Gemma Ercilla

Spanish National Research Council | CSIC · Institute of Marine Sciences

The Sines Contourite Drift (SCD) is a plastered drift with terraced-like morphology, formed by the Mediterranean Outflow Water (MOW) that emplaced in the Alentejo Margin, SW Iberia. The high (~ 27 cm/kyr) and variable sedimentation rates experienced since the Pleistocene resulted in low consolidation, and the development of excess pore pressure, wh...

A modelling approach to understand the tsunamigenic potentiality of submarine landslides will provide new perspectives on tsunami hazard threat, mostly in polar margins where global climatic change and its related ocean warming may induce future landslides. Here, we use the L-ML-HySEA (Landslide Multilayer Hyperbolic Systems and Efficient Algorithm...

The Gulf of Cadiz and the Alboran Sea are characterized by tectonic activity due to oblique convergence at the boundary between the Eurasian and Nubian plates. This activity has favored a variety of tsunamigenic sources: basically, seismogenic faults and submarine landslides. The main tsunamigenic faults in the Gulf of Cadiz would comprise the thru...

Rabaute A.; Gorini C.; Leroy S.; Alonso B.; Le Roy, P .; Frigola J.; Emmanuel L. ; Ketzer M.; Praeg D. ; Lopez-Gonzalez N. and the ALBACORE Scientific party 1 EGU22-6547 EGU General Assembly 2022 © Author(s) 2022. This work is distributed under the Creative Commons Attribution 4.0 License. The Alboran Sea (Western Mediterranean) is a relatively s...

A modelling approach to understand the tsunamigenic potentiality of submarine landslides will provide new perspectives on tsunami hazard threat, mostly in polar margins where global climatic change and its related ocean warming may induce future landslides. Here, we use the Landslide L-ML-HySEA numerical model, including wave dispersion, to provide...

The Gibraltar Arc includes the Betic and Rif Cordilleras surrounding the Alboran Sea; it is formed at the northwest–southeast Eurasia–Nubia convergent plate boundary in the westernmost Mediterranean. Since 2006, the Campo de Dalias GNSS network has monitored active tectonic deformation of the most seismically active area on the north coast of the A...

Carbonate mounds clustering in three fields were characterized on the upper continental slope of the northern Alboran Sea by means of a detailed analysis of the morphosedimentary and structural features using high-resolution bathymetry and parametric profiles. The contemporary and past benthic and demersal species were studied using ROV underwater...

Earthquakes are the most commonly cited cause of offshore slope failure, followed by high sedimentation rates and ensuing pore pressure build-up. In the South Alboran Sea, the moderate seismicity (Mw = 6.4) of the strike-slip Al Idrissi Fault Zone does not appear to control directly the landslides distribution. To provide a preliminary geohazard as...

Deep-sea ecosystems of the Iberian margin have been widely impacted over the past decades, but the limited knowledge on their biodiversity and functioning limits our ability to contribute to their conservation. So far, in the Gulf of Cadiz, research has mostly been focused on megabenthic assemblages associated to mud volcanoes. However, several oth...

We present a multidisciplinary study of morphology, stratigraphy, sedimentology, tectonic structure, and physical oceanography to report that the complex geomorphology of the Palomares continental margin and adjacent Algerian abyssal plain (i.e., Gulf of Vera, Western Mediterranean), is the result of the sedimentary response to the Aguilas Arc cont...

The Holocene morpho-stratigraphic evolution of a compound submarine deltaic system linked with the Antas and Almanzora Rivers on the narrow (< 5 km) shelf along the Palomares margin (southeastern Iberia) has been reconstructed from the integrated analysis of geomorphology, seismo-stratigraphy and sedimentology. The shelf morphology is characterized...

In the Alboran Sea there are a few well exposed Neogene and Quaternary volcanic zones, often geographic highs, that are generally associated with magnetic anomalies. In this paper, we present a characterization of these magnetic anomalies based on a recent and accurate magnetic data compilation for the Abloran Sea area. The anomalies reveal the dis...

Palaeo-tsunamis in glaciated margins from submarine landslides: the case of Storfjorden glacial Fan (SW of the Svalbard Archipelago).

Tsunamis are triggered by sudden seafloor displacements, and usually originate from seismic activity at faults. Nevertheless, strike-slip faults are usually disregarded as major triggers, as they are thought to be capable of generating only moderate seafloor deformation; accordingly, the tsunamigenic potential of the vertical throw at the tips of s...

A marine hazard is a potentially damaging event, phenomenon or activity in the marine environment that may cause loss of human life, social and economic disruption or environmental degradation. In the last 30 years, natural and human-induced hazards have caused over 1.6 million victims and the economic losses average 300 thousand million dollars pe...

Le col El Onsar est un accident morphologique qui sépare les écailles calcaro-dolomitiques de la chaîne calcaire du Haouz, de leurs équivalents de Jbel Dersa. La nature et l’origine de ce col sont à rattacher à son histoire tectonique et à son évolution géomorphologique récente. D’échelle kilométrique et bien visible sur les ortho-images à 1/100.00...

Oceans are no longer inaccessible places for data acquisition. High-throughput technological advances applied to marine sciences ( from genes to global current patterns ) are generating Big Data sets at unprecedented rates. How to manage, store, analyse, use and transform this data deluge into knowledge is now a fundamental challenge for ocean scie...

Here, we want to explain the encountered difficulties to convince data providers for providing their information to the EMODnet ingestion portal, and how we tried to solve them, although we didn’t always achieved it. The difficulties were several, such as: arranging a face-to-face or virtual meetings to explain EMODnet; lack of awareness about the...

Offshore geological hazards can occur in any marine domain or environment and represent a serious threat to society, the economy, and the environment. Seismicity, slope sedimentary instabilities, submarine volcanism, fluid flow processes, and bottom currents are considered here because they are the most common hazardous processes; tsunamis are also...

The Alboran Basin is a Neogene-Quaternary extensional basin located within the Betic-Rif alpine cordillera. The region where the current basin is located holds great oceanographic relevance, as it lies in the area of connection between the western (Atlantic Ocean basin) and eastern seas (ocean basins of the Ligurian Tethys and then Western Mediterr...

The seafloor of the Alboran Sea reflects its complex tectonic, sedimentary, and oceanography dynamics as a consequence of the geological context, involving interaction between the Eurasian and African plates, and oceanographic context, as it is where the Atlantic and Mediterranean waters meet. Their physiography has a semi-enclosed configuration ch...

The seafloor of the Alboran Sea reflects its complex tectonic, sedimentary, and oceanography dynamics as a consequence of the geological context, involving interaction between the Eurasian and African plates, and oceanographic context, as it is where the Atlantic and Mediterranean waters meet. Their physiography has a semi-enclosed configuration ch...

Two Quaternary plastered contourite drifts, with terraced and low-mounded morphologies, make up the continental slope and base-of-slope in the northwestern Alboran Sea, respectively, between the Guadiaro and Baños turbidite systems, close to the Strait of Gibraltar. Considering their significant lateral extent, the link between the contourite drift...

Automation of the throw backstripping method has proven to be an effective tool for the determination of the evolution of tectonic activity in wide fault zones. This method has been applied to the Al Hoceima Bay (southwesternmost Mediterranean, Alboran Sea) for a time period covering the last 280 kyr on 672 faults imaged on 265 high-resolution seis...

The Western Mediterranean Deep Water (WMDW), on its way out toward the Atlantic Ocean, has favored the formation of contourite drifts in the Alboran Sea (SW Mediterranean) since the opening of the Strait of Gibraltar. Resolving the nature of these deposits is crucial for reconstructing the WMDW variability at a millennial scale, deciphering its bot...

Deception Island (South Shetland Islands) is one of the most active volcanoes in Antarctica, with more than 20 explosive eruptive events registered over the past two centuries. Recent eruptions (1967, 1969, and 1970) and volcanic unrest episodes (1992, 1999, and 2014–2015) demonstrate that volcanic activity is likely occurring in the future. This i...

Tsunamis are triggered by sudden seafloor displacements, and usually originate from seismic activity at faults. Nevertheless, strike-slip faults are usually disregarded as major triggers, as they are thought to be capable of generating only moderate seafloor deformation; accordingly, the tsunamigenic potential of the vertical throw at the tips of s...

This article offers an overview of the main sedimentary systems defining the geomorphology of deep sea environments from low to high latitudes. Mass-transport deposits, turbidite systems, contourites, volcaniclastic aprons, glacial trough mouth systems, carbonate mounds and other bathyal systems, such as pelagites, hemipelagites, mid-ocean channels...

The upper continental slope offshore Capo Vaticano (southern Tyrrhenian Sea) is characterized by a contourite depositional system with well-developed elongated sediment drifts. This system is related to a northward paleo-bottom current, similar to the present-day modified-Levantine Intermediate Water (modified-LIW) flowing from the Messina Strait....

El presente documento recoge las principales conclusiones extraídas a partir de la encuesta del “Impacto del confinamiento”, elaborada desde el Grupo de 1 Trabajo de Igualdad del ICM, durante el periodo en que la población se encontraba en Estado de Alarma debido a la crisis sanitaria provocada por la pandemia del COVID-19, concretamente del 15 al...

El presente documento recoge las principales conclusiones extraídas a partir de la encuesta del “Impacto del confinamiento”, elaborada desde el Grupo de 1 Trabajo de Igualdad del ICM, durante el periodo en que la población se encontraba en Estado de Alarma debido a la crisis sanitaria provocada por la pandemia del COVID-19, concretamente del 15 al...

The Sines Contourite Drift (SCD), located in the Alentejo margin, southwest Iberian continental margin, has been through many depositional phases in result of climatic variations and bottom current oscillations, which determined a variable depositional pattern and an irregular sedimentary evolution since the Late Pleistocene. The SCD, being in the...

A morphological and seismic-stratigraphic analysis of the Gulf of Cadiz area near the Strait of Gibraltar is presented in this work, focused on the sedimentary evolution of the upper and proximal middle-continental slope since the Mid-Pleistocene. Based on the analysis of seismic reflection profiles and swath bathymetry data, this work analyses the...

The evolution of the Le Danois contourite depositional systems (CDS) during the Pliocene and Quaternary was investigated based on high-resolution seismic reflection data. From old to young, six seismic units (U1–U6) bounded by major discontinuities (H1–H6) were identified. Regarding variations of the bottom-current circulation, four evolution stage...

A new basin-scale comprehensive view of contourite features, turbidite systems, and mass-wasting deposits comprising the Spanish and Moroccan margins and basins of the Alboran Sea has been achieved after a new detailed seismic stratigraphic analysis and the construction of sedimentary maps for the Pliocene and Quaternary sedimentary units. Multiple...

Progress in the understanding and dating of the sedimentary record of the Alboran Basin allows us to propose a model of its tectonic evolution since the Pliocene. After a period of extension, the Alboran Basin underwent a progressive tectonic inversion starting around 9–7.5 Ma. The Alboran Ridge is a NE–SW transpressive structure accommodating the...

Since the Miocene, the thinned continental crust below the Alboran Sea and its overlying sedimentary cover have been undergoing deformation caused by both convergence of Eurasia and Africa and by deep processes related to the Tethyan slab retreat. Part of this deformation is recorded at the Xauen and Tofiño banks in the southern Alboran Sea. Using...

Spain), a region of confluence between the Atlantic and Mediterranean, with intense maritime traffic. Several geological features, such as canyons, open slopes and contourite furrows and channels, were surveyed by remotely operated vehicle (ROV) observations between depths of 220 and 1000 m. Marine litter was quantified by grouping the observations...

Silicon (Si) is a pivotal element in the biogeochemical and ecological functioning of the ocean. The marine Si cycle is thought to be in internal equilibrium, but the recent discovery of Si entries through groundwater and glacial melting have increased the known Si inputs relative to the outputs in the global oceans. Known outputs are due to the bu...

Abstract. Progresses in understanding the sedimentary dynamic of the Western Alboran Basin lead us to propose a model of evolution of its tectonic inversion since the Pliocene to present-time. Extensive and strike-slip structures accommodate the Miocene back-arc extension of the Alboran Basin, but undergo progressive tectonic inversion since the To...

About six million years ago, the Mediterranean Sea underwent a period of isolation from the ocean and widespread salt deposition known as the Messinian Salinity Crisis (MSC), allegedly leading to a kilometer-scale level drawdown by evaporation. One of the competing scenarios proposed for the termination of this environmental crisis 5.3 million year...

We present a multidisciplinary study of the seismic stratigraphy, sedimentology, geochemistry and magnetism to characterize the Quaternary mass movement deposits (MMD) and the associated deformation in the Portimão Bank (Gulf of Cadiz, offshore SW Iberia). Two scales of approach have been applied. At large-scale (m to km) approach, were recognized...

This work uses seismic records to document and classify contourite features around the Iberian continental margin to determine their implications for depositional systems and petroleum exploration. Contourites include depositional features (separated, sheeted, plastered and confined drifts), erosional features (abraded surfaces, channels, furrows a...

The sedimentary instability dynamics occurring over time throughout the isolated Galicia Bank (Atlantic Ocean, NW Iberian Peninsula) have been studied using a sedimentological and geotechnical approach featuring a quantitative assessment of slope stability under different scenarios, including earthquake activity. The erosion of the scarps in the Ga...

Formed along the Paleotethys suture zone during the Jurassic, South Caspian and Kopet Dagh Basins (north of Iran) have been known as large-scale back-arc basins developed due to the long-term NE-directed Neotethys Subduction. The Kopet Dagh Basin has also been known as the eastern scissor-like crustal extension of the South Caspian Basin. On the ou...

The Djibouti Ville Drift is part of a contourite depositional system located on the southern side of the Djibouti Ville Seamount in the Alboran Sea (Western Mediterranean). The sedimentary record of a core located in the drift deposits has been characterized to achieve the possible sediment sources for the Saharan dust supply and the paleocurrent v...

New insights into the Cenozoic depositional architecture based on the seismic stratigraphy of the northern Argentine continental slope, off Bahia Blanca, allow us to reconstruct its sedimentary evolution. Five major seismic boundaries, B1 to B5 (from oldest to youngest) represent the main discontinuities bounding six seismic units: I (Eocene), II (...

Progresses in understanding the sedimentary dynamic of the Western Alboran Basin lead us to propose a model of evolution of its tectonic inversion since the Pliocene to present-time. Extensive and strike-slip structures accommodate the Miocene back-arc extension of the Alboran Basin, but undergo progressive tectonic inversion since the Tortonian. A...

The Miocene is an essential period in the configuration of the present-day relief of the Betic Cordillera and the South Iberian continental margin, which determined the structure and evolution of the Neogene sedimentary basins (Fig. 3.1). The crustal thinning processes that occurred during the early and middle Miocene, after the main metamorphic ev...

A nearly 400 km long erosion channel through the Strait of Gibraltar has been interpreted as evidence for a catastrophic refill of the Mediteranean at the end of the Messinian salinity crisis, 5.33 milion years ago. This channel extends from the Gulf of Cadiz to the Algerian Basin and implies the excavation of ca. 1000 km$^3$ of Miocene sediment fr...

The C5 core, collected on the Apulia continental slope in the Gulf of Taranto was, sampled with the aim of identifying very high-frequency climatic variations. Sedimentological analyses were performed. They are particle size analysis with laser, calcimetric analysis and terrigenous / biogenous content, the latter observing the sample under a micros...

An integrated analysis of multibeam bathymetry and single- and multichannel seismic records were used to image the morpho-stratigraphy of the Alentejo Margin (Southwest Portuguese Continental Margin). The complex interaction of several alongslope and downslope processes in the area leads to the formation of various bottom current driven depositiona...

This is an interdisciplinary study that combines morphoseismics, sedimentology and numerical modelling to elucidate at different scales of resolution the influence of alongslope processes on the turbidite systems (TSs) and canyons in the Alboran Sea (southwestern Mediterranean). Nine TSs are mapped in the Spanish margin (La Linea, Guadiaro, Baños,...

The Eurasian-African NW-SE oblique plate convergence produces shortening and orthogonal extension in the Alboran Sea Basin (Westernmost Mediterranean), located between the Betic and Rif cordilleras. A NNE-SSW broad band of deformation and seismicity affects the Alboran central part. After the 1993-94 and 2004 seismic series, an earthquake sequence...

In active basins, tectonics can segment the continental shelf and control its stratigraphic architecture and physiography. Segmentation can explain the local evolution and morphology of the continental shelf because of sea-level variations, local tectonic segmentation and hydrodynamic processes. Here we investigate the tectonically active Morocco c...

The seafloor of the Alboran Sea shows morphological evidence of the activity of several tectonic structures that basically correspond to two large families of conjugated strike-slip faults, the first of WNW-ESE to NW-SE trend and right-lateral movement, and the second of NNE-SSW to NE-SW trend and left-lateral movement, likewise it has been recogni...

The Alboran Sea, since the end of the Miocene, has been under a deformation regime resulting from the collision between the Eurasian and African plates. Consequently, a system of conjugate faults NNE-SSW and WNW-ESE with an angle of 75º was formed. These faults develop around the northern end of a rigid block spur of the African plate and are the o...