洪积扇地下水的反向地球化学模拟     

黄支刚  陈杜军  朵天惠  王永利 《地下水》2013,(3):6-8

在四坪山建造极低放射性核废物填埋场,建填废物紧临洪积扇。查明洪积扇地下水的演化特征,可为核废物的安全填埋提供依据。使用地球化学软件PHREEQCI,进行洪积扇地下水的反向地球化学模拟,推测地下水在径流过程中发生的水-岩作用,并计算发生水-岩作用的矿物相的量。  相似文献   

真空堆载预压法控制高速公路软土地基沉降的现场监测试验分析     

尹湃  黄作俊  袁小林 《岩土工程技术》2013,27(1)

真空堆载预压法具有真空预压和堆载预压双重加固效果,真空预压产生的侧向收缩变形与堆载产生的侧向挤出变形相抵消,保证了上部路堤的稳定性,加速地基土的固结,提高了施工速度.依托高速公路软基处理实体工程,设置四个现场监测试验段,对完整有效的观测断面的沉降进行了全程监测.分析结果表明,真空堆载预压法加固的路基沉降量主要发生在初期和中期,沉降速率在监测初期较大、中期时达到最大值,后期的沉降量和沉降速率减小,最后阶段最大沉降速率为0.09 cm/d,小于堆载预压规定的允许值1cm/d的要求,表明真空堆载预压法加固效果显著.  相似文献   

Re–Os isotopic ages of pyrite and chemical composition of magnetite from the Cihai magmatic–hydrothermal Fe deposit, NW China     

Xiao-Wen Huang  Mei-Fu Zhou  Liang Qi  Jian-Feng Gao  Yu-Wang Wang 《Mineralium Deposita》2013,48(8):925-946

The Eastern Tianshan Orogenic Belt of the Central Asian Orogenic Belt and the Beishan terrane of the Tarim Block, NW China, host numerous Fe deposits. The Cihai Fe deposit (>90 Mt at 45.6 % Fe) in the Beishan terrane is diabase-hosted and consists of the Cihai, Cinan, and Cixi ore clusters. Ore minerals are dominantly magnetite, pyrite, and pyrrhotite, with minor chalcopyrite, galena, and sphalerite. Gangue minerals include pyroxene, garnet, hornblende and minor plagioclase, biotite, chlorite, epidotite, quartz, and calcite. Pyrite from the Cihai and Cixi ore clusters has similar Re–Os isotope compositions, with ～14 to 62 ppb Re and ≤10?ppt common Os. Pyrrhotite has ～5 to 39 ppb Re and ～0.6 ppb common Os. Pyrite has a mean Re–Os model age of 262.3?±?5.6 Ma (n?=?13), in agreement with the isochron regression of ¹⁸⁷Os vs. ¹⁸⁷Re. The Re–Os age (～262 Ma) for the Cihai Fe deposit is within uncertainty in agreement with a previously reported Rb–Sr age (268?±?25 Ma) of the hosting diabase, indicating a genetic relationship between magmatism and mineralization. Magnetite from the Cihai deposit has Mg, Al, Ti, V, Cr, Co, Ni, Mn, Zn, Ga, and Sn more elevated than that of typical skarn deposits, but both V and Ti contents lower than that of magmatic Fe–Ti–V deposits. Magnetite from these two ore clusters at Cihai has slightly different trace element concentrations. Magnetite from the Cihai ore cluster has relatively constant trace element compositions. Some magnetite grains from the Cixi ore cluster have higher V, Ti, and Cr than those from the Cihai ore cluster. The compositional variations of magnetite between the ore clusters are possibly due to different formation temperatures. Combined with regional tectonic evolution of the Beishan terrane, the Re–Os age of pyrite and the composition of magnetite indicate that the Cihai Fe deposit may have derived from magmatic–hydrothermal fluids related to mafic magmatism, probably in an extensional rift environment.  相似文献   

Recent development in stratigraphic forward modelling and its application in petroleum exploration     

X. Huang  C. M. Griffiths  J. Liu 《Australian Journal of Earth Sciences》2013,60(8):903-919

In order to better predict the geometry and spatial distribution of reservoir facies and permeability barriers, it is critical to understand stratigraphic geometries and architecture at all scales within a basin. Stratigraphic forward modelling (SFM) allows geologists to forward project the deposition and evolution of sedimentary facies within a stratigraphic framework with given prior boundary conditions. The method can approximate depositional processes while taking into consideration a range of factors that affect basin evolution and sedimentation. This paper presents an overview of recent developments in stratigraphic forward models that are currently available and have been successfully employed in simulating stratigraphic development, including geometric models, diffusion models, Fuzzy Logic models and hydraulic models. In addition, the paper discusses SFM used in the simulation of the behaviour of natural sedimentary systems and verification of the potential for hydrocarbon entrapment and accumulation in a basin using an example from the Ordos Basin, western China.  相似文献   

伏牛山构造带变质流体脉变形特征及构造意义   总被引：1，自引：0，他引：1       下载免费PDF全文

任升莲  宋传中  Lin Shoufa  李加好  涂文传  马涛  宫龙  黄鹏  颊建  杨帆  刘乐 《地质科学》2013,(3):626-637

伏牛山构造带由多条近平行的断裂带和夹持其间的变形岩片组成,洛南-栾川断裂带和瓦穴子-乔端断裂带为其中的两条主要断裂带。这两条断裂带虽遭受多期强烈构造活动的影响,但主造山期的构造特征至今仍然保存完好,并以中深层次的韧性剪切变形为主,形成了典型的糜棱岩和同构造期石英脉。本文从宏观、微观、超微观变形特征及年龄等方面对这些变质流体脉进行了研究,以探讨与其形成密切相关的构造活动特征、年代及其在秦岭造山带和华北板块南缘强变形带中的作用。石英脉中石英颗粒动态重结晶特征总体显示远离剪切带只有少量的膨凸式,靠近断裂带为亚颗粒式,形成核-幔结构,位错特征显示远离剪切带位错密度较小,靠近断裂带较大,位错形态显示瓦乔断裂带以挤压为主,洛南-栾川断裂带以剪切为主。两条断裂带石英脉的变形特征说明它们的糜棱岩化过程均为塑性变形中的晶质塑性变形,形成过程均为挤压在先,剪切在后。所测糜棱岩中石英脉的ESR年龄分别为372.9±30.0 Ma、275.0±20.0 Ma和218.0±20.0 Ma,真实地记录了晚加里东至中-晚海西期北秦岭的构造活动及所受影响。其中372.9±30.0 Ma是宽坪岩块向华北板块下的斜向俯冲汇聚和走滑的年代, 275.0±20.0 Ma是瓦乔断裂带的形成年龄。218.0±20.0 Ma的年龄则反映了华南、华北两大板块印支晚期全面闭合作用在秦岭造山带内部的影响。从以上3个年龄可以看出:北秦岭各构造带自北向南演化,时代上自北向南变新。  相似文献   

特提斯洋对流上地幔Os同位素组成估算的新方法及初步运用     

黄启帅  刘德亮  龚小晗  张晓冉  史仁灯 《地质科学》2013,48(2):532-542

对流上地幔Os同位素组成的准确估算是运用Re-Os同位素体系探讨地幔演化的基础。前人研究主要是以地幔橄榄岩为研究对象,由于地幔橄榄岩Os同位素存在明显的不均一性,因而直接影响估算值的准确性。对流上地幔中包含的不同亏损程度的难熔组分在部分熔融过程中难以熔融,对形成的熔体相的Os同位素组成贡献很少或者没有。因此,与对流上地幔具有相同的Os同位素组成初始值的早期分离结晶岩石(如堆晶岩),结合堆晶岩中锆石的准确定年,可以用来估算对流上地幔Os同位素组成。本文根据这一方法测试了那曲地区弧后盆地堆晶岩的Os同位素组成和锆石U-Pb年龄,推测那曲地区新特提斯洋对流上地幔Os同位素组成为碳质球粒陨石型的。根据这一模型,对比了罗布莎和东巧铬铁矿岩、含矿围岩以及不含矿围岩的Os同位素特征,揭示出矿石及围岩均具有古老大陆岩石圈地幔信息,而不含矿围岩(泽当岩体)的Os同位素组成为碳质球粒陨石型的,无古老大陆岩石圈地幔信息。  相似文献   

MOR型蛇绿岩中地幔橄榄岩的地质特征     

龚小晗  黄启帅  史仁灯 《地质科学》2013,48(2):569-580

地幔橄榄岩是指来自陆下、弧下或洋脊下的岩石圈地幔岩,通常通过构造侵位(冷侵位)的方式存在于造山带中,如造山带橄榄岩、蛇绿岩中的橄榄岩以及火山岩中的地幔橄榄岩等。本文选取了4个具有MOR型属性的蛇绿岩中地幔橄榄岩体,对比研究了其与深海橄榄岩在岩石学、地球化学、同位素地球化学和岩石成因等方面的特征,认为与深海橄榄岩性质的综合对比是识别MOR型蛇绿岩中地幔橄榄岩的有效方法之一,同时在蛇绿岩的分类中具有较好的参考价值。  相似文献   

高地应力区复杂结构河谷应力场特征——以锦屏Ⅰ级水电站为例     

徐佩华  黄润秋  陈剑平  袁中凡 《吉林大学学报(地球科学版)》2013,(5):1523-1532

以锦屏Ⅰ级水电站为例,在实际地质调查基础上,分析整理实测地应力数据,以数值模拟为手段,对高地应力区复杂结构谷坡应力场特征进行了研究。结果表明:高地应力区具有复杂结构的河谷,遭受河谷快速下切改造后,其谷坡应力场存在"四区"分布特征,即应力降低区、应力过渡区、应力增高区及原始应力区;背景构造应力和河谷形态特征是导致谷底高地应力现象出现的2个重要因素;谷坡内的软弱带对应力场分布产生重大影响,尤其是倾坡外断层的存在,更易于谷坡应力卸荷,这是导致锦屏左岸深卸荷形成的重要原因,以及导致左岸卸荷基准面高程低于右岸的原因之一;河谷下切过程中,右岸顺倾岸坡发生应力调整的坡体范围比左岸的反倾岸坡大,因此其原始应力区在更深的深度内才出现。简单探讨了锦屏深裂缝的成因机制,认为河谷迅速下切导致的快速卸荷是锦屏深裂缝形成的原因之一。  相似文献   

柿庄南区块煤层气井早期生产特征及开采建议     

黄少华  孙同英  冀昆  邹婧 《中国煤炭地质》2013,(7)

从水文地质的角度揭示了不同情况下单井的排水采气机理。在此基础上结合柿庄南区块59口井的实际排采数据,综合分析了气水产量,井底流压,套压及动液面随时间的变化曲线;并将早期生产特征归纳为3种类型：①低产水-高产气型,见气早,产气量高（>1000 m3/d）、产量递减缓慢、峰值产量高,日产水量小（<2m3/d）,套压高;②低产水-中低产气型,日产气小于1000 m3,产量衰减明显且波动大,排水期较长;③高产水型,产气极少或无,日产水量大（>10m3/d）,动液面下降缓慢,套压很低或为零。最后针对不同类型的低产井,提出相应的开采建议：低产水-低产气型井可采用二次压裂措施,改善煤层渗透率;高产水井可通过无机堵水或加大排采强度等方式排采;煤层气井排采要勇于实践,探索适合该区不同煤层的成功排采方法。  相似文献   

Conceptual design studies of the 5 m terahertz antenna for Dome A,Antarctica   总被引：1，自引：0，他引：1  

Ji Yang  Ying-Xi Zuo  Zheng LOU  Jing-Quan Cheng  Qi-Zhou Zhang  Sheng-Cai Shi  Jia-Sheng Huang  Qi-Jun Yao  Zhong Wang 《天体物理学报》2013,(12):1493-1508

As the highest, coldest and driest place in Antarctica, Dome A provides exceptionally good observing conditions for ground-based observations over terahertz wavebands. The 5 m Dome A Terahertz Explorer （DATES） has been proposed to explore new terahertz windows, primarily over wavelengths between 350 and 200 pm. DATE5 will be an open-air, fully-steerable telescope that can function by unmanned operation with remote control. The telescope will be able to endure the harsh polar environment, including high altitude, very low temperature and very low air pressure. The unique specifications, including high accuracies for surface shape and pointing and fully automatic year-around remote operation, along with a stringent limit on the periods of on-site assembly, testing and maintenance, bring a number of challenges to the design, construction, assembly and operation of this telescope. This paper intro- duces general concepts related to the design of the DATE5 antenna. Beginning from an overview of the environmental and operational limitations, the design specifications and requirements of the DATE5 antenna are listed. From these, major aspects on the conceptual design studies, including the antenna optics, the backup structure, the pan- els, the subreflector, the mounting and the antenna base structure, are explained. Some critical issues of performance are justified through analyses that use computational fluid dynamics, thermal analysis and de-icing studies, and the proposed approaches for test operation and on-site assembly. Based on these studies, we conclude that the specifications of the DATE5 antenna can generally be met by using enhanced technological approaches.  相似文献