Controls on the development and evolution of structural styles in the Inner Moray Firth Basin
Controls on the development and evolution of structural styles in the Inner Moray Firth Basin
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内马里湾盆地构造样式发育演化的控制
DOI：
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发表时间：
1993
期刊：
影响因子：
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通讯作者：
J. Underhill
中科院分区：
文献类型：
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作者：
K. Thomson;J. Underhill
尽管人们普遍认为内马里湾(IMF)的构造样式在很大程度上受到大格伦断层(GGF)走滑运动的控制，但综合地震和野外研究表明情况并非如此。相反，大多数构造样式似乎是倾滑伸展和热沉陷的结果，而倾滑伸展和热沉陷是二叠纪-三叠纪和晚侏罗世两期裂谷作用的结果，随后在第三纪期间发生了区域抬升和局部反转。整个格陵兰盆地克默里德-波特兰段的明显增厚与陆上露头和取心井的沉积学信息相结合，表明该盆地在晚侏罗世具有半地堑几何结构，沉积中心毗邻赫尔姆斯代尔断层，类似于格陵兰和南维京地堑其他晚侏罗世层序的半地堑几何结构。渐进的海洋超覆表明，在随后的早白垩世沉积期间，在充填不足的盆地中发生了更温和的区域性(热)沉降。然而，地震数据和亚作物信息表明，这些典型的裂谷和热驱动伸展阶段所产生的几何形状被新生代区域抬升和反转所改变，以响应东北大西洋(图勒河)和阿尔卑斯山事件造成的板内挤压。这些事件似乎也影响了GGF的轻微走滑运动，形成了壮观的花状结构和螺旋状几何结构，并导致了一些伸展结构的有限斜滑重新激活。构造样式的最显著变化发生在主要的盆地边界断裂附近地区。特别复杂的构造反转几何图形出现在毗邻Wick断层的盆地西北角，同时由于这些断层上相反的滑移感，在Helmsdale断层和GGF之间的Sutherland Terrace出现了异常倾向的褶皱。
Although it has generally been believed that structural styles in the Inner Moray Firth (IMF) have been largely controlled by strike-slip movements on the Great Glen Fault (GGF), integrated seismic and field studies suggest otherwise. Instead, most structural styles appear to have developed and evolved as a result of dip-slip extension and thermal subsidence consequent upon two phases of rifting during the Permo-Triassic and Late Jurassic and subsequent regional uplift and local inversion during the Tertiary. The integration of demonstrable thickening of Kimmeridgian–Portlandian intervals across the GGF with sedimentological information from onshore outcrops and cored wells suggests that the basin had a half-graben geometry during the Late Jurassic with a depocentre adjacent to the Helmsdale Fault, analogous to half-graben geometries which characterized other Late Jurassic sequences in Greenland and the South Viking Graben. Progressive marine onlap suggests that more gentle regional (thermal) subsidence took place in an underfilled basin, during subsequent Early Cretaceous deposition. However, the seismic data and subcrop information show that the geometries resulting from such classic rift- and thermally-driven phases of extension were modified by Cenozoic regional uplift and inversion in response to intraplate compression resulting from NE Atlantic (Thulean) and Alpine events. These events also appear to have effected minor strike-slip motion on the GGF, with the development of spectacular ‘flower structure’ and ‘helicoidal’ geometries, and caused limited oblique-slip reactivation of some extensional structures. The most notable modification of structural styles occurs in areas adjacent to the major basin-bounding faults. Particularly complex structural inversion geometries occur in the northwest corner of the basin adjacent to the Wick Fault while anomalously-trending folds developed in response to space problems in the Sutherland Terrace, between the Helmsdale Fault and the GGF, as a result of opposing senses of slip on these faults.