煤层气及天然气中的H2S与SO2及其危害性   总被引：4，自引：0，他引：4  

马玉贞  陶明信  张新民  李晓斌  李晶  解光新  王彦龙 《地质学报》2008,82(10):1408-1415

毒害性气体是影响煤层气和天然气质量及安全生产的一个重要因素,但目前缺乏对煤层气中H2S与SO2及其毒害性的系统性研究。本文在介绍H2S和SO2的毒害性及其机理的基础上,研究并讨论了煤层气及天然气中H2S和SO2的含量分布及其存在的主要问题、天然气和煤层气勘探开发中H2S和SO2的腐蚀性与毒性, 提出在优选勘探开发煤层气区时,需考虑H2S和SO2的含量问题。气体中H2S的安全临界含量近似值为0.0013%, SO2的安全临界含量可选取为0.036%(尚需进一步研究)。另外,在煤层气勘探开发选区时,成煤期的沉积古地理环境可作为一个考虑因素。  相似文献   

涂氏磷钙石的形成条件研究     

谢先德  陈鸣 《地球化学》2008,37(4)

用微束矿物学和激光拉曼光谱等分析测试技术,并结合人工高压实验结果,研究了我国随州陨石冲击熔脉中的白磷钙石高压相变形成涂氏磷钙石的必要条件,并对寺巷口陨石冲击熔脉中的白磷钙石虽与林伍德石、镁铁榴石和玲根石等高压矿物共生,但仅表现为结构损伤而未相变成涂氏磷钙石的原因进行了探讨.研究结果发现,随州陨石中白磷钙石或氯磷灰石的存在是涂氏磷钙石得以形成的物质前提,陨石熔脉中高达24 GPa和2000℃以上的高压高温环境是涂氏磷钙石能够形成的条件保障,而压力释放后熔脉极快的冷却速率是涂氏磷钙石得以淬火并稳定保存的关键.研究还查明,寺巷口陨石冲击熔脉比随州陨石的熔脉要宽1至2个量级,其冷却速率比随州陨石慢得多,因此,熔脉中早先形成的涂氏磷钙石,可能在脉内较高的冲击后温度影响下,慢慢退变质成白磷钙矿.  相似文献   

龙门山断裂带北段晚新近纪以来的右行走滑运动及其构造变换研究——以青川断裂为例   总被引：12，自引：1，他引：11       下载免费PDF全文

樊春  王二七  王刚  王世锋 《地质科学》2008,43(3):417-433

龙门山断裂带位于青藏高原东缘,构成了青藏高原和四川盆地的重要构造边界。近年来的研究表明:在新生代晚期,除了存在逆冲推覆之外,龙门山的中段和南段还发生了明显的右行走滑活动。对龙门山北段的青川断裂进行的系统研究发现:断裂具有明显的右行走滑特征,沿断裂发育大量不同规模的水系位错,其中嘉陵江水系位错规模最大,据此可确定青川断裂的最大位移量为17km。进一步的野外工作证实断裂的走滑位移在尾端发生构造变换,位于断裂南西端的轿子顶穹隆是叠加构造,吸收了青川断裂的部分位移量;位于断裂北东端的汉中盆地则是处于伸展应力环境下的断陷盆地,吸收了其大部分位移量。  相似文献   

Spatial operations in a GIS-based karst feature database     

Yongli Gao 《Environmental Geology》2008,54(5):1017-1027

This paper presents the spatial implementation of the karst feature database (KFD) of Minnesota in a GIS environment. ESRI’s ArcInfo and ArcView GIS packages were used to analyze and manipulate the spatial operations of the KFD of Minnesota. Spatial operations were classified into three data manipulation categories: single layer operation, multiple layer operation, and other spatial transformation in the KFD. Most of the spatial operations discussed in this paper can be conducted using ArcInfo, ArcView, and ArcGIS. A set of strategies and rules were proposed and used to build the spatial operational module in the KFD to make the spatial operations more efficient and topographically correct.  相似文献   

Losses from sleet storms in the United States     

Stanley A. Changnon 《Natural Hazards》2008,47(3):465-470

Increasing losses of life and property and damages to the environment due to sleet and related winter storm conditions have increased the need for long-term sleet storm data to better assess the point and regional risks of sleet and their long-term variations. The areas of greatest losses and frequency of catastrophes caused by sleet during 1971–2007 are the Northeast and Central regions of the U.S. These two regions experienced 72% of all the nation’s sleet losses. Most of the western U.S. had no damaging sleet-related events or losses. When sleet losses occurred, they tended to be in 2, 3, or 4 adjacent states. Sleet catastrophes were most common in January with 15 of the 30 events. The earliest storm occurred in October and the latest in March. The temporal distributions of catastrophes and their losses during 1971–2007 were similar. Both showed a secondary peak in 1976–1979, a low in 1988–1991, and then high values during the 1996–2007 period. The temporal distributions of damaging storms and losses indicate an upward trend over time.  相似文献   

Stratigraphy of nutrients and metals in sediment profiles of two dimictic lakes in North-Eastern Germany     

Uwe Selig  Thomas Leipe 《Environmental Geology》2008,55(5):1099-1107

A sedimentological study of two dimitic lakes in North-Eastern Germany provided a record of anthropogenic impacts and historical changes of water quality. The upper 50 cm sediment profiles were compared for major nutrients and selected major trace elements. The sediments were dated by ²¹⁰Pb and ¹³⁷Cs measurement. The upper 50 cm sediment profiles represent approximately the last 100 years of history in both lakes. Element analyses show different characteristic stratigraphic patterns in both lakes. Based on the nutrient and metal stratification, three characteristic time periods can be documented for both lakes. In addition to agricultural use of the catchment area, atmospheric pollution greatly influenced the metal concentration in the sediment layers. Variation in the external loading and redox conditions in the hypolimnion explain the variation in the composition and accumulation of metals in the sediment stratigraphy. No increases or changes in the trophic level of either lake could be documented based on the accumulation of the nutrients C, N and P. The ratio of Fe/Mn and Fe/Ca characterized the changing redox conditions. The stratigraphy of Pb and Zn agrees with the historical variation in atmospheric pollution and confirms literature values for Central and North Europe. The drop in Pb and Zn over the last 10–15 years is a regional effect in North-Eastern Germany.  相似文献   

Geology,fluid inclusion and sulphur isotope characteristics of the El Cobre VHMS deposit,Southern Cuba     

Xiomara Cazañas  Pura Alfonso  Joan Carles Melgarejo  Joaquín Antonio Proenza  Anthony Edward Fallick 《Mineralium Deposita》2008,43(7):805-824

The El Cobre deposit is located in eastern Cuba within the volcanosedimentary sequence of the Sierra Maestra Paleogene arc. The deposit is hosted by tholeiitic basalts, andesites and tuffs and comprises thick stratiform barite and anhydrite bodies, three stratabound disseminated up to massive sulphide bodies produced by silicification and sulphidation of limestones or sulphates, an anhydrite stockwork and a siliceous stockwork, grading downwards to quartz veins. Sulphides are mainly pyrite, chalcopyrite and sphalerite; gold occurs in the stratabound ores. Fluid inclusions measured in sphalerite, quartz, anhydrite and calcite show salinities between 2.3 and 5.7 wt% NaCl eq. and homogenisation temperatures between 177 and 300°C. Sulphides from the stratabound mineralisation display δ ³⁴S values of 0‰ to +6.0‰, whilst those from the feeder zone lie between −1.4‰ and +7.3‰. Sulphides show an intra-grain sulphur isotope zonation of about 2‰; usually, δ ³⁴S values increase towards the rims. Sulphate sulphur has δ ³⁴S in the range of +17‰ to +21‰, except two samples with values of +5.9‰ and +7.7‰. Sulphur isotope data indicate that the thermochemical reduction of sulphate from a hydrothermal fluid of seawater origin was the main source of sulphide sulphur and that most of the sulphates precipitated by heating of seawater. The structure of the deposit, mineralogy, fluid inclusion and isotope data suggest that the deposit formed from seawater-derived fluids with probably minor supply of magmatic fluids.  相似文献   

Deformation-induced polymorphic transformation: experimental deformation of kyanite, andalusite, and sillimanite   总被引：1，自引：0，他引：1  

Eric T. Goergen  Donna L. Whitney  Mark E. Zimmerman  Takehiko Hiraga 《Tectonophysics》2008,454(1-4):23-35

Torsion experiments were performed on the Al₂SiO₅ polymorphs in the sillimanite stability field to determine basic rheological characteristics and the effect of deformation on polymorphic transformation. The experiments resulted in extensive transformation of andalusite and kyanite to sillimanite. No transformation occurred during the hot-press (no deformation) stage of sample preparation, which was carried out at similar P–T conditions and duration as the torsion experiments. Experiments were conducted on fine-grained (< 15 µm) aggregates of natural andalusite, kyanite and sillimanite at 1250 °C, 300 MPa, and a constant shear strain rate of 2 × 10^− 4/s to a maximum shear strain of 400%. Electron back-scattered diffraction (EBSD) analysis of the experiments revealed development of lattice-preferred orientations, with alignment of sillimanite and andalusite [001] slightly oblique to the shear plane. The kyanite experiment could not be analyzed using EBSD because of near complete transformation to sillimanite. Very little strain ( 30%) is required to produce widespread transformation in kyanite and andalusite. Polymorphic transformation in andalusite and kyanite experiments occurred primarily along 500 µm wide shear bands oriented slightly oblique and antithetic to the shear plane and dominated by sub-µm (100–150 nm) fibrolitic sillimanite. Shear bands are observed across the entire strain field preserved in the torsion samples. Scanning transmission electron microscope imaging shows evidence for transformation away from shear bands; e.g. fibrolitic rims on relict andalusite or kyanite. Relict grains typically have an asymmetry that is consistent with shear direction. These experimental results show that sillimanite is by far the weakest of the polymorphs, but no distinction can yet be made on the relative strengths of kyanite and andalusite. These observations also suggest that attaining high bulk strain energy in strong materials such as the Al₂SiO₅ polymorphs is not necessary for triggering transformation. Strain energy is concentrated along grain boundaries, and transformation occurs by a dynamic recrystallization type process. These experiments also illustrate the importance of grain-size sensitive creep at high strains in a system with simultaneous reaction and deformation.  相似文献   

基于3S技术的地质灾害野外调查数字采集系统的研究   总被引：4，自引：1，他引：3  

曾青石  张像源  陈辉 《水文地质工程地质》2008,35(1):121-125

传统上,区域野外地质灾害调查主要是利用罗盘、地质锤、放大镜等工具进行等在野外完成,日后专业人员获取这些灾害点的相关原始数据需要从资料室的资料柜里进行查找并整理后进行统计分析,这种工作模式不利于数据共享与管理,也不适应"数字国土"工程的建设节奏,因此,基于3S技术建立一套集野外数字采集、成图、分析以及数据输出一体化的地质灾害野外调查数字采集系统是解决上述问题的关键所在。本文从需求分析着手,从系统构成、野外数据采集模型、实体模型、系统功能等方面对系统的构建进行探讨研究,最后结合本文的设计,利用国产的嵌入式GIS软件MAPGIS,实现了集野外数据的组织、采集背景文件的发布、采集数据收集一体化工作流程的地质灾害野外数据数字采集系统。  相似文献   

环北京地区土地利用变化监测与分析     

燕云鹏  和正民  李建存  曾福年 《国土资源遥感》2008,(1):64-67,I0008

利用1992和2002年2期Landsat卫星影像,对环北京地区土地利用变化和退化情况进行监测,探讨和分析了北京地区土地利用变化、土地退化的特征和规律.结果表明,北京风沙源区土地利用变化的最大特点是耕地显著减少,林地和牧草地明显增加;整个风沙源区的土地退化格局宏观上受大兴安岭向南延长段和阴山山脉东段的地形地貌控制,并且随所处位置的不同而退化程度有较明显的差异.  相似文献