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371.
372.
为研究贵州北部马鬃岭铝土矿床中富锂铝质粘土岩的物源体系及其锂的来源,对出露于大竹园组顶部的该类岩石进行了锆石U-Pb定年、Lu-Hf同位素及锆石微量元素分析。分析结果表明富锂铝质粘土岩中碎屑锆石普遍发育岩浆振荡环带,为造山作用/弧作用相关的岩浆岩类锆石。碎屑锆石U-Pb年龄从早泥盆世到太古宙(411~3001 Ma)均有分布,具627~879 Ma和925~1018 Ma两个主峰及539~602 Ma一个次峰。εHf(t)值为-27.61~7.03之间,二阶段模式年龄(tDM2)分布在1242~3387 Ma之间。结合碎屑锆石U-Pb-Hf同位素、微量元素特征及区域地质对比,认为富锂铝质粘土岩中碎屑锆石最主要的初始物源区为南岭-云开地体、江南造山带西段新元古代岩浆岩,其锂可能来源于江南造山带西段桂北-黔东地区860~750 Ma的基性岩。 相似文献
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The Austrian node of the Natural Resources Satellite Remote Sensing Cloud Service Platform was established in 2016 through a cooperation agreement between the Land Satellite Remote Sensing Application Center(LASAC),Ministry of Natural Resources of the Peoples Republic of China and the University of Vienna,Austria.Under this agreement panchromatic and multi-spectral data of the Chinese ZY-3 satellite are pushed to the server at the University of Vienna for use in education and research.So far,nearly 500 GB of data have been uploaded to the server.This technical note briefly introduces the ZY-3 system and illustrates the implementation of the agreement by the first China-Sat Workshop and several case studies.Some of them are already completed,others are still ongoing.They include a geometric accuracy validation of ZY-3 data,an animated visualization of image quick views on a spherical display to demonstrate the time series of the image coverage for Austria and Laos,and the use of ZY-3 data to study the spread of bark beetle in the province of Lower Austria.An accuracy study of DTMs from ZY-3 stereo data,as well as a land cover analysis and comparison of Austria with ZY-3 and other sensors are still ongoing. 相似文献
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海洋权益维护信息系统的设计与实现 总被引:1,自引:0,他引:1
介绍了海洋权益维护信息系统的总体结构、数据库组成和主要功能。已开发的基础功能模块和子系统包括:基础地理信息系统数据管理、海域划界、海洋调查项目管理和辅助决策等。 相似文献
377.
等值线构建是G IS开发、数字地图绘制重要的研究内容之一。重点讨论了基于M apInfo数据格式在G IS应用环境下等值线综合方法的实现,首先根据高程采样点跟踪等高线通过点,再利用五点光滑法、正轴抛物线加权平均光滑法以及M apX提供的光滑方法对等值线通过点进行光滑处理,从而绘制出光滑度好、准确美观的等值线,同时发现M apX所提供的光滑方法可能利用的就是正轴抛物线加权平均光滑法。通过大量的数据验证了绘制的正确性。 相似文献
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1Introduction With the development and application of remotesensing technology, people fromthe international re-mote sensing community have realized the issue thatwe have immoderately emphasized characteristics ofvast volume data and great detail of remot… 相似文献
379.
The concept of a spatially distributed unit hydrograph is based on the fact that the unit hydrograph can be derived from the time–area curve of a watershed by the S-curve method. The time–area diagram is a graph of cumulative drainage area contributing to discharge at the watershed outlet within a specified time of travel. Accurate determination of the time–area diagram is made possible by using a GIS. The GIS is used to describe the connectivity of the links in the watershed flow network and to calculate distances and travel times to the watershed outlet for various points within the watershed. Overland flow travel times are calculated by the kinematic wave equation for time to equilibrium; channel flow times are based on the Manning and continuity equations. To account for channel storage, travel times for channel reaches are increased by a percentage depending on the channel reach length and geometry. With GIS capability for rainfall mapping, the assumption of a uniform spatial rainfall distribution is no longer necessary; hence the term, spatially distributed unit hydrograph. An example of the application for the Waiparous Creek in the Alberta Foothills is given. IDRISI is used to develop a simple digital elevation model of the 229 km2 watershed, using 1 km × 1 km grid cells. A grid of flow directions is developed and used to create an equivalent channel network. Excess rainfall for each 1 km × 1 km cell is individually computed by the Soil Conservation Service (SCS) runoff curve method and routed through the equivalent channel network to obtain the time–area curve. The derived unit hydrograph gave excellent results in simulating an observed flood hydrograph. The distributed unit hydrograph is no longer a lumped model, since it accounts for internal distribution of rainfall and runoff. It is derived for a watershed without the need for observed rainfall and discharge data, because it is essentially a geomorphoclimatic approach. As such, it allows the derivation of watershed responses (hydrographs) to inputs of various magnitudes, thus eliminating the assumption of proportionality of input and output if needed. The superposition of outputs is retained in simulating flood hydrographs by convolution, since it has been shown that some non-linear systems satisfy the principle of superposition. The distributed unit hydrograph appears to be a very promising rainfall runoff model based on GIS technology. 相似文献
380.
基于DEM的长江上游土地利用分析 总被引:24,自引:0,他引:24
全球环境变化与可持续发展是当今关切的重大问题之一,而土地利用/覆盖变化研究则是其中的热点和前沿领域。目前,严重的生态环境已成为长江上游地区经济社会发展的重大障碍,也是本区和整个长江流域实现可持续发展的最主要的制约因素。本文在DEM基础上,分析了2000年长江上游高程、坡度和坡向与土地利用的关系。研究结果表明,随着高程、坡度和坡向的变化,2000年长江上游的土地利用类型也有很大差异,这些因素对长江上游的土地利用有着重要的影响。为了保护生态环境,促进本区和整个长江流域实现可持续发展,需进一步因地制宜,结合高程、坡度和坡向等影响因素优化土地利用类型和改善地表覆盖。 相似文献