A review of the pre-Permian geology of the Variscan French Massif Central
A review of the pre-Permian geology of the Variscan French Massif Central
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DOI：
10.1016/j.crte.2008.12.001
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发表时间：
2009-02
影响因子：
1.4
通讯作者：
M. Faure;J. Lardeaux;P. Ledru
中科院分区：
文献类型：
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作者：
M. Faure;J. Lardeaux;P. Ledru
中央地块，像阿尔莫里凯恩地块的南部一样，属于冈瓦纳大陆的北部边缘。中央地块由六个主要构造变质事件造成的推覆体堆叠而成。第一个，D 0，是与晚志留世（约415 Ma）高压（HP）（或超高压）变质作用，相关的结构很少记录。早泥盆世D1事件导致推覆体自上而下向西南位移，与混合岩化作用和高压岩石的折返同时代，约为385- 380 Ma。在中央地块的北方，变质岩石与退变质榴辉岩被晚泥盆世未变形的沉积岩覆盖。晚泥盆世-早石炭世D_2事件为自上而下的北西向剪切作用，与360- 350 Ma的中等压力-温度变质作用同期发生。维先期D3事件是一次广泛分布于中央地块南部的自上而下的韧性剪切作用。同时，在中央地块的北方，D3事件对应于同造山伸展的开始。下两个事件，D4和D5，早石炭世和晚石炭世的年龄，分别对应于同造山和晚造山伸展构造体制。前者受NW-SE向拉伸控制，后者受NNE-SSW向拉伸调节。在地球动力学演化模型中重新考虑了这些构造和变质事件。讨论了微大陆漂移、碰撞和碰撞的一个或两个旋回的可能性。
The Massif Central, like the southern part of the Massif Armoricain, belongs to the north Gondwana margin. The Massif Central consists of a stack of nappes resulting from six main tectonic-metamorphic events. The first, D0, is coeval with a Late Silurian (ca 415Ma) high-pressure (HP) (or ultra high-pressure) metamorphism for which the associated structures are poorly documented. The Early Devonian D1event, responsible for top-to-the-southwest nappe displacement, is coeval with migmatization and the exhumation of HP rocks around 385–380Ma. In the northern part of the Massif Central, metamorphic rocks with retrogressed eclogites are covered by Late Devonian undeformed sedimentary rocks. The Late Devonian-Early Carboniferous D2event involves top-to-the-northwest shearing, coeval with an intermediate pressure-temperature metamorphism dated around 360–350Ma. The Visean D3event is a top-to-the-south ductile shearing, which is widespread in the southern Massif Central. Coevally, in the northern Massif Central, the D3event corresponds to the onset of synorogenic extension. The next two events, D4and D5, of Early and Late Carboniferous age, correspond to the syn- and late orogenic extensional tectonic regimes, respectively. The former is controlled by NW–SE stretching whereas the latter is accommodated by NNE–SSW stretching. These structural and metamorphic events are reconsidered in a geodynamic evolution model. The possibilities of one or two cycles involving microcontinent drifting, rewelding and collision are discussed.