中国东部陆缘中区第三纪构造-火山事件及其对含油气盆地的控制   总被引：3，自引：2，他引：3  

宋维海  张兴洲  王璞珺 《吉林大学学报(地球科学版)》2003,33(4):479-484

中国东部陆缘中区第三纪主要发育5期构造-火山事件高峰，分别发生在58～46Ma、38～36Ma、26～24Ma、20～16Ma、8～4Ma。形成的火山岩岩性相对单一，主要为玄武岩，大量隐伏于新生代含油气断陷盆地中，这与裂谷作用有关，而野外露头区只发育古新世、中新世和上新世火山岩。研究表明，火山作用伴随着盆地发育的全过程。成盆早期的火山岩代表着裂谷作用的开始。成盆中期火山活动相对强烈，不但形成大量火山岩，而且也是盆地生油岩发育的主要时期。盆地形成后期火山作用微弱。新生代火山作用的中心往往成为成盆中心和油气聚集区。  相似文献   

Late Cenozoic deformation subsequence in northeastern margin of Tibet --Detrital AFT records from Linxia Basin   总被引：4，自引：0，他引：4  

郑德文  张培震  万景林  李传友  曹继秀 《中国科学D辑(英文版)》2003,46(Z2)

Two events of Tibet uplifting are revealed by detrital apatite fission track (AFT) age data from Linxia Basin. They occurred at about 14 and 5.4-8.0 MaBP respectively. We interpret the first one to be related to the uplifting of the northern Tibet, which might have resulted from convectively removing the thickened lower lithosphere. The second one is a result of Laji Mountain uplifting. Numerous studies of the Tibetan Plateau suggest that the onset time of the deformation in the northeastern margin of Tibetan Plateau and the time of Tibet attaining to its present elevation is about 8 MaBP. They are approximately coincident with the uplift of Lajishan Mountain. It suggests that the northeastern margin of Tibet propagated northeastwardly to its present site in about 8 MaBP for accommodating the sustained convergence between India-Eurasia plate and for keeping its high elevation. The active block pattern dominating the strong earthquake distribution of Chinese continent probably formed at about 8.0-5.4 MaBP.  相似文献   

Caledonian Low-Temperature Granulite-Facies Metamorphism in the West Kunlun Orogenic Belt—SHRIMP Chronological Evidence from Zircon     

Zhang Chuanlin  Shen Jialin  Wang Aiguo  Zhao Yu  Guo Kunyi  Li Chunhai 《中国地球化学学报》2003,22(4):345-351

The West Kunlun orogenic belt is located at the conjunction of the paleo-Asian tectonic system and the Tethys tectonic system. Petrological and mineralogical studies of the Early Cambrian metamorphic surface crust in this region have shown that in case the metamorphism reached low-temperature granulate facies, the typical mineral assemblage is biotite-garnet-silimanite-K feldspar-plagioclase-quartz. The peak metamorphic temperatures are within the range of 720–740°C and the pressure is 0.6 GPa ±. Three types of metamorphic zircon have been detected in the metamorphic rocks: the complex inclusion-bearing type ; the early relic zircon inclusion-bearing type; and the inclusion-free type. SHRIMP age determination of these three types of metamorphic zircon have revealed that these zircons were formed principally during 400–460 Ma, indicating that pre-Cambrian metamorphic surface crust rocks underwent low-temperature granulite facies metamorphism during the Caledonian. In combination with the geological characteristics of this region, it is considered that when the oceanic basin was closed, there occurred intense intracontinental subduction (type A), bringing part of the Early Cambrian metamorphic basement in this region downwards to the lower crust. Meanwhile, there were accompanied with tectonic deformation at deep levels and medium- to high-grade metamorphism. This study provided important chronological and mineralogical evidence for the exploration of the evolutionary mechanism and process of the West Kunlun Early Paleozoic. Part of the results from the research project “ Research on the West Kunlun pre-Cambrian tectonic events” under the program “ Research on the important geological problems of China’ s pre-Cambrian” (No. 200113900070) sponsored by the China National Geological Surveying Bureau.  相似文献   

Origin and tectonic significance of a Mesozoic multi-layer over-thrust system within the Yangtze Block (South China)   总被引：21，自引：0，他引：21  

Dan-Ping Yan  Mei-Fu Zhou  Hong-Lin Song  Xin-Wen Wang  John Malpas 《Tectonophysics》2003,361(3-4):239-254

In the Yangtze Block (South China), a well-developed Mesozoic thrust system extends through the Xuefeng and Wuling mountains in the southeast to the Sichuan basin in the northwest. The system comprises both thin- and thick-skinned thrust units separated by a boundary detachment fault, the Dayin fault. To the northwest, the thin-skinned belt is characterized by either chevron anticlines and box synclines to the northwest or chevron synclines to the southeast. The former structural style displays narrow exposures for the cores of anticlines and wider exposures for the cores of synclines. Thrust detachments occur along Silurian (Fs) and Lower Cambrian (Fc) strata and are dominantly associated with the anticlines. To the southeast, this style of deformation passes gradually into one characterized by chevron synclines with associated principal detachment faults along Silurian (Fs), Cambrian (Fc) and Lower Sinian (Fz) strata. There are, however, numerous secondary back thrusts. Therefore, the thin-skinned belt is like the Valley and Ridge Province of the North American Applachian Mountains. The thick-skinned belt structurally overlies the thin-skinned belt and is characterized by a number of klippen including the Xuefeng and Wuling nappes. It is thus comparable to the Blue Ridge Province of Appalachia.The structural pattern of this thrust system in South China can be explained by a model involving detachment faulting along various stratigraphic layers at different stages of its evolution. The system was developed through a northwest stepwise progression of deformation with the earliest delamination along Lower Sinian strata (Fz). Analyses of balanced geological cross-sections yield about 18.1–21% (total 88 km) shortening for the thin-skinned unit and at least this amount of shortening for the thick-skinned unit. The compressional deformation from southeast to northwest during Late Jurassic to Cretaceous time occurred after the westward progressive collision of the Yangtze Block with the North China Block and suggests that the orogenic event was intracontinental in nature.  相似文献   

天气学和天气预报的研究进展   总被引：14，自引：4，他引：14       下载免费PDF全文

陶诗言  赵思雄  周晓平  纪立人  孙淑清  高守亭  张庆云 《大气科学》2003,27(4):451-467

全面回顾了75年来中国科学院大气物理研究所科研人员在气团、锋面、梅雨、寒潮、阻高、副高、暴雨、高低空急流、亚澳季风区内涡旋和对流等现象的天气学研究进展及其在不同时期所取得的研究成果,总结了在短中期天气预报及短期气候预测领域在模式发展和改进以及在数值模拟等方面所取得的成就和进展.同时指出模式发展和预测在中国数值天气预报及短期气候预测方面所做出的贡献.  相似文献   

广西异常暴雨天气事件之异常指数初探   总被引：3，自引：1，他引：3       下载免费PDF全文

高安宁  陈业国  吴兴国 《气象》2003,29(1):46-48

对广西异常暴雨天气事件之“异常指数”的设置进行了初步探讨，提出暴雨天气事件中过程日最大暴雨范围，过程持续时间，过程强降雨，特强降雨发生范围等四项异常分指数，然后统计同一过程分指数之和，得总指数，在此基础上分别选出了4－10月各月广西异常暴雨天气事件。  相似文献   

2002年北半球大气环流特征及其对中国气候异常的影响   总被引：1，自引：0，他引：1       下载免费PDF全文

艾子 《气象》2003,29(4):24-27

2002年春末夏初一次新的厄尔尼诺事件形成；1～12月北半球大气环流的主要特征表现为：中纬度地区纬向环流盛行，西太平洋副热带高压持续偏强偏西，我国大部地区气温偏高，降水呈南多北少分布；欧亚地区夏季500hPa位势高度距平场上，中高纬从西到东呈现为“ - ”分布形式，贝加尔湖地区为正距平中心，7月在贝加尔湖地区出现典型阻高；东亚夏季风偏强，南亚夏季风及热带对流指数偏弱；夏季赤道辐合带偏弱等。在上述大气环流的影响下，我国的天气气候发生了异常。  相似文献   

柴达木盆地沙尘暴气候特征及其预报   总被引：3，自引：2，他引：3       下载免费PDF全文

苟日多杰 《气象科技》2003,31(2):84-87

利用1961～2000年柴达木盆地11个气象站的沙尘暴观测资料，分析了柴达木盆地沙尘暴天气的时空分布特征。根据1980～2000年3月至5月的40次沙尘暴天气个例，从高空环流形势、地面冷空气路径、影响因子及其预报指标4个方面进行分析，总结出柴达木盆地春季沙尘暴天气的预报方法。  相似文献   

中国东北地区地表干湿状况的变化及趋势分析   总被引：34，自引：4，他引：34       下载免费PDF全文

孙力  沈柏竹安刚 《应用气象学报》2003,14(5):542-552

利用1961~2000年中国东北地区80个测站的月降水和平均气温资料，通过计算地表最大潜在蒸发、地表干燥度指数和地表水分盈亏量，分析了东北地区及其7个不同气候区域地表干湿状况的时空分布规律及其变化趋势，并探讨了它与降水和气温的关系。结果表明，东北地区及其不同区域的地表干湿状况不仅具有较大的地域差别和年际及年代际变率，而且存在着明显的阶段性和低频变化特征，特别是20世纪90年代中期以来，东北地区呈现出较强的变干倾向，并且由于气温升高所导致的潜在蒸发的加大与降水一样对这一变干倾向也有十分重要的影响。  相似文献   

广西2002年度气候特点及其影响评价     

李艳兰  黄雪松  罗莹 《气象研究与应用》2003,24(1):26-32

2002年度(2001年12月～2002年11月),广西各地平均气温17.1～23.5℃,大部地区偏高0.3～1.2℃。年度降水量1035.0～2897.1mm,桂东大部偏多1～4成,桂西大部正常。日照时数1019～2323h,大部地区偏少10～412h。2002年度主要气候事件以春旱、暴雨洪涝、热带气旋、寒露风较为突出,年度内气候条件对各行业的影响有利有弊。  相似文献