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排序方式: 共有1221条查询结果,搜索用时 15 毫秒
81.
基于对第二松花江流域上游小山、松山、两江水电站中长期水文预报研究成果,论述了综合中长期水文预报的研究思路和定性预报、定量预报的分析研究方法。该研究通过2002年实践检验,具有较高的预报精度。 相似文献
82.
Chronology and Geochemistry of Volcanic Rocks in the Cretaceous Suifenhe Formation in Eastern Heilongjiang, China 总被引:3,自引:0,他引:3
JI Weiqiang XU Wenliang YANG Debin PEI Fuping JIN Ke LIU Xiaoming College of Earth Sciences Jilin University Changchun Jilin Bureau of Land Mineral Resources of Jilin Province Changchun Jilin The State Key Laboratory of Continental Dynamics Northwest University Xi ''an Shaanxi 《《地质学报》英文版》2007,81(2):266-277
Zircon U-Pb ages and geochemical data of volcanic rocks in the Suifenhe Formation in eastern Heilongjiang Province are reported, and their petrogenesis is discussed in this paper. The Suifenhe Formation mainly consists of basalt, andesite, and dacite. Zircon from andesite and dacite are euhedral in shape and show typical oscillatory zoning with high Th/U ratios (0.18-0.57), implying its magmatic origin. Zircon U-Pb dating results by laser ablation inductively coupled plasma mass spectrometer (LA-ICP-MS) indicate that the 206Pb/238U ages of zircons from andesite range within 105-106 Ma, yielding a weighted mean age of 105.5±0.8 Ma (n=14), and that 206Pb/238U ages of zircons from dacite are between 90-96 Ma, yielding a weighted mean age of 93.2±1.3 Ma (n =13). The volcanic rocks from the Suifenhe Formation are subalkaline series and show a calc-alkaline evolutionary trend with SiO2 content of 47.69%-65.47%, MgO contents of 1.42%-6.80% (Mg#= 45-53), and Na2O/K2O ratios of 1.83-3.63. They are characterized by enrichment in large ion lithophile elements (LILE) and light-rare-earth elements (LREE), depletion in heavy rare earth elements (HREE) and high field strength elements (HFSE) (e.g., Nb, Ta, Ti), and low initial 87Sr/86Sr ratios (0.7041-0.7057) and positiveεNd(t) values (039-4.08), implying that they could be derived from a depleted magma source. Taken together, these results suggest that the primary magma of the volcanic rocks might originate from partial melting of the mantle wedge metasomatized by fluids derived from subducted slab under a tectonic setting of active continental margin. 相似文献
83.
ISO9000系列标准是一套国际统一的质量管理标准,应用的主体内容是质量管理模式(质量体系)的建立与运行。其对地勘单位走向市场,到社会投标、承揽地勘项目,保证地勘工作成果质量,提高单位在地质市场中的信誉度具有十分重要的意义。 相似文献
84.
新疆萨吾尔地区两类花岗岩Nd、Sr、Pb、O同位素特征 总被引:10,自引:0,他引:10
新疆西准噶尔萨吾尔地区森塔斯岩体和沃肯萨拉岩体为I型花岗岩,侵入于早石炭世末,具有偏碱性特点,形成于后碰撞阶段的伸展期或挤压—伸展转变期;阔依塔斯岩体和恰其海岩体为A2型花岗岩,侵入于早二叠世初,形成于后碰撞阶段伸展期张性构造环境中。I型花岗岩和A型花岗岩的Nd、Sr、Pb同位素特征相似,显示出幔源特征,它们是同源岩浆不同演化阶段的产物。两类花岗岩在O同位素以及稀土元素特征上存在明显差异。西准噶尔萨吾尔地区I型花岗岩(森塔斯岩体和沃肯萨拉岩体)以及A型花岗岩(阔依塔斯岩体和恰其海岩体)的发育,进一步证实了晚古生代区内地壳的垂向增生作用。对比研究表明,可以将西准噶尔萨吾尔地区的A型花岗岩归入东准噶尔乌伦古富碱火成岩带。 相似文献
85.
86.
A total of 34 thunderstorms around Shanghai and Wuhan of China are analyzed in order to determine the relationship between total lightning activity and precipitation particle characteristics.Precipitation particle concentration data are obtained from the 2A12 product of TRMM/TMI(Tropical Rainfall Measuring Mission/TRMM Microwave Image) and lightning activity data are from the TRMM/LIS(Lightning Imaging Sensor) and SAFIR3000(Surveillance et Alerte Founder par Interferometric Radioelectirque).On a spatial ... 相似文献
87.
库米什盆地的硝酸盐型钾盐矿床 总被引:1,自引:0,他引:1
库米什盆地的硝酸盐型钾盐矿床,是利用~(40)K具有放射性特点,通过航空、地面伽玛能谱测量发现的。本文介绍了具有代表性C矿床的一般地质特征,总结了乌尊布拉克硝酸盐型钾盐矿床地质特征。矿床按其赋存状态可分为固体矿和卤水矿两类。水硝碱镁矾为最主要的工业矿物,共生矿物有钾硝石、钠硝石、杂卤石、芒硝、钠镁矾、石膏、石盐、极少量的泻利盐等。 相似文献
88.
Guo XuequanSoutheast Hubei Geological Party Hubei Bureau of Geology Mineral Resources Daye Hubei 《《地质学报》英文版》1994,68(3)
This paper discusses geological-geophysical-geochemical models of such typical deposits as the Tieshan-type Fe-Cu deposit, the Tonglushan-type Cu-Fe deposit, the Yehuaxiang-type Cu deposit, the Jiguanzui-type Cu-Au deposit, and the Tongshankou-type Cu (Mo) deposit. The models were established based on practical data of the polymetallic deposits dominated by copper ore in southeastern Hubei. These models, which are graphically illustrated in the paper, systematically summarize the metallogenic geological conditions and the geophysical-geochemical characteristics of copper deposits in this area. The models are of practical significance for studying copper deposits, predicting mineral resources, choosing exploration methods, and searching for ore deposits based on existing ones in the study area. 相似文献
89.
Huang Liren Zhao Chengkun Hu Huimmg Yang Guiye Cao XiangchunFirst Land Deformation Monitoring Center SSB Tianjin China Surveying Mapping Bureau of Tianjin Municipality Tianjin China 《中国地震研究》1994,(3)
In this paper,a study of the principal characteristics of the ground deformation disasters in the city of Tianjin caused by the Tangshan earthquake is based on the results from the recent remeasurements of the geodetic controlling network of Tianjin and from on-site investigations after the earthquake.These results show that only the ground deformation in the Ninghe and Hangu areas near the epicenter reflect directly the co-seismic crustal stress,while the serious ground deformation and the engineering earthquake damages in the urban districts of Tianjin are controlled to a great extent by the local engineering geological structures,showing a kind of secondary disaster.Several suggestions are also proposed in the paper concerning the counter-measures for reducing the earthquake damage in big cities. 相似文献
90.
Liu Wei An Weiping Zhao XinpmgSetomological Bureau of Shanxi Province Taiyuan China 《中国地震研究》1994,(3)
In this paper,the basic conditions and characteristics of the Datong-Yanggao earthquake are described in detail.The type of the earthquake,the aftershock activity,the earthquake trend,the characteristics of damage are analyzed and discussed.This earthquake belongs to a sequence of earthquake swarm type and is of the concentratedly occurring characteristics of several main shocks in a time sequence,and the aftershock activity was normally attenuated.Because of the unreasonable design of buildings and repeated vibration by several destructive main shocks within a short period,the damage in the high intensity region was aggravated.The analysis and the prediction procedure of the 1991 Datong-Yanggao earthquake(Ms=5.8)are also briefly given. 相似文献