山西铝土矿Rb-Sr同位素定年

采用Rb Sr全岩与粘土矿物等时线年龄方法测得山西五台剖面 (RS0 1) ,临县剖面 (RS0 2 )和孝义剖面 (RS0 3)的 3个含矿粘土岩的Rb Sr同位素年龄分别为 :316 .9± 1.2Ma ,87Sr/86Sr为 0 .710 5 4± 14 ;315 .5± 1.3Ma ,87Sr/86Sr为 0 .710 86±18;317.3± 1.1Ma ,87Sr/86Sr为 0 .710 5 0± 14。它们代表了铝土矿和含矿系列成矿的同位素年龄 ,相当于晚石炭世早期     

Evidence for fullerenes in solid bitumen from pillow lavas of Proterozoic age from Mítov (Bohemian Massif, Czech Republic)

Andesitic pillow lavas containing biogenic, solid bitumen (SB) are a constituent of a Neoproterozoic volcanosedimentary sequence (Teplá-Barrandian unit, Bohemian Massif) in the Mítov area of the Czech Republic. A black shale formation that is crosscut by these andesitic basalts is 565 Ma old. Carbon disulfide extracts of two powdered samples of SB contain 0.2 and 0.3 ppm of C₆₀, respectively, as determined by high-pressure liquid chromatography. The peak assignment based on retention time is fully supported by high-resolution electron ionization mass spectrometry (EI-MS). No C₇₀ was detected, nor was C₆₀ found in two other SB samples from this locality. Other investigated carbonaceous samples from Bohemia (coals and anthracites of Upper Paleozoic age and anthraxolite, graphitoids, and graphite of Upper Proterozoic age) did not contain fullerenes at concentrations above the detection limit of 0.01 ppm. The absence of C₆₀ in these samples was confirmed by EI-MS. The proposed mechanism of fullerene formation involves a primary algal phase, generation of a hydrocarbonaceous mixture in the course of thermal evolution of the sedimentary series, and their high-temperature transformation related to the extrusion of basalt. An important feature for fullerene conservation was the enclosure of fullerenes in SB with a structure similar to glasslike carbon, where the fullerene was protected against oxidation.     

解析计算法与吴尔夫网投影法求解震源机制结果比较

利用“基于GIS地震分析预报系统”提供的用地震初动符号求震源机制解软件，获得了1999年11月辽宁岫岩—海城交界地区20个ML≥4．0地震的震源机制解．并将求解结果与采用吴尔夫网投影法得到的震源机制结果进行比较。结果表明．二种求解震源机制得到的节面(A、B)、力轴(P、T)比较接近，对应效果比较好。     

Simulation of normal distributed smooth fields by Karhunen-Loéve expansion in combination with kriging

Simulation of multigaussian stochastic fields can be made after a Karhunen-Loéve expansion of a given covariance function. This method is also called simulation by Empirical Orthogonal Functions. The simulations are made by drawing stochastic coefficients from a random generator. These numbers are multiplied with eigenfunctions and eigenvalues derived from the predefined covariance model. The number of eigenfunctions necessary to reproduce the stochastic process within a predefined variance error, turns out to be a cardinal question. Some ordinary analytical covariance functions are used to evaluate how quickly the series of eigenfunctions can be truncated. This analysis demonstrates extremely quick convergence to 99.5% of total variance for the 2nd order exponential (‘gaussian’) covariance function, while the opposite is true for the 1st order exponential covariance function. Due to these convergence characteristics, the Karhunen-Loéve method is most suitable for simulating smooth fields with ‘gaussian’ shaped covariance functions. Practical applications of Karhunen-Loéve simulations can be improved by spatial interpolation of the eigenfunctions. In this paper, we suggest interpolation by kriging and limits for reproduction of the predefined covariance functions are evaluated.     

河南红旗渠沿线地质灾害易发性评价

红旗渠是20世纪60年代河南省林州市人民在国家极其困难时期依靠自力更生、艰苦奋斗，在太行山腰上修建的引漳入林水利工程。建成后灌溉着林州3．6万hm^2农田，解决了98万人口和37万头牲畜的吃水问题，发挥着巨大的经济效益。然而，红旗渠沿线地质条件极为复杂，地质灾害频繁发生，自红旗渠建成运行以来，几乎每年都有崩塌、滑坡、泥石流等地质灾害发生。1960～2000年，红旗渠总干渠因地质灾害造成的决口事件有19次。1996年8月3～4日，由于连降暴雨，引发崩塌、滑坡和泥石流等地质灾害，使总干渠沿线154处渠道淤塞，淤积达94402m^3，给工农业生产和人民生命财产造成巨大损失，直接经济损失达1．17亿元，灾后修复费用达1100万余元。多年来每年用于地质灾害后修复的费用达数百万元。如何有效地防治红旗渠沿线地质灾害，确保顺畅其流，千秋永固，是值得研究的一项重要课题。据调查，共发现各类地质灾害94处，其中危岩体44处，崩塌24处，滑坡12处，泥石流14处。作者基于地质灾害现状，采用定性分析结合定量分析方法，对各类地质灾害进行评价，将红旗渠沿线地质灾害易发性划分为4个区，即高易发区、中易发区、低易发区和不易发区，为红旗渠沿线地质灾害防治规划提供依据。     

1948—2001年全球大尺度区域 6～8月降水的长期变化

研究了1948-2001年南、北半球及欧亚大陆、非洲大陆、澳洲大陆、北美大陆、南美大陆、南极大陆和中国 7个大尺度区域 6～8月降水的长期趋势变化和年代际变化。结果表明，南、北半球 6～8月的降水都为负趋势，但南半球降水的负趋势在统计上不显著。在54年的时间段内，南半球 6～8月降水的递减速度为 0．12 mm／a，仅为北半球同期降水减幅（0．24 mm／a）的一半。南、北半球 6～8月降水量年代际尺度的振荡都非常明显，但是，南、北半球年代际变化的特征明显不同。目前北半球仍是在少雨时间段，而南半球处在降水量正常或多雨的时间段。分析还表明，非洲大陆 6～ 8月降水的年代际特征最明显，降水的负趋势也最为显著；欧亚大陆 6～8月降水也有着明显的年代际变化与明显的负趋势变化；澳洲大陆 6～8月降水的年际变化明显，年代际变化相对来说要小得多；北美大陆 6～8月降水的年际变化明显，但无明显的趋势变化。此外，分析了大尺度区域 6～ 8月降水之间的相关关系，发现部分区域大尺度降水量之间有明显的联系；分析了中国夏季降水的长期变化，发现中国夏季降水的年代际变化明显，但无明显的趋势变化。