西安南郊丰水年秋季土壤水分研究   总被引：4，自引：0，他引：4  

李艳花  赵景波 《中国沙漠》2006,26(1):113-116

 通过对西安南郊丰水年秋季土壤含水量的测定，研究了地下0~6 m之间土壤含水量的变化与土壤干层的恢复问题。研究结果表明，丰水年西安南郊人工林下2~3 m的土壤含水量在20％左右，远远高于正常年份的土壤含水量，而且大于表层和深层的土壤含水量。分析得出，土壤干层发育较弱的地区在降水丰富的年份可以得到一定程度的恢复；西安地区基本适合进行人工造林；通过人工措施，增强降水入渗和土壤含水量，对树木成活和长期的生长应当具有明显的作用。  相似文献   

论四川盆地三叠系地下水水文地质条件   总被引：3，自引：0，他引：3       下载免费PDF全文

林耀庭 《盐湖研究》2006,14(1):1-8

四川盆地三叠系地下水可划分出碎屑岩孔隙裂隙和碳酸盐岩岩溶裂隙两大储集类型。按此处构造开启程度和埋深条件等的不同,下中三叠统地下水有沉积变质水和渗入淋滤水两种基本成因类型,水动力特征各异。沉积变质水处于深埋封闭条件,受地静压力驱动控制;渗入淋滤水分布于背斜露头区和浅部地区,受静水压力驱动控制。并由此控制了盆地三叠系盐类的保存条件。  相似文献   

玛纳斯河山麓冲积扇演变遥感研究   总被引：4，自引：0，他引：4  

崔卫国  穆桂金  夏斌  马妮娜 《地理与地理信息科学》2006,22(3):39-42

基于地质过程,特别是沉积地质过程的理论和方法,通过对航空相片和遥感影像的解译,结合野外考察和地貌与沉积物分析,研究玛纳斯河山麓冲积扇的演变过程,并对其形成和演变原因进行探讨。晚第四纪以来,玛纳斯河山麓冲积扇从第二排山麓到下游冲积平原,可划分为四期规模较大和三期规模较小的冲积扇;玛纳斯河山麓冲积扇的形成演变受气候、构造或气候—构造耦合作用的共同影响,具有多成因性和多层次性。  相似文献   

东北老工业基地核心城市物流体系规划研究——以哈尔滨市为例   总被引：1，自引：0，他引：1  

朱庆伟  相伟  马双全 《地域研究与开发》2006,25(5):14-17

振兴东北老工业基地是我国重大区域发展战略之一，其关键环节在于促使核心城市快速发展，发挥其对区域的带动作用。文章以哈尔滨市为例，分析了核心城市物流发展对推动东北老工业基地振兴的基础作用。在运用城市物流规划理论与方法、借鉴国内外经验的基础上，结合城市发展需要和现存问题，对哈尔滨市城市物流体系规划进行了探讨，为其他城市的物流规划提供了一定的思路和模式借鉴。  相似文献   

三工河流域新老绿洲发育度的比较   总被引：1，自引：0，他引：1  

何新梅  李小玉  肖笃宁  李彦 《干旱区地理》2006,29(3):342-347

绿洲是干旱区最重要的景观单元之一。人工绿洲是在干旱条件下经长期人类活动改造而形成的特殊景观。随着人类对绿洲水土资源开发利用程度的不断加强,绿洲呈现出不同的发展阶段。从天然绿洲到人工绿洲,是人类适应和改造干旱区自然环境的历程。在这一人地相互作用的过程中,绿洲显示出明显的发育演化特征。从多学科综合的角度,提出绿洲发育度的概念,并从灌溉体系的建设状况、水资源的利用水平、植被与生态建设、农业发展程度、社会经济水平和绿洲景观结构等7个方面提出了绿洲发育度的评价指标体系,以天山北坡2个人工绿洲为例,从空间上定量比较2个绿洲的发育程度,其中阜康市绿洲发育度高于222团绿洲(阜北农场)。  相似文献   

青藏高原腹地湖泊沉积对第四纪晚期古季风变化的响应   总被引：2，自引：0，他引：2  

胡东生  张华京  徐冰  李炳元  孔照辰  温景春 《干旱区地理》2006,29(4):483-489

通过对青藏高原腹地的综合科学考察和对中心钻孔岩芯剖面的最新研究,用层序地层学与年代地层学和气候地层学相结合的方法,分辨出可可西里地区湖泊沉积记录(孔深7.25 m)的第四纪晚期距今3万余年以来的古气候变化,沉积物磁化率等因子综合表征的高原古季风变化是波动发展的,发生在仙女木期地质环境事件中的季风活动具有强烈暴发的特点,是高原季风发展中的突变事件,而且地表热点效应对其起到了激发作用。综合分析的研究成果表明,它的变化频谱与激变因子及其运行机制是伴随着青藏高原地质效应的演变而发展的,为研究第四纪冰消期以来的气候变化提供了新的信息。  相似文献   

Memories of Fire: Eduardo Galeano and the Geography of Guatemala     

W. George Lovell 《Geoforum》2006,37(1):31-40

In Memory of Fire, a poetic narration of the history of the Americas from pre-Columbian times to the late 20th century, Eduardo Galeano furnishes readers with over 1200 of his trademark vignettes, some 35 of which pertain to Guatemala. Galeano evokes disparate aspects of the geography of Guatemala, past and present, in grounded miniatures of time, place, and episode. His sketches of the experiences of Maya peoples allow us to see them as survivors of three cycles of conquest: (1) conquest by imperial Spain; (2) conquest by local and international capitalism; and (3) conquest by state terror. Composed in the literary mode of creative non-fiction, Memory of Fire serves as an inspirational classroom text, exposing students not only to factual detail but also a powerful artistic imagination.  相似文献   

Fracture analysis in the south-western Corinth rift (Greece) and implications on fault hydraulic behavior     

Luca Micarelli  Isabelle Moretti  Manon Jaubert  Hakim Moulouel 《Tectonophysics》2006,426(1-2):31

This paper reviews the data concerning the fracture network and the hydraulic characteristics of faults in an active zone of the Gulf of Corinth. Pressure gap measured through fault planes shows that in this area the active normal faults (Aigion, Helike) act, at least temporarily and locally, as transversal seal. The analysis of the carbonate cements in the fractures on both the hangingwall and the footwall of the faults also suggests that they have acted as local seals during the whole fault zone evolution. However, the pressure and the characteristics of the water samples measured in the wells indicate that meteoric water circulates from the highest part of the relief to the coast, which means it goes through the fault zones. Field quantitative analysis and core studies from the AIG-10 well have been performed to define both regional and fault-related fracture networks. Then laboratory thin section observations have been done to recognize the different fault rocks characterizing the fault zone components. These two kinds of approach give information on the permeability characteristics of the fault zone. To synthesize the data, a schematic conceptual 3D fluid flow modeling has been performed taking into account fault zone permeability architecture, sedimentation, fluid flow, fault vertical offset and meteoric water influx, as well as compaction water flow. This modeling allows us to fit all the data with a model where the fault segments act as a seal whereas the relays between these segments allow for the regional flow from the Peloponnese topographic highs to the coast.  相似文献   

Increasing critical sensitivity of the Load/Unload Response Ratio before large earthquakes with identified stress accumulation pattern   总被引：2，自引：0，他引：2  

Huai-zhong Yu  Zheng-kang Shen  Yong-ge Wan  Qing-yong Zhu  Xiang-chu Yin   《Tectonophysics》2006,428(1-4):87-94

The Load/Unload Response Ratio (LURR) method is proposed for short-to-intermediate-term earthquake prediction [Yin, X.C., Chen, X.Z., Song, Z.P., Yin, C., 1995. A New Approach to Earthquake Prediction — The Load/Unload Response Ratio (LURR) Theory, Pure Appl. Geophys., 145, 701–715]. This method is based on measuring the ratio between Benioff strains released during the time periods of loading and unloading, corresponding to the Coulomb Failure Stress change induced by Earth tides on optimally oriented faults. According to the method, the LURR time series usually climb to an anomalously high peak prior to occurrence of a large earthquake. Previous studies have indicated that the size of critical seismogenic region selected for LURR measurements has great influence on the evaluation of LURR. In this study, we replace the circular region usually adopted in LURR practice with an area within which the tectonic stress change would mostly affect the Coulomb stress on a potential seismogenic fault of a future event. The Coulomb stress change before a hypothetical earthquake is calculated based on a simple back-slip dislocation model of the event. This new algorithm, by combining the LURR method with our choice of identified area with increased Coulomb stress, is devised to improve the sensitivity of LURR to measure criticality of stress accumulation before a large earthquake. Retrospective tests of this algorithm on four large earthquakes occurred in California over the last two decades show remarkable enhancement of the LURR precursory anomalies. For some strong events of lesser magnitudes occurred in the same neighborhoods and during the same time periods, significant anomalies are found if circular areas are used, and are not found if increased Coulomb stress areas are used for LURR data selection. The unique feature of this algorithm may provide stronger constraints on forecasts of the size and location of future large events.  相似文献   

High-resolution sedimentary record of lead in the coastal mud of the East China Sea in the past one hundred and fifty years     

Yunchao HAO Zhigang GUO Dejiang FAN 《中国地球化学学报》2006,25(B08):13-13

In the East China Sea （ECS）, there are some mud areas, including the south coastal mud area, the north coastal mud area, and the mud area to the southwest of Cheju Island. X-ray fluorescence （XRF） techniques and Thermal Ionization Mass Spectrometry （TIMS） were used to study the high-resolution sedimentary record of Pb concentrations and Pb stable isotopic compositions in the past one hundred and fifty years in the coastal mud of the ECS. Pb concentrations of a ^210Pb dating S5 core in the study area have increased rapidly since 1980, and reached the maximal value with 65.08 μg/g in 2000, corresponding to the fast economic development of China since the implementation of the ＂Reform and Open Policy＂ in 1978; ^206Pb/^207Pb ratios generally had stabilized at 1.195 from 1860 to 1966, and decreased gradually from 1966 to 2000, indicating that the anthropogenic source Pb contribution to the ECS has increased gradually since 1966, especially since 1980. Pb concentrations decreased distinctly from 2000 to 2003 and ^206Pb/^207Pb ratios increased from 2001 to 2003, corresponding closely to the ban of lead gasoline from 2000 in China. From 1950 to 2003, there occurred four distinct decrease events of ^206Pb/^207Pb, possibly responding to the Changjiang River （Yangtze River） catastrophic floods in 1998, 1991, 1981 and 1954; from 1860 to 1966, there were two decrease periods of ^206Pb/^207Pb, which may respond to the catastrophic floods of Changjiang River in 1931 and 1935, and 1870. As a result of the erosion and drowning by the catastrophic floods, the anthropogenic lead accumulated in soil and water environments over a long period of time was brought into the Changjiang River, then part of them was finally transported into the ECS, which leads to changes in Pb stable isotopic composition.  相似文献