Crustal laminations in deep seismic profiles in France and neighbouring areas
Crustal laminations in deep seismic profiles in France and neighbouring areas
复制标题
法国及邻近地区深部地震剖面中的地壳层理
DOI：
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发表时间：
1987
期刊：
影响因子：
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通讯作者：
Pinet
中科院分区：
文献类型：
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作者：
C. Bois;S. T. E. C. M. CaZeS;Paris La Dqeme;France A. Him;C. U. L. P. Matte;Giol;Place Bataillon Struc.;France A Montpellier;L. Mascle;B. Montadert;Pinet
摘要在法国北方和比斯开湾拍摄的ECORS剖面图以及在西海峡和凯尔特海拍摄的SWAT剖面图上都出现了显著的地壳特征。最引人注目的是下地壳中出现了扁平的纹层。上地壳和下地壳中也存在倾斜事件和纹层，尤其是在SWAT剖面中。它们可以很容易地与构造事件，华力西的年龄，其中一些在外地确定。下地壳中的扁平纹层最初被解释为华力西造山运动期间壳幔转换过程中的拆沉、剪切、岩浆作用和变质作用的结果。这种解释引起了一些困难的空间和时间相关的叠层与华力西造山带。它们似乎是在普利茅斯湾盆地的二叠纪-三叠纪充填之后和比斯开湾早白垩世开口之前侵位的。早至中侏罗世的年龄建议，一个时期时，大型的海盆形成没有明显的延伸。热流增加和岩浆作用被认为是下地壳纹层形成的第二种假说。在这些叠层的造山和非造山原因之间进行选择将需要进一步的深地震剖面以及良好的速度测定。
Summary. Remarkable crustal features appear on the ECORS profiles carried out in northern France and the Bay of Biscay as well as on the SWAT profiles shot in the western Channel and the Celtic Sea. The most striking one is the occurrence of flat laminations in the lower crust. Dipping events and laminations are also present in the upper and lower crust, especially in the SWAT profiles. They can readily be related to tectonic events, Variscan in age, some of them identified in the field. The flat laminations in the lower crust are at first interpreted as resulting from delamination, shearing, magmatism and metamorphism at the crust-mantle transition during the Variscan orogeny. This interpretation raises some difficulty concerning the space and time correlation of the laminations with the Variscan orogeny. They seem to have been emplaced after the Permian-Triassic infilling of the Plymouth Bay basin and before the early Cretaceous opening of the Bay of Biscay. An early to middle Jurassic age is suggested, a period when large cratonic basins were formed without noticeable extension. Heat flow increase and magmatism are proposed as a second hypothesis for the formation of the lower crust laminations. Choosing between orogenic and non-orogenic causes of these laminations will require further deep seismic profiles together with good velocity determination.