Granitoid emplacement during a thrusting event: structural analysis, microstructuel and quartz-c-axis patterns. An example from hercynian plutons in the French Massif Central. - Archive ouverte HAL Access content directly
Journal Articles Journal of Structural Geology Year : 2004

Granitoid emplacement during a thrusting event: structural analysis, microstructuel and quartz-c-axis patterns. An example from hercynian plutons in the French Massif Central.

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Abstract

n the French Massif Central, the Rouergue–Albigeois area consists of three tectonic units stacked during the Hercynian orogeny. The structural analysis of the units and particularly the quartz left angle bracketcright-pointing angle bracket axis, textural and structural observations in the syntectonic Pinet-type plutons allow us to determine the deformation history. A first thrusting event, D1, is responsible for a southwestward emplacement of the high-grade Lévézou nappe, above the Lower Gneiss Unit itself overlying the para-autochthonous micaschists. In Late Devonian–Early Carboniferous, this stack of nappes experienced a second event, D2, characterized by a top-to-the-NW emplacement under medium pressure/medium temperature conditions of the para-autochtonous unit upon the Lower Gneiss Unit. During D2, the Pinet-type plutons were deformed by a shearing consistent with the kinematics recorded in the country rocks. In contrast to previous works, which considered the Pinet-type plutons emplacement to be coeval with the D2 event, we argue that the emplacement of the plutons occurred during the top-to-the-SW D1 nappe stacking. This work emphasizes the importance of the quartz left angle bracketcright-pointing angle bracket axis and microstructure analysis for the identification of the early structural history in polyphase deformed terranes.
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hal-00023846 , version 1 (16-05-2006)

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Manuel Duguet, Michel Faure. Granitoid emplacement during a thrusting event: structural analysis, microstructuel and quartz-c-axis patterns. An example from hercynian plutons in the French Massif Central.. Journal of Structural Geology, 2004, 26, pp.5, 927-945. ⟨10.1016/j.jsg.2003.09.005⟩. ⟨hal-00023846⟩
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