＂霍山窗＂地区现代构造应力场研究   总被引：1，自引：1，他引：0  

倪红玉  刘泽民  洪德全  李玲利  郑先进  徐鑫 《中国地震》2012,28(3):294-303

应用Snoke于2009年提出的利用P、SV和SH波的初动和振幅比联合计算震源机制解的方法,得到“霍山窗”地区1980年以来62次中小地震的震源机制解.基于大量的震源机制解资料,根据应力张量平均法反演得到“霍山窗”地区的平均构造应力场;结果表明,其与震源机制参数统计结果一致,表现为近EW向的水平挤压和近NS向的水平拉张作用.计算单个震源机制解力轴与平均应力场主应力轴的差异,即震源机制的一致性参数θ,进而分析θ随时间变化特征及其与华东地区中强震的关系;结果表明,“霍山窗”地区震源机制的一致性参数θ对华东地区相应中强震似有一定的指示意义.  相似文献   

Picoplankton abundance and biomass in the East China Sea during autumn and winter   总被引：1，自引：0，他引：1  

Fengfeng Le  Xiuren Ning  Chenggang Liu  Xiaobo Ni  Qiang Hao 《Oceanology》2012,52(1):48-59

During Nov. 2006 and Feb. 2007, two investigations were carried out to investigate the abundance, carbon biomass, and distribution of picoplankton (Pico) and its relationship to the hydrological regime in the East China Sea (ECS). Pico consisted of three groups of photosynthetic picoplankton (phPico)—Synechococcus (Syn), Prochlorococcus (Pro) and Picoeukaryotes (PEuk)—and heterotrophic bacteria (HBAC). The average abundance of Pro, PEuk and HBAC was lower in autumn than in winter, but for Syn the opposite trend was observed. Water temperature, salinity, and stability of water column influenced Pico distribution in both seasons. Regression analysis showed distinct positive correlations between HBAC and phPico in both seasons. Syn contributed more to phPico in coastal waters, whereas Pro dominanted in the shelf and slope areas. PEuk was the major contributor to carbon biomass. In the Pico community, HBAC was predominant, both in abundance and in terms of carbon biomass. The phenomenon of subsurface chlorophyll maximum (SCM) was observed ubiquitously in the shelf and slope area, and Pico organisms were the major contributors.  相似文献   

Joint Inversion of Crustal Structure with the Rayleigh Wave Phase Velocity Dispersion and the ZH Ratio   总被引：1，自引：0，他引：1  

Jiajun Chong  Sidao Ni  Li Zhao 《Pure and Applied Geophysics》2015,172(10):2585-2600

  相似文献   

Ground Truth Location of Earthquakes by Use of Ambient Seismic Noise From a Sparse Seismic Network: A Case Study in Western Australia   总被引：1，自引：0，他引：1  

Xiangfang Zeng  Jun Xie  Sidao Ni 《Pure and Applied Geophysics》2015,172(6):1397-1407

  相似文献   

Alteration of Antioxidant Response and Expression of Related Genes by Cadmium in Chinese Rare Minnow Larvae          下载免费PDF全文

Zhi‐Hua Li  Yan‐Hua Wu  Ping Li  Yun‐Feng Li  Zhao‐Hui Ni 《洁净——土壤、空气、水》2015,43(5):671-675

  相似文献   

EMD Method Applied to Identification of Logging Sequence Strata     

Ni Zhao  Rui Li 《Acta Geophysica》2015,63(5):1256-1275

In this work, we compare Fourier transform, wavelet transform, and empirical mode decomposition (EMD), and point out that EMD method decomposes complex signal into a series of component functions through curves of local mean value. Each of Intrinsic Mode Functions (IMFs — component functions) contains all the information on the original signal. Therefore, it is more suitable for the interface identification of logging sequence strata.Well logging data reflect rich geological information and belong to non-linear and non-stationary signals and EMD method can deal with non-stationary and non-linear signals very well. By selecting sensitive parameters combination that reflects the regional geological structure and lithology, the combined parameter can be decomposed through EMD method to study the correlation and the physical meaning of each intrinsic mode function. Meanwhile, it identifies the stratigraphy and cycle sequence perfectly and provides an effective signal treatment method for sequence interface.  相似文献   

青岛灵山岛下白垩统风暴岩与风暴沉积的发现及意义^*          下载免费PDF全文

钟建华  倪良田  邵珠福  李勇  刘选  毛毳  刘圣鑫  孙宁亮  陈彬  王凯  罗可  王韶洁  刘闯  刘宝  熊志强 《古地理学报》2016,18(3):381-398

青岛灵山岛中生界下白垩统碎屑岩中发育了很好的风暴岩与风暴沉积,其特点是:(1)丘状、洼状构造及丘状、洼状交错层理经常可见;丘状交错层理呈对称或近对称丘状,一般发育在三角洲前缘暗色薄层状砂泥岩互层中,薄层一般厚1~2,cm,有时也可以更厚;砂岩中常有平行层理或低角度交错层理,也可以发育丘状交错层理;细层较厚,多在1~2,cm,甚至3~4,cm;但砂岩多数呈块状;洼状交错层理相对较少,多不完善;洼状构造则相对多见。(2)冲刷侵蚀面非常发育。多波状起伏或凹凸不平,起伏可达20~30,cm,甚至更大;内部的冲刷侵蚀面常不连续,但底部的冲刷侵蚀面连续性很好。(3)中厚层状砂岩内部的冲刷侵蚀面可以分为多个次级层,但常因冲刷面的不连续而上下合并在一起。(4)砂岩中常含有内碎屑,以暗色泥砾为主,小者直径多在1~2,cm,大者可达10,cm以上,形态多变;长轴多顺层分布;有时集中在砂岩的顶部。(5)以中细砂岩为主,没有真正的砾岩;砂岩的分选性可以较好。(6)发育了大量的多尺度、多类型软沉积物的变形构造。(7)有时候含有炭屑。灵山岛风暴岩和风暴沉积的发现,揭示了这套沉积是在一个相对较浅水的湖泊条件下形成的,而非海洋深水;此外,风暴形成的砂岩下移到三角洲前缘相中,使其更加靠近烃源岩,优化了生储关系,有利于油气成藏。  相似文献   

Pertrogenesis and tectonic implications of the late Jurassic basic rocks from the northern Shi‐Hang zone,Southeast China          下载免费PDF全文

Qing Zhou  Yao–hui Jiang  Shi–yong Liao  Peng Zhao  Ru–ya Jia  Zheng Liu  Guo–chang Wang  Chun–yu Ni 《Island Arc》2016,25(3):235-250

The tectonic setting of the late mesozoic of South China is in a debate between two schools of thought: an intra‐continental rift zone along a passive continental margin or active rifting associated with subduction of the paleo‐Pacific Plate. In this study, we present new sensitive high‐resolution ion microprobe (SHRIMP) U‐Pb zircon ages, along with geochemical data of three basic dikes that cross‐cut the Dexing porphyry copper deposit. The deposit is the largest of its kind in eastern China and part of large scale mineralization associated with Mesozoic magmatic activity in the area. Our results indicate that the dikes were emplaced in the Late Jurassic with an average U‐Pb age of 153.5 ± 2.4 Ma. The intrusions have bulk ε_Nd(t) of ca +0.7 and zircon ε_Hf(t) value of +1.54 to +6.92. Based on relatively enriched light rare earth elements (LREE) and depleted high‐field‐strength elements (HFSE) abundances with pronounced negative Ta–Nb, Hf–Zr and Ti anomalies in multi‐element diagrams, we propose that these dikes were derived from a subduction‐modified lithospheric mantle source. The variability in Hf isotopes identifies some degree of crustal contaminations. Our data support a scenario with a back‐arc extensional setting or an intra‐arc rift environment associated with the westward subduction of the paleo‐Pacific Plate at or prior to the late Jurassic as the most likely cause for these subduction signatures.  相似文献   

Structure,evolution and regional tectonic implications of the Queshan metamorphic core complex in eastern Jiaodong Peninsula of China   总被引：1，自引：0，他引：1  

ZengMing Xia  JunLai Liu  JinLong Ni  TingTing Zhang  XingMing Shi  Yun Wu 《中国科学:地球科学(英文版)》2016,59(5):997-1013

The Queshan MCC is an important example of a crustal extensional structure in the eastern Jiaodong Peninsula along the southeastern margin of the NCC in the Early Cretaceous. The MCC is a typical Cordilleran-type core complex with a three-layered structure: (1) the upper plate is constituted by the Cretaceous supradetachment basin and Paleoproterozoic basement; (2) the lower plate comprises the Neoarchean high-grade metamorphic complexes and late Mesozoic granitic intrusions; and (3) the two plates are separated by a master detachment fault. A series of late NEN-oriented brittle faults superimposed on and destructed the early MCC. Petrology, geometry, kinematics, macro- and micro-structures and quartz c-axis fabrics imply that the MCC has a progressive exhumation history from middle-lower to subsurface level (via middle-upper crustal level) under the nearly WNW-ESE regional extensional regime. We present structural and geochronological evidence to constrain the exhumation of the Queshan MCC from ca. 135 to 113 Ma. Based on the comprehensive analysis of the different patterns of extensional structures in the Jiaodong and Liaodong Peninsula, we have defined the Jiao-Liao Early Cretaceou extensional province and further divided the crustal extension of it into two stages: the first stage was the intense flow of the middle-lower crust and the second stage was the extension of the middle-upper crust. Combining the tectonic setting, the lithosphere thinning in the Jiao-Liao Early Cretaceous extensional province can be considered a typical model for the response of crust-mantle detachment faulting under regional extension in East Asia.  相似文献   

春季东亚副热带西风急流的变化特征及其与中国沙尘天气的关系     

刘生元  王金艳  王式功  尚可政  倪江波 《中国沙漠》2015,35(2):431-437

利用欧洲中期天气预报中心(European Centre for Medium-Range Weather Forecasts, ECMWF)提供的ERA-Interim全球大气再分析资料及1980-2012年中国北方逐月沙尘暴发生日数资料, 研究了春季东亚副热带西风急流(70°-120°E)的变化特征及其与中国春季沙尘天气之间的关系。结果表明:1980-2012年春季中国上空急流轴存在北移的趋势, 急流中心略向东移, 急流相对强度随年份增强, 与春季沙尘暴发生总站日数的年际变化呈显著负相关。春季沙尘暴多发年, 东亚副热带西风急流有所减弱, 而在哈萨克斯坦东部、蒙古国、中国内蒙古大部分地区及南疆地区等沙尘源地, 200 hPa纬向风速增大; 500、850 hPa风速、位势高度差值场的分布都有利于中国沙尘源地地面风速增大。在中国沙尘源地, 高层西风风速增大, 动量下传, 引起地面大风, 从而容易产生沙尘暴。  相似文献