3D seismic geomorphology and sedimentology of the Chalk Group, southern Danish North Sea
3D seismic geomorphology and sedimentology of the Chalk Group, southern Danish North Sea
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DOI：
10.1144/0016-76492010-047
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发表时间：
2011-02
影响因子：
2.7
通讯作者：
S. Back;H. van Gent;L. Reuning;J. Grötsch;J. Niederau;P. Kukla
中科院分区：
文献类型：
--
作者：
S. Back;H. van Gent;L. Reuning;J. Grötsch;J. Niederau;P. Kukla
摘要：传统上，北海白垩被解释为是在平静、均匀的远洋条件下沉积的，局部再沉积在滑塌和滑坡中。最近对西北欧白垩岩群二维和三维地震反射数据的高度不连续反射模式的观察，导致了对白垩沉积的一些一般观点的修正，提出了长期存在的、轮廓平行的底流对白垩岩内通道、漂积物和土丘的发展产生了主要影响的建议。本研究提出了一种替代的解释，选择内白垩地震和地层不连续性的形成，解释这些是由重力驱动的过程，在激烈的同沉积构造的发展。在研究区域确定的海底物质运输系统包括大规模的滑塌、滑坡、泥石流和浊流。最后一种情况发生在两侧有大型主堤的蜿蜒河道系统中，河道填方在河道深线的外弯处显示出发育良好的次级堤岸和漫滩。这是第一次记录北海白垩的渠道化密度流沉积物，对再沉积白垩单元的解释和预测具有重要影响，同时强调了地下沉积系统分析的详细三维地震不连续性检测的强度。
Abstract: Classically, the North Sea Chalk is interpreted as having been deposited under quiet, homogeneous pelagic conditions with local redeposition in slumps and slides. Recent observations of highly discontinuous reflection patterns on 2D and 3D seismic reflection data from the NW European Chalk Group have led to a revision of some general ideas of chalk deposition, with the suggestion that long-lived, contour-parallel bottom currents exerted a primary influence on the development of intra-chalk channels, drifts and mounds. This study proposes an alternative explanation for the formation of selected intra-chalk seismic and stratal discontinuities, interpreting these as being caused by gravity-driven processes that developed in response to intense syndepositional tectonics. Submarine mass-transport systems identified in the study area include large-scale slumps, slides, debris flows and turbidites. The last occur in sinuous channel systems flanked by large master levees, with the channel fill exhibiting well-developed secondary banks and overbanks on the outer bends of the channel thalweg. This first documentation of channelized density-flow deposits in the North Sea Chalk has important consequences for the interpretation and prediction of redeposited chalk units, emphasizing at the same time the strength of detailed 3D seismic discontinuity detection for subsurface sedimentary-systems analysis.