新疆卡拉达尔布拉克地段铀成矿控因分析     

王守玉  善曹特 《铀矿地质》2019,(4):220-228

通过野外地质调查、室内测试分析,结合砂体平面、剖面特征,总结了卡拉达尔布拉克地段岩性、岩相及油气还原特征,探讨了其与铀富集关系。认为下白垩统克孜勒苏群为凹陷扩张背景下的干旱冲积扇-扇三角洲沉积建造,岩性组合、持续油气还原及层间氧化改造,对铀成矿有明显控制作用。  相似文献   

Butte detachment: how pre‐rift geological structure and drainage integration drive escarpment evolution at rifted continental margins     

Y. Gunnell  D.J. Harbor 《地球表面变化过程与地形》2010,35(12):1373-1385

The erosional pattern of passive margins often follows the fabric of ancient, compressional geological structures exposed by the topographic energy of rifting. As erosion cuts into these belted outcrop systems they impose initial and boundary conditions that steer drainage recession into the plateau edge and control escarpment‐forming conditions. Pattern therefore controls process. Although generic surface process models predict scarp patterns and retreat in settings devoid of geological heterogeneity, they tend to do so only at isolated locations and for periods shorter than the lifespan of the escarpments. Thus, to focus on relatively narrow strike‐perpendicular swaths of passive margin topography misses important aspects of drainage integration, which involves mobile drainage basin boundaries shifting across but also along the strike of inherited geological structures and through continental‐scale bioclimatic zones. Space‐for‐time substitution along three passive margin escarpments (Blue Ridge, Western Ghats, Eastern Ghats) reveals the significance of escarpment jumps and the detachment of topographic outliers, here generically termed ‘buttes’, as key processes of escarpment evolution. The examples show that these continental escarpments are strongly patterned after pre‐rift structural and lithological heterogeneities. As seaward sloping drainages cut into the rift margin, they extend their drainage heads in a non‐uniform and unsteady fashion. As a result escarpments can form, be destroyed, reform, and leave topographic vestiges (buttes) of the retreating escarpment. Given the pre‐rift geological heterogeneities, there are no a priori reasons why escarpment landscape change should be uniform, steady or self‐similar. Copyright © 2010 John Wiley & Sons, Ltd.  相似文献   

Ground penetrating radar application in a shallow marine Oxfordian limestone sequence located on the eastern flank of the Paris Basin, NE France   总被引：5，自引：0，他引：5  

Guy Dagallier  Ari I. Laitinen  Fabrice Malartre  Ignace P. A. M. Van Campenhout  Paul C. H. Veeken   《Sedimentary Geology》2000,130(3-4):149-165

A Ground Penetrating Radar (GPR) survey has been carried out in Upper Jurassic limestones located on the eastern flank of the Paris Basin (NE France). The potential of the investigation method is assessed for delineating geologically meaningful stratifications in the shallow subsurface. The fundamentals of the GPR technique are described. Penetration depth and vertical resolution depends on the soil conditions, the characteristics of input signal and the configuration of the transmitter–receiver assembly. In the studied carbonates the penetration level is rather good and the electromagnetic signal reaches up to 1000 nanoseconds maximum (i.e. approximately 55 m). Several depositional units are outlined on the GPR profiles. Six different lithological units are recognised with distinct GPR reflection characteristics. The profiles illustrate the internal 3D organisation of the carbonate platform and its geometry. They provide detailed insight into the nature of an Oxfordian reefal build-up. The high-resolution subsurface model is directly calibrated with geological field observations and it results in a predictive 3D depositional working model. The GPR method is a non-destructive remote sensing technique that is cost effective. The method is considered complementary to other conventional high-resolution reservoir characterisation studies. It represents a powerful investigation tool in earth science studies concerning the imaging of the structure of the shallow subsurface.  相似文献   

东昆仑五龙沟地区猴头沟二长花岗岩年龄、成因、源区及其构造意义   总被引：5，自引：0，他引：5  

严威  邱殿明  丁清峰  刘飞 《吉林大学学报(地球科学版)》2016,46(2):443-460

对东昆仑造山带五龙沟地区的猴头沟二长花岗岩开展了详细的岩相学、地球化学、锆石U-Pb年龄及Hf同位素的分析测试和研究工作。LA-ICP-MS锆石U-Pb测年表明,猴头沟二长花岗岩的²⁰⁶Pb/²³⁸U加权平均年龄值为(419.0±1.9)Ma,属于晚志留世。岩石地球化学数据表明:猴头沟二长花岗岩属于高钾钙碱性系列的A₂型花岗岩,富SiO₂、K₂O、Y(>33×10^-6)和Yb,贫Al₂O₃和Sr(<100×10^-6),具有强烈的负铕异常;Rb、Th、U、La、Ce、Nd相对富集,Nb、Ta、Ba、Sr、P、Ti亏损。锆石的Hf同位素研究表明,其ε_Hf(t)值为0.2~5.1,对应二阶段模式年龄(T_DM2)为1066~1371 Ma,由此推测花岗岩源区来自中元古代镁铁质下地壳部分熔融。微量元素及其特征比值的构造判别图解表明,猴头沟二长花岗岩形成于早古生代晚志留世东昆仑造山旋回的造山后伸展阶段。据此认为,原特提斯洋在东昆仑地区的最晚闭合时限应该不晚于晚志留世末期(~419 Ma),而不是前人认为的早泥盆世。  相似文献   

碳酸盐缓坡区的露头层序地层研究     

童金南  崔玮霞 《地球科学》2002,27(5):565-569

碳酸盐缓坡区沉积相带宽, 缺乏直观的物理层序界面标志, 但区域上受气候海平面控制的多级岩性旋回发育, 可对比性强, 生物丰富, 因而可借助于旋回地层学和生态地层学方法进行区域露头层序地层研究.通过岩性旋回叠加型式和生境型迁移过程研究, 较好地进行了下扬子区下三叠统露头层序划分, 建立了层序地层格架, 并提出以海侵面为界进行层序划分对于碳酸盐缓坡区露头层序地层研究更有可操作性和实用性.   相似文献   

砂体物性对岩性油藏成藏控制作用物理模拟     

高永进  田美荣  贾光华 《地球科学》2007,32(2):273-278

以东营凹陷岩性油藏为例, 从地质剖析、物理模拟实验和成藏机理等方面探讨了砂体物性变化对岩性油藏含油饱和度增长的控制作用.东营凹陷下第三系被有效源岩包裹砂体的含油性好于处于源岩之外的砂体的含油性, 而且被源岩包裹砂体的含油饱和度具有随砂体物性变好而增加的趋势.在对东营凹陷岩性油藏剖析的基础之上, 应用岩性油藏成藏模拟实验装置, 开展了不同砂体物性对岩性砂体成藏控制的物理模拟实验.模拟实验表明: 在相同压力条件下, 随着砂体粒度的增加, 砂体电阻率变化相同量所需的时间逐渐变短, 即砂体中的含油饱和度达到一定值的速度逐渐变快.这说明砂体物性越好, 越有利于砂体油藏的形成, 砂体物性是影响油气成藏的重要因素.   相似文献   

地震属性技术在郭局子洼陷沙二段岩性油藏描述中的应用   总被引：8，自引：7，他引：1       下载免费PDF全文

陈香朋  韩国庆  田建华  郝志伟 《地球物理学进展》2008,23(3):846-851

郭局子洼陷沙二段储层以滩坝砂体和小型扇体为主,分布规律性不强,勘探程度较低.我们采用弧长属性和相干分析技术较为准确地识别并描述了储层分布范围和低序级断层,有效地指导了该区该类储层的勘探.  相似文献   

应用定量颗粒荧光技术研究岩性油气藏的隐蔽输导通道   总被引：2，自引：0，他引：2  

陈冬霞  庞雄奇  张俊  李明刚 《地质学报》2007,81(2):250-254

应用定量颗粒荧光技术对东营凹陷牛庄洼陷5口井101块沙三段致密储层、薄层粉砂岩进行了定量荧光QGF-E和QGF分析。分析表明,牛24、牛83、牛876、王550、牛872等5口井致密薄储层颗粒具有相对较高的荧光,显示这些较致密的粉砂岩为过去或现在的油气运移路径/运载层,表明致密砂岩、粉砂岩、薄层砂岩可作为烃类运移的通道。这类薄层隐蔽输导通道为深凹带牛庄洼陷深部沙四段上亚段烃源岩生成的油气进入无断层切割的沙三段中、下亚段的砂岩透镜体而成藏提供了重要的依据。该研究结果对于东营凹陷正在进行的隐蔽油气藏成藏机理的研究可能具有重要意义。  相似文献   

利用核磁共振物理模拟实验研究岩性油气藏成藏机理   总被引：9，自引：3，他引：6  

陈冬霞  庞雄奇  姜振学  苗盛  张俊  田丰华 《地质学报》2006,80(3):432-438

本文采用核磁共振成像技术(NMR)进行物理模拟实验,直观地观测了岩性圈闭中油的聚集成藏过程并定量模拟了不同条件下砂体中的含油性。实验结果表明,油气在砂体中的聚集是缓慢的,向上、向下及侧向都有油的运移,但以向上的运移速度较快,其次是侧向,向下较慢;温度、压力、砂体物性和围岩含油性是影响砂体含油性的重要因素。在实验研究的基础上,分析了岩性油气成藏的微观机理,将油气成藏过程划分为三个阶段,第一阶段为在扩散作用力、烃浓度差异压力作为动力克服毛细管阻力下的油气在烃源岩孔隙中心顺干酪根网络运移的过程;第二阶段为在毛细管压力差引导下的油气在砂泥岩界面通过孔隙和喉道渗滤的过程;第三阶段为在浮力作用下克服流体流动粘滞阻力和吸附阻力在砂体内富集的过程。  相似文献   

Coexisting different types of zoned garnet in kyanite‐quartz eclogites from the Sanbagawa metamorphic belt: Evidence of deformation‐induced lithological mixing during prograde metamorphism     

Masaki Enami  Jun‐Ichi Kimura  Motohiro Tsuboi  Yui Kouketsu  Takayoshi Nagaya  Shuaimin Huang 《Island Arc》2019,28(1)

Garnet grains in Sanbagawa quartz eclogites from the Besshi region, central Shikoku commonly show a zoning pattern consisting of core and mantle/rim that formed during two prograde stages of eclogite and subsequent epidote–amphibolite facies metamorphism, respectively. Garnet grains in the quartz eclogites are grouped into four types (I, II, III, and IV) according to the compositional trends of their cores. Type I garnet is most common and sometimes coexists with other types of garnet in a thin section. Type I core formed with epidote and kyanite during the prograde eclogite facies stage. The inner cores of types II and III crystallized within different whole‐rock compositions of epidote‐free and kyanite‐bearing eclogite and epidote‐ and kyanite‐free eclogite at the earlier prograde stage, respectively. The inner core of type IV probably formed during the pre‐eclogite facies stage. The inner cores of types II, III, and IV, which formed under different P–T conditions of prograde metamorphism and/or whole‐rock compositions, were juxtaposed with the core of type I, probably due to tectonic mixing of rocks at various points during the prograde eclogite facies stage. After these processes, they have shared the following same growth history: (i) successive crystal growth during the later stage of prograde eclogite facies metamorphism that formed the margin of the type I core and the outer cores of types II, III, and IV; (ii) partial resorption of the core during exhumation and hydration stage; and (iii) subsequent formation of mantle zones during prograde metamorphism of the epidote–amphibolite facies. The prograde metamorphic reactions may not have progressed under an isochemical condition in some Sanbagawa metamorphic rocks, at least at the hand specimen scale. This interpretation suggests that, in some cases, material interaction promoted by mechanical mixing and fluid‐assisted diffusive mass transfer probably influences mineral reactions and paragenesis of high‐pressure metamorphic rocks.  相似文献