Granite emplacement in orogenic compressional conditions: the La Alberca–Béjar granitic area (Spanish Central System, Variscan Iberian Belt)
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文摘
The La Alberca–Béjar granitic area comprises a set of intrusions of Upper Carboniferous to Lower Permian age located in the hinterland of the Variscan belt of western Spain. Gravity data, anisotropy of magnetic susceptibility, and microstructural studies carried out in the granitoid and its country rocks indicate that the granitoids of this region have tabular and inverted drop shapes and show sub-horizontal magmatic fabrics and SW–NE lineations. The granitoid bodies were intruded episodically, with single intrusive pulses recorded by deformation in the country rocks. All intrusive events took place during D3 compressive stage, in the core of large D1 anticlines, and are not related to structures in the country rock. A syn-orogenic emplacement model for granite intrusion in such conditions is proposed. The proposed model implies the activity of coeval emplacement mechanisms and room generation.