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31.
32.
Analysis of influencing factors on fine sediment flocculation in the Changjiang Estuary 总被引：1，自引：0，他引：1
Based on the test data in dynamic water and static water, the main factors, which influence the fine sediment flocculation, are analyzed with a gray model method of correlation theory. It is shown that the main influencing factors are water temperature, settling time, salinity, grain size, sediment concentration and current velocity according to the correlation coefficients. Among them, the salinity and the sediment grain size are critical type influencing factors (CrTIF); the settling time, the sediment concentration and the velocity are continuous type influencing factors (CoTIF); and the water temperature has the characteristics of both. When the critical values of CrTIF are reached or exceeded, the fine sediments will be flocculated, but values of CrTIF will not influence the settlement strength of floes. The influence of CoTIF is continuous. The values of the CoTIF will not only influence the occurrence of flocculation but also the settlement strength of the floes. 相似文献
33.
ZHANG Ruifeng TIAN Jianzhang HUANG Yuanxin TIAN Ran REN Yi BIAN Yingying WANG Yuanjie CHEN Ling LU Shan 《地学前缘》2023,30(1):229-241
The buried hill in the Jizhong depression contains abundant petroleum reserves and are important production areas. The Ordovician buried hill has restricted the discovery of new oil and gas exploration targets because of its strong reservoir heterogeneity and complex reservoir-controlling factors. Based on a large volume of core, thin section, logging, seismic, and geochemical data and numerous geological analyses, the reservoir-forming conditions and modes were systematically analyzed to guide the exploration and achieve important breakthroughs in the Yangshuiwu and Wen’an slope buried hills. The study revealed that three sets of source rocks of the third and fourth members of the Shahejie Formation from the Paleogene and Carboniferous-Permian were developed in the Jizhong depression, providing sufficient material basis for the formation of buried hill oil and gas reservoirs. The reservoir control mechanism involving the three major factors of “cloud-karst-fault” was clarified, and karst cave, fracture fissure-pore, and cloud pore type reservoir models were established, thereby expanding the exploration potential. Controlled by the superposition of multi-stage tectonic processes during the Indosinian, Yanshanian, and Himalayan, two genetic buried hill trap types of uplift-depression and depression-uplift were formed. Based on the analysis of reservoir-forming factors of the Ordovician buried hill, three buried hill oil and gas reservoir-forming models were identified: low-level tectonic-lithologic composite quasi-layered buried hill, medium-level paleo-storage paleo-block buried hill, and high-level paleo-storage new-block buried hill. Comprehensive evaluations indicate that the reservoir-forming conditions of the low-level tectonic-lithologic composite quasi-layered buried hill in the northern portion of the Jizhong depression are the most favorable and that the Sicundian and Xinzhen buried hills are favorable areas for future exploration. 相似文献
34.
基于ArcGIS的地图符号库的设计与实现 总被引：18，自引：0，他引：18
地理信息系统(GIS)的主要功能之一就是地图制图及输出。地图作为用户能够理解空间信息的主要图件，地图符号作为地图语言则在地图的制作和输出中起着非常重要的作用。美国ESRI公司开发的ARCGIS是功能强大的GIS软件平台，但是它的数据输入、编辑、查询与制图模块ArcMap中自带的符号库不能满足我国基本比例尺地图输出的要求，因此必须为它建立符合地图图式要求的符号库。本文重点论述了ArcGIS环境下地图符号库的设计方法，并分别讨论了点状符号、线状符号和面状符号的实现方式。 相似文献
35.
GIS符号库自适应扩展技术研究 总被引：1，自引：0，他引：1
在ＧＩＳ工程建设和软件开发中,所基于的ＧＩＳ开发平台（如ＡｒｃＩｎｆｏ,ＭａｐＩｎｆｏ等）提供的符号往往不能满足不同用户的需要。因此,在开发过程中,必然涉及到字体符号文件的存取和扩展问题：如何读取字体符号数据：如何制作特殊符号,以及如何存储所制作的符号等。本文重点对ＧＩＳ符号库的扩展所涉及的技术方法进行探讨,并提出自适应扩展的思想,以便更好地满足用户的不同要求。文中主要以ＭａｐＩｎｆｏ的字体符号库结构加以论述,ＭａｐＩｎｆｏ字体符号存取技术在配电自动化地理信息系统（ＤＡＧＩＳ）中得以成功地实现与应用。但该技术方法也同样适用于其他ＧＩＳ平台。 相似文献
36.
IntroductionThe earthquake sequences can be divided as the type of isolation (single shock), mainaftershocks and swarm of earthquake (multi-shocks) (Institute of Geophysics of CAS, 1976; Li,1981; Wu, et al, 1990). Based on the research of earthquake sequence, combined with modernobservation technique and the wide band strong (main) shock records of CDSN, this paper willdetermine the properties of hypocenter and seek the internal relation between the type of earthquake sequence and the hypo… 相似文献
37.
38.
ZHANG Changqing LIU Huan WANG Denghong CHEN Yuchuan RUI Zongyao LOU Debo WU Yue JIA Fudong CHEN Zhenghui MENG Xuyang 《《地质学报》英文版》2015,89(4):1333-1358
Lead and zinc resources are abundant in China, with the reserves of 100 million tons ranking only second in the world. There are more than 3000 lead-zinc mine areas nationwide. The classification of lead-zinc (Pb-Zn) deposits has been a highly controversial issue. From the standpoint of evaluating the potential of mineral resources, we construct a Pb-Zn deposit predictive type of classification scheme, and propose a Pb-Zn deposit comprehensive classification scheme (including 5 classes and 13 sub-types) that regards mineralization as the primary factor and the ore rock as secondary. According to the temporal and spatial distribution of Pb-Zn deposits, we conclude that a multi-period, multi-cycle orogenic environment is the most favorable for lead-zinc deposit growth, that the Proterozoic is the major eon for the growth of igneous-type deposits, the Paleozoic is an important development era for sedimentary Pb-Zn deposits, and the Mesozoic and Cenozoic are the heyday eras of magmatic type lead-zinc deposits. On this basis, we analyse the relationship between tectonic evolution and Pb-Zn metallogenic, and propose that the key factors determining geological mineralization are the metallogenic epoch of mineralization and tectonic environment, which determine the temporal and spatial distribution. 相似文献
39.
YING Lijuan CHEN Yuchuan WANG Denghong TANG Juxing CHEN Zhenghui WANG Chenghui 《《地质学报》英文版》2015,89(1):251-269
Copper resources in China are rich, but imported copper products are still required. Researches on metallogenic regularity of major types of copper deposits by geologists have involved in worldwide classification, significant copper belts, representative copper deposits, etc. Studies on metallogenic regularity of copper deposits in China also have made achievements with a long-term work. Combined with latest exploration advances obtained in recent ten years, this review aims to conclude the achievements of researches on copper metallogenic regularity in China. Based on data of 814 copper deposits and other ore (mineralized) occurrences, ten prediction types of copper deposits have been suggested. Porphyry and skarn copper ores are taken as the key targets. Porphyry copper deposits are the most important one which concentrate in Gangdese, Changdu-Sanjiang, Dexing and East Tianshan. The Cenozoic and Mesozoic are the major metallogenic epochs. Four main metallogenic epochs are been studied based on the copper ore geochronological data including Precambrian Era (Archean and Proterozoic), Paleozoic Era, Mesozoic Era and Cenozoic Era. Based on the study of metallogenic series of ore deposits in China, twenty-seven metallogenic series of copper deposits are proposed. This is suggested to deepen the study of metallogenic regularity of copper ore and provide the theory guide for copper resources prediction in China. 相似文献
40.
The catchment of South Luohe River in Central China is an important region for investigating modern pollen-environment relationship, because it is located in the transitional zone between south and north China, an environment which is sensitive to climate changes. In this study, 40 surface samples under ten vegetation types were collected to reveal the relationship between pollen assemblages and vegetation. The results show that the surface pollen assemblages reflect the vegetation quite well. In forest topsoils, the average of arboreal pollen content is greater than 40%, and the Selaginella sinensis spore is high. As to sparse forest grassland and shrub community, the average arboreal pollen is 13.2% and 16.6% respectively, and the shrub pollen is relatively higher than that of grassland samples. The grassland and farmland are characterized by low percentage of tree and shrub pollen(<10% and <1%), and high percentage of herbs(>80%). Pinus, Quercus and some other arboreal pollen can indicate the regional vegetation because of their dispersal ability. Quercus pollen is under-representative and so is Pinus. Artemisia pollen is significantly over-represented, has poor correlation with the plant coverage, and may reflect human disturbance. Gramineae can indicate plant quite well, but with low representation. High content of Chenopodiaceae probably suggests human impact. Predominant Selaginella sinensis can be used as an indicator of forest environment. Cluster analysis and principal components analysis of pollen assemblages can distinguish forest and non-forest vegetation well. The former method is better at separating pine and mixed forests, while the latter is more stable and could better differentiate farmland and other non-forest area. The first axis of PCA mainly reflects the humidity. 相似文献