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961.
Heavy mining of Jurassic and Carboniferous horizontal coal seams in the Datong coalfield has seriously affected the local geological environment, which is mainly manifested by such geohazards as soil avalanches, landslides, mudflows, surface subsidence, surface cracks, surface solid waste accumulation and surface deformation. More seriously, coal mining causes groundwater to leak. Overpumping of groundwater has resulted in substantial land subsidence of the urban area in Datong City. Based on the previous geo-environmental investigation in the work area, the authors used radar remote sensing techniques such as InSAR (synthetic aperture radar interferometry) and D-InSAR (differential synthetic aperture radar interferometry), supplemented by the optical remote sensing method, for geo-environmental investigation to ascertain the geo-environmental background of the Datong Jurassic and Carboniferous-Permian coalfield and evaluate the effects of the geohazards, thus providing a basis for the geo-environmental protection, geohazard control and prevention, land improvement and optimization of the human environment. In this study 8 cog-nominal ERS-1/2 SAR data frames during 1992 to 2003 were used, but the following processing was made: (1) the multitemporal SAR magnitude images were used to interpret the geological structure, vegetation, microgeomorphology and drainage system; (2) the multi-temporal InSAR coherent images were used to make a classification of surface features and evaluate the coherence change due to coal mining; and (3) the multi-temporal cog-nominal SAR images were used to complete D-InSAR processing to remove the information of differential deformation areas (sites). In the end, a ten-year time series of differential interferograms were obtained using the multi-temporal cog-nominal SAR images. In the tests, 84 deformed areas (sites) were obtained, belonging to those in 1993-1996, 1996-1997, 1997-1998, 1998-2001, 1998-2002 and 2001-2003 respectively. Of the 84 areas, 44 are m  相似文献   
962.
963.
To promote the rational development and use of clean coal resources in China, data on the regional and age distribution of sulfur, arsenic and other harmful elements in Chinese coal was broadly collected, tested for content, and analyzed. Coal in northwestern China is characterized by low to extremely low levels of sulfur; the coal of the Taiyuan Formation in northern China mainly has high-sulfur content; that of the Shanxi Formation is mainly characterized by low sulfur coal; and the Late Permian coal in southern China has overall higher sulfur content; other regions have low sulfur coal. The average content of harmful trace elements in the bulk of China's coal is similar to the corresponding content in the coal of the North America and the rest of the world, whereas the content of various elements (Hg, Sb and Se) is different in magnitude to the corresponding percentage in the crust. The average content of the elements Cr, Se, Co, Be, U, Br in Late Permian coal in S China ranks first in the country whereas the average content of Hg and CI in the coals of Late Carboniferous to Early Permian age in N China are the highest. The average content of Mn in Early and Middle Jurassic coal is higher in NW China. The high content of harmful elements in some coal should cause particular concern both in the development and utilization of coal.  相似文献   
964.
The characteristics of Late Cenozoic tectonic uplift of the southern margin of the Qinghai- Tibet Plateau may be inferred from fluvio-lacustrine strata in the Zanda basin, Ngari, Tibet. Magnetostratigraphic study shows that the very thick fluvio-lacustrine strata in the basin are 5.89- 0.78 Ma old and that their deposition persisted for 5.11 Ma, i.e. starting at the end of the Miocene and ending at the end of the early Pleistocene, with the Quaternary glacial stage starting in the area no later than 1.58 Ma. Analysis of the sedimentary environment indicates that the Zanda basin on the southern Qinghai-Tibet Plateau began uplift at -5.89 Ma, later than the northern Qinghai-Tibet Plateau. Presence of gravel beds in the Guge and Qangze Formations reflects that strong uplift took place at -5.15 and -2.71 Ma, with the uplift peaking at -2.71 Ma.  相似文献   
965.
下庄矿田湖子地区铀矿找矿方向探讨   总被引:2,自引:0,他引:2       下载免费PDF全文
湖子地区位于NNE向诸广-新兴铀成矿带与近EW向大东山-漳州大断裂复合部位,是华南早、晚两期铀成矿热液活动叠加区、放射性高场区,既有"硅化带大脉"型铀矿产出,又有"交点"型铀矿存在,找矿前景良好.文章在论述下庄矿田铀成矿地质环境、铀成矿特征及铀矿定位条件基础上,分析了湖子地区铀成矿条件与找矿前景,指出该区今后铀矿找矿方向是:① 6009号硅化断裂带,在其北段找硅化带大脉型铀矿,在其南段找"交点"型铀矿;②新桥-下庄硅化断裂带和6009号带之间成矿部位,寻找硅化带型和"交点"型铀矿;③NW向、近EW向辉绿岩脉与NNE向、NE向构造交汇部位(交点),寻找"交点"型铀矿.  相似文献   
966.
Three-dimensional modelling from single images remains an interesting topic of investigation in the research community, even though range sensors are becoming a common alternative for the generation of 3D information. The interest in single-image-based modelling is motivated by a wide spectrum of applications such as cultural heritage, civil engineering, urban planning and even criminology. In this paper a complete new production flowline is presented for modelling based on a single image. The modelling process consists of a series of familiar steps in photogrammetry and computer vision: feature extraction, vanishing point computation, camera self-calibration, 3D reconstruction and dimensional analysis. In particular, the methodology developed for single-image-based modelling takes a scientific approach combining several proven techniques with robust estimators. Finally, in order to demonstrate its capabilities, the reported examples include several real situations applied in different contexts.  相似文献   
967.
以济南市南部山区为试验区,探讨在ArcGIS中进行DEM总体精度计算的方法,并分析不同比例尺DEM对地面坡度分级统计的影响。为有效校正地面坡度分级统计的误差,构建高精度的1∶2 000地面坡度与1∶1万地面坡度的"地面坡度转换图谱"。在此基础上根据回归统计得出各级别对应的二次拟合曲线,校正能够大幅度提高地面坡度统计的精度。  相似文献   
968.
针对中国近年来金矿床学领域研究工作,综合讨论了金矿床成矿学理论研究方面的主要进展。它们集中体现在①大型一超大型金矿床;②区域成矿学与成矿系统;③造山带成矿与造山型金矿:从俯冲(增生)造山到碰撞造山成矿的显著发展;④成矿系列、成矿谱系到成矿体系研究;⑤热点、地幔柱及其多级演化:从边缘成矿到板内成矿;⑥成矿时代:从模糊到精确;⑦现代金矿成矿的实时模型;⑧从板块构造演化、超越板块构造到成矿地球动力学等8个方面。  相似文献   
969.
小塔子沟金矿床位于凌源一北票金矿成矿带的中部,为受区域断裂构造、燕山期石英二长岩和太古界小塔子沟组变质杂岩所控制的含金石英脉型和蚀变岩型金矿,通过对矿床地质特征的分析,进一步总结该区成矿控制因素,认为区域上找矿前景广阔。  相似文献   
970.
王河金矿床是李坝金矿田的组成部分。矿床产于秦岭造山带泥盆纪浅变质碎屑岩中,区域地质构造较复杂,岩浆活动频繁且强烈,是一受断裂、岩浆活动和蚀变带控制的蚀变岩型(工业类型为徽细粒浸染型)金矿。通过对矿床地质特征、控矿因素及找矿标志的研究认为,已知矿体深部及西部找矿潜力很大,应进一步开展找矿工作。  相似文献   
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