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101.
昆仑山高原面上的风沙土   总被引:1,自引:0,他引:1  
海拔4000m~5000m以上的昆仑山高原面上, 有风沙土分布。高原风沙土的特点表现在: 形成历史久, 分布广, 类型多, 植被恢复缓慢.高原面上气候干旱、植被稀疏、大风频繁, 构成了风沙土形成的自然条件。  相似文献   
102.
二朗山公路隧道岩爆特征与预测研究   总被引:6,自引:1,他引:5  
根据二郎山公路隧道施工中记录的200多次岩爆资料,总结隧道的岩爆特征,并采用“地质超前预报法”和“σθ/Rb判断现场测定预测法”两种方法,对岩爆预测问题进行有益探讨。  相似文献   
103.
The focus of soil erosion research in the Alps has been in two categories: (i) on-site measurements, which are rather small scale point measurements on selected plots often constrained to irrigation experiments or (ii) off-site quantification of sediment delivery at the outlet of the catchment. Results of both categories pointed towards the importance of an intact vegetation cover to prevent soil loss. With the recent availability of high-resolution satellites such as IKONOS and QuickBird options for detecting and monitoring vegetation parameters in heterogeneous terrain have increased. The aim of this study is to evaluate the usefulness of QuickBird derived vegetation parameters in soil erosion models for alpine sites by comparison to Cesium-137 (Cs-137) derived soil erosion estimates. The study site (67 km2) is located in the Central Swiss Alps (Urseren Valley) and is characterised by scarce forest cover and strong anthropogenic influences due to grassland farming for centuries. A fractional vegetation cover (FVC) map for grassland and detailed land-cover maps are available from linear spectral unmixing and supervised classification of QuickBird imagery. The maps were introduced to the Pan-European Soil Erosion Risk Assessment (PESERA) model as well as to the Universal Soil Loss Equation (USLE). Regarding the latter model, the FVC was indirectly incorporated by adapting the C factor. Both models show an increase in absolute soil erosion values when FVC is considered. In contrast to USLE and the Cs-137 soil erosion rates, PESERA estimates are low. For the USLE model also the spatial patterns improved and showed “hotspots” of high erosion of up to 16 t ha−1 a−1. In conclusion field measurements of Cs-137 confirmed the improvement of soil erosion estimates using the satellite-derived vegetation data.  相似文献   
104.
《China Geology》2020,3(4):511-523
Natural gas hydrate, oil and gas were all found together in the Qilian Mountain permafrost area, northeast of Qinghai-Tibet Plateau, China. They are closely associated with each other in space, but whether they are in any genetic relations are unknown yet. In this paper, a hydrocarbon gas-generation series, gas-fluid migration series and hydrocarbon gas-accumulation series are analyzed to probe the spatial, temporal and genetic relationships among natural natural gas hydrate, oil and gas. The subsequent results show that natural gas hydrate, oil and gas actually form a natural gas hydrate-oil-gas system. Based on the Middle Jurassic and the Upper Triassic hydrocarbon gas-generation series, it is divided into four major sub-systems in the study area: (1) A conventional Upper Triassic gas-bearing sub-system with peak hydrocarbon gas-generation in the late Middle Jurassic; (2) a conventional Middle Jurassic oil-bearing sub-system with low to mature hydrocarbon gas-generation in the late Middle Jurassic; (3) a natural gas hydrate sub-system with main gas source from the Upper Triassic gas-bearing sub-system and minor gas source from the Middle Jurassic oil-bearing sub-system as well as little gas source from the Middle Jurassic coal-bed gas and the microbial gas; (4) a shallower gas sub-system with microbial alteration of the main gas source from the Upper Triassic gas-bearing sub-system. This natural gas hydrate-oil-gas system and its sub-systems are not only theoretical but also practical, and thus they will play an important role in the further exploration of natural gas hydrate, oil and gas, even other energy resources in the study area.  相似文献   
105.
龙门山前陆盆地形成与演化   总被引:23,自引:1,他引:23  
曾允孚  李勇 《矿物岩石》1995,15(1):40-49
本文将龙门山前陆盆地和龙门山冲断带作为一个地质整体进行了研究,并将构造地层学和层序地层学相结合的综合地层学的分析方法作为分析龙门山前陆盆地沉积的基础,以不整合面和其对应面将盆地充填序列分割为构造层序和层序,对应于不同成盆期和同一成盆期不同演化阶段,阐明龙门山前陆盆地充填序列和沉积体积三维空间配置形式及其在时间上的演化,初步建立了龙门山前陆盆地地层格架,进而研究龙门山冲断带逆部推覆作用对龙门山前陆盆  相似文献   
106.
新疆天山苏鲁果勒的峡谷瀑布及其开发构思   总被引:3,自引:2,他引:3  
天山苏鲁果勒的峡谷瀑布是新疆新发现的一处有较高开发价值的旅游资源。构成峡谷的地质体属一套刚硬的变质岩系,峡谷的形成时代比较晚,可能在第四纪晚期。峡谷和瀑布以其谷狭岩刚、比高大、相交汇,瀑布呈梯级群组为特色,具有很高的观赏游憩价值;峡谷和瀑布的完美组合巧夺天工,其险峻、幽深为国内所罕见,尚无可比之例,珍稀度高;资源体量大,适合游览期5~6个月,游览期相对较长。景区开发应突出自然风光,以表现峡谷和瀑布为主,草原为辅,景区内只修步道和观景台,步道分岩道和木栈道。该旅游区可以建成年接待量约10万人的2A级景区。以库尔勒市为依托城市,以库尔勒市和乌鲁木齐大都市圈为基本客源市场,以来疆游客为次级客源市场,成为新疆一个集度假、休闲、科考、探险为一身的新兴旅游地。  相似文献   
107.
张春华  李修楠  吴孟泉  秦伟山  张筠 《地理科学》2018,38(11):1904-1913
利用2015年Landsat 8 OLI遥感影像和DEM作为分类数据源,结合野外调查数据,采用面向对象的分类方法对昆嵛山地区土地覆盖信息进行提取,并对分类结果进行精度评价与比较分析。研究表明:面向对象分类方法提取的各地类连续且边界清晰,分类效果与实际情况基本吻合。昆嵛山地区占主导地位的土地覆盖类型是针叶林,面积为1 546.81 km2。研究区土地覆盖分类的总体精度和Kappa系数分别为91.5%和0.88,其中针叶林、草地、水体和建设用地的生产者精度均达到87%以上。相对于监督分类方法,本研究提出的土地覆盖信息提取方法的总体分类精度和Kappa系数分别提高14.7%和0.17。基于面向对象的中分辨率遥感影像,能够获取较高精度的土地覆盖信息,为大范围土地覆盖分类研究提供方法参考。  相似文献   
108.
通过博格达山北麓白杨河剖面芦草沟组页岩的地球化学特征的综合研究,讨论了芦草沟组页岩的元素富集特征和沉积环境以及源区物源特征和构造背景。结果表明:1研究区页岩P元素极为富集,这受控于页岩中凝灰质火山灰夹层的广泛发育;2对比于世界页岩微量元素分布,白杨河页岩相对富集Li、B、Pr、Tb、Dy、Ho、Er、Tm和Lu元素,其他元素相对亏损;3白杨河剖面页岩地化参数揭示芦草沟组自下而上气候由温湿向干热转变,进而引起水体由淡水向咸水的转变和还原程度的进一步加强;4物源区遭受低级-中等风化程度,物源类型主要为长英质火成岩,其次为铁镁质火成岩;5物源区大地构造背景以大陆岛弧-活动大陆边缘构造背景为主。  相似文献   
109.
秦岭为我国气候分界线和南水北调中线重要水源地,太白山为其最高峰,了解太白山区域的过去干湿变化特征对气候变化机制研究和未来水资源持续利用具有重要意义。基于秦岭太白山地区太白红杉树木年轮资料及其附近的宝鸡、眉县气象站1959—2016年气象数据进行分析,重建了1852—2016年春季(3~5月)SPEI值,分析了近165 a太白山春季干湿变化特征及其与大尺度环流变化关系。结果表明:(1)太白山地区太白红杉径向生长主要受春季气候限制;与春季SPEI值相关性最高,达到-0.72(P<0.01),重建方程方差解释量为51.8%(调整自由度后为51.0%)。(2)重建结果表明,近165 a来,有29 a春季为湿润年份,有23 a春季为干旱年份,分别占比为17.58%和13.94%。极端干旱年份为1892年、1929年、1945年和2006年,极端湿润年份为1881年、1921年和1990年,其中1892年(-1.73)和1881年(1.53)分别为最干旱和最湿润的年份。(3)重建结果得到了周边地区干湿变化重建结果和历史文献灾害记载的验证;太白山地区干湿变化可以准确表征大区域干湿变化且存在2....  相似文献   
110.
Agricultural practices are the main stay of the people of Uttranchal. Out of the total population,more than 75% people are engaged either with the main occupation of agriculture or its allied practices,dominated by traditional subsistence cereal farming.Among them, the main crops are rice, wheat, millet,barley, all types of pulses, all types of oilseeds and almost all types of fruits. The crops, vegetables and fruits of all varieties are grown in the different climatic zones such as tropical, temperate, and cold because, the region is characterized by the different altitudinal zones elevated from 200 m to more than 8000m. As a result, different climates are found from hot tropical to sub temperate and chilly cold. Pulses varieties are grown extensively. Among vegetables,potato, onion, carrot, all types of green leaf vegetables,brinzal, pumpkin, ladyfinger, pea, gram, radish,ginger, garlic, etc, are grown widely. All fruit varieties are grown in the different altitudinal zones. The mainfruits are orange, malta (a big size of orange),elephant citrus, lemon and all other types of citrus,apple, stone fruits including peach and pears, manykinds of nuts, and the fruits which are grown in the low lying areas. In spite of feasible climatic conditions,agricultural dominant society, and availability of all types of crops, the production and productivity of these crops are very low, even they are unable to meet the grain-need of the people in Uttaranchal. Agricultural crops are grown almost in all the altitudinal zones -- from the low-lying areas, which are called ‘Ga. ngarh‘, to the highly elevated region,where the legendary term is given as ‘Danda‘. The growing seasons vary according to the heights. The present paper aims to discuss the agricultural practices including cropping season, cropping pattern,land use, production of cropsagricultural system in thisand ecological aspect of Himalayan state and suggest some measures for developing farming system,which could lead the sustainability, in terms of meeting the food grain needs of the people on the one hand and restoring the ecological balance on the other.  相似文献   
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