Emplacement kinematics of Cisuralian subvolcanic intrusions in the Iberian Chain (NE Spain): new insights from the structural and magnetic study of the Cerro Redondo dacitic intrusion

Abstract

A combined structural, petrological, and anisotropy of magnetic susceptibility (AMS) study of the Cisuralian (285 ± 2 Ma) Cerro Redondo dacitic intrusion (Iberian Chain, NE Spain) has been conducted to reconstruct its emplacement kinematics and determine its 3D geometry at the outcrop scale. This small igneous body, covering only 0.17 km 2 , displays a well-defined magmatic foliation that is affected by asymmetrical, steeply plunging folds at different scales. Our multidisciplinary analysis suggests that the Cerro Redondo intrusion formed through the emplacement of successive magma pulses, during which the original magmatic foliations were passively folded. Detailed AMS data reveal a superposition of three kinematic processes recorded in the magnetic fabric, all occurring prior to complete crystallization: the development of an early planar magmatic fabric, localized simple shear deformation, and subsequent folding of the magmatic foliation. This integrated structural, petrological, and AMS study indicates that the Cerro Redondo intrusion is a sub-vertical, asymmetric subvolcanic body, emplaced at upper crustal levels under the control of extensional (or transtensional) movements of the late-Variscan Pardos Fault.

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