山西地电中短期前兆异常识别方法浅析

用傅氏滑动法、动态距平法、速率法、均值法等对山西大同台、代县台、临汾台的地电异常进行了分析 ,对地电阻率异常的判定、预报方法效能进行了评价 ,对不同的台站 ,从正常的变化形态中找出了突出异常的有效方法 ,从中提取出因地壳应力变化引起的地震前兆异常 ,结果表明 ,5 .0级以上地震在Δ=15 0 km范围内有明显的中短期前兆异常     

山西北部至晋冀蒙交界地区几次中强地震前4.0级地震活动的研究

对山西北部至晋冀蒙交界地区中强地震前的 4 .0级地震进行了研究 ,得出其特征为异常增强—异常平静—信号地震的结论 ,认为该区某些 4 .0级地震活动似可作为某些中强地震的前兆地震而进行进一步的研究。     

Tracking recent recovery from eutrophication in a high arctic lake (Meretta Lake, Cornwallis Island, Nunavut, Canada) using fossil diatom assemblages

Meretta Lake (Resolute Bay, Cornwallis Island, Nunavut, Canada) is a high arctic lake that received raw sewage for almost 50 years from the Canadian Department of Transport Base. The lake was sampled from 1968–72 during the International Biological Programme, as part of the Char Lake Project. As the number of users at the Transport Base declined throughout the 1990s, so too did the lake's nutrient levels, and Meretta Lake is now classified as oligotrophic. A previous diatom-based paleolimnological study revealed marked species assemblage shifts coincident with sewage inputs beginning in the late 1940s; however, because the core was taken at a time when nutrient levels were still relatively high (i.e., 1993), the diatom record did not yet track any signs of recovery. In this present study, we examined fossil diatom assemblages from a sediment core taken in 2001. Our results indicate a shift to the pre-impact diatom assemblages in the most recent sediments, indicating that the paleolimnological record is tracking the decreased nutrient inputs to this high arctic lake, and confirms that no significant lags exist in these largely ice-covered lakes.     

Les dykes basiques du massif ancien de l'Ourika (Atlas de Marrakech,Maroc) : géochimie et significationThe basic dykes of the Ourika old massif (High Atlas of Marrakech): Geochemistry and significance

The Precambrian massif of Ourika is crosscut by two systems of basic dykes, striking N40°E and N90–120°E. Using incompatible trace elements, the two systems form two distinct chemical groups, displaying a continental tholeiitic affinity. The composition variations between the two defined groups can be due to heterogeneities of mantle sources and to contamination, during the magma ascent, by the continental crust. The emplacement of these basic dykes, before the late-PIII formations, can be related to the Neoproterozoic distension generalised to the Anti-Atlas chain. To cite this article: A. Barakat et al., C. R. Geoscience 334 (2002) 827–833.     

覆盖区地球化学异常特征及甄别方法探讨

覆盖区地球化学异常是由自然和人为因素引起的，在土壤垂直剖面上元素有多种分布类型，它反映了元素在土壤中迁移、演化及人为干扰的分布特征；通过对自然和人为污染的地球化学异常源追踪和评价，为环境污染治理和地区经济可持续发展提供决策依据。     

对天然地基承载力计算公式的理解和应用

文章就新老国标和上海标准对地基承载力的计算公式进行了分析比较,并认为在上海地区岩土工程勘察报告中提供天然地基承载力设计值fd更适合。     

某高层建筑刚性桩复合地基设计分析

根据当地工程地质条件，结合工程结构特点和当地施工技术水平，高层建筑软弱地基采用刚性桩和褥垫层处理，形成复合地基，是—种安全、经济的方法，施工难度小，能充分发挥桩和桩间土的承载力．本文分析了刚性桩桩顶设置粒状材料褥垫层后的桩土变形协调原理，桩和桩间土共同承载荷载的受力机制，复合地基的承载力设计和变形计算方法．提出了复合地基的桩和褥垫层施工质量要求．     

高放废物处置库选址中低渗透介质地质研究的几个问题

低渗透介质是阻碍有害物质在地下迁移良好的天然屏障, 因此成为高放废物处置库围岩类型的首选。本文通过对高放废物处置库选址中地质研究的回顾, 阐述了低渗透介质地质研究的特点, 对地质参数测定、取样、水流模拟、地球化学模拟进行了重点介绍。     

层序地层学研究及隐蔽油气藏预测--以南阳凹陷古近系为例

高精度层序地层学已被证明是寻找隐蔽圈闭行之有效的理论方法．运用该理论对南阳凹陷进行了研究，对地震剖面中反射界面的追踪，在古近系中识别出了各级别的层序界面，结合周缘露头、钻井、测井等资料，分析了主要目的层序内体系域的构成及高频单元变化规律，建立了层序地层模式，在此基础上预测南部陡崖式断坡带和北部缓坡式弯折带是低位域砂体和隐蔽岩性油气藏形成的有利区带．     

江西银山多金属矿床高盐度包裹体及其成因意义

流体包裹体岩相学和显微测温学研究表明，银山矿床石英斑岩和金金属矿床中都发现须含石盐的高盐度流体包裹体，表明至少在成矿作用的早期成矿流体为高盐度流体，高盐度流体不是由热水溶液的不混溶作用或沸腾作用形成的，而是直接从饱和水的结晶岩浆熔体中出溶的，银山矿床的成矿流体与斑岩铜矿的成矿流体具有相似性，证实矿床深部可能有隐伏斑岩铜矿。