山东埠后古火山机构显微构造研究

埠后古火山机构由早白垩世陆相火山岩和次火山岩组成,铅、锌、铜、硫矿与后者有关。为了圈定火山通道的大致位置,在熔岩中采制定向切片,进行显微构造分析。通过变形、压密、阻挡、涡流等显微构造标志确定流动方位;利用长条状晶体的长轴方向确定流动线理。根据流动方位和流动线理圈出古火山口位置,进而指出在环火山颈的大断裂一侧,可能具区域找矿前景。     

Blasting Technique and Process for Rock Ridge in a Wave Power Station

A technique of peripheral presplitting blast with multi-ignitions of millisecond detonaters is put forward in this paper based on the characteristics of ridge blast for wave power station, the main ridge blasting with deep hole smooth blasting and casting blast of inclined holes. The formula to calculate explosive charge is established. Finally, the theory and process of this technique for ridge blasting are discussed.     

大庆坪地区溶洞水的分布特征及其开发利用的探讨

<正> 大庆坪地区位于湖南省永州市的西南部,地处湘、桂交界的南岭山脉中段,面积约661平方公里,上游广西补给区267平方公里,为湘桂盆地边缘地带的一个以间互状碳酸盐岩为主的溶丘—洼地类型的岩溶汇水盆地,属干旱严重的岩溶区。建国以来,共建地下水利水电工程16处,几乎所有适合开发利用的点均已利用,共获农业灌溉用水7000万立方米,装机约3000千瓦,从根本上改变了全区岩溶干旱面貌。      

储层裂缝特征测井解释方法综述

为了更好地研究裂缝性砂砾岩储层和其它裂缝性储层裂缝的测井解释问题,综述了目前在裂缝性储层裂缝测井解释中主要采用的常规评价、人工神经网络和斯通利波３类方法在识别裂缝带和定量计算储层裂缝参数两个方面的应用原理和研究现状,并指出了今后的一些研究方向。     

四川盆地西南部第三纪盆地原型及其演化

第三纪是四川盆地大范围陆相沉积历史的最后阶段, 同时又是四川盆地重要的构造定形期.探究该时期原型盆地沉积充填规律与构造演化特征, 是揭示四川盆地形成演化过程, 还原其古地理、古气候演变的关键.在综合利用古地磁、地震、野外露头等资料的基础之上, 从盆-山结合的角度出发, 以地质历史时间为主要线索, 对第三纪原型盆地分阶段、分区域地进行了动态化分析研究.重建了各沉积时期原型盆地构造-古地理格局, 分析了盆地沉积充填规律并复原了不同阶段沉积相带的空间展布特征.主要受周缘山系逆冲推覆作用产生的构造负载和盆地基底构造的影响, 第三纪时期四川盆地沉积范围局限于西南部、南部地区, 以河、湖沉积环境为主, 处于持续地挤压、充填过程而具有萎缩消亡的趋势.现今残余第三系地层由老到新, 主要由名山组、芦山组、大邑砾岩组等地层组成(先后经历了: 受造山带挤压推覆作用和温暖干旱气候等因素影响, 发育湖盆边缘冲积扇和沙漠沉积环境, 处于快速沉降阶段的名山组沉积时期; 以及构造活动相对稳定, 湖盆面积不断减小, 以沙泥质沉积互层为特征的芦山组沉积时期; 和沿山前带由南向北迁移, 以发育大型冲积扇为特征的大邑砾岩组沉积时期).纵观整个第三纪构造演化历史, 反映出四川盆地西南部地区在第三纪时期表现为典型的陆内坳陷沉积盆地性质.同期的大地构造活动和气候变化等因素对原型盆地的形成与演化起到了重要的控制作用, 同时也对该时期盆地古地理格局和沉积充填规律产生了重要影响.     

形变数字化观测曲线畸变与处理——兼论资料预处理中遇到的一些问题

数字化形变台站日常下载、处理直至管理数据,都应用《数字化通讯控制软件》、《形变前兆台站(网)数据处理系统》及《形变前兆数据库服务软件(台站版)》等三个软件交互进行,在实际使用过程中会遇到一些棘手的问题。本文结合我台的观测工作的实践,总结经验,以供台站同行共享。     

Adsorbed silica in stalagmite carbonate and its relationship to past rainfall

Despite considerable work on other trace elements, the incorporation of dissolved silicon from cave waters into speleothems has not been previously investigated. In this study, the controls on dissolved Si in cave waters and on adsorbed Si in resulting speleothems are therefore investigated. Bedrock (dolomite), soil water, dripping water, and cave carbonates were retrieved from Heshang Cave situated in the central Yangtze valley of China and were subjected to analysis of dissolved Si content (plus accompanying Ca and Fe analyses). Soil waters have Si/Ca of 45.5 mmol/mol, compared to only 3.2 mmol/mol in the dolomite bedrock, demonstrating that >80% of the dissolved Si must come from dissolution of silicate minerals in the soil. Drip waters have a dissolved Si concentration of ≈4.2 μg/mL, similar to that in the overlying soil water. Actively growing cave carbonates have a Si/Ca of 0.075 mmol/mol suggesting a partition coefficient for incorporation of dissolved silicon of 0.0014, in good agreement with previous laboratory studies. Extrapolating the results of these laboratory studies to the cave environment suggests that changes in Si/Ca in cave carbonates are likely to be primarily controlled by changes in drip-water Si/Ca. The drip-water Si/Ca will, in turn, be controlled by the rate of wind-blown silicate supply; by soil weathering rates; by rainfall dilution; and by precipitation of calcite. The general expectation is that these effects combine to produce high Si/Ca in speleothems during times of low rainfall. A δ¹⁸O record from a Heshang Cave stalagmite which grew between 20 and 11 thousand years ago allows these controls to be tested. Correlation of high Si/Ca with high δ¹⁸O demonstrates that regional rainfall exerts significant (but not complete) control on speleothem Si/Ca. With further understanding, speleothem Si/Ca may provide a proxy for past rainfall to complement existing proxies such as δ¹⁸O and Mg/Ca.     

北黄海盆地构造几何学研究新进展

北黄海盆地是发育于隆起背景之上的中、新生代沉积盆地。新一轮资源调查研究表明，北黄海中、新生代沉积盆地的基底由古生界沉积岩层和前寒武纪变质岩系等组成，盆地不同程度地发育下构造层（J3-K1）、中构造层（E2-E3）和上构造层（N）；从油气资源和中、新生代地层发育情况出发，将北黄海海域划分为辽东-海洋岛隆起区、北黄海盆地和胶北．刘公岛隆起区等3个一级构造单元，其中北黄海盆地包括6个二级构造单元和24个三级构造单元；盆地褶皱、断裂构造十分发育，褶皱构造可划分为区域挤压型、局部伴生型和披盖型等三类，断裂构造主要可见近EW—NE向、NW向和NNE向三组，其中近EW—NE向和NNE向断裂比较发育，控制着盆地隆、坳分布格局和沉积特征。     

Stability analysis of an ancient landslide considering shear strength reduction behavior of slip zone soil

In this paper, the stability of an ancient landslide during the first impounding of a nearby reservoir is investigated through the analyses of the shear strength reduction behavior of slip zone soil. In view of the experimental observations, an empirical strain-dependent soil model is established and is then incorporated in finite element analyses. The numerical analysis results show that the failing sections progressively develop due to the soil strength declines from peak toward residual, and the shear zone propagates within the front slope. It is demonstrated in the numerical results that the toe weighting measure has a significant effect on restraining the shear displacements of the soils and preventing the progressive failure of the landslide. The field observations further confirmed the stability condition of the reinforced landslide.     

Iron Reduction Along an Inundation Gradient in a Tidal Sedge (<Emphasis Type="Italic">Cyperus malaccensis</Emphasis>) Marsh: the Rates,Pathways, and Contributions to Anaerobic Organic Matter Mineralization

Incubation experiments were adopted to characterize the rates and pathways of iron reduction and the contributions to anaerobic organic matter mineralization in the upper 0–5 cm of sediments along a landscape-scale inundation gradient in tidal marsh sediments in the Min River Estuary, Southeast China. Similar sediment characteristics, single-species vegetation, varied biomass and bioturbation, distinct porewater pH, redox potential, and electrical conductivity values have resulted in a unique ecogeochemical zonation along the inundation gradient. Decreases in solid-phase Fe(III) and increases in nonsulfidic Fe(II) and iron sulfide were observed in a seaward direction. Porewater Fe²⁺ was only detected in the upland area. High rates of iron reduction were observed in incubation jars, with significant accumulations of nonsulfidic Fe(II), moderate accumulations of iron sulfides, and negligible accumulations of porewater Fe²⁺. Most of the iron reduction was microbially mediated rather than coupled to reduced sulfides. Microbial iron reduction accounted for 20–89 % of the anaerobic organic matter mineralization along the inundation gradient. The rate and dominance of microbial iron reduction generally decreased in a seaward direction. The contributions of microbial iron reduction to anaerobic organic matter mineralization depended on the concentrations of bioavailable Fe(III), the spatial distribution of which was significantly related to tidal inundation. Our results clearly showed that microbial iron reduction in the upper sediments along the gradient is highly dependent on spatial scales controlled primarily by tidal inundation.