基于ArcGIS和DEM在水文流域模拟中的应用

利用ArcGIS软件中的水文分析工具,在DEM表面之上再现水流的流动过程,最终完成水文分析过程。列举实例对ArcGIS与DEM数据进行提取河网、河网分级、生成流域边界等水文分析工作,对形成的水文模型与真实地形进行比较和分析误差。实验结果表明模拟出的河网与水利部门提供的地形资料基本相符,后续研究可利用更高质量的DEM影像进行提取。     

Whole rock geochemistry and Sr isotopic compositions of Phanerozoic sedimentary rocks in the Inner Zone of the Southwest Japan Arc

Pre-Cretaceous metasedimentary rocks occurring in the Inner Zone of the Southwest Japan Arc can be divided into three major groups, namely, high P/T metamorphic (Renge and Suo belts), low P/T metamorphic (Hida-Oki, Ryoke and Higo belts), and accretionary terranes (Akiyoshi, Maizuru, Mino-Tamba, and Ashio belts). Major and trace element compositions of most of the sedimentary rocks are typical of relatively mature sedimentary rocks, although abundances of ferromagnesian elements also suggest the presence of a significant mafic to intermediate igneous component. The sedimentary rocks with older Nd model ages (> 2.0 Ga) have high εSr values and major and trace element geochemical signatures typical of mature sediments, whereas those with younger model ages (< 1.45 Ga) have low εSr values and immature geochemical characteristics. With the exception of Hida samples, the sedimentary rocks from other districts have geochemical and isotopic features intermediate between the rocks with old and young Nd model ages. Some of the Hida samples have old Nd model ages, but others are influenced by younger rock fragments and have immature geochemical features. Based on combined isotopic and geochemical evidence, Inner Zone sedimentary rocks with older Nd model ages are interpreted to have been derived from felsic upper continental crustal materials such as Sino-Korean or northwest Yangtze craton granitoids. Compositions of rocks with younger Nd model ages reflect addition of mafic to intermediate detritus, such as island arc basalts and andesites. The rocks with intermediate Nd model ages may have formed in and around the Asian continental margin. The Hida metasedimentary rocks may have been derived from several terranes of varying age and geochemical composition.     

“伊斯兰弧带”动荡的原因分析及对中国安全的警示

2011年发生的埃及等中东-北非国家的持续动荡,均发生在所谓的"伊斯兰弧带"。此次动荡具有持续时间长、影响深、社会基础广泛等特征。骚乱的原因,主要是历史上宗教冲突遗留下的仇恨、美国等西方势力的干涉、中东-北非地区国家内部现代化转型障碍重重等。在更深的层次上,此次乱局也是现有国际政治结构失衡的一种折射。中国需要细致评估动乱对中国安全的警示意义,提升对中东一北非地区事务的政治影响力,更好地维护本国在这一地区的利益。     

Ordovician Macquarie Arc and turbidite fan relationships,Lachlan Orogen,southeastern Australia: stratigraphic and tectonic problems

Ordovician rocks of the Lachlan Orogen consist of two major associations, mafic to intermediate volcanic and volcaniclastic rocks (Macquarie Arc), which aerially comprise several north–south-trending belts, and the quartz-rich turbidite succession. Relationships between these associations are integral to resolving their tectonic settings and opinions range between contacts being major thrusts, combinations of various types of faults, and stratigraphic contacts with structural complications. Stratigraphic contacts between these associations are found with volcaniclastic-dominant units overlying quartz-turbidite units along the eastern boundary of the eastern volcanic belt and along the southern boundary of the central volcanic belt. Mixing between these major associations is limited and reflects waning quartzose turbidite deposition along a gently sloping sea floor not penetrating steeper volcaniclastic aprons that were developing around the growing volcanic centres formed during late Middle Ordovician to early Silurian Macquarie Arc igneous activity. An island arc setting has been most widely supported for the Macquarie Arc, but the identification and polarity of the associated subduction zone remain a contentious issue particularly for the Early Ordovician phase of igneous activity. The Macquarie Arc initiated within a Cambrian backarc formed by sea-floor spreading behind a boninitic island arc and presumably reflects a renewed response to regional convergence as subduction ceased along the Ross–Delamerian convergent boundary at the East Gondwana continental margin. An extensional episode accompanied initiation of the late Middle Ordovician expansion in island arc development. A SSE-dipping subduction zone is considered to have formed the Macquarie Arc and underwent anticlockwise rotation about an Euler pole at the western termination of the island arc. This resulted in widespread deformation west of the Macquarie Arc in the Benambran Orogeny and development of subduction along the eastern margin of the orogenic belt.     

Le domaine Tariquide (arc de Gibraltar,Espagne et Maroc) : succession et hiatus de la sédimentation du Jurassique supérieur au Paléocène

The originality of the Malm–Cretaceous series of the Tariquides (Gibraltar arc), as compared to those of the Rifian–Betic ‘Dorsale’ (Alboran domain), and especially with the Penibetic (Iberia) domain, is emphasized. In the Los Pastores Group, near Algeciras, Upper Tithonian nodular limestones directly lie on the Dogger and are followed by Aptychus-bearing limestones (Late Berriasian to Barremian). In the Musa Group, Rif, radiolarites are followed by siliceous limestones (Kimmeridgian–Tithonian), then by karst and massflow breccias connected to a Berriasian tectonics, by Aptychus-bearing marly limestones, then by karst filled by Turonian limestones, and finally by Maastrichtian–Palaeocene polychrome pelites, whose micropalaeontological and mineral compositions (clay minerals, FeMn nodules) refer to a deep-sea, probably infra-CCD, sedimentation. To cite this article: M. Durand-Delga et al., C. R. Geoscience 337 (2005).     

河北省地震局规划筹建用于地震应急的地理信息数据库的研究

利用Arc／Inf0，结合地震应急与辅助决策的特点，建成了河北省灾害评估与辅助决策系统，实现了以多种方式录入的空间数据，以有效的数据组织形式进行数据库管理、更新、维护、查询、检索，以多种方式输出决策所需的地理空间信息。     

Morphometric analysis to determine floods in the Upper Krishna basin using Cartosat DEM

The evaluation of basin characteristics from the morphometric parameters helps in understanding the physical behaviour of the catchments with respect to floods. The advanced technologies, such as Remote sensing and Geographic Information System (GIS), were used for extraction of drainage networks using Cartosat Digital Elevation Model (DEM) for the Upper Krishna basin, to evaluate the morphometric analysis. Basin morphometric parameters were applied to assess the major influencing catchments which cause flooding in the main Krishna River. The morphometric analysis for the ten major potential flood prone river catchments of the basin reveals that, the river catchments such as Krishna, Koyna, Yerla having the greater tendency to peak discharge in a short period of time to the main Krishna River because of high relief ratio (Rh), high ruggedness number and less time of concentration (Tc). The Don catchment having the highest drainage density (Dd), stream frequency, mean bifurcation ratio and infiltration number causes greater runoff influence on the main Krishna River. The Dudhganga and Panchaganga catchments having highest form factor, medium Dd, texture ratio, Rh and time of concentration causes moderate runoff influence towards main Krishna River. The study indicates that systematic analysis of morphometric parameters derived from Cartosat DEM using GIS provide useful information about catchment characteristics with respect to floods management.     

印度尼西亚西爪哇地区金矿典型矿床

西爪哇金矿位于印度尼西亚西角湾火山岩金、铅锌铜多金属成矿带,该区有众多金矿床(点)。出露的三叠系火山岩地层,以火山喷发沉积为主,岩性组合为安山岩、英安岩、流纹岩及火山角砾岩,具爆发-喷溢沉积的特点,总体表现为火山弧特征。断裂构造破碎带是该地区主要控矿、容矿构造。岩石蚀变强烈,硅化与金矿化关系密切。     

龙门山南段活动构造分布特征

本文在综合解译地质图、遥感影像及数字高程模型的基础上,沿着青衣江河谷对龙门山南段多条断裂进行了详细调查。将前第四纪大规模不整合边界作为断裂的分布范围,同时通过构造地貌标志确定最新的活动断裂位置,如断错山脊、断层槽谷、河道形态变化等。解译过程中也参考了前人研究成果,如开挖探槽位置信息,浅层地震剖面资料。调查结果显示,松潘—甘孜褶皱带与龙门山接触地带发育了中岗断裂、永富断裂,晚第四纪活动特征不明显。龙门山后山、中央、前山3条主干断裂在南段依次对应耿达—陇东断裂、岩井—五龙断裂、与双石—大川断裂,与北段具有相似的断块构造。3条断裂都有断错地貌特征但断裂分支较多,其中盐井—五龙断裂有一条分支为宝兴断裂,双石—大川断裂有小关子断裂一条分支。在前陆地区,基底滑脱带延伸至浅部盖层,断坡处发育了始阳断裂、新开店断裂等浅部分支断裂。通过这些断裂分布样式、断错地貌特征、与实测地质剖面发现,龙门山南段具有纯挤压特征,最新构造活动已经开始改造前陆地区,是扩展的边界。而龙门山北段具有和逆冲相当的走滑分量,表明青藏高原在推挤龙门山的过程中,龙门山北缘向西秦岭方向发生走滑逃逸,龙门山南段由于同时受川滇块体向东推挤作用而呈现纯挤压特征。高原推挤作用集中于松潘—甘孜褶皱带东缘的小金弧形构造,控制了龙门山断裂带南北构造差异。     

云南迪庆春都铜矿控矿地质条件

铜矿体赋存于印支期浅成-超浅成相的石英二长玢岩体内,具斑岩型矿床的蚀变特征,主要控矿因素为岩浆岩、岩浆侵位的地层、热液蚀变作用和构造裂隙等。是印支期甘孜-理塘洋向西俯冲造山晚期与超浅成斑（玢）岩密切有关的斑岩型铜矿床,矿区及外围具有较大的找矿潜力。