...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Marine Geology >Geometry and structure associated to gas-charged sediments and recent growth faults in the Ebro Delta (Spain)
【24h】

Geometry and structure associated to gas-charged sediments and recent growth faults in the Ebro Delta (Spain)

机译：埃布罗三角洲（西班牙）的与含气沉积物和近期生长断层有关的几何结构

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

In the Ebro Delta, NE Spain, small- to large-scale synsedimentary deformation has been observed by means of high- and low-resolution seismics correlated with a network of wells. Lithoseismic units involved are middle-upper Pleistocene clays and gravels and Holocene deltaic sequence. Gassy sediments and large river-floor pockmarks are identified from seismic profiles along the Ebro Delta. Gas-charged sediments are identified by zones of acoustic turbidity and other acoustic anomalies on seismic profiles. Most of the gas is believed to be biogenic in origin, resulting from the decay of organic matter contained within rapidly developing shelf margin deltas. A group of large symmetric river-floor pockmarks also occurs along the inner delta plain, both on the river-floor surface and buried in the sediment column. Listric fault geometry is a typical scope-shaped plane with a steep upper surface (40-60 deg) that passes downward into a horizontal shear plane. The shear plane appears seismically as chaotic and convoluted high-amplitude reflectors and is correlated with well data showing layers that include gravel, sand and clays. Associated structural features include reverse drag of reflectors, antithetic faults, and fluid escapes (methane/water). The growth faulting along the Ebro Delta includes a break-away and thin, near-surface layer created by overstepping of a sandy Holocene delta slope. The over-steeping lies down-dip from growth faults along the shelf-break. The overall growth faults province appears to represent a deeper-seated general movement of the delta mass involving differential loading, overpressure of fluids, diapiric movements, and extensional tectonics that cause listric faults and associated structures at different scales. The recent growth faults are regularly spaced, with the distance between successive faults controlled by the depth to the detachment layer. Three main fault systems have been identified: A first or primary system spaced 5.2-10.5 km above a detachment layer at 55-95 m deep: a second system spaced 3.5-6 km; and a third system spaced 1.5-2.5 km above a detachment layer at 25-30 m. The slope angle calculated by empirical equations ranges between 0.50 deg and 1.0 deg for the three systems.
机译：在西班牙东北部的埃布罗三角洲，已通过与井网相关的高分辨率和低分辨率地震观测到了小规模到大规模的同沉积变形。涉及的岩石地震单元是中上更新世粘土和砾石和全新世三角洲层序。从沿埃布罗三角洲的地震剖面中可以识别出高气态的沉积物和大的河底麻点。含气沉积物通过声波浊度带和地震剖面上的其他声波异常来识别。据信，大部分气体是生物成因的，这是由于迅速发展的陆架边缘三角洲中所含有机物的腐烂所致。沿内三角洲平原也出现了一组大型对称的河底麻点，既在河底表面上，又埋在泥沙柱中。李斯特断层几何形状是典型的示波器形状的平面，具有陡峭的上表面（40-60度），向下向下进入水平剪切平面。剪切平面在地震上表现为混沌和回旋的高振幅反射器，并且与显示包括砾石，沙子和粘土在内的层的井数据相关。相关的结构特征包括反射器的反阻力，对立的断层和流体逸出（甲烷/水）。沿着埃布罗三角洲的生长断层包括一个突破性的，薄的近地表层，该层是由沙全新世三角洲斜坡的超步形成的。堆积过多是由于货架断裂期间的生长缺陷造成的。总体生长断层似乎代表了三角洲质量的更深层次的普遍运动，涉及差异负载，流体超压，底辟运动和伸展构造，这些构造运动造成了不同规模的李斯特断裂和相关结构。最近的生长断层是有规律地隔开的，连续断层之间的距离由到分离层的深度控制。已经确定了三个主要的断层系统：第一个或主要系统，在55-95 m深的分离层上方，间隔5.2-10.5 km;第二个系统，间隔3.5-6 km;第三套系统在25-30 m的分离层上方间隔1.5-2.5 km。对于三个系统，通过经验公式计算出的倾斜角在0.50度至1.0度之间。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号