Ductile extension in alpine Corsica
Ductile extension in alpine Corsica
复制标题
高山科西嘉岛的延性延伸
DOI：
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发表时间：
1990
期刊：
影响因子：
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通讯作者：
Claudie Jourdan
中科院分区：
文献类型：
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作者：
L. Jolivet;Roland Dubois;M. Fournier;B. Goffé;A. Michard;Claudie Jourdan
在高压（P）-低温（T）条件下的韧性变形，由于向西逆冲的海洋物质到一个大陆基底在高山科西嘉是叠加了晚期变形事件与反向剪切的意义（东），发生在不太严重的P-T条件。我们发现，晚期变形可以链接到拉张过程中的裂谷和扩展的利古罗普罗旺斯盆地从晚渐新世晚中新世的时间。主要的挤压逆冲接触被重新激活为韧性正断层，在某些单元中，只能观察到一个穿透性的东向剪切。这种伴随地壳增厚的伸展作用，使在早期阶段经历了非常不同的P-T条件的构造单元紧密接触。巴拉涅推覆体直接覆盖在高压单元之上，既没有明显的韧性变形，也没有明显的变质作用.伸展变形分布在推覆体的整个厚度上，但更重要的是沿着主要的逆冲接触面，它使应变局部化。早期挤压逆冲构造控制了地壳伸展的几何形态。最新的构造是东倾的脆性正断层，它与中新世早期至中期的圣弗洛朗半地堑相连。
Ductile deformation in high-pressure ( P )-low temperature ( T ) conditions due to the westward thrusting of oceanic material onto a continental basement in alpine Corsica is overprinted by a late deformation event with a reverse shear sense (eastward) that took place in less severe P-T conditions. We show that the late deformation can be linked to extension during rifting and spreading of the Liguro Provencal basin from late Oligocene to late-middle Miocene time. Major compressive thrust contacts were reactivated as ductile normal faults and, in some units, only a penetrative eastward shear can be observed. This extension following the thickening of the crust brought tectonic units which underwent very different P- T conditions during the earlier stage into close contact. The Balagne nappe, which shows neither significant ductile deformation nor metamorphism, directly overlies the high- P units. The extensional deformation is distributed through the entire thickness of the nappe stack but is more important along the major thrust contacts, which localize the strain. The geometry of the crustal extension is controlled by that of the early compressive thrusts. The latest structures are east-dipping brittle normal faults which bound the early to middle Miocene Saint Florent half graben.