Late Quaternary Slip Rate of the Xiugou Segment,Eastern Kunlun Fault Zone   总被引：1，自引：0，他引：1  

Feipeng Huang  Junjie Ren  Yanwu Lü  Junxiang Zhao 《地球科学进展》2018,33(3):321-332

The Eastern Kunlun fault zone (EKLF) is a large left-lateral strike-slip fault, whose slip rate is meaningful to seismic hazard assessment and geodynamics of the Tibetan Plateau. Previous studies suggested that the late Quaternary average slip rate was stable and uniform (10~13 mm/a) in the central and western segment of the EKLF. But there were a few researches of accurate slip rate in the central segment on the EKLF. Therefore, we focused on an offset and well preserved alluvial fan from Xiugou basin, located in the east of Xidatan-Dongdatan, to make it clear. Moreover, we used high-resolution satellite images and digital elevation model extracted from SPOT7 stereo image pairs to restore the offset alluvial fan, and combined terrestrial cosmogenic nuclides method, including 13 quartz-rich samples from this fan surface, 1 quartz-rich sample from the main active channel bed and 1 ¹⁰Be depth profile from this fan edge to eliminate the ¹⁰Be concentration of inheritance accurately, with 1 optically stimulated luminescence sample to obtain the reliable age of this alluvial fan together. Referring to field observations, this alluvial fan was offset left-laterally by (1 862±103) m, and its age is (76.55±3.20)~(106.37±3.38) ka which can be determined through the actual geologic setting and improving chi-square test. Thus, we used the Monte Carlo method to obtain a left-lateral slip rate of (20.3+3.5/-2.3) mm/a with 68% confidence envelopes since the late Pleistocene in the Xiugou basin. As a result, combining with the results of previous studies, the left-lateral slip rate indicated that the obviously decreasing activity transferred from late Pleistocene to Holocene on the central segment of the EKLF.  相似文献   

Progress in the Application of Ground Gravity Observation Data in Earthquake Prediction     

Jinglun Mao  Yiqing Zhu 《地球科学进展》2018,33(3):236-247

The mechanism of earthquake inoculation and the process of earthquake occurrence are very complicated. Additionally, earthquakes do not happen very often, and we lack enough cognition to the earth’s interior structure, activity regularity and other key elements. As a result, research progress about the theory of earthquake precursors has been greatly restricted. Ground gravity observation has become one of the main ways to study earthquake precursor information in many countries and regions. This paper briefly summarized the surface gravity observation technology and observation network in China: the surface gravity measurement instrument developed from Huygens physical pendulum in seventeenth Century to today’s high-precision absolute gravimeter, and its accuracy reached to ±1×10^-8 m/s². China has successively established the National Gravity Network, Digital Earthquake Observation Network of China,the Crustal Movement Observation Network of China Ⅰ and the Crustal Movement Observation Network of China, to provide a public platform for monitoring non tidal gravity change, seismic gravity and tectonic movement. The use of specific examples illustrated the role of gravity observation data in earthquake prediction. The gravity observation data of ground gravity can be used to capture the information of gravity change in the process of strong earthquake inoculation, and to provide an important basis for the long-term prediction of strong earthquakes. The temporal and spatial variation characteristics of the regional gravity field and its relation to strong earthquakes were analyzed: Before the earthquake whose magnitude is higher than M_S 5, generally there will be a large amplitude and range of gravity anomaly zones. Strong earthquakes occur mainly in areas where the gravity field changes violently. The dynamic change images of gravity field can clearly reflect the precursory information of large earthquakes during the inoculation and occurrence. Finally, the existing problems of surface gravity technology in earthquake precursor observation were put forward and the use of gravity measurement data in earthquake prediction research was prospected.  相似文献   

月表构造与深部构造的关系     

奚镜伦  陈建平 《江苏地质》2018,42(3):481-494

地球和月球很可能是通过大撞击形成的。在行星地质学中,研究月球的地质-构造现象,对了解月球、地球乃至太阳系的形成与演化历史都有很大帮助。月球的构造分为深部构造与月表构造,寻找它们在分布或成因上的关系,可以为月球甚至地月系的起源和演化历史提供重要参考。利用LROC的宽视角影像数据以及LOLA数据提取解译月表构造,结合深大断裂进行观察分析,并对月球的撞击盆地进行统计,最后以静海地区为例分析构造分布特征,发现月球的质量瘤盆地中具有环状分布的月岭,外侧具有近环状分布的深大断裂,自前酒海纪至酒海纪,具备上述特征的质量瘤盆地占总撞击盆地的比例突然有一个很大的提升,且静海地区西部具有该构造分布特征。推测该特征与撞击、月海沉降等有关,且在酒海纪与雨海纪期间月球有较多的月海玄武岩分布,由此判断静海西部存在质量瘤,发生过撞击与月海沉降。  相似文献   

开挖条件下含陡倾结构面顺层岩质边坡破坏模式与稳定性预测     

王章琼  江志红 《中国地质灾害与防治学报》2018,29(1):40-45

顺层岩质边坡易发生失稳破坏,当边坡中发育有顺坡向陡倾结构面时,更不利于边坡稳定。以贵州某水电站大坝左岸含陡倾结构面顺层边坡为例,在综合分析地质条件及开挖扰动的基础上,结合离散元软件UDEC,分析了边坡的变形破坏模式和稳定性。研究结果表明,边坡可能发生的变形破坏模式主要有滑移、拉裂—滑移两种;自然状况下及开挖后,边坡都有沿断层f_9、卸荷裂隙L_1及岩层面发生滑移的趋势,且工程开挖导致边坡沿该结构面发生内部滑动;对边坡采用预应力锚索加固后,变形得到有效控制,位移数值计算值与实际监测值基本吻合。  相似文献   

Generation and Development of Structures and Their Controls on Ore Mineralization in the Lehong Zinc-lead Deposit,Northeastern YunnanEI北大核心CSCD     

Cui J.  Han R.  Wang J.  Ren T.  Wu Y.  Zhao D. 《大地构造与成矿学》2018,(4):664-680

The Lehong zinc-lead deposit is one of the new-found large Zn-Pb deposits in the Sichuan- Yunnan-Guizhou Zn-Pb poly-metallic mineralization area. The ore-bodies of the Lehong deposit are strictly controlled by structures, and the fault tectonites can be divided into four groups which include morbruk rock, cataclastic rock and tectonic breccia. The mechanical properties of the faults suggest that there are five tectonic systems formed in the Caledonian-early Hercynian, Indosinian-early Yanshanian, mid-Yanshanian, late Yanshanian and Himalayan periods, respectively. The Lehong fault and the Qiaojia-Lianfeng fault are two important ore-controlling structures which might have acted as channel ways of the ore fluids. The ores are hosted in the subordinary fracture zone, joint fracture zone and interlayer fault zones in trailing folds of the Lehong fault and the Baobaoshang syncline and Jinjiagou anticline. Hence, the Lehong deposit is a tectonic -controlled ore deposit. These research do not only lay a foundation for studying deposit genesis and ore-finding direction in the Lehong deposit, but also provides important enlightenments for the ore-finding prognosis of lead-zinc deposits in northwestern Guizhou ore concentration district. © 2018, Science Press. All right reserved.  相似文献   

Paleogene Deformation and its Control Mechanism in the Central Part of Raoyang SagEI北大核心CSCD     

Wang Y.  Qi J.  Zheng R.  Miao Q.  Niu X.  Chen S.  Gao Y. 《大地构造与成矿学》2018,(4):628-638

Various Palaeogenic deformations have been recognized in the central part of the Raoyang Sag. Based on seismic interpretation, the sedimentary sequences, structure features and activity of main faults have been studied. The results show that the Xianxian detachment fault, which is located in the eastern boundary of the Raoyang Sag, was still active during the Cenozoic and controlled the basinal deformation. The detachment depth and deformation of the Xianxian detachment fault are discussed based on the area-balance theory. The results reveal that patterns of the Paleogene structures vary considerably from the north to the south. Activity of the main faults in the hanging wall of the Xianxian detachment led to a westward migration of the deposition center. On the other hand, the uplifting of the dome related to the detachment resulted in fast denudation of the overlying sediments in locals. The deformation of detachment fault and activities of the major faults controlled the Paleogene deformation in the central part of the Raoyang Sag. © 2018, Science Press. All right reserved.  相似文献   

2014年夏季长江流域持续性低温的大尺度环流异常          下载免费PDF全文

杜雪婷  陆尔  赵玮 《大气科学学报》2021,44(5):795-803

采用中国地面站气温逐日观测资料、NOAA全球逐日海表温度资料,及NCEP/NCAR的全球日均再分析资料,研究了2014年持续性低温的三维结构及大尺度环流异常。结果表明,2014年的低温异常,除了在陆地上区域性地出现在长江流域,还以大尺度带状的形式、从陆地延伸到海洋上。这种带状异常不只出现在近地面,在大气各层（925～500 hPa）都能看到。分析指出,大气中的这个低温带主要由高纬大气环流异常造成。在位势高度场上,最重要的异常出现在高纬60°N,有呈带状的位势高度正距平,它引导（距平意义上的）偏北气流从正北和东北偏东方向侵入,在其南侧形成一带状的偏低温区。大气各层均呈现出这种在高纬有位势高度正距平、相应地在稍南的低纬（40°N）有位势高度负距平、两者之间为低温区的分布特征。从低层往上,这种配置型式整体表现出由南往北的倾斜,其垂直剖面表现为距平意义上的、大尺度、类似于锋面的倾斜结构。文中用简单的概念模型对此进行理解,认为这种结构是由大气动力异常和热力异常相互影响、共同作用而形成的。  相似文献   

Late Quaternary chironomid community structure shaped by rate and magnitude of climate change     

Roseanna J. Mayfield  Peter G. Langdon  C. Patrick Doncaster  John A. Dearing  Rong Wang  Gaute Velle  Kimberley L. Davies  Stephen J. Brooks 《第四纪科学杂志》2021,36(3):360-376

Much is known about how climate change impacts ecosystem richness and turnover, but we have less understanding of its influence on ecosystem structures. Here, we use ecological metrics (beta diversity, compositional disorder and network skewness) to quantify the community structural responses of temperature-sensitive chironomids (Diptera: Chironomidae) during the Late Glacial (14 700–11 700 cal a bp ) and Holocene (11 700 cal a bp to present). Analyses demonstrate high turnover (beta diversity) of chironomid composition across both epochs; however, structural metrics stayed relatively intact. Compositional disorder and skewness show greatest structural change in the Younger Dryas, following the rapid, high-magnitude climate change at the Bølling–Allerød to Younger Dryas transition. There were fewer climate-related structural changes across the early to mid–late Holocene, where climate change was more gradual and lower in magnitude. The reduced impact on structural metrics could be due to greater functional resilience provided by the wider chironomid community, or to the replacement of same functional-type taxa in the network structure. These results provide insight into how future rapid climate change may alter chironomid communities and could suggest that while turnover may remain high under a rapidly warming climate, community structural dynamics retain some resilience.  相似文献   

测井地质学前世、今生与未来——写在《测井地质学·第二版》出版之时     

赖锦  王贵文  庞小娇  韩宗晏  李栋  赵仪迪  王松  江程舟  李红斌  黎雨航 《地质论评》2021,67(5):67060005-67060005

测井地质学以地质学和测井学的方法理论为指导,综合运用各种测井信息,来解决基础地质和石油地质的地质问题。经过数十年发展,测井地质学在油气勘探开发各个环节得到广泛应用。非常规油气的兴起使得测井地质学正面临多重挑战和全新探索,亟需建立针对非常规油气的测井地质学综合方法理论体系。本文以《测井地质学·第二版》出版为契机,系统归纳了测井地质学的起源及发展历程、主要研究内容和研究方法流程。然后总结了测井资料与地震、地质信息的匹配性,并分析了不同探测特性测井方法纵向分辨率区间特征。在此基础上评述了测井地质学在井旁构造解析、沉积学特征研究、层序地层划分、地应力方向判别及大小计算、井壁裂缝识别与评价、烃源岩评价以及非常规油气“七性关系”综合评价当中的应用。但由于测井资料的负载能力有限性、测井与地质信息属性不对应性以及测井资料本身的多解性,使得测井地质学在测井—地质转换、非常规油气测井评价及其与人工智能融合方面还存在一定的问题。因此加强基础岩石物理研究,挖掘测井曲线中包含的地质信息,并与人工智能相结合,将拓展测井地质学研究的精度和广度,从而使其未来可更好地应用至非常规油气测井评价等实践工作中。  相似文献   

太行山中段城南庄一带隐伏岩体及找矿前景分析     

吴云霞 《地质与勘探》2021,57(2):315-324

麻棚和赤瓦屋岩体都位于太行山中段热液金属矿成矿区内,在其周围已发现石湖石英脉大型金矿等60余处热液型矿床(点),其深部和外围可能存在找矿前景。本文通过探讨太行山中段城南庄一带遥感环形构造和重力负场特征与金属矿床和岩体的耦合关系,从城南庄卫星式-多层蘑菇群式遥感环形构造群、重力负场、中酸性岩脉侵入和温泉五种证据,推测城南庄深部存在比麻棚和赤瓦屋岩体大近六倍、面积约700 km~2的中酸性隐伏岩体—城南庄隐伏岩体。城南庄隐伏岩体边界基本与布格重力负异常边界吻合,呈长轴北东向宽缓带状展布,向南西方向倾伏,北侧埋深较浅、南侧埋深较深。城南庄隐伏岩体边部(特别是产状缓外倾,具有良好成矿空间的区域)和顶部与围岩的接触带位置、环形构造形成的晚期"小岩体"内部及附近位置和中酸性岩脉附近位置是寻找热液型矿床的有利部位。  相似文献