Mesoproterozoic Earthquake Events and Breakup of the Sino-Korean Plate   总被引：3，自引：0，他引：3  

QIAO Xiufu GAO Linzhi PENG Yang 《《地质学报》英文版》2007,81(3):385-397

In the Mesoproterozoic time, the northern part of the Sino-Korean Plate experienced a period of intensive tectonic extension and breakup. 1. An abundance of sedimentary earthquake records is preserved in the Chuanlinggou, Tuanshanzi and Gaoyuzhuang formations in the Mesoproterozoic Changcheng System （1800-1400 Ma） and in the Mesoproterozoic Wumishan Formation of the Jixian System （1400-1000 Ma）. These earthquake records are characterized by various liquefied sand-veins, carbonate microspar and coarser spar veins, limestone dikes, liquefied breccia and various forms of liquefied contorted bedding. This deformation is always associated with synsedimentary faults and igneous activity. 2. Three liquefaction models for soft carbonate sediments are recognized, including liquefaction in laminated carbonate rocks, liquefaction in thin-bedded carbonates and large-scale liquefaction along huge carbonate dikes. 3. Based on the record of earthquake and volcanic activities, the Sino-Korean Plate experienced at least twice intraplate breakups. One occurred between 1800-1400 Ma, and the other occurred at about 1200 Ma. The last breakup resulted in formation of the Yan-Liao aulacogen, a tectonic zone characterized by deeper material vibrancy, active faults, major igneous activity and frequent earthquakes.  相似文献   

公路隧道围岩地质条件评价方法及其富溪隧道应用研究     

朱正国  乔春生  高保彬 《工程地质学报》2007,15(6):789-795

为了达到快速、准确、可靠的围岩分类,有效指导隧道施工,在充分研究和吸取国内外有关围岩分类的经验和成果基础上,针对隧道施工期间的围岩类别鉴定方法,提出了一种可用于隧道施工期间围岩类别鉴定的快速分类方法,该方法以定量与定性相结合、多专家评分的方式在开挖掌子面现场进行观察、量测及评价,无需复杂试验或测量以及繁杂计算,可迅速得出评价结果。为了更加全面地反映隧道围岩情况,准确评价围岩工程性质,结合目前国际上流行的Q分类系统,在富溪隧道第一手实测资料的基础上,根据快速分类结果和Q指标分类结果对富溪隧道围岩条件进行综合评价,为其隧道施工提供了合理的支护参数。  相似文献   

ANALYSIS ON WAVELET POWER SPECTRUM OF WARM AND COLD EVENTS IN THE NI?O REGIONS     

吴迪生  赵雪  冯伟忠  马毅  乔关玉 《热带气象学报(英文版)》2005,11(2):154-160

We statistically analyze the tropical typhoon forming in the South China Sea and use TC (Tropical Cyclone) for short in the following) by typhoon yearbook. The typhoon quantity is very different in different months and years. TC appears in all months except March, and the most TC quantity in a year is 11, the least is 1 and 6.2 on average. The most TC quantity in a month is 5 and the least is 0. TC lands most in August and no TC lands on Chinese continent from December to the following April. The primary landing area is between Shantou and Hainan Island. The sustaining period of TC is usually between 4 days to 7days, and the longest is 19 days. Only 15% of the TC forming in the South China Sea can intensify to typhoon, and they all form in the ocean area deeper than 150m. The South China Sea is the ocean area over which the TC occurs frequently.  相似文献   

广东旅游休闲产业空间布局模式的构建   总被引：2，自引：1，他引：2  

刘少和  张伟强  乔纪纲 《热带地理》2007,27(2):164-169

从大珠三角与其周边地区的地理梯度特征,可见大珠三角在广东地理、经济、文化中的核心地位,其周边地区的边缘地位。这种“核心”与“边缘”或“中心”与“外围”的关系实际上构造了一个相对稳定的旅游系统,前者主要成为旅游客源地,后者主要成为旅游接待地。大珠三角城际在空间上的逐步融合,构成了广东“环大珠三角城市群游憩带”和“点-轴树状游憩网”,以及“南部濒海游憩廊”的旅游休闲产业空间布局模式。  相似文献   

长江三峡库区云阳-巫山段斜坡坡度对滑坡的贡献率   总被引：4，自引：0，他引：4  

乔建平  吴彩燕  田宏岭 《山地学报》2007,25(2):207-211

三峡库区滑坡发育与多种因素相关,在它的内部因子中除了地层、斜坡高差和坡向等重要因素外,斜坡的坡度是一个非常重要的条件。为了研究坡度与滑坡发育的关系,借助于GIS技术,利用贡献率法重点研究了三峡库区斜坡坡度对滑坡发育的影响,并且定量地给出了二者的相关关系,即坡度对滑坡发育的贡献。该方法是将坡度划分为若干区间,分析每一区间对滑坡发育所起到的贡献作用,并定量评价了其贡献率的大小。所得研究结果与实际情况较吻合,为库区的滑坡防治规划提供了依据。  相似文献   

柴达木盆地北缘西端冷湖花岗岩   总被引：1，自引：0，他引：1  

吴才来杨经绥  王志红乔德武李海兵  史仁灯 《地质通报》2001,20(1):73-81

冷湖花岗岩体由花岗闪长岩和二长花岗岩组成，岩体中发育较多的辉绿岩墙和花岗闪长斑岩岩墙。岩石的常量、稀土、微量元素地球化学研究表明花岗岩类和脉岩类为同源岩浆分异演化而成，Rb-Sr、Sm-Nd同位素特征反映其源岩来自地幔。地球化学判别图解得出，冷湖花岗岩类属I型花岗岩，早期的花岗闪长岩形成于岛弧环境，与柴达木板块、南祁连板块的碰撞有关；晚期的二长花岗岩形成于板块碰撞隆起环境，与阿尔金大型走滑断裂的活动有关。  相似文献   

河北矾山钾质碱性超镁铁岩—正长岩杂岩体Sm—Nd年龄和Sr、Nd同位素特征   总被引：13，自引：11，他引：13  

牟保磊  邵济安  储著银  阎国翰  乔广生 《岩石学报》2001,17(3):358-365

河北矾山侵入杂岩,由层状钾质超镁铁岩--正长岩组成,已知它含有大型磁铁矿磷灰石矿床.现在已测定了岩体的岩石和矿物的Sm-Nd同位素资料,并获得了杂岩体的Sm-Nd同位素年龄.4个矿物样品和2个全岩样品Sm-Nd等时线年龄为243.4±9.7Ma,INd=0.512045,εNd(t)=-5.4;4个矿物样品和7个全岩样品等时线年龄为239±19Ma,INd=0.512055,εNd(t)=-5.3.这些年龄资料表明,矾山岩体可能侵位于早三叠.而矾山岩体的Rb-Sr等时线年龄为218±8Ma,Isr=0.70554,εsr=18.4的事实可能暗示矾山岩体在中三叠才完全固结并达到Rb-Sr体系封闭的温度.上述矾山岩体的Sr、Nd同位素特征表明,矾山岩体的物质源自富集的上地幔.  相似文献   

Carbon and strontium isotope variations and responses to sea-level fluctuations in the Ordovician of the Tarim Basin   总被引：2，自引：0，他引：2  

JIANG Maosheng  ZHU Jingquan  CHEN Daizhao  ZHANG Renhu  QIAO Guangsheng 《中国科学D辑(英文版)》2001,44(9):816-823

In the Ordovician, a carbonate platform system grading from the platformal interior eastwards to basin was developed in the Tazhong area of the Tarim Basin, and the study column is located in the place where the paleoslope occurred. The isotope compositions of the carbonates there are thus considered as having reflected those of simultaneous sea waters in view of its good connection with the open seas. The carbon and strontium isotope compositions of the Ordovician carbonates in the Tazhong area are analyzed, and their relationships to the sea-level fluctuations are discussed as well. Studies have revealed that the carbon isotope composition is related positively with the sea-level fluctuations, whereas an opposing situation occurs to the strontium isotope variation. Similar responses of carbon and strontium isotope compositions to the sea-level fluctuations are reported elsewhere in the world, suggesting that the Ordovician sea-level fluctuations of the Tarim Basin were of eustatic implication.  相似文献   

声波在两种多孔介质界面上的反射和透射   总被引：11，自引：1，他引：11       下载免费PDF全文

乔文孝  王宁 《地球物理学报》1992,35(2):242-248

本文导出了声波在两种多孔介质界面上反射、透射的一般计算公式.作为例子,数值计算了P₁波入射于界面时,P₁、P₂和S波的反射、透射系数与声波频率、入射角等量之间的关系.结果表明,各种模式波的反射、透射系数与入射角、多孔介质性质有关,在Biot特征频率附近与频率有关,并用界面两侧的法向能流相等验证了结果的正确性.若把多孔介质当作均匀固体处理,将会得到显著不同的结果.  相似文献   

新疆天山夷平面形态特征浅析   总被引：1，自引：0，他引：1  

乔木  袁方策 《干旱区地理》1992,15(4):14-19

天山广泛发育着三级夷平面,削平了古、中生代多期构造形态及褶皱岩层。天山夷平面是在古华力西褶皱山脉的基础上,在地壳相对稳定的条件下,经中生代,早第三纪的剥蚀夷平,于晚第三纪末至第四纪初新构造运动作用下,被抬升到不同高度,而后受第四纪以来新构造运动的不断作用及天山独特气候条件的影响,使夷平面在垂直方向或水平方向都存在着明显差异,表面发生了一系列变形。  相似文献