基于共生金属硫化物硫同位素分馏程度约束热液活动温度：以川中下寒武统龙王庙组为例          下载免费PDF全文

刘大卫  蔡春芳  扈永杰  姜磊  王石  彭燕燕  李映涛  李汉敖 《古地理学报》2023,25(1):215-225

硫循环及硫同位素(δ³⁴S)分馏研究对地表圈层的成岩作用具有重要意义,其中多种金属硫化物中硫同位素的分馏程度可以约束成矿热流体温度,进而作为地温计证据约束热液活动。四川盆地龙王庙组储集层内的热液改造影响着该储集层的非均质性,本研究着重讨论目的层中与热液成因白云石所伴生的黄铁矿(FeS₂)-黄铜矿(CuFeS₂)成矿现象：基于详尽的岩石学证据,应用纳米二次离子探针(NanoSIMS)对金属硫化物内部硫同位素分布进行测定,并基于热力学驱动下的硫化物间平衡分馏程度计算其成矿温度,进而约束层段内热液活动过程。研究发现：(1)微区硫同位素分布显示黄铁矿(FeS₂)与黄铜矿(CuFeS₂)沉淀过程中不仅存在热力学分馏,还存在动力学分馏现象,其中动力学分馏程度可以达到40.1‰,应用NanoSIMS微区测定手段可以有效剔除动力学分馏数据影响,获取热力学平衡分馏数据;(2)黄铁矿(FeS₂)与黄铜矿(CuFeS₂)成矿过程或利用不同的硫源,其中黄铁矿...  相似文献   

北京闪电综合探测网(BLNET):网络构成与初步定位结果   总被引：6，自引：5，他引：1  

王宇  郄秀书  王东方  刘明远  苏德斌  沈永海  武智君  刘冬霞  孙竹玲 《大气科学》2015,39(3):571-582

北京闪电综合探测网(Beijing Lightning NETwork, 简称BLNET)由10个观测站组成, 每个子站主要由闪电快、慢电场变化测量仪(也称快、慢天线)和闪电甚高频(VHF)辐射探测仪构成, 实现了对闪电的多频段的综合观测。本文首先详细介绍了BLNET的网络构成, 然后利用蒙特卡罗法对网络的定位误差进行了理论分析, 模拟结果表明网络内部水平定位误差小于200 m, 网络外部100 km处水平定位误差小于3 km, 最后利用Chan氏算法和Levenberg-Marquardt算法相结合的方法, 对发生在2013年7月7日的一次雷暴过程分别进行了地闪和云闪定位, 将定位结果和对应时次的雷达回波进行比较, 发现地闪和云闪都出现在大于30 dBZ的雷达回波区, 表明了探测网络和定位方法的可靠性。  相似文献   

Temperature dependent secondary organic aerosol formation from terpenes and aromatics     

T. M. Svendby  M. Lazaridis  K. Tørseth 《Journal of Atmospheric Chemistry》2008,59(1):25-46

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城市地面沉降的灾害链特征——以天津市为例     

王若柏 《气象与减灾研究》2008,31(1):54-60

以20世纪60-80年代天津地区地面沉降灾害的发展为例,讨论了城市地面沉降灾害的特征,分析了地面沉降引发的次生灾害及其防治问题。结果表明,城市地面沉降灾害主要具有缓释特征、不可逆特征、罪罚特征和灾害链特征,城市地面沉降能够破坏市政设施,引发城市内涝和河流泄洪能力降低,造成地下水质和地质环境恶化,使海平面上升,沿海风暴潮加剧,同时还能造成海拔标高损失等。地面沉降所造成的损失是个巨大的灾害链,损失应当包括硬件和软件,也应当包括当前和远景,以致更深层次的影响。另外,缓释、不可逆的灾链特征对经济发展的布局、远景规划和投资环境影响不可低估;生态地理环境灾害链的影响,其效益损失更难于估计。地面沉降是城市灾害系统中的重要环节,也是城市防灾减灾的重要内容。地面沉降灾害的防治,应当是经济、环境、行政、立法,甚至教育、宣传等各个方面相结合的系统工程。  相似文献   

圣帕台风暴雨的非地转湿Q矢量的诊断分析   总被引：3，自引：2，他引：1  

傅灵艳  寿绍文  黄亿  岳彩军 《气象科学》2009,29(6):727-733

利用WRF中尺度模式模拟了台风"圣帕"登陆后减弱成热带低压造成湖南省大暴雨的过程,使用模拟输出的高分辨率资料,借助非地转湿Q矢量对这次暴雨过程做了详细的诊断分析.结果表明:非地转湿Q矢量能比较清楚地揭示此次暴雨演变过程,尤其700 hPa的非地转湿Q矢量散度场对降水预报具有较好的指示意义,其散度辐合区域对应着降水的落区,散度辐合强度变化指示着降水强度的变化趋势,并且非地转湿Q矢量散度辐合强度的大小可预示着未来3～6 h降水的强弱,是具有预报价值的;非地转湿Q矢量散度是非地转ω方程的强迫项,并与地形条件共同作用激发了地面中尺度系统的发展与次级环流的形成,是此次暴雨得以发展与维持的机制.  相似文献   

Variations of levels and composition of PM₁₀ and PM_2.5 at an insular site in the Western Mediterranean     

Jorge Pey  Xavier Querol  Andrs Alastuey 《Atmospheric Research》2009,94(2):285-299

The insular suburban site of Castillo de Bellver was selected for the study of the variability of PM levels and composition in the Western Mediterranean Basin (WMB).Mean annual (in 2004) PM₁₀ and PM_2.5 levels at this site were 29 and 20 µg/m³, respectively. These levels may be regarded as relatively low when compared with other suburban insular locations in the Eastern Mediterranean Basin (EMB), but they are higher than those recorded at most of the European suburban sites, especially in Northern and Western Europe. Seasonal variability of PM levels at this site is governed by meteorology rather than local emissions, whereas the daily cycles are clearly defined by the anthropogenic emissions, mainly coming from the urban area of Palma de Mallorca and the harbour area of the same city.Concerning the aerosol composition at this site, the main PM constituent is the mineral matter (29% in PM₁₀ and 16 % in PM_2.5), more than 50% (in PM₁₀) being attributable to African dust. The amount of secondary inorganic aerosols is also very high (27% in PM₁₀ and 34% in PM_2.5), with the predominance of fine ammonium sulphate, and in a less proportion fine ammonium nitrate (in winter) and coarse Ca and Na nitrate (with higher importance in summer). The carbonaceous particles, dominantly fine, account for 17% of PM₁₀ and 25% of PM_2.5. The elemental carbon/organic carbon (EC/OC) ratio reached a mean value of 0.17, similar to those observed at regional background sites in the WMB coast of Spain. The sea spray aerosols (mainly coarse) represented around 10% of PM₁₀, and only 4% in PM_2.5. Finally, the unaccounted fraction increased from 15% to 20% in PM_2.5, being mostly attributed to water.The concentrations of trace elements in PM₁₀ and PM_2.5 were usually in the range to those observed in regional background sites in the Iberian Peninsula, with the exception of the typical tracers of road traffic such as Cu, Sb, Zn, Sn and Ba, which presented concentrations in the range of urban sites of Iberia. Other elements such as Cr, Zr, Hf and Co have been identified as the main tracers of the harbour contributions.  相似文献   

东营凹陷陡坡带深层砂砾岩体次生孔隙成因机制探讨   总被引：1，自引：1，他引：0  

王勇  钟建华 《地质科学》2010,45(3):822-831

从岩心、薄片、扫描电镜以及FMI成像测井等资料分析发现,东营凹陷陡坡带深层砂砾岩体储层次生孔隙发育,在埋深大于3 500 m古近系砂砾岩储层中,普遍存在2～4个次生孔隙发育带,次生孔隙度主要分布在2%～10%,次生渗透率主要分布在0.1×10~(-3)～8×10~(-3)μm~2,为低孔低渗储层。研究认为长石、岩屑、碳酸盐和硫酸盐等酸溶组分的溶蚀以及构造运动是深层次生孔隙形成的主导因素。其主要形成机理有:1)有机质热演化过程中产生的酸性流体的溶解作用;2)去石膏化和去白云化以及硫酸盐热化学作用;3)异常高压环境中的幕式排烃、膏岩层导致的生油窗扩展作用以及盐度差导致的H~+浓度的升高;4)构造作用、脱水收缩作用等。  相似文献   

Perspectives on Quaternary outreach and aspirations for the future     

David E. Anderson  Eleanor J. Brown 《Proceedings of the Geologists' Association. Geologists' Association》2010,121(4):455-467

Outreach arising from the study of the British Quaternary offers many benefits for society, especially because of its relevance for understanding contemporary environmental issues and environmental change. Outreach is also important for the long-term health of the academic discipline and research agenda. Through engaging with the formal education system, institutions, policy makers, planners and with the public at large, Quaternary specialists can do much to advance interest in and appreciation of the British landscape and its Quaternary record. This opinion and review article considers the importance and benefits of outreach in its many forms, makes the case for practitioners to continue and increase their involvement, offers examples of good practice, and sets out aspirations for the future.  相似文献   

脉冲星TOA测量误差及几何精度分析     

毛悦  宋小勇  柴飞 《测绘学院学报》2009,(2)

利用信躁比估算法对脉冲星数据库中适宜导航的脉冲星进行了脉冲到达时间测量误差计算。分析了测量误差随观测时间及探测器面积的变化情况。在此基础上,指出了在DOP值分析中脉冲星导航与GPS的不同点;按照脉冲到达时间TOA测量误差较小原则给出了10组脉冲星优选组合。分析了DOP值随观测时间及观测脉冲星数的变化情况。  相似文献   

Long-term behaviour and mineralogical reactions in hazardous waste landfills: a comparison of observation and geochemical modelling     

B. Gade  H. Pöllmann  A. Heindl  H. Westermann 《Environmental Geology》2001,40(3):248-256

 Drill cores from a Bavarian hazardous waste landfill were investigated for their mineralogical composition. Because of the formation of many new minerals, geochemical equilibrium calculations were performed to find the most stable state of the waste body. A comparison of mineralogical observations and geochemical modelling was undertaken. The remaining solubilities of the newly formed secondary mineral assemblages were calculated. Newly formed minerals were shown using electron microscopy. Received: 26 November 1999 · Accepted: 15 May 2000  相似文献