The transition from Alboran to Algerian basins (Western Mediterranean Sea): Chronostratigraphy,deep crustal structure and tectonic evolution at the rear of a narrow slab rollback system |
| |
| Institution: | 1. Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS), Trieste, Italy;2. Dipartimento di Matematica e Geoscienze, Università di Trieste, Via Weiss, 1, 34128 Trieste, Italy;3. Dipartimento di Ingegneria Civile, Ambientale e Architettura, Università di Cagliari, Via Marengo 2, 09123 Cagliari, Italy;4. Dipartimento di Scienze della Terra, dell''Ambiente e delle Risorse, Università Federico II di Napoli, Largo S. Marcellino, 10, 80138 Naples, Italy;5. SIS Schlumberger Information Solutions, Schlumberger Italiana S.p.A., Via dell''Unione Europea, 4 — Torre Beta, 20097 San Donato Milanese, MI, Italy;1. Universidad de Granada, Instituto Andaluz de Geofisica, Granada, Spain;2. Institute of Earth Sciences Jaume Almera, ICTJA-CSIC, Barcelona, Spain;1. Departamento de Geodinámica, Facultad de Ciencias, Universidad de Granada, Fuentenueva s/n, 18071 Granada, Spain;2. Instituto Andaluz Ciencias de la Tierra, Consejo Superior de Investigación Científica, Avenida de las Palmeras 4, 18100 Armilla, Granada, Spain;3. Departamento de Sistemas Físicos, Químicos y Naturales, Universidad Pablo de Olavide, Ctra. de Utrera km. 1, 41013 Sevilla, Spain |
| |
| Abstract: | The eastern Alboran basin and its transition to the Algerian basin is a key area in the Mediterranean realm where controversial kinematic and geodynamical models are proposed. Models imply striking differences regarding the nature of the crust, the prevalence of brittle faulting and ductile shear, the origin of magmatism, the style of Miocene deformation and the driving mechanisms of the Alboran plate kinematics. Combining a new chronostratigraphic chart of the Alboran and Algerian basins based on the Habibas (HBB-1) core drill, deep seismic sections striking WSW-ENE and SSE-NNW, and potential field data, we re-assess the tectonic evolution that controlled the sedimentation and basement deformation of the westernmost limit of the Algerian basin and its transition with the Alboran domain. A WSW-directed extensional tectonic phase has shaped a stretched continental crust with typical tilted blocks along ～100 km from Burdigalian to Tortonian times, which is assumed to result from the WSW-directed migration of the Alboran block driven by a narrow slab rollback. In the Algerian basin, this event was followed by the emplacement of an oceanic-type crust. Potential field signatures of the deep basin as well as geometrical correlations with onland outcrops of inner zones suggest a minimum WSW-directed displacement of the Alboran terrane of ～200 km. At the southern foot of the Algerian basin, the continent-ocean transition is sharp and may result from the westward propagation of a slab tear at depth, forming two segments of STEP (Subduction-Transform Edge Propagator) margins. Our results support models of intense shear tractions at the base of an overriding plate governed by slab rollback-induced mantle flow. Finally, Messinian salt tectonics affected overlying deposits until today. A late Tortonian to Quaternary dominantly transpressive tectonic episode linked to the Africa-Iberia convergence post-dates previous events, deforming the whole margin. |
| |
| Keywords: | Alboran sea Miocene kinematics Tectonics Crustal structure Seismic reflection Potential field data Slab rollback STEP fault margin |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
