

3.
探讨西藏八宿地区侏罗纪花岗岩的岩石学特征,为找矿提供理论依据.通过对花岗岩类岩体的地质、地球化学、成分演化程度、分异程度和氧化状态的分析,结果表明区内侏罗纪花岗岩大量分布,反映了一次大规模岩浆事件.花岗岩由北西—南东向的断裂控制.岩石组合为黑云角闪石英二长闪长岩-黑云母花岗闪长岩-花岗闪长斑岩-黑云母二长花岗岩,为过铝...  相似文献   

4.
辽南梁屯-矿洞沟古元古代岩体包括坎子岩体、卧龙泉岩体、学校后街岩体与梁屯岩体,岩性分别为中细粒二长花岗岩、中细粒似斑状黑云母二长花岗岩、细粒黑云母二长花岗岩、细粒正长岩。学校后街岩体与梁屯岩体LA-ICP-MS锆石U-Pb年龄加权平均值为1 887.2±5.4 Ma、1 883.9±2.6 Ma,为古元古代。从坎子岩体到梁屯岩体岩石化学体现了一个偏铝-过铝型,钙碱性-碱性的演化序列,K及Mg O含量逐渐增高,富集大离子亲石元素K、Rb、Ba、Sr,亏损高场强元素Nb、Ta、Zr、Hf,稀土元素配分模式右倾,属具有负铕异常的轻稀土富集、重稀土亏损型。结合相关构造环境分析,古元古代岩体在辽河岩群沉积完成后存在着一个活动大陆边缘-碰撞造山-造山晚期,岩石类型由I型-S型-A型的演化过程。  相似文献   

5.
在德尔布干深断裂中段西北侧的额尔古纳地块上识别出一套正长岩-花岗岩组合,其形成时代为新元古代晚期,岩石类型为石英正长岩、二长花岗岩、钾长花岗岩.石英正长岩SiO2质量分数为60.86%~66.14%,高Al2O3,高K2O Na2O、富钾,暗色矿物主要为角闪石,为准铝质钾玄岩系列岩石,铕负异常不明显(0.81);花岗岩高硅、富碱,暗色矿物主要为黑云母,铕负异常明显(0.08~0.46).地球化学特征表明:岩石主要形成于晚造山-后造山环境,花岗岩为铝质A型花岗岩,来源于古老陆壳的部分熔融.正长岩-花岗岩组合为探索区域前寒武纪地块晚期演化历史提供了约束.  相似文献   

6.
四川康定折多山超单元地球化学特征   总被引:1,自引:0,他引:1  
根据花岗岩同源岩浆演化序列,将康定县折多山超单元花岗岩体划分为3个单元,岩石组合特征为粗粒似斑状二长花岗岩、中粒二长花岗岩、细粒二长花岗岩,具有明显的成分-结构演化特征,同位素年龄为3.75~15.4 Ma,时代属喜马拉雅期的S型花岗岩.通过岩石化学、稀土元素、微量元素等数据的分析,论述了折多山岩体的物质来源、构造环境及其成因.  相似文献   

7.
北山中部地区闪长岩-花岗岩类成因及构造背景   总被引:10,自引:0,他引:10  
北山中部地区中酸性侵入岩以海西中晚期为主,加里东晚期次之。岩石类型有辉长岩、闪长岩、花岗闪长岩、斜长花岗岩和花岗岩类。岩浆活动分为3个旋回6期,其中海西中期第2,3期和海西晚期岩浆活动员为强烈。研究区岩体多呈岩株、岩枝和岩基产出,围岩普遍发育混合岩化和同化混染,岩石具花岗结构,块状-(巨)斑状构造。岩石化学成分为钙碱性系列,闪长岩分异程度低,斜长花岗岩和花岗闪长岩分异程度中等,花岗岩类相对较高。加里东晚期和海西晚期花岗岩类属S(海西)型花岗岩类,海西中期闪长岩、花岗闪长岩和斜长花岗岩类则属I型(科迪勒拉),闪长岩属交代(花岗岩化)成因,花岗闪长岩-花岗岩类属岩浆成因。加里东晚期花岗岩是中-晚志留世北山地区哈萨克斯坦板块向南俯冲使上地壳局部熔融的结果;海西中期闪长岩是混合岩化(花岗岩化)的产物;花岗闪长岩和斜长花岗岩是裂谷扩张阶段上地慢部分熔融的结果;而海西晚期花岗岩是裂谷萎缩和闭合阶段地壳局部熔融的结果。  相似文献   

8.
华南出露大量加里东期花岗岩,其岩石成因、构造背景长期存在争议。湖南省加里东期花岗岩年代学和地球化学数据显示,其主要形成于416~432 Ma之间,岩性主要为花岗岩和花岗闪长岩。岩石类型除少数为I型花岗岩外,大部分为S型花岗岩。地球化学特征为富硅、过铝质和高钾钙碱性系列花岗岩,富集Rb、Th、U等元素,亏损Ba、Nb、Sr等元素;指示岩浆源区为古-中元古代地壳物质部分熔融的产物,部分花岗岩有幔源物质的加入。区域地质背景和岩石地球化学数据指示湖南加里东期岩体形成于碰撞挤压峰期之后挤压减弱、应力松弛的后碰撞构造环境。区域内加里东期花岗岩中铀含量相对较高,为后期铀成矿提供物质来源。  相似文献   

9.
东昆仑西祁漫塔格地区东沟一带,发育一套成分演化序列的早三叠世花岗岩体,通过系统1∶5万区调工作,对该岩体进行了详细的研究和划分,建立了早三叠世西沟口序列的谱系填图单位,其似斑状二长花岗岩岩体中的局部地段出现大量闪长岩类包体,经对似斑状二长花岗岩和闪长质包体岩石学、矿物学、岩石地球化学等详细研究发现,二者在成因上具联系性,演化上具亲缘性,闪长质包体是不混溶包体.  相似文献   

10.
亚勒—雄勒断裂带是冈底斯板块与羌塘板块的分界断裂带 ,是班公湖—怒江断裂带中段的组成部分。对断裂带侵入岩岩体的岩石类型、岩石化学特征、岩石地球化学特征的研究表明 ,侵入岩石主要为闪长岩、石英闪长岩、角闪石闪长岩和花岗岩 ,属钙碱性岩石系列 ,具“Ⅰ”型花岗岩特征。其形成是由于在冈底斯板块与羌塘板块碰撞过程中 ,地壳物质发生熔融而沿断裂带侵入所致 ,为燕山晚期产物  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   

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