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International audienceThis paper provides a new environmental, sedimentological and stratigraphic context of the Lago Mare deposits from the North Alboran region and clarifies their chronologic location with respect to the Messinian Salinity Crisis. We present new micropaleontological data (dinoflagellate cysts, calcareous nannoplankton, planktonic foraminifers), correlated with field observations and offshore seismic interpretations. We show that the Lago Mare event known in three onshore localities (Río Mendelín near Malaga, Zorreras near Sorbas, Gafares near Níjar) follows the marine reflooding of the Mediterranean Basin which ended the Messinian Salinity Crisis. Chronologically, these Lago Mare deposits last from the latest Messinian to the early Zanclean. In fact, the first influx of Paratethyan- organisms is revealed by the dinoflagellate cyst record from near Malaga within a Gilbert-type fan delta overlying the Messinian Erosional Surface. Invading molluscs and/or ostracods may have persisted in lagoonal coastal areas more or less affected by discontinuous marine influxes (Sorbas and Níjar). The Malaga area is convenient for a paleogeographic and sedimentary reconstruction which shows the prevalent forcing of sea level changes during the time-interval 5.600-5.332 Ma at the difference of the usually solicited prevalent tectonics. The studied Lago Mare event is the third episode resulting in such a paleobiological assemblage in the Mediterranean region and corresponds to the final two-way water exchange at high sea level between the Mediterranean and the former Paratethys. It documents the onset of the modern marine circulation in the Mediterranean after the reflooding ending the Messinian Salinity Crisis

Abstract. -Relations between Alpine detachment-bounded metamorphic domes, crustal-scale strike-slip fault zones and sedimentary basins in the Internal zones of the Betic cordillera are still matter of debate. Current tectonic interpretations of these basins vary from late-orogenic extensional structures to compressional ones associated with strike-slip motions along major still active faults. Structural investigations including new field mapping, meso-scale faults recognition, palaeostress analysis of brittle small-scale faults systems were performed in the sedimentary cover of the Almanzora corridor and the Huércal-Overa basins, located either in the hanging wall unit of the Filabres extensional shear zone or at the termination of the Alhama de Murcia sinistral fault zone. In parallel, a detailed study of the ductile and the ductile-brittle deformation was carried out in the footwall unit of the Filabres extensional shear zone, in the NevadoFílabride complex. Three main brittle events were recognised in the basin cover including two extensional events that occurred prior to a weak tectonic inversion of the basin during a third, still active event. The first one, D1 b is characterized by the development a first stress regime consistent with~NW-SE extensional tectonics. Besides, the consistency between the latest ductile and the brittle kinematics for the Filabres extensional shear zone and the activity of meso-scale fault systems that primarily control the main SW-NE depocentres allow concluding to a top-to-the-NW continuum of strain during the final exhumation of the Nevado-Filábride complex. The resulting overall half-graben architecture of the basins is then related to the combination of the formation of the metamorphic domes that added a local control superimposed on the regional deformation. Indeed, after a consistent top-to-the-west shearing prevailing during most of the Nevado-Filábride exhumation, final exhumation stages were in turn, characterised by important kinematics changes with a subordinate top-to-the-NW sense of shear (D1 b ). The onset of sedimentation in the basins occurred shortly after the crossing of the ductile-brittle transition in the underlying metamorphic domes at ca. 14 Ma into SW-NE fault-bounded troughs. Tectonic subsidence was then maintained during D2 b while extensional kinematics changed to N-S or even locally to SSW-NNE. Extensional tectonics then lasted most of the Tortonian during the final tectonic denudation increments of the Sierra de los Filabres achieved at ca. 9-8 Ma. Intramontane basins are therefore genuinely extensional and clearly related to the latest exhumation stages of the Nevado-Filábride complex in the back-arc domain. Conversely, at ca. 8 Ma, basins started to record a~N-S to NNW-SSE compressional stress regime (D3 b ) and ceased to be active depocentres while shortening within the Internal zones then recorded only the Iberia/Africa convergence. The weak inversion of the basins however resulted either in the reactivation of originally extensional faults such ...

International audienceTwo recent destructive earthquakes in 1994 and 2004 near Al Hoceima highlight that the northern Moroccan margin is one of the most seismically active regions of the Western Mediterranean area. Despite onshore geodetic, seismological and tectonic field studies, the onshore-offshore location and extent of the main active faults remain poorly constrained. Offshore Al Hoceima, high-resolution seismic reflection and swath-bathymetry have been recently acquired during the Marlboro-2 cruise. These data at shallow water depth, close to the coast, allow us to describe the location, continuity and geometry of three active faults bounding the offshore Nekor basin. The well-expressed normal-left-lateral onshore Trougout fault can be followed offshore during several kilometers with a N171 degrees E +/- 3 degrees trend. Westward, the Bousekkour-Aghbal normal-left-lateral onshore fault is expressed offshore with a N020 degrees E +/- 4 degrees trending fault The N030 degrees E +/- 2 degrees Bokkoya fault corresponds to the western boundary of the Plio-Quaternary offshore Nekor basin in the Al Hoceima bay and seems to define an en echelon tectonic pattern with the Bousekkour-Aghbal fault. We propose that these three faults are part of the complex transtensional system between the Nekor fault and the Al-Idrissi fault zone. Our characterization of the offshore expression of active faulting in the Al Hoceima region is consistent with the geometry and nature of the active fault planes deduced from onshore geomorphological and morphotectonic analyses, as well as seismological, geodetic and geodynamic data

The Sorbas Basin is the land reference of the Messinian Salinity Crisis (MSC) that affected the Mediterranean Sea in the latest Miocene. Its stratigraphy has been re-visited using calcareous nannofossils and planktonic foraminifers, which provide a reliable biostratigraphic frame and lead to particularly specify the relationships between the Sorbas and Zorreras members with Yesares evaporites. The evaporites overlie a shallowing upward sequence ending with the deposition of the Reef Unit and Terminal Carbonate Complex (TCC) on the periphery of the basin. The reefal carbonates of the TCC are overlain by clastic deposits that are foreset beds of post-MSC Gilbert-type fan deltas developed on the northern edge of the basin. These sedimentary structures are separated from reefal carbonates and the Reef Unit by the Messinian Erosional Surface (MES). The various facies of the Sorbas Member have been correlated with the bottomset beds of the Gilbert-type fan deltas despite some differences in palaeobathymetry. In the southeastern periphery of the basin, the MES separates the Sorbas Member from the Yesares gypsums. In the central part of the basin, a hiatus characterizes the contact between these members. The Zorreras Member postdates the MSC and entirely belongs to Zanclean. Its white "Lago Mare" layers are lagoonal deposits, the fauna of which is confirmed to result from Mediterranean-Paratethys high sea-level exchange after the post-MSC marine reflooding of the Mediterranean Basin. This study allows to reassert the two-step scenario of the MSC (Clauzon et al., 1996) with the following events:-at 5.971-5.600 Ma, minor sea-level fall resulting in the desiccation of this peripheral basin with secondary fluctuations;-at 5.600-5.460 Ma, significant subaerial erosion (or lack of sedimentation) caused by the almost complete desiccation of the Mediterranean Sea;

We present a high-resolution analysis of planktonic foraminifers, calcareous nannofossils, ostracods, dinoflagellate cysts and pollen grains in four sequences from DSDP-ODP holes in the southwestern Mediterranean Alboran and Balearic basins (976B, 977A, 978A and 134B) encompassing the previously defined Messinian-Zanclean boundary.The study focuses on (1) the marine reflooding, which closed the Messinian Salinity Crisis prior to the Zanclean GSSP; (2) the nature of the Lago Mare in the deep basins (indicated by Paratethyan dinoflagellate cysts), which appears to comprise several Paratethyan influxes without climatic control; and (3) the depositional context of the youngest Messinian evaporites which accumulated in a marine environment relatively close to the palaeoshoreline. Isolation of the Aegean Basin during the paroxysmic second step of the crisis is considered to have stored Paratethyan waters, which may then have poured into the Mediterranean central basins after deposition of the evaporitic sequence.

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The formation of sedimentary basins in the Alboran domain is associated with the exhumation of metamorphic core complexes over a circa 15 Ma period through a transition from regional late-orogenic extension to compression. An integrated study coupling field analysis and gravity data acquisition was performed in the Sorbas basin in the southeastern Betic Cordillera. Detailed field observations revealed for the first time that extensional tectonics occurred before shortening in this basin. Two extensional events were recorded with NW-SE to N-S and NE-SW kinematics, respectively; the first of which being likely responsible for the basin initiation. Tectonic inversion of the basin then occurred around 8 Ma in an overall approximately N-S shortening context. Two-dimensional gravity sections reveal that the basin acted as an active depocenter as the basin floor locally exceeding 2 km depth is characterized by a marked asymmetric architecture. Based on this integrated study, we explore a new evolutionary scenario which can be used as a basis for interpretations of the Neogene tectonic history of the southeastern Betics.