仙女山-九畹溪断裂带断层泥石英微形貌特征及其年代学意义

在仙女山-九畹溪断裂带野外地质调查的基础上采集12件断层泥样品,并对样品进行石英碎砾提取和扫描电镜微形貌观察。结果表明,仙女山断裂为一条以粘滑为主的活动断裂,最近一次较大规模的运动发生在中-晚更新世;九畹溪断裂带具有多期活动迹象,早期活动强于晚期,近期强烈活动在上新世至中更新世,为一条以粘滑运动为主的活动断裂。仙女山-九畹溪断裂带所构成的V型断裂组合表现为以仙女山断裂带为主导的构造格局。     

宜昌附近第四纪断层研究的新进展

通过野外地震地质调查，发现：（１）北东向新场—古老背断裂带的地表形迹和更新世多期活动的地层、构造岩证据；（２）近南北向虎牙第四纪断层及其粘滑快速断错的剩余形变特征；（３）北西向天阳坪断裂带南支早第四纪粘滑快速断错的剩余形变特征及其上覆晚更新世末期堆积（１４Ｃ１６４００±４３９年）未受断错所揭示的时间上限约束。     

宜昌葛洲坝库区西南邻域地壳垂直形变

本文通过近10年跨仙女山、天阳坪断裂带上6处短水准垂直形变资料分析,指出:控制葛洲坝库区西南邻域地壳垂直形变的是仙女山断裂;其断层东(下)、西(上)盘升降趋势,受力状态南北地段不一致,且发生明显的反向运动。前5年(1981—1985年),南段的东盘下降,区域力为挤压;北段东盘上升,区域力为拉张,1985年后发生明显的反向运动。库区南侧的天阳坪断裂的东段近期较稳定,西段变化则是受仙女山断层变化的影响,产生同步运动,东西向的区域力对断层两盘的作用一致。1988年12月16日兴山县北发生M_L为3.9级地震,认为与仙女山断层明显的反向运动关系密切,断层运动趋势及其与地震的关系有待今后进一步探索。由于库区西部仙女山断层的活动,能量有所释放,不可能发生大震,因此库区及大坝比较安全。     

神农架断块西缘北北西向板桥断裂带新活动调查研究

北北西向上地壳板桥断裂带位于神农架三角形穹状断块西缘 ,长达 50 km,走向330°,倾向南西 ,倾角 45°～ 85°,具有左旋走滑的新构造运动特征 ,发育宽大的新构造强变形带和断层破碎带 ,切割第四纪断层堆积。其灰黑色断层岩粉年代鉴定值为1 4 C 2 970 0± 60 0 a和 1 890 0± 660a,显示了晚更新世末期的断层新活动。分段性研究将其评定为 6级潜在震源区。     

鲜水河断裂带现今构造形变

本文利用经过拟稳和伪逆平差等方法处理过的大地测量资料,分析了鲜水河断裂带的现今构造形变。表明该断裂带在近东西向区域压应力作用下,呈压性反扭,为典型的蠕滑—粘滑型断裂带。 断裂带蠕动段以水平反扭为主,前兆显示“V字型”异常形态,震后呈对数衰减。在虾拉沱,水平蠕动年速率为7.17±0.03毫米,倾向蠕动年速率为1.04±0.03毫米,两者之比为7:1。在粘结阶段,断裂带闭锁段无明显活动;而快速错动阶段,震中区发生大量级的水平反扭错动(达米级)及其伴随的松驰下沉(达分米级)运动。 现今构造形变和历史大震表明:道孚以北为蠕动段,以南为闭锁段。据此,鲜水河断裂带来来如果发生大震,则危险区可能在南段。     

断裂带形变的分形模型及其应用

用两个相连的“三联点”模拟一条断裂带，在自相似规则下，构造了断裂带内各级断层的分布。引入分形维数，建立了断裂带内各级断层的相对运动速度与断裂带外围（板块或亚板块之间）相对运动速度之间的关系。用圣安德烈斯断裂带的运动数据初步验证了模型给出的断裂带内主断层相对运动速度与板块相对运动速度之间的关系的正确性。引入ｂ值与分维数的关系，获得了由断层相对运动速度计算ｂ值的方法，并得出结论：在板块相对运动速度稳定不变的条件下，主断层相对运动速度的显著增加是断裂带内孕育大地震的中期前兆信息。     

对鄂西仙女山断裂带的几点认识

仙女山断裂带是鄂西一条区域性活动构造。本文利用重、磁资料、人卫象片地质解释和野外地质调查结果,重点对断裂的延伸规模、切割深度和輓近时期的活动性提出了讨论,指出该断裂带是一条基底大断裂,其北段已过长江,是黄陵断块构造的西部边界。由于輓近时期的断裂活动,仙女山断裂是鄂西一条不可忽视的地震构造带。     

焦家断裂带对成矿的制约

焦家金矿田内矿体稳定、规模巨大,勘查深度已超过2000m,探获金金属量已超千吨,是我国重要的金矿产地。矿体严格受NNE向焦家断裂带控制,产状与构造面产状基本一致。从断层岩岩性和构造面表面形态入手,构建了三维构造模型,研究了断层面形态和断层岩岩性差异对成矿的约束作用。系统收集焦家金矿田内500个钻孔地质资料,通过二维三维相结合方式,发现断层岩岩性从浅部向深部发生明显变化,由断层泥渐变为糜棱岩,而上盘矿体数量和蚀变分带也随着断层岩的改变发生明显变化。对构造面进行表面坡度分析,发现矿体主要赋存在表面坡度较小部位,且沿倾向上表面坡度由陡急速变缓部位易于形成厚大矿体。     

长乐-诏安断裂带东支东山段晚更新世活动的年代学证据及其意义

长乐-诏安断裂带是福建沿海的主要活动断裂之一,沿断裂带曾发生多次破坏性地震,是福建省陆域上的主要发震构造。中国东部地区破坏性地震的发生与晚更新世活动断裂有密切联系,因此研究长乐-诏安断裂带在晚更新世的活动具有重要意义。在对福建省东山县最新发现的长乐-诏安断裂东支东山段剖面的野外详细调查的基础上,通过对断层下盘地层和断层上断点以上地层中钾长石光释光测年,确定了长乐-诏安断裂带东支东山段的具体活动时间在(34.8±8.3)～(48.0±3.5)ka之间,显示该断裂至晚更新世晚期仍有活动,属晚更新世活动断裂;通过震级(M)与地震断层位错量(D)经验关系拟合法估算,该断裂的最大发震能力为6.5～7.0级地震。该晚更新世活动断裂的确定和最大震级估算,为长乐-诏安断裂带的活动性提供了确切年代学证据,为东山县地区城市安全评价提供了依据。     

仙女山断裂带北段已过长江

近南北向仙女山断裂带位于湖北宜昌地区西部,是影响葛洲坝和拟建的三峡高坝库区工程稳定性的重要活动构造。因此,它历来引起有关方面的极大关注。据以往地质成果,仙女山断裂带南起五峰县渔洋关,北至秭归荒口,长约100公里。但对该断裂带北延是否过长江众说纷纭。为此,宜昌地区行署地震办公室会同有关单位组成联合考察组,先后于一九八     

Thermohaline structure inhomogeneity associated with polynia at the northern margin of Emery Ice-shelf

Based on the hydrographic data in austral summer during the 22nd Antarctic Expedition of China(2005/2006),some features can be found about the northern margin of Emery ice shelf as follows.The heat content in the surface layer(0-50 m) at the eastern end and the western end of the ice-shelf margin is much higher than that at the middle.The upper mixing-layer depth and the seasonal thermocline depth at the middle of the ice-shelf northern margin are much shallower than those at the both ends.However there is much less difference between the middle and the ends in the bottom layer.The remote sensing photos show that the inhomogeneity in the surface-layer water is closely related to the spatial distribution of the floes and polynia in the area.     

Phylogenetic analysis of cultivable bacteria isolated from Arctic sea-ice

Phylogenetic analysis based on 16S rDNA of 8 strains of cultivable bacteria isolated from Arctic sea-ice was studied.The results showed that strain BJ1 belonged to genus Planococcus,which was a genus of low mole percent G C gram-positive bacteria;strain BJ6 belonged to genus Burkholderia of β-proteobacteria and the rest 6 strain all belonged to γ-proteobacteria,of which strain BJ8 was a species of Pseudoalteromonas,strain BJ2-BJ5 and BJ7 were members of genus Psychrobacter.Phylogenetic analysis also indicated that bacteria of genus Psychrobacter of the isolates formed a relatively independent phylogenetic cluster in comparison with other bacteria belonged to genus Psychrobacter.     

Information for authors

正1 Aims and Scope Advances in Polar Science(APS)is an international,peer-reviewed journal jointly sponsored by the Polar Research Institute of China and the Chinese Arctic and Antarctic Administration.APS is a comprchensive academic journal dedicated to presentation of multi-disciplinary achievements in Arctic and Antarctic expeditions and research.Its primary purpose is to publish achievements in fundamental research,applied     

Advances in Polar Science CONTENTS(Volume 25,2014)

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Guide to Authors： Journal of Mountain Science

<正>AIMS AND SCOPE(Editorial Policy)The Journal of Mountain Science(JMS)is devoted to mountains and their surrounding lowlands-ecoregions of particular global importance,with a particular emphasis on the important highlands/mountains in the world,such as the Tibetan Plateau,the Himalayas,the Alps,the Andes,the Rockies and many other mountain ranges of our planet.     

Journal of Mountain Science(JMS)

<正>The Journal of Mountain Science(JMS),founded in2004,is an international English-language journal on mountain sciences.JMS is supervised by the Chinese Academy of Sciences(CAS),sponsored by the Chengdu Institute of Mountain Hazards and Environment,CAS,published by Science Press China,and distributed by Springer exclusively throughout the world(excluding Mainland China).The JMS is published bimonthly,fulltexted in SpringerLink and CNKI,indexed/abstracted by     

Influence of livestock soil eutrophication on floral composition in the Pyrenees mountains

Livestock behaviour in the Pyrenees includes free grazing and a long resting period that provokes the accumulation of dung and urine in some places,so-called camping areas. The aims of this study were （i） to analyze any change in floral composition,and in nutritional and chemical contents of plants in a livestock camping area; and （ii） to relate the floral composition with soil chemical properties. In a linear transect,five sampling zones were established,from the centre of the camping area to the surrounding Nardus stricta-dominant pasture. The above ground plant biomass and the topsoil were sampled in each zone with 6 replicates per zone. Plant species were classified and weighed to calculate above ground biomass,nutritional and chemical contents,and Shannon diversity and evenness indices. Additionally,soils were sampled in two periods,at the beginning and at the end of grazing period. Soil available nutrients （nitrate,ammonium,phosphorus,potassium,calcium and magnesium）,total nitrogen,organic carbon and pH were measured.
Plant chemical contents （protein,lignin and others） were significantly related to the proportions of grasses,legumes and other plants; so,the protein content is positively correlated with legumes plant biomass while lignin content is negatively correlated with grasses. Both plant and soil nutrients increased linearly towards the centre of the camping area. However,the relationship among plant species richness,diversity and evenness relative to its position along the studied transect was bell-shaped. From the outskirts to the centre of the camping area,plants with low nutrient demand were progressively replaced by those with medium and high nutrients demand and by pioneers.
Nardus stricta-dominant pasture has low plant diversity and plant nutrient content as well as a poor soil nutrient availability. The presence of the camping area introduced patches with more soil nutrients and new species in the large spatial scale. However at a small spatial scale,the strong soil nutrien     

General Table of Contents(Vol.11,2014)

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介绍GPS定位中的几个概念

文章概略介绍了利用卫星进行定位的原理 ;由卫星信号传播、信号接收和SA政策等引起的理论误差 ;给出了多种快速、高精度定位的工作模式和观测点选择的原则 ;列出了将WGS - 84坐标转换为我国坐标的公式及解算参数的具体方法 ,供读者在GPS工作中参考。