The Third Editorial Committee of Earth Science Frontiers A BRIEF INTRODUCTION TO OVERSEA MEMBERS OF THE EDITORIAL BOARD     

郭安林张国伟  孙延贵程顺有 《地学前缘》2007,14(3):83-83

位于青藏高原东北缘的多福屯第三纪火山岩，为钠质基性火山岩系。该火山岩（La／Yb）N值在6—11，∑REE平均为117，样品普遍具有不相容元素富集、Pb亏损以及弱的Nb、Ta正异常，Nb／U和Ce／Pb平均值分别为30和17；样品的87^Sr／^86Sr值为0．7041～O．7069，Nd初始值为0．5129（εNd（t）=6），△^207Pb／^240Pb和△^208Pb／^204Pb分别在11～19和73-84之间，结合高的Sr初始值，表现了特征的Dupal（高放射成因铅）异常。地球化学特征表明，该火山岩属于似OIB性质的陆内火山岩，源区具有DM与EMⅡ混合特点。个别岩石表现出明显陆壳混染的迹象。火山岩源区特征反映了OIB类岩石的复杂性，可能由区域原、古特提斯地幔继承而来，因而是原地的和固有的，并非与青藏高原物质向东挤出有关。通过与邻区同时代火山岩的对比推断，整个高原东北缘新生代火山岩幔源区具有小尺度的不均一性。高原东北缘新生代火山岩的发育可能与较大规模的贺兰-川滇南北复合构造有关。  相似文献   

Farmers＇ vulnerability to flood risk： A case study in the Poyang Lake Region   总被引：2，自引：0，他引：2  

MA Dingguo CHEN Jie ZHANG Wenjiang ZHENG Lin LIU Ying 《地理学报(英文版)》2007,17(3):269-284

This paper quantitatively explores farmers＇ vulnerability to flood in the Poyang Lake Region （PLR） with the supports of GIS spatial functions. The analysis consists of three major steps, which is based on the spatial unit of township. Firstly, the spatial extent and characteristics of flood risk areas were determined using a digital elevation model （DEM） derived from the 1：50,000 topographic map. Secondly, for each of the township, six indices indicating the economic activities of local farmers were calculated. These indices are： rural population proportion, cultivated land proportion, GDP per unit area, employment proportion of primary industry, net rural income per capita and agricultural income proportion. These six indices were then normalized and used for later vulnerability assessment. Thirdly, the normalized indices （as GIS data layers） were overlaid with the flood risk areas to produce the risk coefficient for each township and to calculate the overall vulnerability for each township. The analysis results show that in the PLR there are high flood risk areas where the farmers＇ livings are seriously influenced or threatened. About 55.56% of the total 180 townships in the flood risk areas have a high degree of flood vulnerability. The townships under flood risk are mainly distributed in the areas around the Poyang Lake and the areas along the ＂five rivers＂.  相似文献   

Distribution, migration and derivation of Mesozoic-Cenozoic regional fault systems in the central continental margin of eastern China     

Sun Xiaomeng  Hao Fujiang  Bian Weihua  Gao Yi  Bao Yafan 《Frontiers of Earth Science》2007,1(1):12-20

Deep-large faults in the central continental margin of eastern China are well developed. Based on the regularity of spatial and temporal distribution of the faults, four fault systems were divided: the Yanshan orogenic belt fault system, the Qinling-Dabie-Sulu orogenic belt fault system, the Tanlu fault system and the East China Sea shelf basin-Okinawa trough fault system. The four fault systems exhibit different migration behaviors. The Yanshan orogenic belt fault system deflected from an EW to a NE direction, then to a NNE direction during the Indo-Chinese epoch-Yanshanian epoch. The thrust-nappe strength of the Qinling-Dabie orogenic belt fault system showed the tendency that the strength was greater in the south and east, but weaker in the north and west. This fault system faulted in the east and folded in the west from the Indo-Chinese epoch to the early Yanshanian epoch. At the same time, the faults also had a diachronous migration from east to west from the Indo-Chinese epoch to the early Yanshanian epoch. On the contrary, the thrust-nappe strength was greater in the north and west, weaker in the south and east during the late Yanshanian epoch-early Himalayan epoch. The Tanlu fault system caused the basin to migrate from west to east and south to north. The migration regularity of the East China Sea shelf basin-Okinawa trough fault system shows that the formation age became younger in the west. The four fault systems and their migration regularities were respectively the results of four different geodynamic backgrounds. The Yanshan orogenic belt fault system derived from the intracontinental orogeny. The Qinling-Dabie-Sulu orogenic belt fault system derived from the collision of plates and intracontinental subduction. The Tanlu fault system derived from the strike-slip movement and the East China Sea shelf basin-Okinawa trough fault system derived from plate subduction and retreat of the subduction belt. Translated from Journal of Jilin University (Earth Science Edition), 2005, 35(5): 554–563 [译自: 吉林大学学报 (地球科学版)]  相似文献   

Adsorption characteristics of perchloroethylene in natural sandy materials with low organic carbon content   总被引：2，自引：0，他引：2  

Changwen Ma  Yanqing Wu  Chengxing Sun  Leonora Lee 《Environmental Geology》2007,52(8):1511-1519

Laboratory batch tests were conducted to investigate the sorption isotherms and sorption kinetics of the chlorinated hydrocarbon perchloroethylene (PCE) in five natural sandy materials with an organic carbon content (f _oc) in the range 0.080–0.540%. The amended non-linear dual-mode model can describe the sorption isotherms in materials with f _oc in the range 0.080–0.090%. For a sample with a much higher f _oc of 0.54%, the absorption isotherm was found to fit a linear model. These results may indicate that organic carbon is not the main factor influencing the sorption isotherm. The sorption kinetics of PCE in samples with f _oc in the range 0.080–0.090% are not first-order and are different from those observed in the samples with higher f _oc. The sorption process in the materials with lower f _oc involves fast sorption, fast desorption and an equilibrium stage. The results may imply that the factors affecting sorption kinetics of PCE in low f _oc media are pore filling and capillary condensation rather than organic carbon content.  相似文献   

枣庄岩溶塌陷形成条件及主要影响因素     

武雄  高明显  张顺峰  孙燕冬  管清花  吴海燕 《地学前缘》2007,14(6):227-233

近年来枣庄市岩溶塌陷频繁发生。通过野外地质调查、现场采样和室内试验相结合的综合手段,对该区的岩溶塌陷覆盖层进行系统地取样并进行深入细致的实验及分析,论述了覆盖层特征对该区岩溶塌陷的影响;运用宏观调查、细观测量和微观分析相结合的研究方法详细论述了地质构造对岩溶塌陷的影响;结合历年水文动态资料、地下水开采量等论述了地下水活动对岩溶塌陷影响。综合认为,地层岩性、覆盖层性质、构造因素是枣庄岩溶塌陷频繁发生的内因,而超量开采地下水则是外部诱发因素。  相似文献   

塔里木盆地海相碳酸盐岩与油气   总被引：1，自引：0，他引：1  

孙龙德 《海相油气地质》2007,12(4):10-15

塔里木盆地碳酸盐岩主要分布于台盆区寒武系—奥陶系,它既可以作为油气的储层和源岩,也可以作为油气的盖层或遮挡体。碳酸盐岩主要发育于碳酸盐岩台地相和斜坡相之中,其中开阔台地及台地边缘坡折带的生物碎屑滩和砂屑滩、局限台地的白云岩坪是主要的储集相带。潜山溶孔溶洞型白云岩、石灰岩及礁滩复合体中的生物碎屑灰岩、砂屑灰岩、鲕粒灰岩、礁灰岩以及潮坪白云岩是主要的储集岩。寒武系—下奥陶统、中—上奥陶统都发育有较好的碳酸盐岩烃源岩。根据油气的分布与聚集特点,对碳酸盐岩油气藏作了分类。论述了塔里木盆地碳酸盐岩油气勘探的前景和重要目标。  相似文献   

闽西南地区块状硫化物矿床的喷流-沉积成矿作用     

郑志强  林东燕 《福建地质》2007,26(4):222-228

通过对闽西南地区石炭纪—早二叠世主要块状硫化物矿床的区域成矿背景、贮矿层位特征以及矿石矿物成分、结构构造,硫同位素地球化学特征、成矿温度等分析研究,指出该地区石炭纪—早二叠世块状硫化物矿床的形成多与海底火山活动有关,贮矿层中伴有典型的喷流沉积岩—硅质岩,并提出闽西南地区块状硫化物矿床存在海底喷流-沉积成矿作用的新认识。  相似文献   

磷矿石中磷、钙、镁、锶、氟测定方法评述   总被引：2，自引：0，他引：2  

孙琳 《贵州地质》2007,24(4):322-324

本文系统分析了磷矿石高含量磷、钙、镁、锶、氟诸元素存在时对其测定的相互影响及其测定中存在的问题,比较全面地总结了国内分析工作者针对该问题,对诸难测元素在常规分析方法方面的工作进展。  相似文献   

反射光谱技术:研究南极企鹅古生态演化的一种新方法   总被引：2，自引：0，他引：2  

孙静  刘晓东  孙立广  刘文齐 《极地研究》2007,19(3):203-212

为探求快速、廉价、无损和同步的光谱技术在南极生态环境研究中的可能性,本文利用南极阿德雷岛的四根企鹅粪土沉积柱样品的反射光谱,通过逐步多元线性回归和主成分回归两种数学运算方法,建立了反射光谱数据与企鹅粪九种标型元素浓度之间的关系,并探讨了南极企鹅粪土沉积物光谱数据的古生态意义。结果表明:南极粪土沉积样品反射率光谱与企鹅粪九种标型元素(P、Ca、Cu、F、Ba、S、Zn、Sr、Se)含量之间存在良好的相关性,预测值与实测值之间的相关系数R都达到了0.9以上,在深度剖面上预测浓度与实测浓度具有非常一致的变化趋势;南极粪土沉积物光谱数据包含有明确的古生态变化信息,可利用主成分分析快速恢复历史时期企鹅数量演化过程。本研究结果为在偏远的南极地区开展古生态环境研究提供了一种新的快捷方法和技术途径。  相似文献   

近年国外传统村镇旅游研究进展及启示   总被引：1，自引：0，他引：1  

王莉  陆林  卢松 《地域研究与开发》2007,26(5):79-84

近年来,随着传统村镇旅游的日益兴起,有关传统村镇的旅游学研究日益受到学术界重视和关注.总结了国内外关于传统村镇的旅游学研究进展,指出国外研究成果主要集中在传统村镇旅游发展影响研究、传统村镇旅游发展与文化原真性保持之间的关系、传统村镇旅游可持续发展等方面.国内研究与之相比,在研究内容、方法、领域、深度等方面仍有很大差距,有待进一步扩展和深入.今后应注意以下几方面问题:研究内容流于表层,应加强研究领域的延伸和深度的扩展;研究方法、手段较为单一,研究理论和方法焏待提高;理论研究滞后于旅游发展实践的现状焏待改善.  相似文献