Submarine canyons and related features in the Alboran Sea: continental margins and major isolated reliefs

The analysis of a data set of multibeam bathymetry plus high resolution seismic and parametric profiles allow us to characterize the geomorphologic units on the Alboran Sea-floor as well as the evolution of morpho-sedimentary systems along the Pliocene and Quaternary, later than the main erosive Messinian event. Since the opening of the Gibraltar Straits, the sedimentary evolution of this basin has been controlled by the interchange of water masses between the Atlantic Ocean and the Mediterranean Sea. Basin physiography is also a consequence of the Pliocene-Quaternary compression which has progressively uplifted the sourrounding reliefs and deforms the interior and the margins of the basin. On this scenario, several submarine canyons and gullies have been developed in this basin which traverse especially the northern margin and the flanks of the Northern Alboran Ridge, without affecting the African margins. This fact must be related to the action of bottom contour currents which constitute the main morpho-sedimentary process. The influence of water masses distributed the sedimentary input carried by rivers and coming from the erosion of surrounding ranges. In the southern margin of this basin this influence is stronger and inhibits the development of transversal submarine canyons

Tectonic indentation in the central Alboran Sea (westernmost Mediterranean)

The Alboran Sea constitutes a Neogene–Quaternary basin of the Betic–Rif Cordillera, which has been deformed since the Late Miocene during the collision between the Eurasian and African plates in the westernmost Mediterranean. NNE–SSW sinistral and WNW–ESE dextral conjugate fault sets forming a 75° angle surround a rigid basement spur of the African plate, and are the origin of most of the shallow seismicity of the central Alboran Sea. Northward, the faults decrease their transcurrent slip, becoming normal close to the tip point, while NNW–SSE normal and sparse ENE–WSW reverse to transcurrent faults are developed. The uplifting of the Alboran Ridge ENE–WSW antiform above a detachment level was favoured by the crustal layering. Despite the recent anticlockwise rotation of the Eurasian–African convergence trend in the westernmost Mediterranean, these recent deformations—consistent with indenter tectonics characterised by a N164°E trend of maximum compression—entail the highest seismic hazard of the Alboran Sea

The lobe complex of the distal Almeria turbidite system: architecture and depositional history over the last 575,000 years

This paper presents the stratigraphic architecture of the lobe complex (LC) of the distal Almeria turbidite system over the last 575 ka based on very high-resolution data (seismic parametric sub-bottom profiles, bathymetry and stable oxygen isotope core data). Its depositional architecture suggests the 575 ka oldest lobe represents a lobe system, which is essentially organized in vertical stacking of channel-levee/lobes. Their morpho-sedimentary characteristics point to: (i) this turbidite system roughly matches that of mixed sandmud composition systems; and (ii) the lateral relocation of turbidites may be conditioned by factors such as the sediment load, the energy of gravity flows, related avulsion processes and the local morphological confinement. The detailed seismofacies analysis enabled the identification of channel-levee/lobes, mass-transport deposits and hemipelagites formed over the last 269 ka. Their lateral and vertical distribution suggests that an increased submarine canyon activity and mass-movements took place during lowstand stages (MIS 8, MIS 6, MIS 4 and MIS 2) whereas hemipelagic settling dominated during the highstand stages (MIS 7 and MIS 5)Se presenta la arquitectura estratigráfica del complejo de lóbulo (LC) del sistema turbidítico distal de Almería de los últimos 575 ka basada en datos geológicos de muy alta resolución (perfiles sísmicos paramétricos, batimetría e isotopos estables de oxígeno). Su arquitectura deposicional sugiere que el lóbulo más antiguo (575 ka) está organizado por el apilamiento vertical de complejos de canal-dique/ lóbulo. Sus características morfo-sedimentarias apuntan a: (i) su coincidencia con las de los sistemas mixtos de composición areno fangosa y que (ii) la reubicación lateral de los depósitos turbidíticos pudo estar condicionada por la carga de sedimento, la energía de los procesos gravitacionales, los procesos de avulsión y el confinamiento local. El análisis detallado de las sismofacies permite la identificación de lóbulos canalizados, depósitos de transporte en masa, y hemipelagitas formados durante los últimos 269 ka. Su distribución lateral y vertical sugiere que la actividad del cañón submarino y los movimientos en masa fueron mayores durante las etapas de bajo nivel del mar (MIS 8, MIS 6, MIS 4 y MIS 2) y la sedimentación dominante sería hemipelágica durante las etapas de alto nivel del mar (MIS 7 y MIS 5)

Defensa, conservación y creación de Parques Naturales submarinos : Un estudio piloto

28 pages, 4 figuresSe parte de dos premisas que los constituyentes del equipo que se propone creen fundamentales: a) Es necesario un estudio profundo de todos los aspectos de la biología marina en nuestras costas, no sólo para un mejor conocimiento de las mismas, sino para detectar y combatir los efectos que sobre las comunidades marinas tienen agentes extraños (contaminación). [...]Peer reviewe