2026-06-07T13:54:19Zhttps://docta.ucm.es/rest/oai/request

oai:docta.ucm.es:20.500.14352/184552024-09-03T14:19:53Zcom_20.500.14352_14col_20.500.14352_15

00925njm 22002777a 4500 dc Calvín Ballester, Pablo author Ruiz Martínez, Vicente Carlos author Villalaín Santamaría, Juan José author Casa Sainz, Antonio María author Moussaid, Bennacer author 2017-12 A paleomagnetic and magnetic fabric study is performed in Upper Jurassic gabbros of the central High Atlas (Morocco). These gabbros were emplaced in the core of preexisting structures developed during the extensional stage and linked to basement faults. These structures were reactivated as anticlines during the Cenozoic compressional inversion. Gabbros from 19 out of the 33 sampled sites show a stable characteristic magnetization, carried by magnetite, which has been interpreted as a primary component. This component shows an important dispersion due to postemplacement tectonic movements. The absence of paleoposition markers in these igneous rocks precludes direct restorations. A novel approach analyzing the orientation of the primary magnetization is used here to restore the magmatic bodies and to understand the deformational history recorded by these rocks. Paleomagnetic vectors are distributed along small circles with horizontal axes, indicating horizontal axis rotations of the gabbro bodies. These rotations are higher when the ratio between shales and gabbros in the core of the anticlines increases. Due to the uncertainties inherent to this work (the igneous bodies recording strong rotations), interpretations must be qualitative. The magnetic fabric is carried by ferromagnetic (s.s.) minerals mimicking the magmatic fabric. Anisotropy of magnetic susceptibility (AMS) axes, using the rotation routine inferred from paleomagnetic results, result in more tightly clustered magnetic lineations, which also become horizontal and are considered in terms of magma flow trend during its emplacement: NW-SE (parallel to the general extensional direction) in the western sector and NE-SW (parallel to the main faults) in the easternmost structures. 0278-7407 10.1002/2017TC004578 https://hdl.handle.net/20.500.14352/18455 http://dx.doi.org/10.1002/2017TC004578 http://onlinelibrary.wiley.com Emplacement and deformation of mesozoic Gabbros of the High Atlas (Morocco): paleomagnetism and magnetic fabrics