雅浦海沟南缘铁锰结核矿物与地球化学特征及其成因研究     

田举  徐继尚  李广雪  刘明  庄自贤  来志庆  张洋  李舒豪 《中国海洋大学学报(自然科学版)》2019,(8):75-84

本文采用X射线衍射、全岩地球化学和电子探针等测试方法,对雅浦海沟南部附近海域获得的铁锰结核样品进行了显微构造、矿物和地球化学分析,并探讨了其成因。结果表明:铁锰结核的显微构造主要包括平行纹层构造、柱状构造、叠层状构造和同心环状构造;显微构造和探针结果显示铁锰结核在生长初期处于底部海洋动力比较强烈的环境,后期生长环境逐渐趋于稳定;铁锰结核的矿物组分以水羟锰矿、钠水锰矿、石英和钙十字石为主;样品中Fe、Mn元素含量较高且含量比较接近,Cu、Co、Ni和REE相对富集,REE分布模式整体比较平缓并都出现较强的Ce正异常和重稀土元素亏损现象;文中两块铁锰结核都为水成成因,成矿物质主要来自同期的海水沉淀,同时也受一定海底火山物质和陆源风尘物质的影响。  相似文献   

利用改进型MODIS火点探测算法实现河北省秸秆焚烧火点识别          下载免费PDF全文

魏英策  桑会勇  张涛  丛杨  谷祥辉 《全球定位系统》2019,44(1):125-130

为准确地了解河北省秸秆焚烧火点的空间分布,为秸秆焚烧监测的实现、禁烧工作的开展、环境质量改善提供支持.基于MODIS L1B数据、MODIS标准火点产品MOD14、全国秸秆焚烧火点日报数据为基础,采用改进型MODIS火灾探测算法,并通过IDL语言实现,得到秸秆焚烧火点空间分布信息,并进行空间与定量精度分析.研究表明:火点大部分位于河北省南部的一些地区,其中尤以邢台、石家庄、邯郸火点数量最为突出;该算法运算速度快,获取的秸秆焚烧火点数据具有一定检测精度和可靠性,对秸秆焚烧的监测具有一定的实用价值.  相似文献   

Semantic segmentation of high spatial resolution images with deep neural networks     

Haiping Yang  Jiancheng Luo  Fang Chen 《地理信息系统科学与遥感》2019,56(5):749-768

Availability of reliable delineation of urban lands is fundamental to applications such as infrastructure management and urban planning. An accurate semantic segmentation approach can assign each pixel of remotely sensed imagery a reliable ground object class. In this paper, we propose an end-to-end deep learning architecture to perform the pixel-level understanding of high spatial resolution remote sensing images. Both local and global contextual information are considered. The local contexts are learned by the deep residual net, and the multi-scale global contexts are extracted by a pyramid pooling module. These contextual features are concatenated to predict labels for each pixel. In addition, multiple additional losses are proposed to enhance our deep learning network to optimize multi-level features from different resolution images simultaneously. Two public datasets, including Vaihingen and Potsdam datasets, are used to assess the performance of the proposed deep neural network. Comparison with the results from the published state-of-the-art algorithms demonstrates the effectiveness of our approach.  相似文献   

Simulation of landscape spatial layout evolution in rural-urban fringe areas: a case study of Ganjingzi District   总被引：2，自引：0，他引：2  

Jun Yang  Andong Guo  Yonghua Li  Yuqing Zhang  Xueming Li 《地理信息系统科学与遥感》2019,56(3):388-405

In recent years, the rapid expansion of urban spaces has accelerated the mutual evolution of landscape types. Analyzing and simulating spatio-temporal dynamic features of urban landscape can help to reveal its driving mechanisms and facilitate reasonable planning of urban land resources. The purpose of this study was to design a hybrid cellular automata model to simulate dynamic change in urban landscapes. The model consists of four parts: a geospatial partition, a Markov chain (MC), a multi-layer perceptron artificial neural network (MLP-ANN), and cellular automata (CA). This study employed multivariate land use data for the period 2000–2015 to conduct spatial clustering for the Ganjingzi District and to simulate landscape status evolution via a divisional composite cellular automaton model. During the period of 2000–2015, construction land and forest land areas in Ganjingzi District increased by 19.43% and 15.19%, respectively, whereas farmland, garden lands, and other land areas decreased by 43.42%, 52.14%, and 75.97%, respectively. Land use conversion potentials in different sub-regions show different characteristics in space. The overall land-change prediction accuracy for the subarea-composite model is 3% higher than that of the non-partitioned model, and misses are reduced by 3.1%. Therefore, by integrating geospatial zoning and the MLP-ANN hybrid method, the land type conversion rules of different zonings can be obtained, allowing for more effective simulations of future urban land use change. The hybrid cellular automata model developed here will provide a reference for urban planning and policy formulation.  相似文献   

Improved Priority‐Flood method for depression filling by redundant calculation optimization in local micro‐relief areas     

Li‐Yang Xiong  Ru‐Qiao Jiang  Qing‐Hui Lu  Bi‐Sheng Yang  Fa‐Yuan Li  Guo‐An Tang 《Transactions in GIS》2019,23(2):259-274

Depression filling is a critical step in distributed hydrological modeling using digital elevation models (DEMs). The traditional Priority‐Flood (PF) approach is widely used due to its relatively high efficiency when dealing with a small‐sized DEM. However, it seems inadequate and inefficient when dealing with large high‐resolution DEMs. In this work, we examined the relationship between the PF algorithm calculation process and the topographical characteristics of depressions, and found significant redundant calculations in the local micro‐relief areas in the conventional PF algorithm. As such calculations require more time when dealing with large DEMs, we thus propose a new variant of the PF algorithm, wherein redundant points and calculations are recognized and eliminated based on the local micro‐relief water‐flow characteristics of the depression‐filling process. In addition, depressions and flatlands were optimally processed by a quick queue to improve the efficiency of the process. The proposed method was applied and validated in eight case areas using the Shuttle Radar Topography Mission digital elevation model (SRTM‐DEM) with 1 arc‐second resolution. These selected areas have different data sizes. A comparative analysis among the proposed method, the Wang and Liu‐based PF, the improved Barnes‐based PF, the improved Zhou‐based PF, and the Planchon and Darboux (P&D) algorithms was conducted to evaluate the accuracy and efficiency of the proposed algorithm. The results showed that the proposed algorithm is 43.2% (maximum) faster than Wang and Liu's variant of the PF method, with an average of 31.8%. In addition, the proposed algorithm achieved similar performance to the improved Zhou‐based PF algorithm, though our algorithm has the advantage of being simpler. The optimal strategies using the proposed algorithm can be employed in various landforms with high efficiency. The proposed method can also achieve good depression filling, even with large amounts of DEM data.  相似文献   

Sentinel-1A SAR影像及其在矿区地面沉降监测中的应用研究     

李新  陶秋香  宋杨  罗莹玉  孙翠羽 《测绘与空间地理信息》2019,42(3):31-34,38

详细介绍了Sentinel-1A SAR影像数据的基本参数、工作模式、应用领域等。利用2016.11.09—2017.03.09的5景Sentinel-1A C波段SAR影像数据进行矿区地面沉降监测试验。基于SARscape利用双轨D-In SAR技术进行差分干涉处理,得到了研究区地面沉降分布图,直观地再现了研究区在2016.11.09—2017.03.09的沉降分布、沉降量级等。结果表明济宁某矿区在监测期间地面相对稳定,未有大面积和大量级的地面沉降发生,4个干涉对监测到的最大沉降都未超过3 cm。  相似文献   

基于Landsat遥感数据武汉地区植被覆盖度动态变化监测分析   总被引：1，自引：0，他引：1  

韩富圆  王天明  孙阳 《测绘与空间地理信息》2019,42(4):90-92

旨在研究受人类经济活动影响的植被资源及其动态变化趋势的程度,采用基于归一化植被指数的像素二分模型,利用2002—2010年(武汉市每年8月)的卫星遥感数据,对武汉地区6年间的植被覆盖变化进行监测分析。结果表明,植被覆盖度变化与武汉GDP增长率有着紧密联系:2002—2007年,武汉经济较缓慢上升,植被覆盖度基本维持在55%左右;而2007—2008年武汉GDP总值增长率高达26.06%,但随之而来的是植被覆盖度由高峰期的61.68%下降到49.18%,是历年来的最低水准; 2008—2010年经济发展放缓,植被指数有小幅度回升。人类经济活动是影响植被资源的重要因素。  相似文献   

珠江口盆地珠三坳陷文昌组有机质碳同位素异常成因     

何智同  尹相东  陈世加  雷明珠  朱必清  刘杨  赵荣茜  刘宇阳 《地质学报》2024,98(1):266-279

部分中国近海湖盆和大西洋裂谷盆地发现了腐泥型有机质碳同位素偏重的现象,并伴随异常高总有机碳含量和生烃潜力。本文依据泥岩有机碳测试、孢粉分析、主微量元素、泥岩和原油碳同位素及饱和烃色质色谱资料,并结合现代湖泊盘星藻发育特征,从有机质来源、古环境条件和有机质保存改造三个方面探讨了珠江口盆地珠三坳陷古近系文昌组碳同位素正偏移的成因机制。珠三坳陷文昌组碳同位素异常与气候、古生产力、古水深和藻类勃发等古环境因素有关。然而,从三级层序尺度看,古水深可能是一个不可忽视的重要因素：指示水深的Rb/K比值随深度加深而增加,与碳同位素和TOC含量变化趋势一致。同时现代湖泊研究也证实了盘星藻分布于不同水深范围,因此“深水型盘星藻”的繁盛很可能是珠三坳陷文昌组二段烃源岩碳同位素偏重的根本原因。  相似文献   

中国锂矿的多旋回深循环内外生一体化成矿理论及其找矿应用     

王登红  代鸿章  刘善宝  王成辉  李建康  李鹏  陈郑辉  于扬  秦锦华  孙艳  娄德波  姚佛军 《地质学报》2024,98(3):889-897

中国锂资源的分布具有卤水型与硬岩型相伴相随、若即若离的特点。“多旋回深循环内外生一体化”成锂理论,在多年三稀金属矿产找矿实践和理论研究的基础上不断丰富完善。中国锂矿的形成与“多旋回”构造运动密切相关,从前寒武纪到新生代均有成矿潜力,可构成一个完整的多旋回成矿谱系。锂的“深循环”,一是锂深度参与成岩成矿的物质循环;二是需要一个“圈闭”的构造背景将锂“捕获”以避免其过度分散,锂从开始加入到岩浆与最终定位的深度之差,是硬岩型锂矿成矿的关键之一,压差越大越有利于伟晶岩型锂矿的形成。大量锂矿实例显示锂的物质循环是“内外生一体化”的统一过程,高海拔地区(山上)的含锂地质体(花岗岩类甚至直接就是含锂矿床)经风化剥蚀之后,可能成为沉积型锂矿的物质来源之一;而富含锂的沉积岩经过埋藏、变质、深熔也可以形成含锂的岩浆岩、伟晶岩。我国西部塔里木盆地、四川盆地、扎布耶盆地及东部的江汉盆地、吉泰盆地、周田盆地等大小不一的盆地均含锂,而其周边造山带中也不同程度发育硬岩型锂矿,这就为区域找矿指明了方向。“多旋回深循环内外生一体化”成锂理论是三稀矿产成矿理论的重要组成部分,为我国锂矿找矿工作提供了指导和借鉴,在甲基卡、可尔因、阿尔金、幕阜山等锂矿矿集区的找矿实践中发挥了积极作用。  相似文献   

寒武系乌训组滑塌建造的物源及其意义          下载免费PDF全文

王文杰  杨光忠  刘灵  林泽渊  李永刚  杨贵龙  罗邦良 《贵州地质》2024,(1):18-24

沉积岩中普遍发育滑塌滑移建造。贵州天柱大河边地区寒武系第二统乌训组即普遍发育滑塌滑移建造,通过地质调查分析,可见滑塌滑移角砾岩建造、瘤状灰岩建造、散布于炭质粘土岩中的“钙质结核”和灰岩中的泥岩脉,以及一系列滑移褶皱褶曲等软沉积物变形构造等类型。根据滑塌滑移角砾岩建造中的鲕粒灰岩角砾和乌训组沉积建造处于大陆斜坡环境的古地理背景分析,滑塌滑移角砾岩建造中的鲕粒灰岩角砾应来源于乌训组北西侧处于台地边缘相的清虚洞组,结合灰岩中的泥岩脉即典型震积泥岩脉现象,综合认为,乌训组普遍发育的各种类型滑塌滑移角砾岩建造和其它变形建造,系地震营力及其导致的滑塌滑移事件作用的结果。  相似文献