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391.
肖芊 《国土资源遥感》2000,11(4):19-23,38
根据鸡西合作区煤系及煤岩曾有过的成烃和聚气过程,寻找其遥感影像、地球化学及放射性能谱特征,从而总结出该区煤层气的综合地质特征,进而研究其周边地区聚气成烃的可能性,为扩大寻找煤成气提供可应用的资料。  相似文献   
392.
定西地区1995-2000年间土壤侵蚀的变化与治理对策   总被引:6,自引:2,他引:4  
严重的土壤侵蚀是定西地区生态环境恶化的主要原因,也是社会经济发展的主要限制性因素之一。利用数字遥感影像人机交互解译技术对1995年和2000年的土壤侵蚀进行调查,结果显示5 a来定西地区土壤侵蚀面积减少1 446.39 km2,减少了7.36%。其中轻度侵蚀减少5.63%,中度减少1.4%,强度减少0.03%,极强度减少0.30%。侵蚀程度整体上有所减轻,表明水土保持工作取得了一定成效。但土壤侵蚀面积仍然占土地总面积的80%以上,而且强度和极强度侵蚀面积减少不明显,土壤侵蚀仍然十分严重,水土保持的任务还相当艰巨。积极开展水土保持是定西地区实现山川秀美、脱贫致富和可持续发展的根本途径。  相似文献   
393.
阳泉矿区3#煤煤层气解吸特性的研究   总被引:1,自引:0,他引:1  
实验测定了阳泉矿区3#煤煤层气的解吸特性。利用煤粒中吸附煤层气扩散微分方程式计算出煤层气的解吸时间,并用作图法确定出3#煤煤层气的解吸时间,为阳泉矿区3#煤煤层气的开发和利用提供了重要的参数。   相似文献   
394.
烟台市区主要环境工程地质问题及防治对策研究   总被引:4,自引:1,他引:3  
分析烟台市区工程地质环境基本要素,研究烟台市区环境工程地质问题的主要类型,并探讨烟台市区环境工程地质问题的系统防治技术。  相似文献   
395.
This paper investigates the relative importance of climatic and topographic factors on the fluctuations of two adjacent palaeoglaciers in the Chilean Lake District. Geomorphological mapping of the landforms around two lakes occupied by the palaeoglaciers has identified a series of intersecting moraine limits and ice-marginal meltwater channels, which allow the relative timing of glacier fluctuations to be established. The broad pattern of advance and retreat is the same in the two basins, with at least one synchronous major advance sometime after 19 500 yr BP, but there is also evidence of discordant behaviour, with one glacier advancing less often and lagging the other glacier during retreat. Seventeen radiocarbon dates suggest a similar chronology to other palaeoglaciers in the Chilean Lake District, but the advance after 19 500 yr BP may have been 1500 14C yr later than major advances of palaeoglaciers situated immediately south. The empirical evidence of differential behaviour can be simulated by a glaciological model, which suggests that the differences in glacier response are due to contrasts in basin topography. Contrasts of this magnitude between the timing of some glacier advances has important implications for regional and interhemispheric correlation of Chilean Lake District glacier chronologies to other climate proxy records. © 1997 by John Wiley & Sons, Ltd.  相似文献   
396.
The Lake District terrane of northern England comprises Upper Cambrian–Silurian sediments and volcanics accumulated at the northern margin of the Avalonian Plate during growth and demise of the Iapetus Ocean. Ocean closure and suturing resulted in Late Ordovician and Acadian tectonism and were accompanied by emplacement of a large regional batholith. Palaeomagnetic study of intrusive igneous rocks, including application of thermal demagnetization, field tests and principal component analysis, identifies a history of Ordovician to Devonian magnetization. Late plutons (Shap and Skiddaw granites and/or aureoles) record a shallow dipolar (A3) axis (mean declination/inclination (D/I=278/+17°) dating from emplacement in late Early Devonian times (c. 395 Ma). Although this axis is recorded as a sporadic overprint in older rocks, no pervasive remagnetization is attributable to batholith emplacement. Instead, the Carrock Fell Complex Layered Gabbros have a mid- to late Ordovician (A1) remanence (D/I)=17·4/−58·1°, 36 samples, α95=4·8°) predating regional F2 folding. Later events in this igneous complex comprise the Carrock Fell Granophyre with a post-folding Ordovician remanence, and Round Knott Dolerite with a remanence linked to hydrothermal alteration late in the Ordovician magmatic episode. A Late Ordovician (Ashgill) palaeofield is also defined by remanence (A2) in the Threlkeld–St John's Microgranite and aureole (438 Ma, D/I=236·5/63·3°, 41 samples, α95=4·7°). Other intrusions carrying a remanence predating the Acadian deformation include the Great Cockup Picrite (458 Ma, D/I=43·2/−31·8°, 31 samples, α95=7·7°) and basic intrusives in the aureole of the Eskdale Granite (429 Ma, D/I=174·5/25·8°, 32 samples, α95=8·8°). Collectively the palaeomagnetic data from this terrane identify a hairpin in the apparent polar wander path during Late Ordovician (Caradoc–Ashgill) times corresponding to ‘soft’ closure of the Iapetus suture and accompanying deformation. The same motion is recognized in contemporaneous data from the Welsh Caledonides where declinations are rotated by c. 55° relative to contemporaneous results from the Lake District. Adjustment for this (probable late Acadian) rotation beings fold trends of the Paratectonic Caledonides into alignment and identifies a parallel mid- to late Ordovician destructive plate margin comprising forearc (Lake District) and backarc (North Wales). This arc was oriented latitudinally in mid-southerly latitudes during formation and the bulk of the magmatism occurred during a single normal-polarity chron. The relationships between magnetization and folding in both the Lake District and Welsh Borderlands identify the importance of Late Ordovician deformation along this arc during collision of Avalonia and Laurentia. Arc-related volcanism was succeeded in Silurian times by parallel foreland basins embracing the Welsh Basin and southern Lake District as the Laurentian Plate overrode the Avalonian Plate. © 1997 John Wiley & Sons, Ltd.  相似文献   
397.
王旭 《吉林地质》2020,39(1):87-91
浑江区水系发育,地质条件复杂,构造发育,地层发育较齐全。区内地质灾害种类齐全,地质灾害的发生是地形地貌、地质构造、岩土体结构类型、降水、植被、人类工程活动等诸多因素共同作用的结果。从区域上看,地质灾害点分布不均匀,中北部明显多于西南部。在地质灾害成因上,大部分地质灾害点与人类活动密切相关,区内的所有崩塌、滑坡、不稳定斜坡、地面塌陷基本上是由人为修路切坡及采石、开采煤炭资源、修建住宅等工程引发的;泥石流的形成与人为耕种、毁林开荒等工程活动有较密切关系。纵观全区地质灾害发育的分布特征,不难发现,在该区人类工程活动强烈的地区,地质灾害点就越多。本文重点在说明区内地质灾害发育特征及分布规律的基础上,阐述其形成条件及影响因素。  相似文献   
398.
关中地区农业土壤重金属污染评价   总被引:7,自引:0,他引:7  
1Introduction The harm of soil heavy metals pollution on soil environment and human health and its control have become a hot topic in the current environmental research field.There are many relevant research results at home and abroad in this field(Chen,1…  相似文献   
399.
为解决高密度城市公园绿地供需不平衡的问题,论文提出了一套改进的两步移动搜索模型,并以上海市黄浦区为例,对其现有公园绿地进行步行条件下的空间可达性分析.首先从网络爬取研究范围内居住小区POI信息,将其聚合在边长100 m的正六边形蜂窝网内,计算得到每个人口单元的人数及人口密度,并利用百度地图API路径规划接口爬取各供给点...  相似文献   
400.
硒是动物和人体所必需的微量元素之一,其丰缺与人和动植物的健康有着密切关系。近年来研究成果表明西藏缺硒土壤主要分布在雅鲁藏布江(简称“雅江”)以北地区,而雅江以南存在土壤全硒含量较高且面积较大区域。西藏山南市乃东区位于青藏高原中南部雅江流域,为雅鲁藏布江流域重要的农业区,也是西藏粮仓之一。本文以西藏山南市乃东区为研究对象,采用原子荧光光谱法(AFS)等方法测定了研究区1022件表层土壤、30组青稞籽实样及根系土壤样品中的硒等元素含量;同时对西藏山南市乃东区雅江两侧农用地及周边牧草地、林地表层土壤硒的分布特征和影响因素进行了研究。结果表明:雅江北侧土壤硒含量算术平均值为0.14mg/kg,接近西藏土壤硒含量平均值0.15mg/kg;雅江南侧土壤硒含量算术平均值为0.30mg/kg,高于西藏土壤硒含量平均值的一倍,略高于中国土壤硒含量平均值0.29mg/kg。乃东调查区不同土地利用类型土壤硒含量的平均值由大到小为:耕地(0.24mg/kg)>牧草地(0.22mg/kg)>林地(0.19mg/kg)。研究结果显示乃东调查区雅江两侧土壤硒含量差异较大;土壤硒元素含量除了受地质背景影响...  相似文献   
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