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Report on the environmental monitoring (geophysics, seabed sampling, physical and chemical characteristics, and planton) made on the submarine volcano of Tagoro (El Hierro Islands) to evaluate the degree of affection and recovery on the marine ecosystem of the last volcanic eruption in the Canary region, making it extendable to other regions of the Canary Islands of possible hydrothermal or volcanological interest. In this sense, the "Enmedio" volcano has been investigated, between the islands of Gran Canaria and Tenerife., Instituto Español de Oceanografía

This study focuses on the Alboran Sea area (Westernmost Mediterranean), where a seismic analysis of the Pliocene and Quaternary stratigraphy was conducted in the Alboran Sea (Westernmost Mediterranean) using ~2000 profiles consisting of single and multi-channel seismic records. The seismic facies and architectural analysis of the deposits evidence the presence of bottom-current deposits (plastered, sheeted, elongated-separated and confined monticular drifts) and associated erosive features (terraces, scarps, moats and channels). Many of these deposits were previously considered to be open slope turbidite deposits which have now been reinterpreted as contourites.The contourite features have developed under the continuous influence of Mediterranean water masses, after the opening of the Strait of Gibraltar (roughly divided into light and dense Mediterranean waters), with plastered drifts dominating on the Spanish and Moroccan continental slopes, and sheeted drifts infilling the subbasins. The location and growth of contourite features have been mainly controlled by two main factors: i) tectonics, which has governed the relocation of the main pathways of the water masses; and ii) climate, which has influenced both water mass conditions and the depth of interfaces, as well as hinterland sediment sources, conditioning the morphoseismic characteristics of the drifts (facies and geometry) and terrace formation (dimensions). The mapping of the contourite facies through time has allowed defining three main scenarios for deep water circulation since the opening of the Strait of Gibraltar, which are: i) Atlantic Zanclean flooding; ii) the Pliocene sea, with two different stages caused by the progressive relocation of flow pathways; and iii) the Quaternary sea, with well defined characteristics and mostly stable flow pathways for the AW, and light and dense Mediterranean waters.This work lead us to consider the geologic framework characterizing the Alboran Sea may have played an important role in the interaction of the Mediterranean Waters before entering the Strait of Gibraltar, and thus in forming the MOW. Additionally, the results of this work may help in understanding the sedimentation in other Mediterranean margins affected by the same water masses and other partly land-locked basins with exchanges of waters over a confining sill.

13 pages, 9 figures, 1 table

2nd Deep-Water Circulation Congress: The Contourite Log-book, 10-12 September 2014, Ghent, Belgium.-- 2 pages, 2 figures, The Gulf of Cadiz records the interplay of a variety of sedimentary processes related to the circulation of water masses. The most important one is the Mediterranean Outflow Water (MOW) that exits the Mediterranean Sea, but other water masses also affect the seafloor, with complex variations along time and space. This work studies the interplay between oceanographic and gravitational sedimentary processes on the Guadalquivir Ridge, based on bathymetry and high-resolution seismic profiles. A series of morphological features including flat terraces, circular/elliptical depressions, semicircular scarps and valley-shaped features are analysed in order to better understand the interaction between water masses circulation and mass-wasting processes of the Gulf of Cadiz, This research has been funded by MINECO through the projects MONTERA (CTM2009-14157-C02-02) and MOWER (CTM2012-39599-C03-02)

The seafloor morphology of the Passage of Lanzarote has been analysed with the aim to know the active processes on the bottom surface related to the oceanographic context. Multibeam bathymetric data and high and very high resolution seismic profiles obtained in the SUBVENT2 cruise have been used. Five main morphological groups have been analysed: (a) Volcanic or diapiric submarine hills; (b) Tectonic features on the continental slope (linear scarps and a rhombohedral depression) related to normal faults; (c) Submarine venting at top of diapirs initially triggered circular depressions; (d) Sedimentary instabilities (gullies, canyons, mass transport deposits) are present specially on the Fuerteventura-Lanzarote ridge; and (e) Contouritic bottom features both erosive (central valley, marginal valleys) and depositional (plastered drifts) are on the central part of the passage, and are generated by the interaction of MW and the interface MW-AAIW with seafloor., SI

A multiple Contourite Depositional System has been defined in the Plio-Quaternary sedimentary register in the Alboran Sea. This multiple system formed by the Atlantic and the low density and high density Mediterranean Waters, which shaped the margins and basins since the opening of the Gibraltar Strait. Three different (paleo)circulation scenarios are proposed since then: the Atlantic water Flooding;the Pliocene circulation, characterized by immature low and high density Mediterranean waters and a strong countercurrent in the Western Basin; and the Quaternary circulation, characterized by tabular Mediterranean water masses with multiple current dynamics,an increasing influence of density contrasts, and climate shifts causing major vertical and horizontal displacements of their interfaces., SI

The seabed morphology and the sub-superficial characteristics of the Cristóbal Colón diapir located on the continental slope of the Gulf of Cadiz have been analysed from data obtained in the framework of the LIFE+INDEMARES/CHICA project. The aim of this study is to recognize the morphological features and the geological processes generated by the bottom water masses and their influence on the habitats and associated benthic communities. The NACW affects the generation of morphological features on the summit, revealing that different oceanographic conditions favoured the carbonate mound growth in the past. The interface between the NACW and the MOW sweeps the bottom from the SE to the NW and the presence of benthic communities dominated by filter feeders on the contouritic drift indicates that this current is strong enough to favour the availability of nutrients and organic particles and to develop both the contouritic deposits on the SE flank and the moats on the N and W flanks., SI

La interpretación de una serie de registros de sísmica de muy alta resolución con ecosonda paramétrica TOPAS obtenidos en las campañas CADHYS0713, INDEMARES/CHICA1011 y ARSA 0313 en el sector oriental de la plataforma continental y talud superior del Golfo de Cádiz entre los 50 y los 400 m de profundidad, ha permitido identificar una serie de estructuras tectónicas que deforman tanto los depósitos de edad Holoceno y Pleistoceno Superior, como la superficie del fondo . Estas unidades estratigráficas se han identificado sobre la Superficie Transgresiva Posglacial, datada en 18 ka. Las principales estructuras identificadas son fallas normales y fallas inversas, cuya actividad se ha relacionado con fases de elevación de estructuras diapíricas de naturaleza salina que se extienden desde zonas emergidas hasta zonas distales del margen continental del Golfo de Cádiz., Very high resolution parametric echosounder (TOPAS) data interpretation obtained during CADHYS0713, INDEMARES/CHICA1011 and ARSA0313 cruises along the middle, external shelf and upper slope of the eastern Gulf of Cadiz between 50 and 400 m depth has allowed us the identification of several active tectonic structures acting since the Holocene. To date this activiy, it have been identified along the study area three postglacial discontinuities, Postglacial Trangressive Surface (TS) of 18 ky BP; the maximum flooding surface (MFS) of 6.5 ky; and the 3.5 ky Mid highstand deposits surface (MHS). Active normal and reverse faults have been identified whose recent activity is closely linked to the uplift episodes of salt diapirs structures from onshore to distal areas of the continental margin.

Dialogue Between Contourite and Oceanography processes International Workshop, University of Hull, 28-26 January 2013, University of Hull, UK, The analysis of high-resolution (sparker, 3-channel Airgun) and very high-resolution (TOPAS, Parasound) seismic reflection profiles and multibeam bathymetry compiled during several oceanographical cruises in the northern Alboran Sea (SW Mediterranean), have allowed to study the morphology and origin of negative-relief features located on the contourite deposits developed in the vicinity of the seamounts - Avempace, Herradura, and Djibouti Ville (Al-ldrissi) - on the Motril Marginal Plateau (northern Alboran Sea). Two types of negative-relief features have been identified according to their circular or elongated morphology. Circular-like shapes match with pockmark and scour mark morphologies. The pockmarks are placed at the N and NW of the Avempace Seamount from 672 to 740 m water depth. 48 pockmarks have been described and they al1 display V-shaped cross-section. They are 1-19 m high and 50-400 m wide and but only some show higher backscatter than the surrounding areas. The scour marks occur isolated or clustered in the surroundings of the Herradura Seamount at 750-900 water depth. These negative-relief features are both V- and U-shaped in cross-sections. Ushaped scour marks display flat-bottom and truncated reflectors along their walls. Elongated-like shapes match with tectonic depressions and furrows. Tectonic depressions are NNE-SSW linear features, isolated and forming groups with a rhombshape distribution, that locate at 650-1,000 m water depth. The furrows are smallsized erosive ENE-WSW features 1-5 m high and 200 m wide, located at the NW of Avempace and Herradura seamounts from 720 to 900 m water depth. They show Ushaped cross-section running parallel the regional slope. The pockmark formation is attributed to the escape of seepage of gas and interstitial fluids from contourite sediments they affect. The Pockmark field location could be also related to normal basement faults that have favoured the upward migration of the fluid following pre-existing pathways. Scour marks are associated with the vorticity arising when bottom currents flow around a seamount. Upstream of the seamount, a turbulence are develops favouring the whirls occurrence that erode seafloor creating the scour marks. Tectonic depressions are related to the vertical displacement of a NNW-SSE strike-slip fault system and associated to seafloor rupture along the Pliocene Quaternary Faults that have affected even the most recent sediments. Additionally, they can perform as small channels that control the water flow to the SW. Furrows

Several attempts for establishing a good Plio-Quaternary stratigraphy were proposed and disputed since the beginning of the studies in the Alboran Sea during the 80’s. Now, we have reviewed all the available data with the purpose of improving the detail of the previous stratigraphy by adding new chronostratigraphic boundaries (Lower Pliocene Revolution –LPR-, Base Quaternary Discontinuity –BQD- and Middle Pleistocene Revolution –MPR-) with paleoclimatic and paleoceanographic significances. Their addition have allowed tracking the effects of the Mediterranean water masses on the sedimentation since the opening the Strait of Gibraltar. The new results indicate that the Pliocene and Quaternary sedimentary record is mainly characterized by contourites, comprising both depositional and erosive features, that contribute to the outbuilding of the margins and infilling of the basins. Thus, a new Plio-Quaternary sedimentary evolution model with dominance of the alongslope processes has been established for the Alboran Sea., Desde el inicio de la investigación científica en el Mar de Alborán en los años 80 se han presentado varios trabajos de estratigrafía Plio-Cuaternaria. Recientemente hemos revisado todos los datos disponibles con el propósito de mejorar el nivel de detalle de la estratigrafía previa, añadiendo nuevos límites cronoestratigráficos (Lower Pliocene Revolution –LPR-, Base Quaternary Discontinuity –BQD- y Middle Pleistocene Revolution –MPR-) con significados paleoclimático y paleoceanográfico. Su inclusión nos ha permitido rastrear los efectos de las masas de agua mediterráneas sobre la sedimentación desde la apertura del Estrecho de Gibraltar. Los nuevos resultados indican que el registro sedimentario Plio-Cuaternario está principalmente caracterizado por contornitas, que comprenden tanto rasgos deposicionales como erosivos, que contribuyen a la construcción de los márgenes y relleno de las cuencas. Esto ha permitido establecer un nuevo modelo de evolución sedimentaria durante el Plio-Cuaternario con dominancia de los procesos longitudinales para el Mar de Alborán., Sí

We present some of the results of a geophysical and hydroacoustic exploration survey achieved in November-December 2011 in the El Hierro Island (Canarian Archipelago) aboard the RV “Sarmiento de Gamboa”. We used different geophysical techniques like multichannel seismic reflection and wide angle reflection, gravity measurements and parametric sounding, together with high resolution bathymetry mapping. The broad frequency range of the acoustic systems allows imaging the injection of buoyant volcanic plumes driven by gas bubbles exsolved from magma during the long lasting eruption of the submarine volcano., Sí

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VIII Simposio sobre el Margen Ibérico Atlántico (MIA15), del 21 al 23 de septiembre de 2015, Málaga.-- 4 pages, 2 figures, The Diego Cao channel is located on the central-north middle slope of the Gulf of Cadiz. It separates the Bartolomeu Dias and Faro sheeted drift plateaus to the north of the Guadalquivir Bank margin uplift. A striking linear series of circular depressions occur parallel to the channel on the Bartolomeu Dias sheeted drift (western channel flank), while a remarkable amphitheater-shaped escarpment affects the channel eastern flank. Their morphological and high- and medium-resolution stratigraphic analysis allows inferring their origin as the result of a complex interplay between oceanographic (bottom currents), mass-wasting and tectonic processes. All features seem to have a common origin, related to an especially active tectonic phase during the Mid-Pleistocene, probably related to adjustments of the deep structural features. Since then, the action of the bottom currents and the local influence of structural processes have shaped the present-day topography. The Diego Cao channel is re-interpreted as a contourite moat associated to a complex mounded, separated drift that includes the circular depressions. They result from contourite deposition over the erosional surface originated by widespread mass-wasting events during the Mid-Pleistocene, This research is part of the projects MONTERA (CTM-14157-C02-02) and MOWER (CTM-2012-395599-C03) funded by the Spanish Ministry of Economy and Competitivity. The research of Marga Garcia has been funded by a Juan de la Cierva and a Talentia Grant (Ref. 267226)

VIII Simposio sobre el Margen Ibérico Atlántico (MIA15), del 21 al 23 de septiembre de 2015, Málaga.-- 4 pages, 5 figures, This work presents results from bioturbation intensity and trace fossil analysis of the piston core PC07, recovered at Portimão Bank during the MONTERA cruise in 2012. The aim was to investigate the potential of bioturbation analysis as an indicator for mass movement events. Bioturbation and trace fossil identification was complemented with results from sedimentological analysis (grain-size, carbonates, organic matter), measurements of magnetic fabric parameters (mass magnetic susceptibility and anisotropy of magnetic susceptibility), and AMS 14C dating. Considering the vertical zonation of bioturbation, magnetic fabric changes, sedimentology and AMS radiocarbon dating, two intervals were identified, Interval A (0-180 cm) and Interval B (180-356 cm), being the limit between them placed at 180-181cm. These intervals seem to replicate almost the same vertical zonation of bioturbation and the trend of carbonates and organic matter changes downcore. The magnetic fabric parameters (degree of anisotropy – Pj and shape – T of the magnetic susceptibility ellipsoid) show the major change at about 180 cm. Geochronological results indicate that the age of sediments in Interval A is 8590 yr BP (31-32 cm) and 14 300 yr BP (103-104 cm). Otherwise, ages in Interval B are the following: 5035 yr BP (181-182 cm), 8900±50 yr BP (219-220 cm), 18999±120 yr BP (303-305 cm). These results point to the emplacement of sediments of Interval A on top of youngest sediments of Interval due to landsliding. Since no internal deformation is seen, probably this indicates translational movement and short transport from the source, This work was supported by MONTERA (CTM2009-14157-C02-MONTERA) and MOWER (CTM2012-39599-C03-02) projects

The Guadalfeo and the Adra submarine deltas off the northern coast of the Alboran Sea have been built up under the direct influence of short and mountainous rivers. The area is subjected to strong climatic seasonality, with sporadic winter torrential floods and high summer aridity. In addition numerous anthropogenic activities have affected these systems, mostly during the last two centuries. In order to decode the influence of climatic variability and anthropogenic impacts on sediment supplies during the recent past, five sediment cores were collected from the Guadalfeo and Adra submarine deltas. Benthic foraminiferal and sedimentological analyses, combined with radiocarbon dating, were performed. The impact of torrential floods alternating with periods of low rainfall or dry periods were recorded in the Adra and Guadalfeo prodeltas. Periods with low abundance of benthic foraminifera and high amounts of coarse-grained sediments, were interpreted as the result of enhanced sediment supply to the shelf triggered by major flood events. On the other hand, periods with high amounts of fine-grained sediments and high abundances of colonizers and opportunistic foraminiferal species indicate the establishment of new environments with distinct ecological constraints. These environments were driven by lower sediment supplies during low rainfall or dry periods. The most recent sedimentation seems to reflect the human interventions in the rivers basins, such as deviation of the main river courses and dams construction, which reduced the sediment input and promoted the deposition of shallow-water submarine deltas.

The construction and evolution of submarine deltaic deposits are influenced by a combination of allogenic and autogenic factors. Numerical simulation of turbidity currents are used to propose a morphodynamic model that quantifies the effect of the slope and river input variations on delta development/construction for the case of mountainous rivers subjected to a seasonal Mediterranean climate, such as those located in the northern shelf of the Alboran Sea. These simulations were performed by using both constant and variable rates of fluvial flows. Both theoretical and real bathymetric profiles were used in the simulations. The results indicate that both the river flow and the depositional basin slope are key features for the development of morphostratigraphic features of submarine deltas at different spatial scales.

The northeastern sector of the Gulf of Cadiz continental margin has been deeply studied the last two decades. The seafloor is characterized by the Gulf of Cadiz Contourite Depositional System, strong diapirism and seepage related to the mobility of the frontal units of the Gibraltar Arc. Since 2010 high resolution bathymetric data and high and very high resolution seismic reflection and parametric echosounder profiles have improved the resolution of the previous collected data set. These data allow to analyze the middle continental slope morphology and its shallow structure with the aim to know the active tectonic processes on the seafloor. Two types of structures have been considered: (a) anticline domes and (b) normal faults which produce linear scarps and tectonic depressions. The shallow tectonics in this region is mainly related to the high mobility of geological formations in the subsoil and their ductile mechanical behaviour.

The evolutionary stages of the submarine delta off the Adra River are investigated in this study, under the context of climatic fluctuations entangled with increasing human activities and interventions in the drainage basins and adjacent shores during the Middle to Late Holocene. To achieve that goal, we used an extensive database comprising a set of bathymetric data covering different time slices, a dense grid of high-resolution seismic data and several sediment cores collected in the two submarine lobes of the Adra River delta. Two main evolutionary phases can be identified. The first one extended through most of the construction history and was mediated by major climatic events at the Mediterranean scale; this phase included three major progradational events occurring during the Mid Holocene, the Roman time and the Little Ice Age. The most recent phase is strongly determined by human modifications of the fluvial channels, and resulted in a drastic transformation of the submarine sedimentary environment.