载金石英的阳离子效应及其对含矿性的指示意义   总被引：2，自引：0，他引：2  

颜文  傅平秋 《矿产与地质》1993,7(4):273-277

石英的阳离子效应指石英结构中Al~(3+)与Si~(4+)的置换作用.在分析海南戈枕断裂金成矿带石英中普遍存在的这一作用,以及由此造成的石英粉末红外谱(IR)、顺磁共振谱(EPR)及热释光曲线(TL)特征,进而讨论了这些特征与金成矿的关系.  相似文献   

运城地区水氟回升原因及重病区水氟有效值的确定     

张毅  吕栓过 《水文地质工程地质》1993,20(6):53-55

本文介绍了山西省运城地区十年改水的基本情况，指出了改水井口氟加升的主要原因，探讨了有别于国家饮水标准的重病区水氟防治有效值的确定方法、并对今后的降氟改水工作提出了几点意见。  相似文献   

震级——频度关系的b值谱及其在地震预报中的应用     

冯德益  田山  蒋淳  大内彻 《高原地震》1993,(3)

本文引进了震级——频度关系的b值谱的概念,给出了计算b值谱的矩方法,对我国华北和西北地区分别计算和分析了以半年为单位的不同时段M_L≥3.0地震的b值谱线。所得结果表明,在研究区内发生6级左右以上大震前半年至一年半之内,b值谱的形态要出现较明显的前兆异常变化,因而可在地震预报中加以应用。  相似文献   

首都圈断层活动性研究   总被引：10，自引：0，他引：10  

车兆宏 《华北地震科学》1993,11(2):23-34

本文分析了首都圈47处监测断层活动性的大地形变测点资料,给出了各处断层现今活动情况及速率。研究认为,首都圈现今应力场受华北区域应力场的支配,活动剧烈的断层主要有:沿河城—南口山前断层、八宝山—黄庄—高丽营断层、南口—孙河断层;1987年之后断层活动平均速率上升到0.40mm/年,应力场处于加强过程;应力集中地段在黄庄—高丽营断层北端、沿河城—南口山前断层北端,狼山断层、怀来—涿鹿北缘断层近年活动剧烈,其北端也是应力加强地区;构造运动的活跃与地震活动同步,目前构造运动继续处于活跃状态。上述应力集中地段的地震危险性应予以重视。  相似文献   

BED FORMS AND RESISTANCE PROPERTIES OF LIGHT-WEIGHT BED MATERIAL     

WANG Guixian  WANG Xingkui  GUO Jiachao Professor  Sediment Research Laboratory  Dept. of Hydraulic Engineering  Tsinghua University  Beijing  China. Associate Professor  Dept. of Hydraulic Engineering  Tsinghua University. Assistant  Dept. of Hydraulic Engineering  Tsinghua University. 《国际泥沙研究》1993,(3)

I. INTRODUCTIONResistance to flow in alluvial streams is one of the crucial problems in fluvial hydraulics. Despite that large amount of studies have been conducted for centuries, no perfectmethod describing and calculating the resistance to flow in alluvial streams is availablehll now. Investigation on bed forms and resistance properties of light--weight bed materials is even more scarce. USWES (1936) has conducted systematic experiments onlight--weight materials in a flume & m long an…  相似文献   

太原盆地历史地震活动特征及未来地震形势估计     

光春云  孙国学 《山西地震》1993,(1):3-8

对公元1000－1985年太原盆地M≥4.0地震进行了时序分析，结果表明，它们在时间轴上和山西地震带及至华北地区有着相似的平静一起伏变化特点，以此划出4个地震活动期和若干活动幕，指出活动最大地震存在逐步升级现象；在空间上重复性高，形成3个地震巢和以巢为主的地震条带与地震跳迁现象，认为在2000年前后，太原盆地将处在地震高活动时段，有可能在地震巢附近发生若干个中强地震，山西和华北地区强震活动也有可能与之同步。  相似文献   

新疆北天山晚古生代洋盆演化与推覆构造   总被引：5，自引：4，他引：5  

李向东 《新疆地质》1993,(3)

通过实地考察并综合区域及深部物探资料,研究了北天山逆冲推覆系统的构造样式、结构特征和组合方式;认为北天山晚古代洋盆为板内地壳扩张活动形成的裂陷构造产物,存在时限短暂、对生物群迁移基本没有阻隔作用,不应具有分隔岩石圈板块的大地构造意义。  相似文献   

铀矿床勘探类型之定量划分     

何金周 《铀矿地质》1993,(1)

本文提出矿化连续性分类法,它根据大矿体储量比例,将铀矿床划分为9个勘探类型。  相似文献   

Three-dimensional structure of the crust and upper mantle beneath the south China area from long period surface waves     

《地震学报(英文版)》1993,6(3):619-629

In the present study the long period surface wave records of 238 wave-paths from 79 earthquakes within China and its adjacent regions received by 30 seismic network stations are measured by using the improved match-filtering frequency-time analysis technique and the grid dispersion inversion method to obtain the rayleigh pure-path dispersion values for 147 slant grids of 4° × 4° in this area, then a three-dimensional shear wave velocity model of the crust and upper mantle beneath south China area to a depth of 170 km is inversed. It is found that there are obvious differences among the main structural units, and there are also certain differences among the subordinate elements even in the individual unit. The crustal thickness of this area is ranging from 30 to 43 km, and is getting thicker gradually from the east to the west. The average shear velocity of crust is ranging form 3.48 to 3.68 km/s with the lowest in the northeast part and highest in the west part. No obvious crustal low velocity layer of large scale is detected. There exist upper mantle low velocity zones in the most of south China area with the starting depth ranging from 75 to 106 km. The lowest shear velocity within the low velocity zones is about 4.28–4.38 km/s. Despite of the existing of upper mantle low velocity zones beneath the most of south China area, the interfaces between the important layers are quite clear, the variation of the bedding surfaces is very gentle, and the lateral changes measured in a larger scale of the underground structure are rather small. It may indicate that the crustal and upper mantle structure of the main part of south China area belongs to the relatively stable structure of the continental blocks except for the fringe areas such as the fold-faulted region in the west part and the fault system along the southeastern coast which may belong to the tectonically active area. The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,15, 159–167, 1993. This subject is supported by the National Science Foundation of China.  相似文献   

Lateral heterogeneities in the upper and mid-mantle conductivity in Argentina     

Ana Osella  Alicia Favetto  Patricia Martinelli 《Pure and Applied Geophysics》1993,141(1):139-156

Regional studies of Sq variations measured at five permanent observatories in Argentina were performed to estimate the distribution of the electrical conductivity of the upper and mid-mantle, reaching a depth of approximately 800 km. After separating the total field into its parts of external and internal origin, the in duced field was modeled, applying two-dimensional techniques. Additionally, induction arrows and an equivalent apparent resistivity curve were calculated A north-south heterogeneity was detected, showing an increase of the conductivity of the shallower layers north of the profile, which may be related to the presence of high volcanic activity in the area.Also at CONICET (Consejo Nacional de Investigaciones Científicas y Técnicas).  相似文献