山旺盆地的成因及其地质意义

前人一般认为山旺盆地是一个深度不大的封闭性淡水剥蚀盆地。笔者认为它是一个火山口成因的封闭—半封闭盆地。盆地的发展经历了3个发展阶段:早期为火山喷发作用形成火山口,并造成火山碎屑物堆积:中期堆积了较厚层的沉积物,主要为粘土质岩石,如硅藻质页岩、泥岩,此外,还有少量的砂岩、砾岩;晚期为玄武岩充填,致使整个盆地完全封闭。在盆地发展过程中,早期为封闭环境,中、晚期为半封闭环境。火山碎屑物的再堆积和分解对于生物死亡和埋藏可能具有重要的意义;该区第三纪中心式火山作用非常强烈,通过详细的区域地质调查,有可能找到更多的化石产地和硅藻土矿。     

灰岩碳氧同位素特征与隐伏花岗岩的关系——以栗木水溪庙矿区为例

对栗木水溪庙矿区泥盆系上统融县组灰岩的碳氧同位素进行了研究,该地区灰岩的碳氧同位素组成可提供隐伏花岗岩隆起及其相关流体的重要信息。受隐伏花岗岩侵入驱动的流体与上覆融县组灰岩发生反应的温度在110℃左右,流体的初始同位素组成为δ18OSMOW=-3‰,δ13CPDB≤-7‰,反应的水岩比值（w/r）可能小于5。这种岩浆水与大气降水的混合流体与围岩之间的水岩反应使得地表灰岩的δ18O和δ13C值降低,产生负异常。研究表明,围岩的δ18O值降低受反应的水岩比值和温度控制;δ13C值降低主要与反应的水岩比值有关。反应的温度越高,w/r值越大,灰岩的碳氧同位素负异常越明显。因此,水溪庙矿区地表出露的碳酸盐地层中的碳氧同位素变化可在地球化学勘查中用于指示下伏花岗岩岩脊的隐伏位置。     

Magnetic properties,characteristic spectra and colors of turquoise

The unique bright bluish-green color of turquoise as a high-grade jade has long received wide attention. The relationship between the color of turquoise and its composition and structure is described in this paper on the basis of chemical data, EPR, magnetic susceptibility, absorption and Mössbauer spectra. The results show that the basic color of turquoise (bright blue) is related to the existence of octahedrally on the amount of iron. EPR, magnetic susceblue through green to earth-yellow is dependentcoordinated Cu²⁺ and the shade variation from ptibility, and crystal-field spectra of Cu²⁺ have been analyzed and compared with the theoretical calculations. A preliminary discussion is also made of the color change as a function of temperature.     

三维地质图制作方法——以1∶50万海南岛地质图为例

将Global Mapper、ArcGIS、MapGIS三款GIS软件有效结合起来,以海南岛为例进行基于DEM的三维晕渲地质图的制作方法研究。首先将SRTM数据和矢量地理数据在不同地图参数下进行自动配准,然后实现地质要素与DEM模型的精准匹配,最后根据DEM对第四系地质界线进行微调,实现了1∶50万海南岛三维地质图的制作。同时总结了不同椭球体与坐标系统下的数据转换、DEM空白区数据填补、晕渲地质图生产的方法。三维地质图制作所采用的DEM数据完全满足1∶50万三维地质图的制图要求;与传统地质图相比,其立体感和可读性明显增强,图件信息量显著增大,图面呈现清晰的三维地质结构,很好地提高了制图精度。该方法为我国三维地质图的制作提供了一个新的方法和思路,并为其他三维图件制作提供了参考借鉴。     

Mapping hydrothermal alteration in the Comstock mining district,Nevada, using simulated satellite‐borne hyperspectral data

Hydrothermal alteration mapping with spaceborne hyperspectral data was simulated in the Comstock mining district, Nevada in order to evaluate the mineral mapping capabilities of the proposed Australian Resource Information and Environment Satellite (ARIES‐1). As a result, a suite of hydrothermal alteration minerals, including kaolinite, dickite, illite, chlorite, alunite and carbonate was identified from the simulated data in the 0.4–2.5 μm wavelength region and their areal abundance variations mapped accordingly. The recognised alteration zoning shows a major change in alteration assemblages across the Comstock and Silver City Faults, and a gradual variation from north to south along the faults. In the bleached Miocene volcanic rocks, dickite, kaolinite, illite and alunite were recognised. Coexistence of dickite of relatively high temperature, high‐crystallinity kaolinite of medium temperature and low‐crystallinity kaolinite of low temperature suggests supergene processes overprinting earlier hypogene alteration. The bleached rocks probably represent hydrothermal alteration in the fluid up‐flow zones in the central and shallower parts of the hydrothermal system. Illite in the bleached zones is characterised by relatively short AI–OH band wavelengths (2190–2200 nm), indicating no or very low Fe and/or Mg contents. Fault‐controlled propylitic alteration is mapped in the central part of the district mainly in the footwall of the Comstock Fault. The associated illite is characterised mainly by medium AI–OH band wavelengths (2200–2208 nm). This propylitic alteration may be contemporaneous with Au–Ag mineralisation. Additional and more extensive propylitic zones, containing illite with long AI–OH band wavelengths (2204–2216 nm), were mapped in the southern part of the district. These zones resulted from either a pre‐mineralisation propylitic alteration, or the peripheral hydrothermal alteration in the fluid down‐flow zones of the Miocene hydrothermal system.     

Estimation of Block Sizes for Rock Masses with Non-persistent Joints

Summary  Discontinuities or joints in the rock mass have various shapes and sizes. Along with the joint orientation and spacing, the joint persistence, or the relative size of the joint, is one of the most important factors in determining the block sizes of jointed rock masses. Although the importance of joint persistence on the overall rock mass strength has long been identified, the impact of persistence on rock strength is in most current rock mass classification systems underrepresented. If joints are assumed to be persistent, as is the case in most designs, the sizes of the rock blocks tend to be underestimated. This can lead to more removable blocks than actually exist in-situ. In addition, a poor understanding of the rock bridge strength may lead to lower rock mass strengths, and consequently, to excessive expenditure on rock support. In this study, we suggest and verify a method for the determination of the block sizes considering joint persistence. The idea emerges from a quantitative approach to apply the GSI system for rock mass classification, in which the accurate block size is required. There is a need to statistically analyze how the distribution of rock bridges according to the combination of joint orientation, spacing, and persistence will affect the actual size of each individual block. For this purpose, we generate various combinations of joints with different geometric conditions by the orthogonal arrays using the distinct element analysis tools of UDEC and 3DEC. Equivalent block sizes (areas in 2D and volumes in 3D) and their distributions are obtained from the numerical simulation. Correlation analysis is then performed to relate the block sizes predicted by the empirical equation to those obtained from the numerical model simulation. The results support the concept of equivalent block size proposed by Cai et al. (2004, Int. J. Rock Mech. Min. Sci., 41(1), 3–19).     

深圳“12.20”渣土场远程流化滑坡动力过程分析

文章采用DAN3D数值方法对深圳人工堆填体滑坡运动过程进行了模拟研究,探讨了深圳“12.20”滑坡远程动力成灾过程。通过研究得到以下几点结论:（1）滑坡后破坏运动主要分为两个阶段:前一阶段为滑源区内运动,体现了高孔隙水压力下滑剪切;后一阶段为在流通区和堆积区内运动,体现了高饱和度滑体流动（涌动）剪切。（2）饱水渣土滑坡远程流化运动分析中,摩擦模型适合模拟孔隙水压力作用下的滑源区渣土体的失稳下滑运动过程;宾汉姆模型适合模拟非牛顿流体饱和渣土体的流化剪切过程;摩擦-宾汉姆组合模型更适用于该类型滑坡全过程的反演运动分析。（3）深圳滑坡后破坏运动速度变化主要经历了“启动-加速-持速-减速”的运动过程,高含水渣土的固-流转化致使滑坡远程运动,并造成巨大伤亡损失。（4）模拟结果显示:堆积区平均堆积厚度为11 m,堆积范围为0.4 km 2,最大运动速度为30 m/s,最大速度发生于距滑坡后缘620 m处,堆积范围、堆积厚度和运动速度同滑坡实际值基本一致。上述研究思路和方法对城市地质中渣土滑坡灾害的危险区划和渣土场科学选址评估具有一定借鉴意义。     

内陆河流域分布式日出山径流模型——以黑河干流山区流域为例

应用常规的气象水文数据并结合GIS,建立了一个适合西北干旱区内陆河山区流域的以日为步长的分布式径流模型,并对黑河干流山区出山径流进行了模拟计算和讨论。模型以子流域作为最小的产流、汇流单元,根据植被覆盖将各子流域分为裸地区、乔木区、牧草区和冰川区,并根据实际调查将土壤分为 3层,各分区单独进行水量平衡计算。产流过程以土壤储水能力和储水量表征,而储水能力和储水量等则由土壤的孔隙度、干密度和厚度等表征。入渗原理基于土壤储水率平衡原理,并考虑重力势的作用。实际蒸散发与蒸发力和土壤体积含水量的乘积成正比,不同的土壤和植被具有不同的调节参数。模拟结果表明,模拟效果较差的原因是区域日降水过程具有较大的随机性,难以用有限的站点合理计算区域日降水量。寻找一个合适的区域日降水量计算方法是目前少资料大型流域分布式水文模型模拟成功的关键。     

Absorption properties of urban/suburban aerosols in China

The broadband diffuse radiation method is improved to retrieve the aerosol refractive index imaginary part （AIP） and broadband （400-1000 nm mean） single scattering albedo （SSA）. In this method, four sets of SSA selection criteria are proposed for quality control. The method is used to retrieve AIP, SSA and absorptive optical thickness （AbOT） from routine hourly-exposed pyrheliometer and paranometer measurements over 11 sites （meteorological observatories） in China during 1998-2003. Apart from one suburban site （Ejin Qi）, the other urban sites are all located around big or medium cities. As shown in the retrieval results, annual mean SSA during 1998-2003 changes from 0.941 （Wuhan） to 0.849 （Lanzhou）, and AIP from 0.0054 to 0.0203. The 11-site average annual mean SSA and AIP are 0.898 and 0.0119, respectively. SSA during winter is smaller for most sites. There is an evidently positive correlation between SSA and aerosol optical thickness （AOT） for all sites. There is also a positive correlation between SSA and relative humidity for most sites, but a negative correlation for a few sites, such as Kashi and ǚrǚmqi in Northwest China.     

Vertical Observations and Analysis of PM2.5, O3, and NOx at Beijing and Tianjin from Towers during Summer and Autumn 2006

During the period between 18 August and 22 September 2006, an ultraviolet photometric O3 analyzer, a NO-NO2-NOx chemiluminescence analyzer, and a quartz micro-oscillating-scale particle concentration analyzer were simultaneously used for monitoring at three different heights each at Beijing (325-m tower) and Tianjin (255-m tower). These towers belong to the Institute of Atmospheric Physics (IAP) of the Chinese Academy of Sciences (CAS) and to the Tianjin Municipal Meteorological Bureau, respectively. These measurements were used to continuously measure the atmospheric O3 and NOx volume-by-volume concentrations and the PM2.5 mass concentration within a vertical gradient. When combined with meteorological data and information on the variation of vertical characteristics of the various atmospheric pollutants in the two cities, analysis shows that these two cities were seriously polluted by both PM2.5 and O3 during summer and autumn. The highest daily-average concentrations of PM2.5 near the ground in Beijing and Tianjin reached 183 μg m-3 and 165 μg m-3, respectively, while the O3 concentrations reached 52 ppb and 77 ppb, and NOx concentrations reached 48 ppb and 62 ppb for these two cities, respectively. The variations in the daily-average concentrations of PM2.5 between Beijing and Tianjin were demonstrated to be consistent over time. The concentrations of PM2.5 measured in Beijing were found to be higher than those in Tianjin. However, the overall O3 concentrations near the ground in Tianjin were higher than in Beijing. NOx concentrations in Tianjin were consistently lower than in Beijing. It was also found that PM2.5 pollution in Beijings atmosphere may also be affected by the pollutants originating in and delivered from Tianjin, and that Ti