新疆和静县巴音铜矿区地质特征矿床成因及成矿模式          下载免费PDF全文

王啟宴  王玉杰 《山东国土资源》2014,30(8)

巴音铜矿区位于中天山中段的南缘,伊犁地块东南缘,南临南天山缝合带,处在阿吾拉勒山与那拉提山交会处,属那拉提铜、镍、金成矿带,其地质、构造特征比较复杂,成矿地质条件较为有利。通过分析区域成矿背景及矿区地质特征,总结矿床成因及控矿因素,证实该区矿化分为火山-火山热液型、脉岩型和热液脉型3种类型,就成矿机理而言,这3种矿化的形成有着密切的内在联系,在本质上都与该区晚志留世火山活动密切相关。结合区内各种矿化所占的比重和形成时间的先后顺序,其成因类型可概括为:巴音铜矿为以晚志留世海相火山-火山热液型矿化为主,伴有晚期脉岩矿化,局部受海西早期花岗质岩浆热液叠加、改造的中—低温铜矿床。不同类型矿化的主要控矿因素不同,火山岩型矿化的控矿因素主要为火山活动形式、活动阶段及岩性,同时断裂构造也有一定的控制作用;脉岩型矿化系受岩性和脉体本身(出露部位和规模)控制,较好矿化一般出现于脉岩规模较大者中,或脉岩的局部膨大部位;热液脉型矿化主要受角闪花岗岩体及其接触带控制,局部还受到后期断裂破碎带控制,矿体沿断裂破碎带充填而成。  相似文献   

Hybrid region merging method for segmentation of high-resolution remote sensing images     

《ISPRS Journal of Photogrammetry and Remote Sensing》2014

Image segmentation remains a challenging problem for object-based image analysis. In this paper, a hybrid region merging (HRM) method is proposed to segment high-resolution remote sensing images. HRM integrates the advantages of global-oriented and local-oriented region merging strategies into a unified framework. The globally most-similar pair of regions is used to determine the starting point of a growing region, which provides an elegant way to avoid the problem of starting point assignment and to enhance the optimization ability for local-oriented region merging. During the region growing procedure, the merging iterations are constrained within the local vicinity, so that the segmentation is accelerated and can reflect the local context, as compared with the global-oriented method. A set of high-resolution remote sensing images is used to test the effectiveness of the HRM method, and three region-based remote sensing image segmentation methods are adopted for comparison, including the hierarchical stepwise optimization (HSWO) method, the local-mutual best region merging (LMM) method, and the multiresolution segmentation (MRS) method embedded in eCognition Developer software. Both the supervised evaluation and visual assessment show that HRM performs better than HSWO and LMM by combining both their advantages. The segmentation results of HRM and MRS are visually comparable, but HRM can describe objects as single regions better than MRS, and the supervised and unsupervised evaluation results further prove the superiority of HRM.  相似文献   

2000～2010 年环渤海省市海岸带土地利用变化分析   总被引：1，自引：1，他引：0  

吴莉  侯西勇 《海洋科学》2015,39(9):101-110

作为陆海生态系统的交错带,海岸带是地表生态系统最为脆弱的地带,研究海岸带土地利用变化具有重要意义。以环渤海省市海岸带为研究区,基于2000、2005和2010年的Landsat TM/ETM遥感影像进行多时相海岸带土地利用制图,进而分析10 a间的土地利用变化特征,包括土地利用结构、土地利用动态度、土地利用程度区域差异和海陆梯度、海陆格局变化等特征。结果表明:(1)环渤海省市海岸带土地利用以耕地、建设用地和人工湿地为主,2010年比例分别为36.09%、17.16%和15.72%,不同行政单元及不同缓冲带之间土地利用结构空间差异明显。(2)2000~2005年、2005~2010年,土地利用发生转移的面积分别为2 126.419 km2和3 092.39 km2,建设用地扩展占用耕地、人工湿地和滨海自然湿地,以及滨海自然湿地变为人工湿地是主导的变化过程,但不同行政单元及不同缓冲带之间土地利用变化的空间差异明显。(3)2000~2005年、2005~2010年,综合土地利用动态度分别为0.73%和1.06%,17个地市级行政单元综合土地利用动态度以东营和天津较高,各缓冲带内综合土地利用动态度均为随时间不断增加,空间上则由海向陆波动下降。(4)2000~2010年,土地利用程度总体上不断升高,表明海岸带土地利用处于发展期,除沧州和潍坊,其他区域土地利用程度随时间不断上升;各缓冲带土地利用程度均随时间不同程度增长,空间上则由海向陆波动上升。  相似文献   

塔城地区西北部低山草甸植被指数变化及其驱动力     

和海秀  付爱红  王川 《中国沙漠》2023,43(1):187-196

以新疆塔城地区西北部低山草甸植被为研究对象,利用2001—2020年归一化植被指数（NDVI）、气象数据（年均气温和降水量）及社会经济发展数据（年末牲畜存栏数、肉类总产量和农牧民人均纯收入）,运用ArcGIS 10.5软件、R语言和matlab等语言,运用相关分析法和趋势分析法,研究了不同时段低山草甸植被NDVI、气象因子和社会经济发展数据的时空变化特征,从气候变化和人类活动角度探讨了影响低山草甸植被NDVI变化的驱动力,揭示了以往采取的草地恢复措施的有效性和时效性。结果表明：2001—2008年低山草甸植被处于“绿化”状态,“绿化”现象主要分布在研究区的西南、南部和东部,但存在“褐化”趋势,NDVI的降幅在夏季最大;2009—2020年处于“褐化”状态,“褐化”现象分布在除了研究区西南部的其他区域,但存在微弱的“绿化”趋势,NDVI的增幅在夏季最大;2001—2020年生长季总体呈“暖干”趋势,但2009年以来“暖干”趋势有所减缓,低山草甸的南部经历了一个降水减少的暖化过程,而西北和东北部则表现出降水增加的冷却过程;过去20年年末牲畜存栏数和肉类总产量都呈现先急速增加后平缓增加而又急...  相似文献   

西部地区生态状况变化及生态系统服务权衡与协同   总被引：4，自引：0，他引：4  

牛丽楠  邵全琴  宁佳  黄海波 《地理学报》2022,77(1):182-195

西部大开发战略实施20年以来,一系列重大生态建设工程使得西部地区的生态状况和生态服务发生了重要变化,本文分析西部地区生态状况变化及其生态服务时空变化特征,并运用相关分析法研究其服务功能权衡协同关系。研究发现西部地区2000—2019年间：① 聚落和湿地生态系统面积显著增加,草地有逐年下降趋势。② 植被覆盖度呈波动上升趋势,存在年际差异且空间差异较大。③ 水源涵养服务有轻微下降趋势,下降区域主要分布在藏东南地区、三江源西部地区、喀斯特石漠化地区等;土壤保持服务波动中呈上升趋势,上升区域主要黄土高原地区、川滇西部地区、藏西北地区、藏东南地区等;防风固沙服务呈下降趋势,大幅下降区域主要位于内蒙古中西部地区、西藏和北疆部分地区。④ 生态系统供给与水源涵养、土壤保持主要为协同关系,与防风固沙主要为权衡关系且分布在农牧交错带地区。⑤ 生态工程区内生态系统服务协同程度大于非工程区。定量评估生态系统服务变化及其权衡协同关系有助于进行科学化生态管理,最大化生态效益。  相似文献   

长三角地区市场分割的时空演变及其空间 溢出效应     

孔翔  陈开航  李一曼 《世界地理研究》2022,31(4):827-836

消除市场分割是长三角区域一体化发展的题中之义。基于商品流通、劳动力流动的市场分割“一体两面”视角,综合运用相对价格法、空间计量模型等方法,对2008—2017年35个长三角地区城市面板数据进行分析,刻画长三角地区市场分割地理过程、格局,探究其对地区经济增长的空间溢出效应。研究发现：①近十年间,长三角地区商品与劳动力市场分割水平在波动中呈现下降趋势,降幅分别为63%和48%。②长三角地区的市场分割凸显多尺度空间分异特征。在省级尺度上,商品和劳动力市场分割水平保持总体下降趋势。各省的商品分割水平年际变化趋势较为一致,而劳动力市场分割则在2012年后出现较大差异。在市级尺度上,核心区城市的商品市场分割水平降幅较大,分割水平位序下移;非核心区城市劳动力市场分割水平降幅较大,分割水平位序下移。③空间计量模型的结果表明,长三角地区的两类市场分割均对地区经济增长形成负向空间溢出效应。其中,劳动力市场分割的空间溢出主要通过直接效应体现,而间接抑制效应并不显著。  相似文献   

The Spatio-temporal Evolution of Ski Resorts in the Beijing- Tianjin-Hebei Region: Characteristics and Influencing Factors     

WU Liyun  XU Jiayang  YAN Zhixin  GAO Shan  LIN Wanzhao  XIA Bing 《资源与生态学报(英文版)》2022,13(4):592-602

Ski resorts are one of the bases for the development of ice-snow sports and tourism, and they are also a hot topic of social concern. Taking 117 ski resorts in Beijing, Tianjin and Hebei as the research object, geospatial analysis methods such as kernel density and spatial autocorrelation were used to explore the spatial and temporal distribution patterns of the ski resorts. The geographic detector was used to deeply explore the underlying factors influencing the spatial and temporal distribution of ski resorts in terms of policy factors, natural factors and economic and social factors. This study found that the spatial and temporal distribution of ski resorts in the Beijing-Tianjin-Hebei Region showed a significant Olympic event-driven characteristic. From 2009 to 2021, the spatial pattern of Beijing-Tianjin-Hebei ski resorts has changed from “single-core development”, to a “single-core with multi-point” layout, and then to a “multi-core” layout. The spatial pattern has changed from agglomeration to diffusion. Cold and hot spots of the spatial and temporal characteristics in Beijing-Tianjin-Hebei ski resort have shifted from north to south, from the initial suburbs of Beijing to the southern cities of Baoding, Shijiazhuang, Xingtai and other cities in Hebei Province. The spatial and temporal distribution of Beijing-Tianjin-Hebei ski resorts has been influenced by many factors, from “GDP per capita” to “population density” to “policy quantity”, showing a shift from “Economic-driven” to “population-driven” to “policy-driven” processes.  相似文献   

Climatic versus halokinetic control on sedimentation in a dryland fluvial succession   总被引：1，自引：1，他引：0  

Steven G. Banham  Nigel P. Mountney 《Sedimentology》2014,61(2):570-608

Fluvial systems and their preserved stratigraphic expression as the fill of evolving basins are controlled by multiple factors, which can vary both spatially and temporally, including prevailing climate, sediment provenance, localized changes in the rates of creation and infill of accommodation in response to subsidence, and diversion by surface topographic features. In basins that develop in response to halokinesis, mobilized salt tends to be displaced by sediment loading to create a series of rapidly subsiding mini‐basins, each separated by growing salt walls. The style and pattern of fluvial sedimentation governs the rate at which accommodation becomes filled, whereas the rate of growth of basin‐bounding salt walls governs whether an emergent surface topography will develop that has the potential to divert and modify fluvial drainage pathways and thereby dictate the resultant fluvial stratigraphic architecture. Discerning the relative roles played by halokinesis and other factors, such as climate‐driven variations in the rate and style of sediment supply, is far from straightforward. Diverse stratigraphic architectures present in temporally equivalent, neighbouring salt‐walled mini‐basins demonstrate the effectiveness of topographically elevated salt walls as agents that partition and guide fluvial pathways, and thereby control the loci of accumulation of fluvial successions in evolving mini‐basins: drainage pathways can be focused into a single mini‐basin to preserve a sand‐prone fill style, whilst leaving adjoining basins relatively sand‐starved. By contrast, over the evolutionary history of a suite of salt‐walled mini‐basins, region‐wide changes in fluvial style can be shown to have been driven by changes in palaeoclimate and sediment‐delivery style. The Triassic Moenkopi Formation of the south‐western USA represents the preserved expression of a dryland fluvial system that accumulated across a broad, low‐relief alluvial plain, in a regressive continental to paralic setting. Within south‐eastern Utah, the Moenkopi Formation accumulated in a series of actively subsiding salt‐walled mini‐basins, ongoing evolution of which exerted a significant control on the style of drainage and resultant pattern of stratigraphic accumulation. Drainage pathways developed axial (parallel) to salt walls, resulting in compartmentalized accumulation of strata whereby neighbouring mini‐basins record significant variations in sedimentary style at the same stratigraphic level. Despite the complexities created by halokinetic controls, the signature of climate‐driven sediment delivery can be deciphered from the preserved succession by comparison with the stratigraphic expression of part of the system that accumulated beyond the influence of halokinesis, and this approach can be used to demonstrate regional variations in climate‐controlled styles of sediment delivery.  相似文献   

黔北务正道铝土矿矿体特征及找矿前景——以务川大竹园铝土矿床为例     

潘忠华  翁申富  程悦 《四川地质学报》2014,34(3):377-380

以黔北务川大竹园铝土矿床为例,对其矿体厚度、矿石品位沿走向和倾向变化特征进行分析,以探寻此类矿床应如何实现找矿突破。通过大量资料分析认为,就黔北务正道铝土矿进行勘查而言,与务川大竹园铝土矿床矿体沿走向、倾向变化特征进行类比,其找矿前景较为理想。  相似文献   

地震勘探技术在内蒙古自治区四子王旗德日存呼都格矿区的应用     

赵限维  ;高登辉  ;胡安顺 《山东地质》2014,(10):46-48

地震勘探技术以其成本低、效率高的优势在煤田勘探中被广泛的应用。内蒙古自治区四子王旗德日存呼都格矿区采用地震勘探技术,在解释煤层、构造等方面取得了良好的效果,给煤矿的开采设计施工提供了参考依据,为煤炭勘查做出了重要贡献。  相似文献