西秦岭温泉钼矿床矿石矿物特征及钼的赋存状态   总被引：2，自引：1，他引：1  

欧阳玉飞  刘继顺  韩海涛  刘卫明  吴自成 《矿物岩石地球化学通报》2009,28(4):336-343

通过显微镜鉴定、电子探针（EPMA）及X射线粉晶衍射法等方法,首次对温泉钼矿的矿物组合、矿石类型、矿石结构构造和钼的赋存状态进行了研究。结果表明,矿石矿物为中温热液成因,并受温泉斑岩体的控制;钼矿物主要为辉钼矿。辉钼矿的多型为2H型（六方晶系）,为自形—半自形,呈细小鳞片状、片状、板条状分布于岩石中;辉钼矿的粒度主要集中在0.08-0.16 mm粒级范围,占总量的51.65%;黄铁矿中钼含量较高,且形成越早钼含量越高。  相似文献   

土地开发整理辅助决策支持系统研究   总被引：10，自引：1，他引：9  

向洪普  万湘黔  程纲  何庆  王志成  陈刚  雷双友  易为民 《测绘通报》2005,(5):53-55

介绍将信息技术特别是"3S"技术应用于土地开发整理工作的原理和实践.开发、利用各种信息技术,从不同深度、不同层次全方位地介入土地开发整理工作,使土地开发整理工作效率提高、规划科学、指标精确、方案优化、过程和成果规范,达到计算机辅助土地开发整理工作的目的.  相似文献   

北京西山东狼沟组钾质火山岩成因及其动力学机制   总被引：7，自引：1，他引：6  

李晓勇  范蔚茗  郭锋  王岳军  李超文  彭头平 《地球化学》2004,33(4):353-360

北京西山东狼沟组火山岩为钾质系列岩石(K2O=3.40%～4.70%,K20/Na20＞1),由玄武质粗安岩和粗安岩组成.它们表现出LREE富集[(La/Yb)N=31.4～44.6]和HREE弱分馏[(Dy/Yb)N=1.64～2.01]的REE分布模式,Eu表现出弱的负异常(Eu/Eu*=0.81～0.86),富集Ba、K、LREE和相对亏损Nb-Ta、Th-U.较高的Sr[(87Sr/86Sr)i=0.705 7～0.705 9]和低Nd[δNd(t)=-14.7～-12.4],类似于辽西义县组和华北陆内同时代的EM I型基性火成岩.其Th-U相对Ba、La的强烈亏损,暗示早期可能有华北古老的下地壳再循环进入源区.结合区域构造研究,东狼沟组火山岩可能为陆内伸展拉张环境下早期交代富集的岩石圈地幔部分熔融作用的产物,并在岩浆演化过程中经历了橄榄石 辉石 斜长石的分离结晶作用.  相似文献   

机器学习与统计模型在石羊河流域气候降尺度研究中的适用性对比     

宫毓来  马绍休  刘伟琦 《中国沙漠》2022,42(1):196-210

高分辨率气候数据是研究气候变化对农业、生态、水文影响的驱动数据,动力和统计降尺度模型是两类常用的生成高分辨率气候数据的方法,近年来机器学习模型也被用到气候变化的研究中,但针对不同站点(下垫面)的多种统计降尺度模型的对比研究较少.石羊河流域土地利用类型多样,海拔变化显著,适合研究降尺度模型的适用性.本研究选择2种传统统计...  相似文献   

钻孔后压浆技术在苏通大桥基础工程中的应用   总被引：1，自引：0，他引：1  

布克明  殷坤龙  龚维明 《岩土力学》2008,29(6):1697-1700

钻孔灌注桩后压浆技术,使水泥浆液在高压下渗透、充填和挤密,与沉渣、泥皮、桩周和桩端土体发生物理化学固结,增大了土体和桩端的强度,改变了桩的受力类型,提高了桩侧摩阻力和端阻力,从而提高了单桩的承载力。在苏通大桥超长大直径桩中应用了桩底后压浆技术。通过试桩静载试验,决定在工程施工中采用U型压浆管方案。试桩结果表明,压浆后极限承载力测试值是压浆前的1.48～2.0倍,压浆后端阻力是压浆前的2.46～7.21倍,表明利用后压浆技术达到了节约工程投资、提高工程施工质量及可靠性的目的,并产生了较大的技术经济效益和良好的社会环境效益,这将促进我国公路桥梁建设的桩基技术迈向一个新台阶。  相似文献   

现行地震应急预案的局限与对策研究     

龚平  邹琼  王恒希 《国际地震动态》2008,(11)

自2005年国家出台新地震应急预案以来,根据预案制定要"纵向到底,横向到边"的精神要求,上至国家地震主管部门,下至基层地震单位,以及横向到与地震应急有关的部门和单位大都制定了地震应急预案.这些预案的法律、法规的依据是1997年颁布的<中华人民共和国防震减灾法>,1995年制定的<破坏性地震应急条例>和2005年制定的<国家突发公共事件总体应急预案>.  相似文献   

Late Quaternary surface deformation and rupture behavior of strong earthquake on the segment north of Mianning of the Anninghe fault   总被引：7，自引：0，他引：7  

YongKang Ran  LiChun Chen  JianWu Cheng  HuiLing Gong 《中国科学D辑(英文版)》2008,51(9):1224-1237

The Anninghe fault is an important active fault along the eastern boundary of Sichuan-Yunnan active tectonic block, and the study of its surface deformation and rupture behavior during strong earthquake in the late Quaternary is of fundamental importance for understanding the future seismic risk of the fault zone or even the entire western Sichuan region. Using the methods of detailed geomorphic and geological survey, digital image analysis, total station instrument survey, excavation of combined trench and dating, we analyze the geomorphologic sequences of the offset strata at several sites where the late Quaternary deformation remnants are fairly well preserved and obtain some new results as follows: Strong earthquake events with left-lateral displacements of about 3 m occurred at the two sites of Zimakua and Yejitong at 1634-1811, 1030-1050 and 280-550 a BP, respectively, and the recurrence interval is 520-660 a; The youngest event in the area of Dahaizi-Ganhaizi should be the earthquake of 1536, other events are at 1768-1826, 2755-4108 and 4108-6593 a BP, respectively, with a recurrence interval of 1300-1900 a. The strong earthquake activity shows a clustering character. The possibility of occurrence of a strong earthquake exists on the north segment of the Anninghe fault sometime in the future.  相似文献   

Coupling relationships between brachiopods and Girvanella during the Late Devonian F-F transition in Guilin, South China     

Ran Xu  YiMing Gong  JianWei Zeng 《中国科学D辑(英文版)》2008,51(11):1581-1588

The abundance curves derived from area proportions of brachiopods and Girvanella in the thin sections from the Yangdi section, South China, exhibits complex relationships during the Late Devonian Frasnian-Famennian transition. The living activity of brachiopods such as grazing and borrowing did great damage to the growth of Girvanella. However, there was more to just a mere a survival competing relationship between them, Girvanella actually improved marine environments by oxygenating the dysoxic ambient sea-water through photosynthesis in the lower Kellwasser Horizon. Profited from this improvement brachiopods’ abundance increased subsequently and suppressed Girvanella again. Nonetheless, without Girvanella’s photosynthesis, brachiopods were wiped out by the farther anoxic environments in the upper Kellwasser Horizon. The complex relationships between Girvanella and brachiopods may be a key to unlocking the relationships between geomicrobes and metazoans in the geological overturn periods. Supported by NSFC Innovation Research Group Program (Grant No. 40621002), MOE Innovative Research Team Program (Grant No. IRT0546), the National Natural Science Foundation of China (Grant Nos. 40472020, 40730209, 40802005 and 40872001) and SINOPEC Project (Grant No. G0800-06-ZS-319)  相似文献   

静载荷下黄土地基矩形地下连续墙现场试验研究   总被引：1，自引：0，他引：1  

宋章  程谦恭  龚维明  陈晓东 《岩土力学》2008,29(10):2713-2718

采用自平衡测试技术,在国内外首次进行了竖向静载荷作用下黄土地基中矩形地下连续墙现场试验研究,根据测试结果及黄土的物理力学性质,对黄土地基中矩形地下连续墙的荷载传递性状进行了详细分析。结果表明：黄土地基中矩形地下连续墙的承载特性具有端承摩擦桩的性质;墙的承载力由墙侧摩阻力和端阻力共同承担;墙侧摩阻力和端阻力的发挥与墙土的相对位移量及黄土的物理力学性质等因素有关;墙体达到极限荷载时,墙端阻力荷载分担比为40.3 %;各土层墙侧摩阻力随着墙土相对位移的增加而增大,但其增长幅度不等;加载时墙身轴力在加载处最大,随着各土层墙侧摩阻力作用的发挥,墙身轴力随着离荷载箱距离的增加而减小。  相似文献   

Hydrogen and oxygen isotope evidence for fluid–rock interactions in the stages of pre- and post-UHP metamorphism in the Dabie Mountains     

Yong-Fei Zheng  Bin Fu  Yilin Xiao  Yiliang Li  Bing Gong 《Lithos》1999,46(4):224-693

Hydrogen and oxygen isotope studies were carried out on high and ultrahigh pressure metamorphic rocks in the eastern Dabie Mountains, China. The δ¹⁸O values of eclogites cover a wide range of −4.2 to +8.8‰, but the δD values of micas from the eclogites fall within a narrow range of −87 to −71‰. Both equilibrium and disequilibrium oxygen isotope fractionations were observed between quartz and the other minerals, with reversed fractionations between omphacite and garnet in some eclogite samples. The δ¹⁸O values of −4 to −1‰ for some of the eclogites represent the oxygen isotope compositions of their protoliths which underwent meteoric water–rock interaction before the high to ultrahigh pressure metamorphism. Heterogeneous δ¹⁸O values for the eclogite protoliths implies not only the varying degrees of the water–rock interaction before the metamorphism at different localities, but also the channelized flow of fluids during progressive metamorphism due to rapid plate subduction. Retrograde metamorphism caused oxygen and hydrogen isotope disequilibria between some of the minerals, but the fluid for retrograde reactions was internally buffered in the stable isotope compositions and could be derived from structural hydroxyls dissolved in nominally anhydrous minerals.  相似文献