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81.
正断层的阶区构造及生长机制:以狼山山前断层带为例   总被引:2,自引:0,他引:2  
正断层带在生长过程中内部发育有阶区构造,阶区在正断层的相互作用、连接过程中起重要控制作用,同时阶区还影响地表径流和沉积盆地的发展、流体的运移和圈闭的形成。位于内蒙古河套断陷西缘的狼山山前断裂是晚新生代以来持续活动的大型正断层系统,断层带内部发育有不同类型的阶区构造。识别出了两种类型阶区的连接方式,一种是两条平行断层之间的斜坡从"软连接"到"硬连接"的演化过程;另一种是楔状阶区通过一条断层向另一条断层扩展的方式连接产生。基岩中的先存构造要素控制并影响山前正断层的展布方位及阶区的形态:基底内部NNE向糜棱面理控制山前断层带的走向,早期向SE倾斜的逆冲断层面被正断层局部利用。沿断层倾向方向,山前正断层逐渐向盆地方向扩展,最新活动的断层位于盆地边缘甚至盆地内部;沿断层走向方向,狼山山前正断层逐渐向南西侧扩展。  相似文献   
82.
蒙古国查干苏布尔加大型铜-钼矿床地质特征及成因   总被引:8,自引:2,他引:8  
查干苏布尔加斑岩铜钼矿床位于西伯利亚板块南缘近东西向和北东向深大断裂所夹持的南蒙古构造岩浆带内,容矿围岩二长花岗斑岩与花岗闪长斑岩主量元素高SiO2(64.69×10-2~73.42×10-2),高Al2O3(15.33×10-2~18.35×10-2),贫MgO(0.13×10-2~0.56×10-2),微量元素Sr二长花岗斑岩略低(144×10-6~175×10-6).花岗闪长斑岩表现为高Sr(样品>300×10-6,476×10-6~720×10-6),二者均低Y(Y<18×10-6,2.21×10-6~10.20×10-6),低Yb(Yb<1.9×10-6,0.30×10-6~1.48×10-6),高Sr/Y(Sr/Y>20,21.8~63.52),稀土元素特征为亏损重稀土,无明显负铕异常,(87Sr/86Sr)i=0.70154~0.70397,(143Nd/144Nd)i=0.512290~0.512600,εNd(t)为+2.4~+8.5,二长花岗斑岩和花岗闪长斑岩均具有埃达克质岩特征,但二长花岗斑岩与花岗闪长斑岩主、微量和稀土元素又存在一定差别,它们可能是岩浆不同演化阶段的产物.通过年龄测定,获得辉钼矿Re-Os等时线年龄为(370.0±5.9)Ma,二长花岗斑岩锆石SHRIMP U-Pb加权平均年龄为(365.7±3.6)Ma,铜钼矿形成时代与二长花岗斑岩形成时代相近,均形成于晚泥盆世.铜钼矿床与二长花岗斑岩、花岗闪长斑岩紧密共生,矿区范围内二长花岗斑岩与花岗闪长斑岩多被蚀变并矿化,表明二长花岗斑岩、花岗闪长斑岩与铜钼矿化存在密切的时空关系,为铜钼成矿提供了主要成矿物质和流体来源.  相似文献   
83.
载金黄铁矿显微构造变形与金富集关系可以从显微-超显微尺度揭示金成矿作用和地质过程,探讨金的再活化或再聚集作用。在胶东焦家金矿带成矿期识别出4种类型的黄铁矿,文章应用光学显微镜、扫描电镜(SEM)、透射电镜(TEM)、电子背散射衍射(EBSD)和电子探针(EMPA)等技术方法,探讨黄铁矿显微构造特征、超微观结构与金的富集关系。结果显示:载金黄铁矿均不发育环带,其中w(Fe)为45.70%~46.85%,w(S)为52.57%~53.37%;显微构造变形既有脆性变形又有塑性变形;黄铁矿晶体优选方位(CPO)主要表现为平行于晶轴极密和复杂极密;黄铁矿晶格间距为0.58 nm,主要发育刃位错。焦家金矿带在金成矿作用过程中,可见金集合体经历了从复杂的纳米尺度到宏观尺度矿物载体富集的过程,包括成矿流体中金络合物、金-铋-硫族化合物富集等化学结构变化过程和纳米金、载金黄铁矿纳米颗粒、岩矿石显微-超显微构造微环境变化过程。因此,不同类型载金黄铁矿CPO受到化学结构变化和显微-超显微变形微环境变化的联合制约,间接反映出载金黄铁矿中金的富集与黄铁矿内部变形、表面形貌和结构缺陷有密切关系。  相似文献   
84.
海洋地理信息系统(MGIS)研究进展   总被引:5,自引:1,他引:5  
海洋占全球面积的71%,21世纪是海洋开发的时候,其中海岸带及近海为开发利用的重点,海洋产业部门、沿海国家的各级政府及军事部门均需要快速获得有关海洋环境的综合信息和行为的决策依据。最近国际上出现的海洋地理信息系统(MGIS)已成为发展“数字海洋”的核心,通过MGIS的内涵基本功能,决策支持系统及应用实例介绍MGIS的应用前景。  相似文献   
85.
The Tahe Oilfield is a complex petroleum reservoir of Ordovician carbonate formation and made up of spatially overlapping fracture-cavity units. The oilfield is controlled by a cave system resulting from structure-karst cyclic sedimentation. Due to significant heterogeneity of the reservoir, the distribution of oil and water is complicated. Horizontally, a fresh water zone due to meteoric water can be found in the north part of the Akekule uplift. A marginal freshening zone caused by water released from mudstone compaction is found at the bottom of the southern slope. Located in a crossformational flow discharge zone caused by centripetal and the centrifugal flows, the main part of the Tahe Oilfield, featuring high salinity and concentrations of CI^- and K^++Na^+, is favorable for accumulation of hydrocarbon. Three types of formation water in the Tahe Ordovician reservoir are identified: (1) residual water at the bottom of the cave after oil and gas displacement, (2) residual water in fractures/pores around the cave after oil and gas displacement, and (3) interlayer water below reservoirs. The cave system is the main reservoir space, which consists of the main cave, branch caves and depressions between caves. Taking Cave System S48 in the Ordovician reservoir as an example, the paper analyzes the fluid distribution and exploitation performance in the cave system. Owing to evaporation of groundwater during cross-formational flow, the central part of the main cave, where oil layers are thick and there is a high degree of displacement, is characterized by high salinity and Br^- concentration. With high potential and a long stable production period, most wells in the central part of the main cave have a long water-free oil production period. Even after water breakthrough, the water content has a slow or stepwise increase and the hydrochemistral characteristics of the produced water in the central part of the main cave are uniform. From the center to the edge of the main cave, displacement and enri  相似文献   
86.
The northern margin of the Qinghai-Tibet Plateau is currently the leading edge of uplift and expansion of the plateau. Over the years, a lot of research has been carried out on the deformation and evolution of the northeastern margin of the Qinghai-Tibet Plateau, and many ideas have been put forward, but there are also many disputes. The Altyn Tagh Fault constitutes the northern boundary of the Qinghai-Tibet Plateau, and there are two active faults on the north side of the Altyn Tagh Fault, named Sanweishan Fault with NEE strike and Nanjieshan Fault with EW strike. Especially, studies on the geometric and kinematic parameters of Sanweishan Fault since the Late Quaternary, which is nearly parallel with the Altyn Tagn Fault, are of great significance for understanding the deformation transfer and distribution in the northwestward extension of the Qinghai-Tibet Plateau. Therefore, interpretation of the fault landforms and statistical analysis of the horizontal displacement on the Sanweishan Fault and its newly discovered western extension are carried out in this paper. We believe that the Sanweishan Fault is an important branch of the eastern section of the Altyn Tagh fault zone. It is located at the front edge of the northwestern Qinghai-Tibet Plateau and is a left-lateral strike-slip and thrust active fault. Based on the interpretation of satellite imagery and microgeomorphology field investigation of Sanweishan main fault and its western segments, it's been found that the Sanweishan main fault constitutes the contact boundary between the Sanweishan Mountain and the alluvial fans. In the bedrock interior and on the north side of the Mogao Grottoes, there are also some branch faults distributed nearly parallel to the main fault. The main fault is about 150km long, striking 65°, mainly dipping SE with dip angles from 50° to 70°. The main fault can be divided into three segments in the spatial geometric distribution:the western segment(Xizhuigou-Dongshuigou, I), which is about 35km long, the middle segment(Dongshuigou-Shigongkouzi, Ⅱ), about 65km long, and the east segment(Shigongkouzi-Shuangta, Ⅲ), about 50km long. The above three segments are arranged in the left or right stepovers. In the west of Mingshashan, it's been found that the fault scarps are distributed near Danghe Reservoir and Yangguan Town in the west of Minshashan Mountain, and we thought those scarps are the westward extension of the main Sanweishan Fault. Along the main fault and its western extension, the different levels of water system(including gullies and rills)and ridges have been offset synchronously, forming a series of fault micro-geomorphology. The scale of the offset water system is proportional to the horizontal displacement. The frequency statistical analysis of the horizontal displacement shows that the displacement has obvious grouping characteristics, which are divided into 6 groups, and the corresponding peaks are 3.4m, 6.7m, 11.4m, 15m, 22m and 26m, respectively. Among them, 3.4m represents the coseismic displacement of the latest ancient earthquake event, and the larger displacement peak represents the accumulation of coseismic displacements of multi-paleoearthquake events. This kind of displacement characterized by approximately equal interval increase indicates that the Sanweishan Fault has experienced multiple characteristic earthquakes since the Late Quaternary and has the possibility of occurrence of earthquakes greater than magnitude 7. The distribution of displacement and structural transformation of the end of the fault indicate that Sanweishan Fault is an "Altyn Tagh Fault"in its infancy. The activities of Sanweishan Fault and its accompanying mountain uplift are the result of the transpression of the northern margin of the Qinghai-Tibet Plateau, representing one of the growth patterns of the northern margin of the plateau.  相似文献   
87.
对海南岛屯昌花岗闪长岩中的闪长质淬冷包体进行了较详细的研究。岩石和岩石地球化学特征均显示包体是由来自地幔的高温镁铁质岩浆注入地壳长英质岩浆混合而成,是深部壳幔岩浆混合作用的岩石学记录。它表明海南岛自中晚侏罗世以来发生的岩石圈伸展—减薄—双峰式构造岩浆作用于白垩纪达到了鼎盛阶段。  相似文献   
88.
BVOCs对全球碳收支、对流层化学反应及臭氧的形成和气候变化都有很大的影响.选取森林覆盖率高且BVOCs排放尚未有研究报道的中国东北地区作为研究区域,利用美国NCAR中心提供的1°×1°的6 h NCEP再分析资料,运行MM5模式,得到模拟结果,从中提取GloBEIS模型所需要的近地面层的温度、湿度、风速和云量的格点气象数据,实现了将MM5模式与GloBEIS相结合对BVOCs进行研究.研究中需要的植被种类及分布数据来自于最新的"植被信息系统"数据库,选取温度较高,太阳辐射较强,植被生长茂盛的2006年7月和2010年7月作为模拟时段,运行GloBEIS模型,对研究区域内的BVOCs的排放情况进行了估算.模拟结果与温度和云量等气象要素的分析结果表明,异戊二烯的排放速率受温度和PAR(光合有效辐射通量)的共同影响,日变化趋势显著,随着温度升高,PAR增强,异戊二烯的排放速率增大,在午后14:00左右达到最大值,之后降低.由于云量与PAR成反比,因此云量越少,异戊二烯的排放量就越高,反之,则越低;与异戊二烯不同,温度是单萜烯和其他VOC的排放的主导因素,受PAR和云量的影响较小,温度越高,排放量越大,反之,则越小.  相似文献   
89.
海南岛中北部三叠纪花岗岩的锶、钕同位素初始比值分别为I(Sr)0. 7080 ~0. 71505、εNd(t) -10 ~-5,表明这些花岗岩属壳源型,其源岩主要为海南岛结晶基底中元古界抱板群,但受到了幔源岩浆的混染。这些花岗岩所表现出来的基本一致的锶、钕同位素特征,表明测区具有统一的前寒武纪基底。  相似文献   
90.
塔河地区奥陶系油田水分布与运动学特征研究   总被引:1,自引:0,他引:1       下载免费PDF全文
塔河油田是我国最大的陆上整装碳酸盐岩油田,其油田水分布与运动特征反映了油气运移规律。该区奥陶系油田水现今总体矿化度高,南北向存在从低到高再到低的3个矿化带,各带内平面分割性强,纵向层间差异大。塔河油田奥陶系的流体经历了多期次活动,奥陶系储层共捕获了4~5期盐水包裹体,其均一温度范围集中在60~80℃,90~105℃,110~140℃和145~170℃,盐度集中在0.5%~4%、5%~10%、10%~13%、14%~18%、>18%,反映出奥陶系储层曾经历过了4~5期热流体活动,对照埋藏史与油气运移史,高盐度流体活动与油气运移具有良好的匹配关系,油田水化学指标(油田水变质系数、碳酸盐岩平衡系数等)反映出塔河油区现今保存条件良好。井剖面包裹体纵向温度、盐度纵向不规则变化表明流体的活动以侧向运移为主。流体势分析说明运移方向不仅包括塔河东、南面是烃源岩方向,而且具有高流体势的西面也可能是油气来源方向。  相似文献   
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