Correlation Fractal and Multifractal Characteristics of Seismic Activity in the Taiwan Area, China   总被引：2，自引：0，他引：2  

XU Jiandong  HUANG Jianf  WEI Fuquan  YAN Yunpeng  LI Yaping  LIN Chien-te Institute of Geology  China Earthquake Administration  Beijing  Chin  Earthquake Administration of Fujian Province  Fuzhou  Fujian  China China Aero Geophysical Survey  Remote Sensing for Land  Resources  Beijing  China Leader University  Tainan  Taiwan  China 《《地质学报》英文版》2005,79(2):225-232

Based on the analysis of newly collected data of plate tectonics, distribution of active faults and crustal deformation, the Taiwan area is divided into two seismic regions and six seismic belts. Then, correlation fractal dimensions of all the regions and belts are calculated, and the fractal characteristics of hypocenteral distribution can be quantitatively analyzed. Finally, multifractal dimensions Dq and f(α) are calculated by using the earthquake catalog of the past 11 years in the Taiwan area. This study indicates that (1) there exists a favorable corresponding relationship between spatial images of seismic activity described with correlation fractal dimension analysis and tectonic settings; (2) the temporal structure of earthquakes is not single but multifractal fractal, and the pattern of Dq variation with time is a good indicator for predicting strong earthquake events.  相似文献   

Geochemical Information Indicating the Water Recharge to Lakes and Immovable Megadunes in the Badain Jaran Desert   总被引：1，自引：0，他引：1  

CHEN Jiansheng  ZHAO Xi  SHENG Xuefeng  Wang Jiyang  GU Weizu  and CHEN Liang State Key Laboratory of Hydrology-Water Resources  Hydraulic Engineering  Hohai University  Nanjing  Jiangsu  E-mail: jschen@hhu.edu.cn Institute of Isotope Hydrology Research  Hohai University  Nanjing  Jiangsu Institute of Geology  Geophysics  Chinese Academy of Sciences  Beijing 《《地质学报》英文版》2005,79(4):540-546

1 Introduction The Badain Jaran Desert, located in western Inner Mongolia, China, has a unique landscape containing 144 lakes (72 of which are still watery) with a total water area of about 23 km2, and the world’s highest stationary sand dunes with a height between 200 m and 500 m. Much attention has been paid to the water recharge of the desert in the past decade. Investigations on the resources of water system there have been performed continuously since the early 1990s, which lead to th…  相似文献   

Structure Refinement of Cs-rich Na-Li Beryl and Analysis of Its Typomorphic Characteristics of Configurations     

LIU Yan  DENG Jun  LI Guowu  SHI Guanghai  State Key Laboratory of Geological Processes  Mineral Resources  China University of Geosciences  Beijing Key Laboratory of Lithosphere Tectonics  Lithoprobing Technology of the Ministry of Education  China University of Geosciences  Beijing Laboratory of Single-Crystal X-Ray Diffraction  China University of Geosciences  Beijing 《《地质学报》英文版》2007,81(1):61-67

1 Introduction Natural beryl is an accessory mineral mainly in pegmatite, partly in some highly diffractionated granite or metamorphic rocks, with the crystal shapes beingprismatic, or occasionally tabular. For tabular beryl found in pegmatite it is believed that the tabular configuration is connected with alkali metals (Bieus, 1960; Wang et al., 1981) and geneses of the tabular configuration have been reported before. In recent years, tabular beryl has been found in the Xuebaoding W-Sn-Be d…  相似文献   

Organic Carbon Isotopic Evolution during the Ediacaran-Cambrian Transition Interval in Eastern Guizhou, South China： Paleoenvironmental and Stratigraphic Implications   总被引：5，自引：2，他引：3  

YANG Xinglian ZHU Maoyan GUO Qingjun ZHAO Yuanlong 《《地质学报》英文版》2007,81(2):194-203

Secular variations of carbon isotopic composition of organic carbon can be used in the study of global environmental variation, the carbon cycle, stratigraphic delimitation, and biological evolution, etc. Organic carbon isotopic analysis of the Nangao and Zhalagou sections in eastern Guizhou reveals a negative excursion near the Precambrian-Cambrian boundary that correlates with a distinct carbonate carbon isotopic negative excursion at this boundary globally. Our results also demonstrate that several alternating positive and negative shifts occur in the Meishucunian, and an obvious negative anomaly appears at the boundary between the Meishucunian and Qiongzhusian. The isotope values are stable in the middle and lower parts but became more positive in the upper part of the Qiongzhusian. Evolution of organic carbon isotopes from the two sections in the deepwater facies can be well correlated with that of the carbonate carbon isotopes from the section in the shallow water facies. Integrated with other stratigraphic tools, we can precisely establish a lower Cambrian stratigraphic framework from shallow shelf to deep basin of the Yangtze Platform.  相似文献   

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   

南岭西段花山-姑婆山A型花岗质杂岩带:岩石学、地球化学和岩石成因   总被引：40，自引：4，他引：36  

朱金初张佩华  谢才富张辉　杨策 《地质学报》2006,80(4):529-542

花山-姑婆山花岗质杂岩带由同安、花山、牛庙、金子岭、乌羊山、里松和姑婆山等岩体所组成,岩性为闪长岩、石英二长岩、二长花岗岩和正长花岗岩等,富含中基性暗色包体,主要侵位时代为160～163 Ma.岩带以富碱,高钾,富含Rb、K、Ba、Pb等大离子半径亲石元素(LILE)及富含Th、U、REE、Y、Nb、Ta、Zr、Hf等高场强元素(HFSE)为主要特征.中酸性主岩和暗色包体的ISr值分别在0.70501～0.70742和0.70473～0.70570范围内,εNd(t)值分别在-0.37～-3.21和-0.47～+1.94范围内.这是一个以地幔物质略占优势的A1亚型花岗质杂岩带,其源区物质可能主要是经过交代和富集的具有OIB型微量元素特征的岩石圈地幔和下地壳.在后造山阶段大陆地壳拉张减薄的构造环境下,软流圈地幔沿超壳深断裂的上涌和底侵,导致了强烈的壳幔相互作用,源区物质不同程度、不同深度和多批次的熔融,以及硅酸盐熔浆不同程度的分离结晶和地壳混染,是形成岩带中不同类型中酸性岩浆岩的主要机制.  相似文献   

塔里木北部周缘前陆盆地早二叠世快速迁移与沉积相突变:俯冲板片拆沉的响应   总被引：6，自引：0，他引：6  

张传恒  杜维良  刘典波  汪剑  王梦华 《地质学报》2006,80(6):785-791

塔里木北部周缘前陆盆地发育于泥盆纪末至早三叠世期间,完整地记录了南天山造山带的发育过程。该盆地在早二叠世由复理石盆地转化为磨拉石盆地,同时发生快速南移。同期幔源物质加入,有山根地壳熔融的岩浆活动、南天山造山带的整体隆升、热液成矿作用集中发育和变形、变质作用的激化使俯冲岩片的拆沉成为盆地转化与迁移的最佳机制。相同的转化过程及深部机制在其他造山带中也明显存在,表明俯冲岩片拆沉是造山作用一个不可或缺的环节。  相似文献   

南岭东段龙源坝复式岩体La-ICP-MS锆石U-Pb年龄及其地质意义   总被引：19，自引：0，他引：19  

张敏  陈培荣  黄国龙  谭正中  凌洪飞  陈卫锋 《地质学报》2006,80(7):984-994

龙源坝岩体是南岭花岗岩体群的一个重要组成部分,位于南岭东段,研究程度十分薄弱,至今未见可靠的同位素年龄报道。本文在运用阴极发光技术对岩体中的锆石进行细致的内部结构分析的基础上,利用La-ICP-MS锆石U-Pb原位定年方法进行了同位素年龄测定。结果表明,龙源坝岩体是一个印支期—燕山期多期次岩浆侵入形成的复式岩体,其中主体形成于印支期,尤其是印支早期。印支早期花岗岩的单颗粒锆石U-Pb年龄为241.0±5.9Ma和241.0±1.3Ma(两个样品),印支晚期花岗岩为210.9±3.8Ma,燕山期正长岩为149.4±1.2Ma。龙源坝岩体在时代和成因上不同于其东侧的陂头岩体,但相同于北侧的诸广山岩体有亲缘关系,因此在探讨该区的铀成矿前景时,应把诸广山与龙源坝两岩体整合起来考虑,并加强对龙源坝岩体的铀矿找矿工作。  相似文献   

A Nonlinear Model of Surf Beat     

Nicholas Dodd 《中国海洋工程》1995,(2)

A nonlinear short-wave-averaged (surf beat) model is presented. The model is based on that of Roelvink (1993), but the numerical techniques used in the solution are based on the so-called weighted-averaged flux (WAF) method (eg Watson et al., 1992), with time-operator splitting used for the treatment of some of the source terms. This method allows a small number of computational points to be used, and is particularly efficient in modelling breaking long waves. The short-wave (or primary-wave) energy equation is solved using a more traditional Lax-Wendroff technique. Results of validation indicate that the model performs satisfactorily in most respects.  相似文献   

珠江口滨海湿地退化现状、原因及保护对策   总被引：1，自引：0，他引：1  

李团结  马玉  王迪  王爱军  周英 《热带海洋学报》2011,(4)

2007年和2008年秋季对珠江口滨海湿地进行了环境现状综合调查,结果表明,珠江口滨海湿地退化主要表现在4个方面:天然湿地面积减少、湿地生产力不断下降、湿地环境状况持续恶化和湿地景观破碎化。珠江口滨海湿地退化的原因主要为滩涂开发与围填海、污染物排放、养殖污染、海平面上升、过度捕捞、海砂开采和港口码头建设以及水土资源开发等因素。滨海湿地保护与利用对策主要有:制定有关滨海湿地保护的法律法规和湿地保护与利用规划;加强人才队伍建设和滨海湿地有关技术研究;建立滨海湿地动态监测体系;加大滨海湿地保护区建设的力度;加强宣传和教育。  相似文献