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31.
祁阳山字型构造质疑 总被引:5,自引:1,他引:4
结合区域构造演化背景及构造变形特征,对祁阳弧形构造的形成机制进行研究。分析表明,传统山字型构造机制难以解释祁阳弧形构造的诸多特征,且前人认为变形动力来源于东西向挤压应力场,也与印支期区域构造应力场实为NWW向的构造背景不符,因此祁阳弧形构造并不属典型山字型构造。基于研究区构造活动的客观实际,提出祁阳弧形构造的可能形成机制:NW向基底隐伏断裂和NNE-NE向主干断裂分别于印支期和燕山期产生强烈左旋走滑活动,从而使区域NNE向构造线在中段产生左旋偏转成为NNW向,从而形成S形的祁阳弧形构造。这一机制可较好解释祁阳弧形构造的若干特征,如关帝庙穹窿呈NWW走向、北反射弧构造形迹不显著、北弧弧顶脱位及内弧曲率大于外弧、南弧弧顶脱位、紫云-中田-高峰串珠状穹窿的形成等。上述认识对华南地区弧形构造研究具有一定启示意义:除山字型构造作用和砥柱作用外,还应注意断裂走滑等其他构造活动对弧形构造的制约,以及多次构造活动叠加对构造形迹可能造成的影响。 相似文献
32.
33.
Open source, spatial analysis, and activity-travel behaviour research: capabilities of the aspace package 总被引:2,自引:0,他引:2
This paper reports on recent experience with the development of aspace, an Open Source (OS) library for the geographic visualization and analysis of activity-travel behaviour. The paper begins
with an overview of recent progress with respect to the convergence of Open Source technology, spatial analysis, and travel
behaviour research. The remainder of the paper focuses on aspace; a collection of functions that, when combined with data describing the geographical location of daily activities, can be
used to visualize and describe spatial properties of individual and household activity spaces. These properties include: size,
orientation, shape, and the geographical dispersion of activity locations contained within the activity space. Several planar
geometries are used to transform measurable spatial properties into intuitive objects for visualizing spatial patterns of
activity participation. Experiments are conducted, using data from the first wave of the 2003 Toronto Travel Activity Panel
Survey, to demonstrate the potential application of aspace for basic and applied policy-based research into activity-travel behaviour. The toolkit is distributed as a downloadable
‘package’ from the Open Source R Project for Statistical Computing.
相似文献
34.
35.
评“河南西峡盆地产恐龙蛋地层研究新进展” 总被引:11,自引:0,他引:11
"河南西峡盆地产恐龙蛋地层研究新进展"一文主张用"走马岗组"、"赵营组"和"六爷庙组"来替代正式命名的一套地层名称,这样做既不符合地层命名原则,又易引起新的不必要的混乱。在晚白垩世时西峡、淅川两盆地在岩性组合特征上是相似的,浙川盆地并不是"岩性特征简单",西峡盆地也不是"岩性复杂"。西峡盆地晚白垩世"红层"应采用"高沟组、马家村组和寺沟组"这套地层名称。 相似文献
36.
本文在解放军土地管理局研制的“军用土地管理信息系统”的基础上,从系统设计和应用的角度出发,明确了系统应包括的基本功能,提出了改进和完善系统的方法。 相似文献
37.
A geochemical evaluation of the Szc-Halimba-Kisld area, Hungary, covering an area of more than 200 km2 is presented using different statistical and geostatistical methods. The study area is a representative example of allochtonous karst bauxite accumulation. The three groups of deposits studied here have been explored and mined since 1950. Several thousand boreholes have been drilled, and bauxite cores were analyzed for the five main chemical components. A total of 80,000 pleces of analytical data were processed, followed by a geological examination of borehole logs and of mining excavations.The quantitative geochemical evaluation of the data set led to both geochemical and practical results: The geochemical behavior of the allochtonous, clastic karst bauxite deposits differs essentially from that of the autochtonous and parautochtonous ones, as well as that of the lateritic bauxite deposits. The deposits of the study area can be split into several subsequent geochemical-sedimentological units, each representing an event of bauxite transport and accumulation. Clear regional patterns can be revealed in the composition of these units. The geostatistically measured chemical variability of the geochemical units is rather different, the lowest units showing the smallest variability. The interrelations of the main chemical components are weaker and more irregular in the studied deposits than in the autochtonous lateritic bauxite deposits. Additional local genetic features, such as transport routes, can be delineated by the methods applied. Within each deposit, local changes of chemical composition and of its variability can be determined more precisely. These results can be used in bauxite prospecting and exploration, because areas of high or low bauxite quality can be predicted. 相似文献
38.
Limin REN Bing QIN Wenchun TANG Zhendong MA Yikeng HU 《中国地球化学学报》2006,25(B08):10-10
Mercury is a pollutant of concern due to its toxic and bioaccumulative properties. Studies on the distribution and hazard of mercury in the environment are mainly focused on its forms, toxicity and the environment standard, and progresses and results have been achieved. But these studies in the past were concentrated on the scales of laboratory or smaller districts merely, such as a small unit of mineral area, vegetable base, paddy field, lake, etc. Multi-target regional geochemical survey carried out by China Geological Survey from the 1990s to now is a fundamental and commonweal geological survey, large-scale and systematical inquisition and research were conducted in 19 provinces (or municipalities directly under the Central Government) in the eastern overlay region of China, and the purpose is to provide the basic geochemical data for national economic construction, adjustment of industrial and agricultural structures and sustainable social development. Geochemical studies aim at investigating soils in these regions and 52 elements have been tested, producing a great amount of data at the same time. Methods: based on the data from 3061 samples of surface soil and 832 samples of deep soil from the project of multi-purpose geochemical survey in the Chengdu Basin, Sichuan, China, this paper describes the correlation relationship between Hg and other 48 elements and their spatial distribution in surface and deep soils of these areas by applying the method of linear regression and factor analysis. 相似文献
39.
Relations between climatic variability and hydrologic time series from four alluvial basins across the southwestern United States 总被引:1,自引:3,他引:1
Hydrologic time series of groundwater levels, streamflow, precipitation, and tree-ring indices from four alluvial basins in the southwestern United States were spectrally analyzed, and then frequency components were reconstructed to isolate variability due to climatic variations on four time scales. Reconstructed components (RCs), from each time series, were compared to climatic indices like the Pacific Decadal Oscillation (PDO), North American Monsoon (NAM), and El Niño-Southern Oscillation (ENSO), to reveal that as much as 80% of RC variation can be correlated with climate variations on corresponding time scales. In most cases, the hydrologic RCs lag behind the climate indices by 1–36 months. In all four basins, PDO-like components were the largest contributors to cyclic hydrologic variability. Generally, California time series have more variation associated with PDO and ENSO than the Arizona series, and Arizona basins have more variation associated with NAM. ENSO cycles were present in all four basins but were the largest relative contributors in southeastern Arizona. Groundwater levels show a wide range of climate responses that can be correlated from well to well in the various basins, with climate responses found in unconfined and confined aquifers from pumping centers to mountain fronts. 相似文献
40.
本文采用流量级频率分析和统计分析方法,对黄河下游流量及泥沙含量对水环境容量的影响进行了研究分析.分析结果:河流在平滩流量时不仅输沙能力最大[8],而且输运污染物能力也最大,黄河下游水环境容量萎缩是平滩流量降低的必然结果. 相似文献