Localization of deformation and kinematic shift during the hot emplacement of the Ronda peridotites (Betic Cordilleras,southern Spain) |
| |
| Institution: | 1. Geo-Resources Laboratory, Water Research and Technologies Center Borj-Cedria & Carthage University, Faculty of Sciences of Bizerte, Tunisia;2. King Abdulaziz University, Faculty of Earth Sciences, Department of Structural Geology and Remote Sensing, Jeddah, Saudi Arabia;3. Aix Marseille Univ, CNRS, IRD, INRAE, Coll France, CEREGE, Aix-en-Provence, France;4. Hans Ramberg Tectonic Laboratory, Uppsala University, Uppsala, Sweden;1. Laboratorio de Paleomagnetismo, Universidad de Burgos, Spain;2. Departamento de Ciencias de la Tierra, Universidad de Zaragoza, Spain;3. Laboratoire de « BGIM », Ecole Normale Supérieure, Université Hassan II. Casablanca, Morocco;1. School of Earth and Environmental Sciences, University of Manchester, Oxford Road, Manchester, M13 9PL, UK;2. The University of Texas at Austin, Bureau of Economic Geology, Jackson School of Geosciences, Austin, TX, USA;3. Basins Research Group (BRG), Department of Earth Science and Engineering, Imperial College London, South Bennington Campus, SW7 2BP, UK |
| |
| Abstract: | The Ronda peridotites form the largest mass of subcontinental mantle outcropping on land. Unlike other orogenic lherzolite massifs, the two main bodies of Ronda (the Sierra Bermeja and Sierra Alpujata massifs) are unique cases where ductile shear zones linked to the hot thrusting of mantle over continental crustal rocks are well exposed. We present a new insight into the deformation localization in these shear zones based on structural, fabric and petrological data. The Ronda peridotites show increasing deformation towards the continental footwall rocks, from porphyroclastic rocks to ultramylonites. Garnet-pyroxenites from the basal shear zone of the Alpujata massif yield ca. 1100 °C and 1.4 GPa for the mylonitization. Such conditions promoted partial melting and the formation of felsic dynamothermal aureoles from the underlying crustal rocks. Subsequent deformation is mainly localized in the dynamothermal aureoles, since they are weaker than the peridotites. Both aureoles show marked strain gradients towards the contact but record different kinematics. In Sierra Alpujata, kinematic criteria indicate a top-to-the ENE shear sense, whereas in Sierra Bermeja the felsic mylonites provide a top-to-the NNW motion. A transpressional setting is proposed to explain such kinematic shift. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
