内蒙古中部大青山新地沟-卯独庆金矿床的 构造-蚀变-成矿作用   总被引：1，自引：0，他引：1  

赵维宽  徐九华  席忠  李德亭  贾长顺 《地质通报》2008,27(4):575-583

新地沟和卵独庆金矿赋存于新太古界色尔腾山群柳树沟岩组中,是典型的与韧性-脆韧性剪切变形有关的绿岩型金矿.构造-蚀变岩石的主要类型有千糜岩化石英绢云片岩、千糜岩化绿泥绢云片岩、糜棱岩化绿泥石英片岩、绢云绿泥长英质糜棱片岩、长英质碎裂岩、黄铁绢英岩质构造片岩等.构造-蚀变岩石的岩石地球化学特征与中基性火山岩类似.其稀土元素总量∑REE(44.9×10-6～155.4×10-6)、LREE/HREE比值(7.0～26.1)、δEu(0.6～1.2)也显示了中基性火山原岩的特点.构造-蚀变-成矿流体的特征为富CO2的低盐度的较高密度的流体,具有造山型金矿的特点.前寒武纪绿岩带建造变质镁铁质火山岩分布的地区构造-蚀变作用强烈的地段是重要的找矿有利地区.  相似文献   

基于精确距离模型的改进R-D算法     

吴照宪  韩松 《测绘科学》2008,33(5)

本文利用合成孔径雷达(SAR)最为精确的标准斜视距离模型,推导出了一种适合斜视SAR精确成像的改进距离-多普勒(R-D)算法。文章进一步分析了SAR的四种距离模型,将已有的三种R-D算法以及本文提出的改进R-D算法和四种距离模型之间建立了一一映射,指出了四种R-D算法之间的本质区别。最后对四种R-D算法进行了仿真,结果表明本文给出的改进R-D算法最能够适应斜视情况下的精确成像。  相似文献   

准噶尔盆地西北缘五八开发区二叠系佳木河组火山岩储层特征   总被引：10，自引：1，他引：9  

匡立春  吕焕通  薛晶晶  朱筱敏  李德江 《高校地质学报》2008,14(2)

基于岩心、薄片及成像测井(FMI)等资料,对准噶尔盆地西北缘五八开发区火山岩储层特征分析表明,该储层主要分布于二叠系佳木河组(P1j),包括熔岩和火山碎屑岩。熔岩的平均孔隙度和渗透率分别为6.94%和6.68×10-3μm2;火山碎屑岩的平均孔隙度和渗透率分别为10.01%和7.93×10-3μm2。火山岩经历早期的冷却固结和脱玻化阶段以及后期的构造破裂作用、溶蚀溶解作用和充填交代等作用,使得储集空间主要以次生孔隙为主,并伴随有裂缝发育。安山岩、凝灰岩和火山角砾岩的岩性差异,以及溶蚀和不整合面等成岩、构造作用是影响火山岩储层质量的主要因素。  相似文献   

单向压缩状态下上海地区软土的蠕变变形与次固结特 性研究   总被引：1，自引：0，他引：1  

徐珊  陈有亮  赵重兴 《工程地质学报》2008,16(4):495-501

基于上海地区原状软土的一维固结试验,讨论了在不同加荷比、加荷速率及超载预压情况下软土的蠕变变形特性和次固结特性。试验结果表明:蠕变变形随应力水平、加荷速率的增大而增大。相同应力水平下,加荷比较大的土样蠕变变形较小。蠕变变形为非线性,随着应力水平的增加,蠕变变形从粘弹性到粘塑性转变,加荷比较大时,这种转变更明显。对试验结果进行曲线拟和,确定Metchell一维经验模型参数,拟和曲线与试验结果吻合较好。通过对次固结阶段试验数据的线性拟合可知,对于正常固结土,次固结系数Ca值受应力水平和加荷比的影响不大,而与加荷速率密切相关,加荷速率较大时,Ca值随荷载的增大急剧增大后略有降低。超载预压可有效减小次固结系数,从而有利于减小工后次固结沉降。  相似文献   

巴楚地区碳酸盐岩中深成侵入岩特征及其对储层发育的影响   总被引：1，自引：1，他引：0  

聂保锋  于炳松  朱金富 《地学前缘》2008,15(2):90-99

为了深入探讨深部岩浆活动对碳酸盐岩储层发育的影响,文中通过显微鉴定、地球化学分析以及流体包裹体测试,对巴楚地区和3井奥陶纪钻遇的火成岩进行了详细研究。和3井碳酸盐岩中的火成岩是紫苏辉长岩,为深成侵入岩体,辉长岩的w(SiO2)介于44.89%～45.39%,w(K2O+Na2O)为4.04%～4.67%,w(Na2O)/w(K2O)为2.16～4.23,属钠质碱性系列,形成于板内构造环境。微量元素分配模式以Ba富集Sr亏损为特征。∑REE介于163.43×10-6～215.99×10-6,LREE/HREE介于5.14～5.58,LaN/YbN介于5.192～5.980,δEu介于0.926～1.002,稀土配分模式属轻稀土富集型,通过对和3井碳酸盐岩孔隙度、渗透率以及其中流体包裹体的分析,孔隙度和渗透率的变化与辉长岩的分布有关,流体包裹体温度介于62～161℃,和3井碳酸盐岩受到过热事件的影响,辉长岩的侵入改善了和3井碳酸盐岩的储层物性。  相似文献   

枞阳县拔茅山矿区拔茅山—余家园－李家湾－石庄环状成矿带地质特征及找矿潜力分析     

汪忠兴  程加云 《安徽地质》2008,18(3):182-184

由余家园、李家湾、石庄、拔茅山铜矿带环绕皂树咀辉石粗安玢岩体与上侏罗统砖桥组火山岩系地层内外接触带附近构成未封闭的环状矿带,具面状蚀变,铜草发育,矿化多呈细脉浸染状,地表矿化普遍较强,寻找与拔茅山铜矿类似近接触带细脉浸染型带状斑岩型铜矿具一定潜力。  相似文献   

利用生排烃动力学研究海相及煤系烃源岩的残留烃及其裂解成气特征     

王云鹏  田静  卢家烂  刘德汉 《海相油气地质》2008,13(4)

以煤与海相泥岩的块状样品为研究对象进行多升温速率下的排烃模拟实验,借助生烃动力学方法处理实验模拟结果,对煤与海相泥岩的残留烃特征进行了研究。结果表明:海相泥岩残留烃在Ro为1.0%时达到高峰,然后逐渐降低,而煤中残留烃在Ro为1.0%时达到高峰后便基本上保持稳定。煤吸附能力比海相泥岩的强,其残留烃量也比海相泥岩大。成熟作用对于煤及海相泥岩残留烃都有很大的影响。高过成熟阶段海相地层中烃类构成以油藏或输导层中原油裂解气为主,源岩中的残余液态烃也有一定的贡献,而煤在排烃结束以后煤中分散液态烃对裂解气的贡献更大些。煤中残留烃主要是前期形成的烃类由于排烃效率不高而聚集起来的,而海相残留烃基本上随着残余生烃潜力的降低而降低,这一方面说明海相残留烃受生烃作用的影响,另一方面也受排烃效率的影响。模拟样品中的残留烃及残余生烃潜力均可以与自然样品对比,表明了该方法的实用性。  相似文献   

Formation and Development of a Mountain-induced Secondary Center inside Typhoon Morakot(2009)     

Xuwei BAO  Leiming MA  Jianyong LIU  Jie TANG  Jing XU 《大气科学进展》2018,35(9):1160-1176

The structural evolution of Typhoon Morakot(2009) during its passage across Taiwan was investigated with the WRF model. When Morakot approached eastern Taiwan, the low-level center was gradually filled by the Central Mountain Range(CMR), while the outer wind had flowed around the northern tip of the CMR and met the southwesterly monsoon to result in a strong confluent flow over the southern Taiwan Strait. When the confluent flow was blocked by the southern CMR, a secondary center(SC) without a warm core formed over southwestern Taiwan. During the northward movement of the SC along the west slope of the CMR, the warm air produced within the wake flow over the northwestern CMR was continuously advected into the SC, contributing to the generation of a warm core inside the SC. Consequently, a well-defined SC with a warm core, closed circulation and almost symmetric structure was produced over central western Taiwan, and then it coupled with Morakot's mid-level center after crossing the CMR to reestablish a new and vertically stacked typhoon. Therefore, the SC inside Morakot was initially generated by a dynamic interaction among the TC's cyclonic wind, southwesterly wind and orographic effects of the CMR, while the thermodynamic process associated with the downslope adiabatic warming effect documented by previous studies supported its development to be a well-defined SC. In summary, the evolution of the SC in this study is not in contradiction with previous studies, but just a complement, especially in the initial formation stage.  相似文献   

Bridging High School and Introductory Undergraduate Courses in Geographic Information Science and Technology     

AP® GIS&T Study Group 《The Journal of geography》2018,117(4):165-173

This article presents the findings of a study to determine the degree of consistency in what is taught and learned in high school and college-level introductory courses in geographic information science and technology (GIS&T). A content analysis identified sixteen topics that are generally representative of the knowledge, skills, and abilities developed in introductory undergraduate courses. The findings were used to propose a standard college-level survey course in GIS&T that could inform future efforts to introduce more academically rigorous GIS&T coursework in high schools, such as through the Advanced Placement Program.  相似文献   

Multiple dolomitization and later hydrothermal alteration on the Upper Cambrian-Lower Ordovician carbonates in the northern Tarim Basin,China     

《Marine and Petroleum Geology》2016

Thick Upper Cambrian-Lower Ordovician carbonates were deposited on a shallow marine platform in the northern Tarim Basin, which were extensively dolomitized, particularly for the Upper Cambrian carbonates. The resulting dolomite rocks are predominantly composed of matrix dolomites with minor cement dolomites. Based on petrographic textures, matrix dolomites consist of very finely to finely crystalline, nonplanar-a to planar-s dolomite (Md1), finely to medium crystalline, planar-e(s) dolomite (Md2), and finely to coarsely crystalline, nonplanar-a dolomite (Md3). Minor cement dolomites include finely to medium crystalline, planar-s(e) dolomite (Cd1) and coarsely crystalline, nonplanar saddle dolomite (Cd2), which partially or completely fill dissolution vugs and fractures; these cements postdate matrix dolomites but predate later quartz and calcite infills. Origins of matrix and cement dolomites and other diagenetic minerals are interpreted on the basis of petrography, isotopic geochemistry (O, C and Sr), and fluid inclusion microthermometry. Md1 dolomite was initially mediated by microbes and subsequently precipitated from slightly modified brines (e.g., evaporated seawater) in near-surface to very shallow burial settings, whereas Md2 dolomite was formed from connate seawater in association with burial dissolution and localized Mg concentration (or cannibalization) in shallow burial conditions. Md3 dolomite, however, was likely the result of intense recrystallization (or neomorphism) upon previously-formed dolomites (e.g., Md1 or Md2 dolomite) as the host carbonates were deeply buried, and influenced by later hydrothermal fluids. Subsequent cement dolomite and quartz crystals precipitated from higher-temperature, hydrothermal fluids, which were contributed more or less by the extensive Permian large igneous province (LIP) activity in Tarim Basin as evidenced by less radiogenic Sr in the cement and parts of matrix dolomites. This extensive abnormal hydrothermal activity could also have resulted in recrystallization (or neomorphism) on the previous matrix dolomites. Faults/fractures likely acted as important conduit networks which could have channeled the hydrothermal fluids from depths. However, the basin uplift triggered by the Late Hercynian Orogeny from the Late Permian would have facilitated downward infiltration of meteoric water and dilution of hydrothermal fluids, resulting in precipitation of later calcites in which lighter C and more radiogenic Sr components demonstrate such a switch of fluid properties. This study provides a useful analogue to understand the complicated dolomitizing processes and later hydrothermal alteration intimately related to the Permian LIP activity within Tarim Basin and elsewhere.  相似文献