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1.
长江流域岩体的时空分布与碎屑锆石物源示踪   总被引:2,自引:0,他引:2  
结合区域大地构造演化,系统总结并讨论了长江流域火成岩的时空分布特征及其对长江中下游沉积物物源的指示意义.结果表明,长江流域岩体的时空分布特征与区域构造演化密切相关;青藏高原新生代酸性侵入岩和火山岩以及云贵川高原晚二叠世峨眉山玄武岩及伴生酸性岩是长江上游地区的特征岩体;汉江和湘江—赣江流域早古生代中酸性侵入岩是长江中游地区的特征岩体;白垩纪中酸性侵入岩和火山岩是长江下游地区的特征岩体.这一成果可直接用于指导长江中下游地区利用碎屑锆石U-Pb年代学和Hf同位素进行物源示踪的工作.在钻孔沉积物中准确识别出这些特征年龄信息,并结合沉积物古地磁年代的标定对研究长江的地质演化历史具有重要指示意义.  相似文献   

2.
在粒级分离的基础上,对长江河口及邻近陆架22个表层沉积物进行了磁学表征,探讨了磁性特征对物源、输运、沉积动力等环境信息的指示意义.研究结果表明,长江入海泥沙、残留砂及废黄河物质是长江口外水下三角洲及邻近陆架沉积物磁性特征的主要物源影响因素,但3者的空间分布不同.沉积物磁化率(c)、饱和等温剩磁(SIRM)、硬剩磁(HIRM)及非磁滞剩磁磁化率(c ARM)的空间变化指示了长江入海泥沙出口门后向南及东南方向输运. SIRM与c及退磁参数(S–100)与SIRM关系图表明,大于63μm粒级沉积物来自残留砂与现代长江粗颗粒,其分布大致以30 m等深线为界;小于16μm粒级沉积物受长江和废黄河物质的影响,口内为长江源,口外北部贴岸以废黄河源为主,口外其他区域则表现为以长江物质占主导的混合源.沉积物粒度和磁学特征的空间变化反映了动力的粒度和密度分选作用,并体现在沉积环境分区磁性特征差异及分粒级组分对全样SIRM贡献的空间变化上.粒级分离减小了粒度效应对全样磁性特征的干扰,提高了沉积物物源判别的准确性,在反映三角洲地貌变化及物源定量识别上具有重要意义.  相似文献   

3.
李恩菊  董治宝 《河南科学》2014,(8):1565-1570
在第四纪沉积物研究中,特别是现代沉积环境的研究中,沉积物的地球化学特征在分析物源和重建古环境等方面发挥积极的作用.通过采集了巴丹吉林沙漠不同区域、不同类型沙丘、不同地貌部位的沙样,分析了巴丹吉林沙漠沉积物的地球化学特征,得出巴丹吉林沙漠沉积物在矿物学上和沉积学上的成熟度较低,但是具有很好的均质性的结论.这一结论对于推断巴丹吉林沙漠沉积物的物源有很好的指示意义,同时对于研究巴丹吉林沙漠高大沙山的成因也有一定的线索意义.  相似文献   

4.
水系的变化导致物源区的变化,反映在相关沉积盆地中表现为沉积物中矿物组合的改变,以及特征矿物的出现.通过对三峡出口处宜昌地区第四纪沉积物中重矿物特征的研究,结合区域地质资料、野外沉积特征研究和样品EsR测年资料,认为0.73 Ma以前的冲积扇一扇三角洲沉积中重矿物特征明显不同于之后的阶地沉积及现代河床沉积物.这种重矿物组合的不同反映了0.7 Ma前后物源区的改变,同时也指示长江三峡贯通的时间.  相似文献   

5.
黄河源头区碎屑锆石U-Pb年龄及其地质意义   总被引:1,自引:0,他引:1  
利用LA-ICP-MS分析技术,对黄河源头区沉积物碎屑锆石进行U-Pb年代学研究,据此分析黄河源头区地壳物质的来源.结果显示,黄河沉积物碎屑锆石年龄主要分布于以下区间:200-230Ma、240-320Ma、350-490Ma、1700-2000Ma和2300-2650Ma,少量碎屑锆石年龄分布于700-900Ma.分析表明,1700-2000Ma和2300-2650Ma的碎屑锆石主要来自于华北块体;350-490Ma的碎屑锆石主要来自于东昆仑造山带、祁连造山带、柴达木板块和秦岭造山带;240-320Ma的碎屑锆石主要来自于东昆仑造山带和柴达木板块北缘;200-230Ma的碎屑锆石来自于区域内出露的印支期花岗岩.由于黄河源头区沉积物主体反映了松潘-甘孜造山带西部三叠系沉积物的组成,因此,碎屑锆石年龄结构指示该区三叠系沉积物主要来自于华北块体、东昆仑造山带、柴达木板块、祁连造山带和秦岭造山带,无明显扬子块体和大别造山带地壳物质的加入.松潘-甘孜造山带西部与东北部在沉积物源组成上具有较好的一致性,反映它们属于同一个沉积中心.  相似文献   

6.
为明确敦煌盆地五墩凹陷中间沟组一段物源体系及展布,以岩矿与主量元素分析为基础,结合水动力条件、地震剖面反射特征和古地貌分析,研究砂体的发育程度、物源方向与搬运通道,探讨五墩凹陷侏罗系中间沟组不同井区的沉积物来源。研究结果表明:XC1与D2井具有同源性,岩屑类型以变质岩岩屑为主,D1井物源表现出一定差异性,岩屑类型以岩浆岩岩屑为主,主量元素分析结果与岩屑类型分析结果相一致;XC1、D2井主要为近源扇三角洲沉积,D1井主要为远源辫状河三角洲沉积;XC1和D2井区主要接受南部三危山隆起物源区的沉积物供给,D1井区主要接受北部北山物源区的沉积物供给。重新落实的物源体系展布对于研究区砂体展布规律具有重要的指导意义。  相似文献   

7.
利用井-震结合、地层对比、沉积相及古地貌分析等方式识别沟谷-坡折带,重点分析了沟谷-坡折带特征及对储层分布的控制作用.研究表明:松辽盆地西斜坡早白垩世发育的两极挠曲坡折带在平面上呈北东向展布;沟谷顺物源分布,垂直于坡折带走向;在基准面旋回变化过程中,沟谷-坡折带对沉积物的体积分配和相分异有特定的控制作用,进而与储层的分布有着密不可分的关系;沟谷是控制水系和沉积物搬运的通道,坡折带是沉积物卸载的场所,沟谷-坡折带体系控制了沉积物的类型和平面分布.  相似文献   

8.
从土壤包气带铅污染源示踪、沉积物铅污染源示踪、水环境铅污染源示踪及现代水环境监测、水岩相互作用示踪等几个方面介绍了铅同位素方法的应用,并初步展望了其在水文地质调查、地下水污染监测、饮水安全以及地下水资源保护和评价等领域的应用前景.  相似文献   

9.
东海陆架北部长江、黄河沉积物影响范围的定量估算   总被引:5,自引:0,他引:5  
采用粒度分析、扫描电镜观察(SEM)、ICP-AES分析等方法,得到了关于长江、黄河入海沉积物的示踪粒级以及示踪指标,并提出沉积物物源定量识别的非线性规划数学模型,进而实现了东海陆架北部表层沉积物中长江型、黄河型物质的定量估算。  相似文献   

10.
黏土矿物是认识沉积环境变化和示踪物质来源的重要环境指标。应用粉晶X射线衍射(XRD)方法对长江口启东嘴潮滩的岩芯沉积物的黏土矿物组成进行分析,结果表明:伊利石含量最高,均值为54.11%;其次为绿泥石和蒙脱石,均值分别为21.30%、16.21%;高岭石最低,均值为8.37%。组合类型多样,主要为Ⅰ型(伊利石+绿泥石+蒙脱石+高岭石)、Ⅱ型(伊利石+绿泥石+高岭石+蒙脱石)、Ⅲ型(伊利石+蒙脱石+绿泥石+高岭石)。物源分析结果显示,研究区沉积物与南黄海物质的关系最为密切。南黄海沉积物受到长江和黄河的共同影响,在长期的地质过程作用下具有混合源特征。沉积物来源的变化与沉积动力环境的变化密切相关。人类围垦活动造成分流角加大,接近90°,导致长江北支分流比急剧下降,河槽性质发生质的变化,涨潮流成为主要动力作用。来自口外南黄海的悬浮泥沙,在涨潮动力的携带下扩散倒灌成为研究区主要的物质来源。  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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