Gravitational potential stresses and stress field of passive continental margins: Insights from the south-Norway shelf
Gravitational potential stresses and stress field of passive continental margins: Insights from the south-Norway shelf
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DOI：
10.1016/j.epsl.2008.11.014
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发表时间：
2009-01
影响因子：
5.3
通讯作者：
C. Pascal;S. Cloetingh
中科院分区：
文献类型：
--
作者：
C. Pascal;S. Cloetingh
一般认为被动大陆边缘的应力状态主要是由洋脊推压所控制，而其他应力源在时间和/或空间上的影响是有限的。我们表明，通过数值模拟，所观察到的岩石圈结构和海拔从边缘到大陆内部的变化也可能产生显着的重力位应力与山脊推力引起的竞争。我们测试这一假设的实际情况下，丰富的地质和地球物理数据集，挪威南部和邻近的挪威南部山区（或南部斯堪的纳维亚）的货架。模拟结果与三个关键观测量的主要特征一致：（1）截断大地水准面的波动（反映岩石圈重力势能的变化），（2）海上和陆上的显著应力旋转和（3）挪威南部的地震活动模式。南部斯堪的纳维亚对区域应力模式的贡献似乎比以前预期的要大得多。此外，该模型为挪威南部神秘的地震活动提供了物理解释。被动大陆边缘与大陆边缘之间的岩石圈结构变化所产生的重力位应力，可以与洋脊推挤一起对大陆边缘的动态演化产生重要的控制作用。
It is commonly assumed that the stress state at passive margins is mainly dominated by ridge push and that other stress sources have only a limited temporal and/or spatial influence. We show, by means of numerical modelling, that observed variations in lithosphere structure and elevation from a margin towards continental interiors may also produce significant gravitational potential stresses competing with those induced by ridge push forces. We test this hypothesis on an actual case where abundant geological and geophysical datasets are available, the shelf of southern Norway and adjacent southern Norwegian mountains (or Southern Scandes). The modelling results are consistent with the main features of three key-observables: (1) undulations of the truncated geoid (reflecting variations in gravitational potential energy in the lithosphere), (2) significant stress rotations both offshore and onshore and (3) the seismicity pattern of southern Norway. The contribution of the Southern Scandes to the regional stress pattern appears to be far more significant than previously anticipated. In addition, the modelling provides a physical explanation for the enigmatic seismicity of southern Norway. Gravitational potential stresses arising from variations in the lithospheric structure between a passive margin and its continental borderlands, can exert a significant control on the dynamic evolution of the margin in concert with ridge push.