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11.
新疆第四纪盐类矿产的形成和控制因素——兼论“高山深盆”成盐模式 总被引:1,自引:0,他引:1
根据袁见齐教授“高山深盆”成盐模式,探讨新疆天山对第四纪盐类矿床的形成和控制作用,阐述了天山地貌、气候、水文特征与盐类矿产的分布规律和特征。认为“高山深盆”并非一定是四周环山的深盆,可以是某一高山与其间深盆或两侧盆地的有机组合。高山的屏障作用造成了垂直的气候分带,在潮湿多雨的山区利于成盐组份的析出并迁移到干旱少雨的闭流深盆中,形成盐类矿床。 相似文献
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A local-scale model for temperature-dependence of water-retention curves may be applicable to large scales. Consideration of this temperature dependence is important for modeling unsaturated flow and transport in the subsurface in numerous cases. Although significant progress has been made in understanding and modeling this temperature effect, almost all the previous studies have been limited to small scales (on the order of several centimeters). Numerical experiments were used to investigate the possibility of extending a local-scale model for the temperature-dependence of water retention curves to large scales (on the order of meters). Temperature effects on large-scale hydraulic properties are of interest in many practical applications. Numerical experiment results indicate that the local-scale model can indeed be applicable to large-scale problems for special porous media with high air entry values. A typical porous medium of this kind is the porous tuff matrix in the unsaturated zone of Yucca Mountain, Nevada, the proposed geologic disposal site for national high-level nuclear wastes. Whether this finding can approximately hold for general cases needs to be investigated in future studies. 相似文献
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Lower Cretaceous red sedimentary rocks from the depositional basin of East Qilian fold belt have been collected for a paleomagnetic study. Stepwise thermal demagnetization reveals two or three components of magnetization from dark red sandstones. Low-temperature magnetic component is consistent with the present Earth Field direction in geographic coordinates. High-temperature magnetic components are mainly carried by hematite. The mean pole of 19 sites for high-temperature magnetic components after tilt-correction is λ=62.2°N, φ=193.4°E, A95=3.2°, and it passes fold tests at 99% confidence level and reversal tests at 95% confidence level. The paleopole is insignificantly different from that of Halim et al. (1998) from the same sampling area at the 95% confidence level. Compared with paleomagnetic results for North China, South China, and Eurasia, our results suggest that no significant relative latitudinal displacement has taken place between Lanzhou region and these blocks since Cretaceous time. Remarkably, the pole of Lanzhou shows a 20° clockwise rotation with respect to those of North China, South China, and Eurasia. Geological information indicates that the crustal shortening in the western part of Qilian is greater than that in eastern part. In this case, the clockwise rotation of sampling area was related to India/Eurasia collision, and this collision resulted in a left-lateral strike-slip motion of the Altun fault in north Tibetan Plateau after the Cretaceous. 相似文献
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西安翠华山山崩地质遗迹资源保护 总被引:5,自引:3,他引:5
文论述了西安翠华山山崩地质遗迹资源保护的目的,进行了保护分区,将其分为核心保护区、缓冲区和视域保护区三个区,重点分析了核心保护区的保护现状,并在此基础上提出了相应的保护内容和对策,以实现山崩地质遗迹资源的可持续利用和发展。 相似文献
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《The Professional geographer》2002,54(3):454-478
Books Reviewed Colbert C. Held, Middle East Patterns: Places, People, and Politics Barbara A. Weightman, Dragons and Tigers: A Geography of South, East, and Southeast Asia Henry J. Bruman, Alcohol in Ancient Mexico Brian W. Blouet, Geopolitics and Globalization in the Twentieth Century M. A. B. Siddique (ed.), International Migration into the 21st Century: Essays in Honour of Reginald Appleyard Michael R. Haines and Richard H. Steckel (eds.), A Population History of North America Emilio Moran, Human Adaptability: An Introduction to Ecological Anthropology Jeremy Leggett, The Carbon War: Global Warming and the End of the Oil Era Susan B. Marriott and Jan Alexander (eds.), Floodplains: Interdisciplinary Approaches William S.Logan, Hanoi: Biography of a City Alex Krieger and David Cobb (eds.) with Amy Turner, Mapping Boston Eric Sandweiss, St. Louis: The Evolution of an American Urban Landscape Carl Abbott, Greater Portland: Urban Life and Landscape in the Pacific Northwest Arthur D. Murphy, Colleen Blanchard and Jennifer A. Hill (eds.), Latino Workers in the Contemporary South Yanek Mieczkowski, The Routledge Historical Atlas of Presidential Elections 相似文献
20.
海南省五指山土壤中的重金属元素含量 总被引:6,自引:0,他引:6
海南省地处热带地区,山地面积占25.4%,五指山是海南山地的核心,也是海南最高峰,从下而上依次分布着砖红壤、赤红壤、黄壤、灌丛草甸土。五指山土壤普遍遍缺,而Zn、Ni、Pb、Cd、Cr、Co含量属正常值。在成土过程中,Cd有一定积累,其他元素有明显淋溶。在自下而上的垂直带谱中,Zn、Co含量呈现递减,Cd则相反,Ni、Pb、Cu、Cr含量呈现波浪式变化。气候因素是影响五指山土壤重金属元素含量及分布的主导因素。 相似文献