Heterogeneous characteristics of streambed saturated hydraulic conductivity of the Touchet River,south eastern Washington,USA

Traditionally a streambed is treated as a layer of uniform thickness and low saturated hydraulic conductivity (K) in surface‐ and ground‐water studies. Recent findings have shown a high level of spatial heterogeneity within a streambed and such heterogeneity directly affects surface‐ and ground‐water exchange and can have ecological implications for biogeochemical transformations, nutrient cycling, organic matter decomposition, and reproduction of gravel spawning fish. In this study a detailed field investigation of K was conducted in two selected sites in Touchet River, a typical salmon spawning stream in arid south eastern Washington, USA. In‐stream slug tests were conducted to determine K following the Bouwer and Rice method. For the upper and lower sites, each 50 m long and 9 m wide and roughly 20 m apart, a sampling grid of 5 m longitudinally and 3 m transversely was used. The slug tests were performed for each horizontal coordinate at 0·3–0·45, 0·6–0·75, 0·9–1·05 and 1·2–1·35 m depth intervals unless a shallower impenetrable obstruction was encountered. Additionally, water levels were measured to obtain vertical hydraulic gradient (VHG) between each two adjacent depth intervals. Results indicated that K ranged over three orders of magnitude at both the upper and lower sites and differed between the two sites. At the upper site, K did not differ significantly among different depth intervals based on nonparametric statistical tests for mean, median, and empirical cumulative distribution, but the spatial pattern of K varied among different depth intervals. At the lower site, K for the 0·3–0·45 m depth interval differed statistically from those at other depth intervals, and no similar spatial pattern was found among different depth intervals. Zones of upward and downward water flow based on VHG also varied among different depth intervals, reflecting the complexities of the water flow regime. Detailed characterization of the streambed as attempted in this study should be helpful in providing information on spatial variations of streambed hydraulic properties as well as surface‐ and ground‐water interaction. Copyright © 2009 John Wiley & Sons, Ltd.     

特大目标分类别的地震抢险方案模型设计研究

研究“十五”“地震应急指挥技术系统”中“地震应急指挥辅助决策系统”的一部分。主要研究“特大目标分类别的抢险设计方案和通用性建议模型”,它主要是为地震应急指挥提供辅助决策背景支持信息和特大目标分类别的抢险设计方案,通过检索和查询应急基础数据库,生成专题图表,显示特大目标的相关信息,并结合灾区实际情况,为指挥部成员提供提醒性的决策参考信息。     

浙江地下流体在汶川8．0级地震中的映震效应研究

通过“十五”改造,浙江省目前有地震地下流体观测台站5个,10项测项,主要是水位,水温和水氡。在2008年5月12日四川汶川8．0级地震中有明显映震效应的台站为100％,测项为80％。水氡测值表现为临震向上突跳异常,最大异常幅度达23．7％,创历史之最;水温测项主要出现临震突跳或阶跃;水位测项主要是同震效应现象,为水震波引起的脉冲和阶跃变化。认为同震效应可能是地震发生后地震波传播引起的含水层弹性形变所致。并且认为观测效果不一定是井位越深越好,而是要看含水层封闭情况和仪器观测传感器的位置,没有明显的优劣之分。好的静水位观测井记录的水震波效果明显优于动水位观测井。由于前兆数字化仪器采样率相对较底（1次／min）,记录数据缺失较多,记录的同震变化波形不完整,很难进一步分析。     

Age and nature of eclogites in the Huwan shear zone,and the multi-stage evolution of the Qinling-Dabie-Sulu orogen,central China

In situ LA-ICPMS U-Pb, trace element, and Hf isotope data in zircon demonstrate a Carboniferous age for eclogite-facies metamorphism in Siluro-Devonian protoliths in the Huwan shear zone, Dabie Mountains, Central China. This age contrasts with the more prevailing Triassic age for high- to ultrahigh pressure (HP to UHP) metamorphism in the Qinling-Dabie-Sulu orogen. Metamorphic zircon in two eclogite samples from Sujiahe is characterized by low Th/U ratios, small negative Eu anomalies, flat HREE patterns, and low ¹⁷⁶Lu/¹⁷⁷Hf ratios. These geochemical signatures suggest that the zircon crystallized in the presence of garnet and in the absence of plagioclase feldspar. Furthermore, temperatures of ~ 655 and ~ 638 °C, calculated using the Ti content of zircon, are consistent with their formation during eclogite-facies metamorphism. The weighted mean ²⁰⁶Pb/²³⁸U age of 309 ± 4 Ma (2δ) for this zircon improves previous age estimates for eclogite-facies metamorphism in the Huwan shear zone, ranging from 420 to 220 Ma. Metamorphic zircon from one eclogite sample from Hujiawan, most likely formed during prograde metamorphism, yields an equivalent age estimate of 312 ± 11 Ma. Magmatic zircon cores in the three samples yield ages for the magmatic protoliths of the eclogites ranging from 420 ± 7 to 406 ± 5 Ma, and post-dating the middle Paleozoic collision of the North China and the Qinling terrain. The zircon crystals in the three eclogite samples display a large variation of ε_Hf (t) values of ? 4.9 to 21.3. The metamorphic zircon overgrowths show the same range of ε_Hf (t) values as those of the inherited magmatic crystal interiors. This suggests that the metamorphic zircon overgrowths may have formed by dissolution-reprecipitation of pre-existing magmatic zircon thereby preserving their original Hf isotopic composition. The high ε_Hf (t) values suggest that the protoliths were derived from depleted mantle sources, most likely Paleotethyan oceanic crust; while the low ε_Hf (t) values are attributed to crustal contamination. Some eclogites in the Huwan shear zone have a distinctive signature of continental crust most probably derived from the Yangtze Craton. The coexistence of Paleozoic oceanic crust and Neoproterozoic continental crust with similar metamorphic ages in the Huwan shear zone implies that Paleozoic Paleotethyan oceanic crust was produced within a marginal basin of the northern Yangtze Craton. The opening of the Paleo-Tethyan ocean was slightly younger than the collision of the North China Craton and the Qinling terrain during the Late Paleozoic in the Qinling-Dabie-Sulu orogen. Subduction of the Paleo-Tethyan oceanic crust and associated continental basement resulted in the 309 ± 2 Ma (2σ) eclogite-facies metamorphism in the Huwan shear zone. The subsequent Triassic continent-continent collision led to the final coalescence of the Yangtze and Sino-Korean cratons. Amalgamation of the Yangtze and North China cratons was, therefore, a multistage process extending over at least 200 Ma.     

大别山花岗质岩浆的形成：脱水或含自由水体系的熔融：—以天堂寨和九？…

本文以北大别地块中典型燕山期花岗岩－－天堂寨、九资河花岗岩为例,研究了其黑云母、角闪石的矿物成分及岩石包体特征;并结合当前有关脱水熔融和含自由水体系的熔融实验岩石学成果,对花岗质岩浆的形成方式进行了讨论,认为天堂寨、九资河花岗岩是由含自由水体系的熔融作用形成的,含水流体的主要来源可能为南大别地块。     

大别山花岗质岩浆的形成:胶水或含自由水体系的熔融——以天堂寨和九资河花岗岩为例

本文以北大别地块中典型燕山期花岗岩——天堂寨、九资河花岗岩为例,研究了其黑云母、角闪石的矿物成分及岩石包体特征;并结合当前有关脱水熔融和含自由水体系的熔融实验岩石学成果,对花岗质岩浆的形成方式进行了讨论,认为天堂寨、九资河花岗岩是由含自由水体系的熔融作用形成的,含水流体的主要来源可能为南大别地块。     

多普勒雷达资料对中尺度系统短期预报的改进

文中给了一种由单多普勒雷达资料反演风矢量场的变分方法 ,并由此形成预报初始场。运用美国风暴分析预报中心 ( CAPS)的改进的区域系统模式对移经美国俄克拉何马州的一个强雷暴系统进行了数值预报试验 ,结果表明 ,初始场中引入多普勒雷达观测资料后明显地改进了预报。     

云开元古宙眼球状花岗岩Sm—Nd和Rb—Sr同位素体系定年及其动力学意义

对云开核部韧性-流变剪切变形眼球状花岗岩石样品进行了全岩Sm-Nd、Rb-Sr同位素年龄测定,获得1414±68Ma的Sm-Nd等时线和490±36Ma的Rb-Sr等时线年龄,它们分别代表这套花岗岩的形成时代和加里东期韧性-流变剪切部分熔融构造热事件发生时间,表明云开地区不仅在加里东期发生造山运动,而且在中元古晚期发生了更为重要的构造—岩浆造山运动,其时代与全球性的格林威尔造山运动时间可以对比。     

沈抚灌区石油污染土壤恢复方案的数值模拟

在沈抚灌区野外调查和室内外试验的基础上, 建立水分-反应性石油污染物运移的耦合数学模型, 采用数值方法模拟可溶性油(有效油) 的分布规律, 并定量分析了石油污染土壤不同恢复方案的可行性.研究结果表明, 土壤中的化学作用使可溶性油运移速度远远小于土壤水的入渗速度, 所以可溶性油主要分布在土壤耕作层之内, 难以通过灌溉污水的入渗直接污染地下水; 另外, 清污混合灌溉和改变作物结构的控制方案虽然可以大大降低土壤中可溶性油的含量, 但石油污染土壤的彻底恢复还必须依靠地表水或地下水的合理灌溉      

福建永泰云山碱性流纹岩的厘定及其地质意义

福建永泰云山破火山石帽山群第三旋回顶部的霏细流纹岩含有霓石、钠铁闪石等碱性铁镁矿物。化学成化富硅、富碱,碱性指数（ＡＫＩ值）大于０．９０,Ｒｂ、Ｔｈ、Ｚｒ、Ｇａ等元素的含量高,Ｇａ／Ａｌ值大;贫钙、镁、铝和过渡族元素,轻、重稀土比值较小,并具有显著的负铕异常。在Ｋ２Ｏ－Ｎａ２Ｏ及以Ｇａ／Ａｌ值为基础的多种判别图上均投影在Ａ型花岗岩区。上述特征与其邻近的魁歧典型碱性花岗岩相似,也可与国外有关典型碱性