Sub-seismic scale fracture pattern and in situ permeability data in the chalk atop of the Krempe salt ridge at Lägerdorf, NW Germany: Inferences on synfolding stress field evolution and its impact on fracture connectivity     

Fabrizio Storti  Fabrizio BalsamoFederico Cappanera  Giambattista Tosi 《Marine and Petroleum Geology》2011,28(7):1315-1332

Chalk is exposed in the Heidestrasse quarry at Lägerdorf, at the top of the NE-SW trending Krempe salt ridge. Structural data indicate the presence of two joint sets, striking almost parallel and perpendicular to the salt ridge, respectively, and of a set of conjugate extensional faults and fault zones striking NW-SE, i.e. almost perpendicular to the salt ridge. Within the overall NW-SE trend of joints and faults, strike variations occur from the massive chalk exposed in the lower half of the quarry, to the overlying layered chalk. A large variability characterizes the normalized spacing of both joint sets, which does not show any clear trend with layer dip. In situ measurements indicate that the cross-sectional permeability of tight joints increases 1-2 orders of magnitude with respect to the undeformed chalk. We propose that joint and fault azimuthal variability resulted from changes through time of the stress ellipsoid at the top of the salt ridge, while joint spacing variability is associated with the weak mechanical influence of bedding in chalk. Azimuthal variability improves fracture connectivity and, hence, permeability and fluid flow.  相似文献   

Choppy waters ahead in “a sea of peace cooperation and friendship”?: Slow progress towards the application of maritime joint development to the East China Sea     

Clive H. Schofield  Ian Townsend-Gault 《Marine Policy》2011

China and Japan’s June 2008 agreement in principle on maritime cooperation in the East China Sea raised hopes of a significant breakthrough in the parties' complex and long-standing disputes in the area. Subsequent progress towards the realisation of a legally binding, formal treaty on, for example, offshore petroleum joint development has been slow to materialise. In fact, the area under dispute appears to have become more rather than less extensive. This paper examines competing maritime and sovereignty claims in the East China Sea together with progress towards maritime cooperation in the context of overlapping jurisdictional claims. The paper identifies some of the key challenges that need to be overcome in realizing a functioning joint resource management regime in the East China Sea.  相似文献   

Urban spatial development and land use in Beijing: Implications from London’s experiences     

TAN Minghong  GUY M. Robinson  LI Xiubin 《地理学报》2011,21(1):49-64

Beijing is facing a huge challenge to manage the growth of its built-up area whilst also retaining both productive arable land and land for conservation purposes in order to simultaneously realize the three aims of economic development, protecting arable land and generating environmental improvements. Meanwhile, London, as a world city with more than 200 years of industrialization and urbanization, has accumulated rich theoretical and practical experiences for land use planning in a major urban area, such as the creation of Garden Cities, a designated Green Belt and New Towns. This paper firstly analyzes the main characteristics of the spatial distribution of the built-up area, arable land and conservation land in Beijing. Then, some of the key aspects of urban fringe planning in the London region are examined. Lastly, several implications from the experience of London are provided with respect to land-use planning for Beijing, concentrating on a re-appraisal of land-use functions around Beijing, measures to improve the green belt, the development of small towns to house rural-urban migrants and urban overspill, and effective implementation of land-use planning.  相似文献   

钦-杭结合带硅质岩的分布特征及其地质意义   总被引：3，自引：0，他引：3  

李红中  周永章  杨志军  高乐  何俊国  梁锦  曾长育  吕文超 《地学前缘》2015,22(2):108-117

钦州—杭州(钦-杭)结合带位于中国东南部地区,跨越浙江、江西、湖南、广东和广西5省(区)。大致以南岭为界,该带可划分为北、中、南三段。中段与南岭带重合,大致分布在北纬24°~27°范围,以北为北段,包括江西、浙江及安徽南部,以南为南段,包括粤西桂东南地区。钦-杭结合带跨带内沉积硅质岩广泛发育,地质和地球化学证据展示它们主要为热水成因。硅质岩相关的热水活动分布偏向于靠近结合带的两侧。钦-杭结合带"北、中、南"三段的硅质岩时空分布存在明显差异:南段及两侧邻区大规模热水活动集中于晚古生代,中段及两侧邻区的集中于早古生代,北段及邻区的热水活动集中于元古宙。这种大规模热水活动自北向南逐渐变新的特点与钦-杭结合带分段演化具有较好的对应关系。作为热水活动地质遗迹的硅质岩,其形成与大地构造与地球动力学背景的演化有密切的关系,特别是与钦-杭结合带的几个拉张阶段存在较好的对应关系。富含硅质的热水活动伴随了丰富的成矿作用,热水喷流沉积型块状硫化物矿床和热水沉积型金矿在该构造带内均较为典型。  相似文献   

南秦岭略阳鱼洞子岩群磁铁石英岩形成时代的锆石U-Pb年代学约束   总被引：1，自引：0，他引：1  

王洪亮  徐学义  陈隽璐  闫臻  李婷  朱涛 《地质学报》2011,85(8):1284-1290

鱼洞子杂岩是秦岭造山带出露的重要太古宙基底,也是该地区最古老的复杂地质体.鱼洞子杂岩主要由变质地层(鱼洞子岩群)和规模不等的花岗质变质侵入体(花岗片麻岩)组成.各地质体间多以构造面理接触.鱼洞子岩群是重要的铁矿产出层位,铁矿及其赋矿围岩的形成时代一直没有可靠的依据.本次选择小沟山矿区磁铁石英岩分选出大量锆石.CL影像特...  相似文献   

扬子东部冶山和山里陈埃达克质侵入岩年代学与地球化学:岩石成因和动力学意义   总被引：3，自引：0，他引：3  

资锋  王强  刘新华  邱华宁 《矿物学报》2011,31(2):185-200

冶山和山里陈岩体构造上属于扬子地块东部,毗邻郯庐断裂带东侧,主要岩石类型为石英闪长玢岩。它们的单矿物(角闪石,黑云母)40Ar/39Ar坪年龄分别为131.22±0.77 Ma和130.07±0.48 Ma。冶山和山里陈岩体具有与埃达克岩类似的地球化学特征,如w(SiO2)>56%,高Al2O3[w(Al2O3)=14.95%～17.67%]、Sr[w(Sr)=495×10-6～2086×10-6]、Sr/Y(44～159)和La/Yb(26～68),低重稀土元素,如w(Yb)=0.82×10-6～1.56×10-6),w(Y)=9.14×10-6～20.32×10-6,无明显-正Eu异常(δEu=0.90～1.11)。另外,样品普遍具有较高的MgO[w(MgO)=2.01%～4.98%]、IMg(45～71)和Cr[w(Cr)=19.2×10-6～199×10-6]、Ni[w(Ni)=13.8×10-6～58.8×10-6]。它们的Sr-Nd-Pb同位素特征为:(87 Sr/86 Sr)i=0.7059～0.7062,εNd(t)=-14.75～-12.15,(206 Pb/204 Pb)t=16.082～16.847,(207 Pb/204 Pb)t=15.303～15.461,(208Pb/204Pb)t=35.889～36.919。冶山和山里陈埃达克质侵入岩可能是由于扬子与华北地块在三叠纪的碰撞及扬子地块东部的地壳拆离作用,导致下地壳增厚并发生拆沉熔融,岩浆在上升过程中与地幔橄榄岩发生了反应。郯庐断裂带两侧早白垩世时期的埃达克(质)岩可能形成于断裂带早白垩世时期由左行平移向伸展活动转变的阶段,其源动力很可能是受到滨太平洋板块构造的影响。  相似文献   

基于广义的炮偏移方法实现地表多次波和一次波联合成像   总被引：4，自引：4，他引：0       下载免费PDF全文

郭书娟  李振春  仝兆岐  马方正  叶月明 《地球物理学报》2011,54(4):1098-1105

多次波是地下反射层的多次波反射,也蕴含了地下反射界面的信息,因此并不是绝对地只能被当做噪音来处理.为实现对地下构造的准确成像,本文基于广义概念上的炮偏移成像算法,对常规一次波偏移方法从用于向下延拓的上、下行场以及成像条件方面进行了改进,将同时含有表层多次波的炮记录与脉冲震源之和作为下行延拓的震源波场,将同时含有表层多次...  相似文献   

Determination of gravity anomaly at sea level from inversion of satellite gravity gradiometric data   总被引：1，自引：0，他引：1  

Mehdi Eshagh  Lars E. Sjberg 《Journal of Geodynamics》2011,51(5):366-377

Gravity gradients can be used to determine the local gravity field of the Earth. This paper investigates downward continuation of all elements of the disturbing gravitational tensor at satellite level using the second-order partial derivatives of the extended Stokes formula in the local-north oriented frame to determine the gravity anomaly at sea level. It considers the inversion of each gradient separately as well as their joint inversion. Numerical studies show that the gradients T_zz, T_xx, T_yy and T_xz have similar capability of being continued downward to sea level in the presence of white noise, while the gradient T_yz is considerably worse than the others. The bias-corrected joint inversion process shows the possibility of recovering the gravity anomaly with 1 mGal accuracy. Variance component estimation is also tested to update the observation weights in the joint inversion.  相似文献   

额尔齐斯碰撞带东段结构与形成时代   总被引：2，自引：1，他引：1  

洪涛  相鹏  游军  张连昌  吴楚  吴琪  徐兴旺 《岩石学报》2015,31(2):571-593

阿尔泰地体与萨吾尔岛弧之间的额尔齐斯碰撞带其结构与形成时代是中亚造山带构造演化研究的热点问题之一。本文报道了额尔齐斯碰撞带东段结构与形成时代的研究结果。新的结果显示:额尔齐斯碰撞带东段由4个走向NWNNW陡立的韧性变形带组成,剖面上呈扇状挤压变形的结构;这4个韧性变形带的应变类型为收缩应变与平面应变;片理带的变形从宏观到微观都表现出对称的结构,不同变形带不同地段可具变化的流动方向而表现出"奶油饼结构",其可能整体形成于共轴挤压机制;玉勒肯与老山口韧性变形带花岗闪长质糜棱岩、花岗闪长质超糜棱岩中变质重结晶锆石U-Pb定年结果显示韧性变形时间约为360Ma。这可能意味着早石炭世时卡拉先格尔地区已进入碰撞阶段,即萨吾尔岛弧与阿尔泰地体间在360Ma时已发生碰撞。  相似文献   

秦岭-大别-苏鲁印支造山带连接枢纽的形成时代——来自宁陕断裂带同构造花岗岩锆石U-Pb年代学的限定   总被引：1，自引：0，他引：1  

李源  许志琴  裴先治  张健  赵佳楠  张岚  武勇 《岩石学报》2015,31(12):3595-3608

最新的研究表明,南秦岭勉略缝合带可以经宁陕左行走滑断裂带与大别苏鲁的高压/超高压变质带相连。对于这个模型,两带间的"连接枢纽"—宁陕走滑断层的活动时间是关键问题之一。研究显示宁陕断裂带是南秦岭中的一条走向近E-W的走滑剪切带,早期为左行韧性剪切变形,晚期叠加了左行脆性剪切变形。对带内千糜岩化石英片岩中的两期同构造花岗岩脉的构造地质学、岩石学和锆石U-Pb和Lu-Hf同位素研究,获得早期面理化细粒花岗岩的年龄为214.4±1.1Ma(MSWD=1.3),εHf(t)主要集中在-8.58~-0.29之间,tDM2=2.45~1.62Ga;晚期钾长花岗岩脉的年龄212.8±1.6Ma(MSWD=2.1),εHf(t)=-5.79~2.07,tDM2=2.53~1.49Ga。同位素数据表明两期花岗岩脉具有相同的岩浆源区,是古老地壳物质的再循环;晚期钾长花岗岩脉是早期花岗岩演化的产物。两期同构造花岗岩脉年龄的确定,表明宁陕左行走滑断层至少从晚三叠世中期之前就已经开始活动,而不是前人认为的早-中侏罗世或晚三叠末。尤其是宁陕左行走滑断裂带与勉略缝合带具有相同的左行韧性走滑叠加晚期脆性走滑的构造样式和活动时间,表明二者的形成可能都与古特提斯洋的斜向俯冲或者扬子板块的顺时针旋转有关。本研究成果为南秦岭的"古特提斯洋缝合带"——勉略缝合带向东经宁陕断裂带与大陆俯冲和深俯冲形成的耀岭河-桐柏-大别-苏鲁高压/超高压变质带相接提供了关键的年代学证据。  相似文献