Ricardo León

Instituto Geológico y Minero de España | IGME · marine geology

Multibeam bathymetry, sub-bottom parametric profiler, multichannel seismic reflection data and sediment cores were used to detail the nature, morpho-sedimentary and internal structure of five newly discovered submarine mud volcanoes (MVs) in the Moroccan margin of the Gulf of Cadiz. The Henriet and Subvent MVs are located at 300–400 m water depth,...

Within the framework of the LIGCANARIAS research project (2018-2021), the Inventory of Geological Sites of Interest of the Canary Islands has been carried out, which is part of the Spanish Inventory of Places of Geological Interest (IELIG) for the domain of this archipelago. The inventory has used the IELIG methodology adapted to an eminently volca...

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...

This paper integrates sedimentary, tectonic and volcanic geological processes inside a model of volcano-tectonic activity in oceanic intraplate domains related to rifted continental margins. The study case, the eastern Canary Basin (NE Atlantic), is one of the few places in the world where giant MDTs and Quaternary volcanic and hydrothermal edifice...

EXECUTIVE REPORT SUMMARY The main achievement of the GARAH project is a harmonized, scientifically based, geological analysis and assessment of the conventional and unconventional offshore hydrocarbon resources (Geological Analysis and Resource Assessment of selected Hydrocarbon systems (GARAH) – GeoERA). This contributes to sustainable and afforda...

This paper characterizes in detail for the first time the gravitational instabilities in two zones of the northern Galicia Area (Bay of Biscay, NE Atlantic): the Jean Charcot ridge (3700 to 4950 mwd) and the Castro marginal platform (1900 to 2500 mwd). Mass transport deposits (MTDs) show different seismo-stratigraphic structures depending on their...

In this work, we integrate five case studies harboring vulnerable deep-sea benthic habitats in different geological settings from mid latitude NE Atlantic Ocean (24–42° N). Data and images of specific deep-sea habitats were acquired with Remoted Operated Vehicle (ROV) sensors (temperature, salinity, potential density, O2, CO2, and CH4). Besides doc...

This paper presents a geohazard assessment along the European continental margins and adjacent areas. This assessment is understood in the framework of the seafloor’s susceptibility to (i.e., likelihood of) being affected by the presence of hydrate deposits and the subsequent hazardous dissociation processes (liquefaction, explosion, collapse, crat...

A geomorphological analysis of the submarine landslides GIS catalogue of the Geological Survey of Spain has revealed three main groups of submarine landslides associated with: i) deep ocean seamount ridges (extinct spreading centres), ii) volcanic islands and iii) continental margins. These three groups have statistically significant morphometric d...

Large national programs in the United States and several Asian countries have defined and characterised their marine methane hydrate occurrences in some detail, but European hydrate occurrence has received less attention. The European Union-funded project “Marine gas hydrate – an indigenous resource of natural gas for Europe” (MIGRATE) aimed to det...

The morphometrical analysis of the Spanish submarine landslides shows a different trending depending on the geological/tectonic context where they have been developed. Three main groups can be separated depending on the significant differences detected between minimum or maximum bathymetry versus sphericity (maximum width/run out): deep ocean ridge...

A new temporal history of mass wasting processes for the west of the Canary volcanic province is presented. Its onset has been estimated in the middle–upper Miocene (∼13.5 ± 1.2 Ma), matching with a critical period of construction for this volcanic province. Seismic profiles show an emplacement longevity (from the Miocene to Quaternary) in multiple...

A new temporal history of mass wasting processes for the west of the Canary volcanic province is presented. Its onset has been estimated in the middle–upper Miocene (∼13.5 ± 1.2 Ma), matching with a critical period of construction for this volcanic province. Seismic profiles show an emplacement longevity (from the Miocene to Quaternary) in multiple...

A joint study and mapping of the morphological features and architecture of the Galicia margin based on high-resolution multibeam bathymetry data and multichannel seismic profiles, provides new insights of the margin morphostructure. Tectonic processes are the major control of the margin's morphology, where the imprint of the North Atlantic rifting...

A GIS catalogue of gas seeps around the Iberian Margin has been performed for the first time in the framework of the EMODNET-Geology-3 European project. Gas seep-related features include mud volcanoes and pockmarks but also other indicators of seabed fluid venting as the occurrence of methane-derived authigenic carbonates (MDACs) and chemosynthetic...

Morphometric parameters of the submarine landslides reveal a relationship between the geological and tectonic controls where they have developed. Three main groups with significant differences between minimum or maximum bathymetry versus sphericity are defined: deep mid-ocean spreading ridges, volcanic islands and continental margins. While minimum...

This paper presents a Geographic Information System catalogue of the submarine landslides of the Spanish continental margin and describes the problems associated with harmonizing the catalogue with its onshore homologue. The data model structure is described to explain how to apply the rules and specifications following the Infrastructure for Spati...

Submarine geomorphology is the study of landforms and processes in the underwater domain. The ocean hosts a tremendous variety of forms that reflect the action of a range of tectonic, sedimentary, oceanographic, chemical and biological processes at multiple spatio-temporal scales. Submarine geomorphological mapping provides fundamental and effectiv...

High-resolution multibeam bathymetry, seismic reflection data, sediment core and water samples were used to first detail the morpho-sedimentary structure and seepage environment of a recently discovered mud volcano (MV) in the Atlantic Moroccan margin during the SUBVENT-2 cruise. Henriet MV is the most eastern edifice of the Gulf of Cadiz, located...

The seabed geomorphology of the Passage of Lanzarote (PoL), between the Lanzarote and Fuerteventura islands and the West Africa Continental Margin (WACM), has been considered with the aim to improve the knowledge of the main active processes working on the seafloor. We have analyzed the acoustic data obtained in the oceanographic cruise SUBVENT2 ca...

EMODnet es una iniciativa de la Comisión Europea (“Estrategia para el Conocimiento Marino 2020”) creada con el fin de desarrollar una infraestructura europea de datos marinos y facilitar el uso y acceso a la información a organismos gubernamentales, la industria y centros de investigación.

Spanish submarine landslides show different trends depending on the geological/tectonic context where they have been developed. Three main groups of landslides have been separated depending on the significant differences detected between minimum or maximum bathymetry versus sphericity ((maximum width/runout)and area-frequency distributions: deep oc...

The increasing volume of high-resolution multibeam bathymetry data collected along continental margins and adjacent deep seafloor regions is providing further opportunities to study new morphological seafloor features in deep water environments. In this paper, seafloor mounds have been imaged in detail with multibeam echosounders and parametric sub...

The morphometrical analysis of the Spanish submarine landslides shows a different trending depending on the geological/tectonic context where they have been developed. Three main groups can be separated depending on the significant differences detected between minimum or maximum bathymetry versus sphericity (maximum width/run out): deep ocean ridge...

The western Iberian margin has a complex morphology controlled by both geological and oceanographic processes. Compared to the submarine canyons in the southern part of this margin (e.g. Nazaré and Setubal), the canyons in the northern part (e.g. Ferrol and A Coruña) have received little attention. This study maps the geomorphological features arou...

This work presents a 3D geological model of the El Golfo debris avalanche, island of El Hierro (Canary Archipelago, Spain). The 3D model has been developed combining onshore and offshore geological and morphological data (Leon et al., 2017). This methodology is a valuable tool in assessing the tsunamigenic potential of flank collapses in oceanic vo...

Derived digital elevation models (DEMs) are high-resolution acoustic technology that has proven to be a crucial morphometric data source for research into submarine environments. We present a morphometric analysis of forty deep seafloor edifices located to the west of Canary Islands, using a 150 m resolution bathymetric DEM. These seafloor structur...

Landslides are common in aquatic settings worldwide, from lakes and coastal environments to the deep sea. Fast-moving, large-volume landslides can potentially trigger destructive tsunamis. Landslides damage and disrupt global communication links and other critical marine infrastructure. Landslide deposits act as foci for localized, but important, d...

Landslides are common in aquatic settings worldwide, from lakes and coastal environments to the deep-sea. Fast-moving, large volume landslides can potentially trigger destructive tsunamis. Landslides damage and disrupt global communication links and other critical marine infrastructure. Landslide deposits act as foci for localised, but important de...

New seismic profiles, bathymetric data and sediment-rock sampling document for the first time the discovery of hydrothermal vent complexes and volcanic cones at 4800-5200 m depth related to recent volcanic and intrusive activity in an unexplored area of the Canary Basin (Eastern Atlantic Ocean, 500 km west of the Canary Islands). A complex of sill...

Submarine volcanic eruptions are frequent and important events, yet they are rarely observed. Here we relate bathymetric and hydroacoustic images from the 2011-2012 El Hierro eruption with surface observations and deposits imaged and sampled by ROV. As result of the shallow submarine eruption, a new volcano named Tagoro grew from 375 to 89 m depth....

Mercator mud volcano has been explored by direct visual observations using a ROV at 350 to 370 m depth. Underwater images, taken mainly at the summit, have allowed characterizing the fluid venting environment, where different microforms, habitats and associated biota, with typical seepage components have been identified. Chemosynthetic bacterial co...

This paper presents a combined onshore-offshore morpho-structural characterization of the El Golfo giant landslide, island of El Hierro (Canary Archipelago, Spain). Offshore data from multibeam echosounders, chirp sub-bottom profiles and multichannel seismic reflection data and onshore data coming from water wells and galleries have been analyzed....

High-resolution single channel and multichannel seismic reflection profiles and multibeam bathymetric and backscatter data collected during several cruises over the period 1999 to 2007 have enabled characterising not only the seabed morphology but also the subsurface structural elements of the Yuma, Ginsburg, Jesús Baraza and Tasyo mud volcanoes (M...

A wide variety of marine mineral deposits were recovered from 750 to 1400 m water depths on Galicia Bank, Iberian margin. Mineral deposits include: (1) carbonate fluorapatite phosphorite slabs and nodules that replaced limestone and preserved original protolith fabric. (2) Ferromanganese vernadite crusts with high Mn and Fe (Mn/Fe = 1) contents, an...

This study shows an onshore-offshore morpho-structural characterization of the El Golfo flank collapse and debris avalanche on El Hierro (Canary Islands, Spain). Erosive and depositional features have been identified based on: LIDAR topography and geology from water galleries (onshore); and high-resolution 3.5 kHz and multichannel seismic reflectio...

This study presents the first version of a GIS catalogue of submarine landslides affecting the Spanish Continental Shelf pursuant UNCLOS (United Convention for the Law of the Sea) that comprise continental-type margins (Atlantic and Mediterranean) as well as hot-spot type volcanic islands and seamounts (Canary Archipelago). This first version compi...

The margin of the continental slope of the Volcanic Province of Canary Islands is characterised by seamounts, submarine hills and large landslides. The seabed morphology including detailed morphology of the seamounts and hills was analysed using multibeam bathymetry and backscatter data, and very high resolution seismic profiles. Some of the elevat...

Extrusive edifices and structural reliefs, catalogued as mounds and located on the seafloor to the west of Canary Islands were analyzed by acoustic data obtained with multibeam and parametric echosounders during several oceanographic expeditions. They were carried out at deep waters, from 4800 to 5200 m, and they have allowed characterizing 41 newl...

The Passage of Lanzarote is an example of a wide oceanic corridor. It extends between the eastern Canary Islands and the Western Africa continental margin. Seafloor morphology of this passage has been analyzed with the aim to know the morphogenetic processes related to both the oceanography and the geology. Multibeam bathymetric data and high and v...

The mud volcanism in the Iberian and Moroccan margins of the Gulf of Cadiz is well known over more than a decade. Nevertheless, new structures and morphologies related to fluid venting are still discovered in the recent oceanographic cruise SUBVENT2 in 2014 along the Moroccan margin. Four new mud volcanoes have been identified along two sector of M...

The continental slope of the Canary Islands volcanic province is characterized by the occurrence of several seamounts and large landslides that have been widely documented. A detailed morphological study of the Echo seamount has been done by using multibeam bathymetry, backscatter data and very high resolution seismic profiles. The seamount shape,...

We report precursory geophysical, geodetic, and geochemical signatures of a new submarine volcanic activity observed off the western coast of El Hierro, Canary Islands. Submarine manifestation of this activity has been revealed through acoustic imaging of submarine plumes detected on the 20-kHz chirp parasound subbottom profiler (TOPAS PS18) mounte...

New data and discoveries of marine Co-rich ferromanganese deposits from the Canary Islands recovered during the DRAGO 2011, SUBVENT 2013 and SUBVENT 2014 cruises are reported. These mineral deposits coat seamounts and submarine volcanoes from the southwest of the Canary Archipelago (Lat. 23º-27ºN). The volcanic rocks are largely covered with ferrom...

Integrating novel and published swath bathymetry (3,980 km2), as well as chirp and high-resolution 2D seismic reflection profiles (2,190 km), this study presents the mapping of 436 pockmarks at water depths varying widely between 370 and 1,020 m on either side of the Strait of Gibraltar. On the Atlantic side in the southeastern Gulf of Cádiz near t...

We report, for first time, the occurrence of cold-water coral mounds and large number of living Lophelia reefs along the Galicia Bank (Atlantic NW Iberian margin). Detection and mapping of living coral reefs and mounds have been carried out by means of multibeam bathymetry, backscatter images, ultra-high resolution and high-resolution multichannel...

Potencial de la minería submarina: Aplicación SIG para el estudio previo de contratos de exploración de costras de ferromanganeso con alto contenido en cobalto en los fondos marinos internacionales conforme al código minero regulado por la AIFM (Kinsgton, Jamaica) RESUMEN El control de los recursos naturales, cambiantes a lo largo de la historia, h...

Structure of mud volcano systems and pockmarks in the region of the Ceuta Contourite Depositional System (Western Alborán Sea), Marine Geology (2012), doi: 10.1016/j.margeo.2012.06.002 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscr...

An extensive terrace comprising sandy sheeted drifts characterises the proximal sector (close to the Straits of Gibraltar) of the Contourite Depositional System (CDS) of the Gulf of Cadiz and the western continental margin of Portugal. A novel morphosedimentary study over this terrace has been executed based on new multibeam echosounder data, seism...

A morpho-structural analysis of several mud volcanoes on the Moroccan Atlantic margin (Gulf of Cádiz) is presented. Multibeam data (bathymetry and backscatter), very high resolution seismic profiles from ultra-high resolution topographic parametric sounder (TOPAS) and gravity core data have been used. Analysis reveals an episodic mud extrusion dyna...

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 feede...

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 sound...

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 sound...

Ferromanganese nodule fields and hardgrounds have recently been discovered in the Cadiz Contourite Channel in the Gulf of Cadiz (850–1000 m). This channel is part of a large contourite depositional system generated by the Mediterranean Outflow Water. Ferromanganese deposits linked to contourites are interesting tools for palaeoenviromental studies...

A suite of ferromanganese nodules were sampled during the MVSEIS-2008 cruise aboard of the R/V Hespérides in the flanks of Meknes mud volcano (Moroccan margin, NE Central Atlantic). The nodules were collected at water depths between 750-850 m within a seabed area characterized by high acoustic backscatter values. Debris of cold water corals and hyd...

During the MVSEIS-08 cruise of 2008, ten new mud volcanoes (MVs) were discovered on the offshore Moroccan continental margin (Gulf of Cádiz) at water depths between 750 and 1,600 m, using multibeam bathymetry, backscatter imagery, high-resolution seismic and gravity core data. Mud breccias were recovered in all cases, attesting to the nature of ext...

This paper applies, for the first time in offshore deepwater, a method based on geographic information systems for seafloor susceptibility assessment as a first approach to marine geohazard mapping in fluid leakage areas (slope instabilities, gas escapes, seabed collapses, pockmarks, etc.). The assessment was carried out in a known seabed fluid-flo...

Multibeam bathymetry, high resolution multi-channel, and very high resolution single-channel (3.5kHz) seismic records were used to depict the complex geomorphology that defines the Galicia Bank region (Atlantic, NW Iberian Peninsula). This region (≈620–5,000m water depth) is characterized by a great variety of features: structural features (scarps,...

Son muchos los trabajos relacionados con las estructuras y morfologías a gran escala espacio-temporal relacionados con los procesos tectónicos en el talud continental del Golfo de Cádiz, sin embargo, son escasos los trabajos dedicados al estudio detallado de los procesos neotectónicos que pongan de manifiesto la actividad tectónica actual de este s...

An extensive set of multibeam bathymetry, high resolution multi-channelseismic data, and TOPAS and 3.5 kHzsub-bottom profiles acquired during BREOGHAM, ERGAP 1 and ERGAP2 have allowed the characterization of the imprints of the Mediterranean Outflow Water current on the Galicia Bank (NW iberian Margin). The study area, located from 600 to 1200 m wa...

Herein we describe a suite of fluid escape depression features, including pockmarks and collapse structures, discovered in the Gulf of Cádiz (Spain) during several recent cruises. We also establish an evolutionary model for these depressions and discuss the generation of bottom undercurrent furrows from fluid-flow structures, considering the oceano...