Origin of morphological depressions on the Guadalquivir Bank uplifted area (Gulf of Cadiz middle slope)

We have investigated the origin of morphological depressions (circular-elliptical depressions, amphitheatre-shaped escarpments and valleys) on the Guadalquivir Bank uplifted area (Gulf of Cadiz middle slope). This work is based on swath bathymetry and high- and mid-resolution reflection seismic datasets. Depressions occur on the distal (depositional) sector of the Gulf of Cadiz Contourite Depositional System, which has been developed under the influence of the Mediterranean Outflow Water (MOW). The Guadalquivir Bank is a NE-oriented relief that was uplifted along the Neogene and Quaternary. It forms the southern limit of the Bartolomeu Dias and Faro Sheeted Drift (SD) plateaus that are separated by the NW-trending Diego Cao Contourite Channel. Circular-elliptical depressions occur on the Bartolomeu Dias SD plateau, aligned parallel to the rim of the Diego Cao Channel. Irregular, crescent-shaped depressions occur to the SE of the study area and a valley surrounds the Guadalquivir Bank. The origin of these features is interpreted as the result of the interplay between oceanographic, mass-wasting, tectonic and fluid-escape processes. Four stages define the development of these features: 1) Onset of a contourite mounded drift associated with a proto-Diego Cao moat originated by a weak MOW circulation as it interacted with the structural features of the Guadalquivir Bank during the Lower Pliocene; 2) Evolution to a more complex multi-crest drift and moat system, probably as a result of an enhanced MOW and increased deformation of the underlying structures during the Upper Pliocene-Early Quaternary; 3) Event of enhanced tectonic activity that provoked widespread mass-wasting events along middle slope sheeted drift plateaus during the Mid Pleistocene. It was recorded in a prominent erosive surface under the present-day Diego Cao channel western rim and numerous slide scars displaying amphitheatre shapes on the limits of the plateaus; 4) Final stage (Late Quaternary) when the Mediterranean Intermediate Branch started flowing towards the N-NW along the deep gateway that was opened as a result of the mass-wasting event and/or structural adjustments. The contourite system evolved, due to tectonic events, to the present-day channel and a complex separated drift that includes circular depressions. They result from the interaction between the bottom current and the irregular basal surface created by the slide scars. During this phase, crescent-shaped depressions were created, probably by the interplay between bottom currents and fluid escape processes, and the marginal valley around the Guadalquivir Bank resulted from current reworking of the irregular topography of contouritic deposits affected by slide scars

Modelización de los end-members para reconocer fuentes de aporte sedimentario en contornitas: un caso de estudio en el Mar de Alborán

Contourite drifts are one the main morphosedimentary features in the Alboran Sea and their sediments are important archives of the past oceanographic conditions and sedimentary processes. The end-member modelling approach lets to decompose multimodal grain-size distribution into genetically meaningful subpopulation that may be related to different sediment transport mechanisms and source areas. Three end-members have been identified in the contourite drift and moat system located at the southern side of the Dijbouti Ville seamount that have been interpreted in terms of sediment sources. Two end-members point to an eolian source and comprise fine silt (EM1) and coarse silt (EM2) as modal grain-sizes, characterized by high and low contents, respectively, of terrigenous elements (Al, Si, Ti and K). The third end-member (EM3) indicates a fluvial origin and is mainly defined by a clay modal grain-size of intermediate and homogeneous content in terrigenous elements. Downcore variation of the relative proportion of these EMs can be used to decipher paleocenographic and paleoclimatic conditions in the Alboran Sea.Versión del edito

Interacción entre procesos sedimentarios longitudinales y transversales en el Mar de Alborán durante el Plioceno y Cuaternario

Several morphosedimentary signatures produced by the interaction between alongslope and downslope sedimentary processes have been identified in the Pliocene and Quaternary records as well as on the present-day seafloor of the Alboran Sea. The scenarios of interaction move between two-end-members: from bottom currents dominating gravity flows to gravity flows dominating contour currents. In between these extreme cases, the alternation and balancing of both processes can occur; bottom current activity influencing the gravity flows has been also detected. Although interaction occurs in the Spanish and Moroccan margins, it is especially complex and varied on the Spanish margin, with regional and local effects on the turbidite systems. In contrast, the interaction on the Moroccan margin primarily inhibits the formation of canyons and related fan lobe deposits.Versión del edito

Detailed analysis of the interaction between alongslope and downslope sedimentary processes in the Alboran Sea during the Pliocene and Quaternary

This work aims to analyze the interaction between alongslope contouritic and downslope gravitational processes in the Alboran Sea. Recent results (Juan et al., 2012, 2016) demonstrated that the Pliocene and Quaternary stratigraphic architecture is mostly made up the vertical stacking of contourites interrupted by turbidite systems (TSs). The accurate analysis of all available seismic profiles has revealed several morpho-sedimentary signatures produced by the interaction of the Atlantic Water (AW) and Mediterranean waters (MWs) with the gravity flows in the Pliocene and Quaternary sedimentary record, as well as on the present-day seafloor. Different levels of interaction have been identified and they move between two-end-members: from bottom currents dominating gravity flows, to gravity flows dominating bottom currents. In between these extreme cases, a range of possibilities can occur. First, downslope and alongslope processes can alternate, with vertical and cyclic stacking of both types of deposit. Second, these processes can be balanced, allowing the simultaneous outbuilding of contourites and gravity flow deposits. Last, bottom currents can influence gravity flows. This last interaction is the most common in the Alboran Sea, resulting in the migration of the fan deposits in the direction of the dominant current, and also with effects on the architecture of the turbidite fans, and on their sedimentary composition (grain size). The different levels of interaction change in space and time. These changes have controlled the different depositional architecture displayed by the Spanish and Moroccan margins and the lateral changes along the Spanish margin as a consequence of the different architecture of the turbidite systems. Although interaction occurs in both margins, it is especially complex and varied on the Spanish margin, where the alongslope action is related to the AW, the light intermediate and the dense deep Mediterranean waters (LMw and DMw, respectively). This complex interaction has resulted in a depositional architecture that changes laterally as a consequence of the different architecture of the turbidite systems. Contrasting, on the Moroccan margin the alonsglope action is dominant, being mainly governed by the energy of the AW and the WMDW, that primarily inhibits the formation of canyons and related fan lobe deposits. This inhibition has been interpreted to be result of the topographical acceleration of the WMDW core that would favour an intense alongslope sediment transport, preventing deposition, avoiding the convergence of sediment, and thus inhibiting the formation of downslope gravity flows

Seismic architecture of mud volcano systems in the Ceuta

Analysis of a new dataset of high-resolution seismic and swath bathymetry data acquired during the CONTOURIBER-1 cruise in the Ceuta Contourite Depositional System (Western Alborán Sea), reveals the detailed architecture of several mud volcanoes systems that comprises both surface and buried constructional edifices as well as their subsurface feeder complex which pierces the contourite deposits. Seismic characterization, distribution and interpretation of structural elements associated to the mud volcano system promotes a more comprehensive understanding of the processes involved in their genesis and evolution.El análisis de los datos batimétricos y de sísmica de alta resolución durante la campaña CONTOURIBER-1 en el Sistema Deposicional Contornítico de Ceuta (Mar de Alborán occidental) muestran la arquitectura en detalle de varios sistemas de volcanes de fango que comprenden edificios en el fondo marino y edificios enterrados, así como sus complejos de alimentación a través de los depósitos contorníticos. La caracterización sísmica, distribución e interpretación de estos elementos estructurales que componen el sistema de volcán de fango constituyen una importante ayuda para un mejor y mayor conocimiento de su génesis y evolución.Publicado

Palaeoceanographic implications of current-controlled sedimentation in the Alboran Sea after the opening of the Strait of Gibraltar

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

Djibouti Ville Drift (SW Mediterranean): Sedimentation and record of bottom-current fluctuations during the Pleistocene and Holocene

Seismic profiles and sedimentological data (bulk fraction) of two sediment cores recovered from the Djibouti Ville Drift (SW Mediterranean Sea) indicate that bottom currents have played a fundamental role in shaping the sediment drift. The deposits are composed of biogenous to mixed muddy and silty contourites. A grain size analysis of the terrigenous fraction together with mineralogical, magnetic susceptibility, 14C-AMS dating and stable oxygen isotope data have been analysed to reconstruct glacial and interglacial changes in the bottom currents during the last 133kyr. The sharp vertical grain size changes in the moat and drift indicate that there were substantial bottom current acceleration and deceleration events with faster flow speeds being registered in the moat environment. In sediments from glacial periods (MIS2, MIS3, and MIS6) and stadials 5b and 5d, there is a low carbonate content, high levels of terrigenous elements and paleocurrent proxy values suggest faster flows with the exception of MIS4. Deposits from the interglacial period (MIS1) and interstadials 5a, 5c and 5e, have a high carbonate content, low levels of terrigenous elements, and the paleocurrent proxy values indicate slower flows.Versión del edito

Water mass footprints in uneven turbidite system development in the Alboran Sea

Multidisciplinary work between oceanography, geomorphology and sedimentology has uncovered evidence explaining the uneven development of the turbidite systems (TSs) in the Alboran Sea. Nine TSs have been mapped in the Spanish margin, ranging from sandy to mixed sand-mud fans, and which become sandier towards the Strait of Gibraltar; in contrast TSs do not develop in the Moroccan margin, where three canyons incise the continental slope but there is no TS formation. We interpret that the uneven development of TSs in the two margins and their variable architectures are conditioned by the interaction of alongslope with downslope processes. Two different interaction scenarios with varying intensities are proposed.Versión del edito

(Paleo)circulation models in the Alboran seas during the Pliocene and Quaternary

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.Versión del edito

New approaches for the identification of KChIP2 ligands to study the KV4.3 channelosome in atrial fibrillati

Resumen del trabajo presentado en el VIII Congreso Red Española de Canales iónico, celebrado en Alicante (España) del 24 al 27 de mayo de 2022.Ion channels are macromolecular complexes present in the plasma membrane and in intracellular organelles of the cells, where they play important functions. The dysfunction of these channels results in several disorders named channelopathies, which represent a challenge for study and treatment.[1] We are focused on voltage-gated potassium channels, specifically on KV4.3. Kv4.3 is expressed in smooth muscle, heart and brain. Within the heart, Kv4.3 channels generate the transient outward potassium current (ITO). However, ITO characteristics are only observed when Kv4.3 assemble with accessory subunits as KChIP2 and DPP6. KV4.3 channelosome play a key role in atrial fibrillation (AF),the most common cardiac arrhythmia, with an estimated prevalence in the general population of 1.5–2%. However, current antiarrhythmic drugs for AF prevention have limited efficacy and considerable potential for adverse effects.[2] KChIP2 (Potassium Channel Interacting Protein 2) belongs to the calcium binding protein superfamily. It is the KChIP member predominantly expressed in heart and a key regulator of cardiac action potential duration. The identification of novel KChIP2 ligands could be useful to understand the role of KV4.3 channelosome in AF and it could help to discover new treatments for AF. [3] In this regard, structure-based virtual screening could be an important tool to accelerate the identification of novel KChIP2 ligands. In this communication, we will describe a multidisciplinary approach that, starting with a structurebased virtual screening, followed by an iterative process of synthesis/biological evaluation/docking studies, has led to the identification of new KChIP2 ligands.PID2019-104366RB-C21, PID2019-104366RB-C22, PID2020-114256RB-I00 and PID2020-119805RB-I00 grants funded by MCIN/AEI/10.13039/501100011033; and PIE202180E073 and 2019AEP148 funded by CSIC. C.V.B. holds PRE2020-093542 FPI grant funded by MCIN/AEI/10.13039/501100011033. PGS was recipient of an FPU grant (FPU17/02731). AB-B holds BES-2017-080184 FPI grant and A.P-L.holds RYC2018-023837-I grant both funded by MCIN/ AEI/ 10.13039/501100011033 and by “ESF Investing in your future