F. Javier González Sanz | Geological Survey of Spain-Instituto Geológico de España (IGME) (original) (raw)

Papers by F. Javier González Sanz

Marine Geology, 2020

Hydrothermal iron (Fe)-rich sediments were recovered from the Tagoro underwater volcano (Central ... more Hydrothermal iron (Fe)-rich sediments were recovered from the Tagoro underwater volcano (Central Atlantic) that formed during the 2011-2012 volcanic event. Cruises in 2012 and 2014 enabled the monitoring and sampling of the early-stage establishment of a hydrothermal system. Degassing vents produced acoustic flares imaged on echo-sounders in June 2012, four months after the eruption. A novel hydrothermal vent system was discovered and sampled in 2014 during a ROV dive. The system is characterized by hornito-like structures and chimneys showing active CO 2 degassing and anomalous temperatures at 120-89 m water depth, and along the SE flank at 215-185 m water depth associated with secondary cones. Iron-and silica-rich gelatinous deposits pooled over and between basanite in the hornitos, brecciated lavas, and lapilli. The low temperature, shallowwater hydrothermal system was discovered by the venting of Fe-rich fluids that produced a seafloor draped by extensive Fe-flocculate deposits precipitated from the neutrally buoyant plumes located along the oxic/photic zone at 50-70 m water depths. The basanite is capped by mm-to cm-thick hydrothermally derived Fe-oxyhydroxide sediment, and contains micro-cracks and degasification vesicles filled by sulfides (mostly pyrite). Mineralogically, the Fe-oxyhydroxide sediment consists of proto-ferrihydrite and ferrihydrite with scarce pyrite at their base. The Fe-rich endmember contains low concentrations of most trace elements in comparison with hydrogenetic ferromanganese deposits, and the sediments show some dilution of the Fe oxyhydroxide by volcanic ash. The Fe-oxyhydroxide phase, with a mean particle size of 3-4 nm, low average La/Fe ratios of the mineralized deposits from the various sampling sites, and the positive Eu anomalies indicate rapid deposition of the Fe oxyhydroxide near the hydrothermal vents. Electron microprobe studies show the presence of various organomineral structures, mainly twisted stalks and sheaths covered by iron-silica deposits within the mineralized samples, reflecting microbial iron-oxidation from the hydrothermal fluids. Sequencing of 16 s rRNA genes also reveals the presence of other microorganisms involved in sulfur and methane cycles. Samples collected from hornito chimneys contain silicified microorganisms coated by Fe-rich precipitates. The rapid silicification may have been indirectly promoted by microorganisms acting as nucleation sites. We suggest that this type of hydrothermal deposit might be more frequent than presently reported to occur in submarine volcanoes. On a geological scale, these volcanic eruptions and low-temperature hydrothermal vents might contribute to increased dissolved metals in seawater, and generate considerable Fe-oxyhydroxide deposits as identified in older hot-spot seamounts.

Geological Society London, 2023

This study summarizes a compilation of studies and cartographical work on seabed mineral deposit ... more This study summarizes a compilation of studies and cartographical work on seabed mineral deposit types in pan-European seas developed under the GeoERA-MINDeSEA project. In total, 692 occurrences and 1194 individual mineral samples of volcanogenic massive sulfides and hydrothermal mineralization, ferromanganese crusts, phosphorites, marine placer deposits, polymetallic nodules, and their associated strategic and critical raw material (CRM) elements have been characterized. The GeoERA-MINDeSEA project has been built based on extensive studies carried out previously, which include geophysical surveys, sampling stations, underwater photography and remotely operated vehicle (ROV) surveys, and mineralogical, geochemical and isotopic studies. This study develops pan-European and national databases, and expands strategic and CRM knowledge through a compilation of mineral potential and metallogenic studies of CRM resources in European seas. For the first time, the GeoERA-MINDeSEA portal publishes harmonized marine mineral resource information, case studies and maps, and identifies potential areas for responsible resource exploration and extraction, strategic management, and marine spatial planning. This study also provides recommendations for future target areas, studies and standards to be used across Europe as part of this project.

World Atlas of Submarine Gas Hydrates in Continental Margins, 2022

Gas hydrate systems in the Scotia Sea, the deep-water oceanic gateway between Antarctica and Sout... more Gas hydrate systems in the Scotia Sea, the deep-water oceanic gateway between Antarctica and South America, exist in a unique polar setting characterized by: (1) Very low bottom water temperatures (e.g., as low as −0.5°C at water depths of 2000-4000 m); (2) strong bottom currents sourced both from the ice stream discharge in the Weddell Sea and from the Antarctic Circumpolar Current that, combined with high sediment supply, generates giant contourite drifts; (3) high lateral variability of the geothermal gradient due to near-surface magmatism and hydrothermal activity, which is associated with a system of oceanic ridges and relict subduction arcs within the Scotia plate. In this area, the base of the gas hydrate stability zone as inferred from a gas hydrate-related bottom simulating reflector adapt to this changing environment, producing a peculiar association with gas-related structures in the subsurface.

World Journal of Engineering, 2021

This study aims to present the results of inductively coupled plasma mass spectrometry (ICP-MS) d... more This study aims to present the results of inductively coupled plasma mass spectrometry (ICP-MS) determination of economically significant metals including rare-earth elements and Y (REY), Co 1 Ni 1 Cu obtained from the Fe-Mn deposits (FMD) of different areas selected along the Atlantic Ocean. Design/methodology/approach-The description of the instrumental part of the analysis was shown in detail, including the choice of the acquisition mode and other settings of the quadrupole ICP-MS Agilent 7700x, which allow to eliminate spectral overlaps as much as possible and to achieve good precision and accuracy of the measurement. The accuracy of the obtained results was controlled by analysis of certified reference materials (CRM) of Fe-Mn nodules of the US Geological Survey-NOD-A-1 and NOD-P-1, as well as the Russian CRM samples of Fe-Mn nodule OOPE 603 (SDO-6) and ore crust OOPE 604 (SDO-7). Statistical processing of the analysis results demonstrated the acceptability of chosen sample preparation technique and ICP-MS tunes for the determination of REY in FMD. Findings-The performed analytical research allowed giving a geochemical characteristic of studied FMD. The precision for the elements to be determined according to the relative standard deviation (RSD) was within 5.0%. Originality/value-To move away from the subjective visual assessment of the analytical results quality in terms of absence (or presence) of the REE sawtooth distribution, an original objective mathematical method was proposed.

Geological Society London, 2019

On the basis of 2D multichannel and very-high-resolution seismic data and swath bathymetry, we re... more On the basis of 2D multichannel and very-high-resolution seismic data and swath bathymetry, we report a sequence of giant mass-transport deposits (MTDs) in the Scan Basin (southern Scotia Sea, Antarctica). MTDs with a maximum thickness of c. 300 m extend up to 50 km from the Discovery and Bruce banks towards the Scan Basin. The headwall area consists of multiple U-shaped scars intercalated between volcanic edifices, up to 250 m high and 7 km wide, extending c. 14 km downslope from 1750 to 2900 m water depth. Seismic sections show that these giant MTDs are triggered by the intersection between diagenetic fronts related to silica transformation and vertical fluid-flow pipes linked to magmatic sills emplaced within the sedimentary sequence of the Scan Basin. This work supports that the diagenetic alteration of siliceous sediments is a possible cause of slope instability along world continental margins where bottom-simulating reflectors related to silica diagenesis are present at a regional scale.

Quaternary Science Reviews, 2020

The South China Sea (SCS) is connected to the West Pacific through a deep channel in the Luzon St... more The South China Sea (SCS) is connected to the West Pacific through a deep channel in the Luzon Strait. Thus the SCS deep water is sensitive to the evolution of Pacific Ocean circulation, which significantly influences the global climate system. Geochemical data (Pb isotope and redox-sensitive elements data) and magnetic data were determined for a FeeMn nodule obtained from Jiaolong seamount in the central SCS. These records reflect interactions between changes in ice sheets, deep Pacific circulation, and weathering inputs to the deep SCS during the Pliocene and Quaternary. Our results show that the SCS deep-water environment can be divided into three major Stages (Stages 1e3). Stage 1 (~4.8e1.4 Ma) was characterized by a well-oxygenated Pacific Deep Water (PDW) and lower dust inputs; then moderate stable deep-water ventilation and greater inputs of Asian dust occurred during Stage 2 (1.4e0.9 Ma). During Stage 3 (<0.9 Ma), a more isolated PDW was accompanied by sluggish Pacific overturning circulation, probably due to the weakened southern-sourced deep-water formation. In general, the progressive intensification of northern hemisphere ice-sheet play an active role in controlling the variation of the deep-water environment in the SCS. Interestingly, the variation in deep-water ventilation lagged behind weathering and erosion around the Middle Pleistocene Transition, which strongly indicates that the ocean and continent environments had different sensitivities to the global paleoclimatic changes at the glacial climate boundary.

Marine and Petroleum Geology, 2021

Contourites are globally-distributed features along continental margins where deep-water masses c... more Contourites are globally-distributed features along continental margins where deep-water masses come across the seafloor; however, the genesis and metal-sources of marine mineral deposits associated with contourite deposits remain largely unknown. Abundant Fe-rich nodules were recovered along the continental margin of the South China Sea, where extensive cold-seep systems were also discovered. We measured synthetically geochemical elements, δ 13 C, Sr and Nd isotopic data and organic proxies in Fe-oxy-hydroxide deposits from the upper and lower slope. Fe-rich nodules recovered from the upper slope represent the effect of an integrated diagenetic-hydrogenetic formation environment, in which fluid venting from deep-seated hydrocarbon reservoirs and deep-water erosion and chemistry could play an important role. In contrast, another kind of ferromanganese nodule forming along the lower slope and predominantly hydrogenetic is connected to a distinct deep-water flow from the North Pacific. These results give us a new insight into the mineralization processes associated with Fe oxidation-reduction processes on continental margins affected by contourite systems with abundant hydrocarbon seep, bottom water, and terrigenous inputs.

Marine Geology, 2019

A joint study and mapping of the morphological features and architecture of the Galicia margin ba... more A joint study and mapping of the morphological features and architecture of the Galicia margin based on highresolution 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 and opening and later subduction of the Bay of Biscay and compressional events are still well preserved. The West Galicia margin, which is up to 350 km wide, is composed from east to the west of inner, transitional and outer sectors. The inner sector shows a graded upper slope strongly dissected by a system of submarine canyons and valleys that flow into the 170 km long and 40-60 km wide NW-SE Valle Inclán Valley. The transitional sector, which is up to 75 km wide, displays a smooth relief dominated by landslides and giant craters. Finally, the outer sector is characterised by several banks, N-S sub-parallel ridges and elongated valleys that project seaward over 200 km (i.e., Galicia Bank, Half-Graben, Deep Galicia margin and Peridotite Ridge domains). The North Galicia margin is characterised by a system of terraces up to 30 km wide, that form a stepped slope followed by an abrupt lower slope affected by large-scale rotational failures. The Galicia margin constitutes an exceptional area within the Atlantic margins for identifying different morphostructure styles that characterised the main stages of the margin's evolution along the Wilson cycle. The Galicia margin hosts the transition between two end-members of continental margin styles: a western hyperextended rifted margin (being the conjugate with the Newfoundland margin during the Late Jurassic) and a northern convergent margin (now fossilised) associated with the partial subduction of the southern sector of the Bay of Biscay underneath the North Iberian margin, which occurred in Paleocene-Eocene times. Thus, the morphostructure of the West Galicia margin still reflects the detached fault systems and tilted blocks that resulted from the Mesozoic North Atlantic rifting. Furthermore, the Coruña and Jean Charcot seamounts, which are adjacent to the Galicia margin, correspond to spreading ridges formed by the simultaneous opening of North Atlantic Ocean and the Bay of Biscay in the Upper Cretaceous. The rest of the terraced morphology of the North Galicia margin is derived from extensional faults caused by an overriding of the Iberian plate in relation to the subduction of the Bay of Biscay oceanic crust during Cenozoic times. Since the late Neogene, compressional tectonics resulting from the reorganisation of the Eurasia/Iberia and Africa plates is also reflected on the presentday morphology as the following: (i) an elevation of the Biscay Abyssal Plain up to 150 m over the Iberia Abyssal Plain; (ii) deep-seated landslides associated with an uplift of the Galicia Bank; and (iii) an orientation of submarine canyons along NW-SE strike slip faults. 1. Introduction The evolution of ocean basins and continental margins according to the "Wilson Cycle" (Wilson, 1966), a paradigmatic concept in plate tectonics, can be described in the following three phases: (1) opening and spreading; (2) foundering of the passive margins and development of new subduction zones; and (3) consumption and closure. The Wilson Cycle is not only registered in the geological record but is also

Ore Geology Reviews, 2020

The Ab-Bagh clastic-and carbonate-hosted stratabound and stratiform Zn-Pb deposit in the Sanandaj... more The Ab-Bagh clastic-and carbonate-hosted stratabound and stratiform Zn-Pb deposit in the Sanandaj-Sirjan zone, in the southeastern corner of the Malayer-Esfahan metallogenic belt of Iran, is typical of several sedimentary-exhalative (SEDEX) deposits in this metallogenic belt. The deposit is hosted in a late Jurassic-early Cretaceous sedimentary sequence. Based on position, there are two Zn-Pb-bearing stratigraphic ore horizons. Ore horizon 1 is hosted by late Jurassic-early Cretaceous black shale and siltstone. The wedge-shaped ore body is located close to a synsedimentary normal fault. Petrographic studies indicates that mineralization comprises three sulfide ore facies: stockwork, bedded and massive ore facies. Ore horizon 2 occurs in early Cretaceous carbonates and comprises a massive-replacement ore facies that is concordant with host rock layering; it is also underlain by a stockwork facies. Textures include framboidal, laminated, breccia, replacement, massive and vein-veinlet. Hypogene sulfide minerals are predominantly sphalerite, galena, pyrite and chalcopyrite. Calcite and quartz are major gangue minerals. Silicification and carbonatization are the main wallrock alteration styles; alteration intensity increases towards the feeder zone. Based on relationships between ore minerals and rockforming minerals, sulfide mineralization in the Ab-Bagh deposit formed during two main stages: fine-grained sulfide bands (stage I) are intricately interlayered with organic matter-rich beds of black shale and siltstone. Sulfide bands exhibit classic sedimentary textures, such as laminations and bedding, indicative of a synsedimentary origin. Coarser-grained stage II base metal sulfides show breccia and vein-veinlet textures, and are considered to have formed by replacement during sub-seafloor fluid flow. Fluid inclusion microthermometry was carried out on calcite associated with sulfides of the stockwork ore facies. Homogenization temperatures are in the range of 180-301°C, and the average salinity is 17.93 wt% NaCl eq. The size distribution of pyrite framboids of the bedded ore, geochemistry of host rock and presence of organic matter, collectively suggest anoxic to locally suboxic ambient conditions for the host basin. The δ 34 S composition of pyrite, sphalerite, and galena ranges from −5.08 to +4.51‰. The highest δ 34 S values are from massive and stockwork ore facies (+2.66 to + 4.51‰) and the lowest from bedded ore (−5.08 to −4.72‰). In the bedded ore facies, the main sulfur source was bacterially reduced seawater sulfate. Whereas in massive and stockwork ore facies, thermochemically reduced seawater sulfate was the main source of sulfur. The 87 Sr/ 86 Sr ratios of calcite indicate that origin of ore forming fluids is Paleozoic radiogenic basement. Collectively, the isotopic, sedimentological, textural, mineralogical, fluid inclusion, and geochemical data for the Ab-Bagh deposit support a vent-proximal sub-seafloor replacement SEDEX ore deposit.

Marine Geology, 2019

Deep-water ferromanganese (Fe-Mn) nodules cumulate trace elements from the underlying sediment po... more Deep-water ferromanganese (Fe-Mn) nodules cumulate trace elements from the underlying sediment pore-water and seawater during the concentric mineral layers' growth process over millions of years. They can record longterm tectonic movements and paleoceanographic changes. To systematically ascertain paleoceanographic evolution of the deep South China Sea (SCS) since the last 3.2 Ma, we comprehensively investigated microstructure, mineralogy, geochemical element concentrations as well as Sr, Nd and Pb isotopic compositions in the Fe-Mn nodules nearby the Dongsha Islands in the northern SCS. Results indicate that these deposits were formed in a continental marginal environment by a mixture of diagenetic and hydrogenetic processes. Overall, the studied nodules can be divided into three stages with different microstructures and chemical compositions, which indicate different formation environments. Stage 1a is the innermost and oldest layer with a porous mottled texture, and has the lowest Mn/Fe ratio, Cu, Ni and Zn, which implies comparatively high oxidization conditions. In contrast, the Mn mineralogy of Stage 2 shows conditions similar to those of buserite formed under less oxidative conditions. Between Stage 1a and 2, Stage 1b represents a mixture of Stage 1a and 2 and has inhomogeneous growth structures. Based on the Nd and Sr isotopic composition of the detrital phases and Pb isotopes, three potential terrigenous source regions including South China, Luzon and Taiwan that discharge into the northern SCS from 3.2 Ma to 1.06 Ma. After 1.06 Ma, the terrigenous fraction in the Fe-Mn deposits on the northern slope of the SCS is a two end-members mixture of fluvial input from Taiwan Islands and eolian dusts from the Chinese loess. Our study indicates that SCS bottom water variation occurred at~3.2 Ma, 2.1 Ma, and 1.06 Ma, respectively, which could be attributed to global cooling and the influence of Luzon arc-forearc uplift.

Acta Oceanologica Sinica, 2018

Ferromanganese nodules and crusts contain relatively high concentration of rare earth elements (R... more Ferromanganese nodules and crusts contain relatively high concentration of rare earth elements (REE) and yttrium (REY), with a growing interest in exploitation as an alternative to land-based REY resources. On the basis of comprehensive geochemical approach, the abundance and distribution of REY in the ferromanganese nodules from the South China Sea are analyzed. The results indicate that the REY contents in ferromanganese deposits show a clear geographic regularity. Total REY contents range from 69.1×10 –6 to 2 919.4×10 –6 , with an average value of 1 459.5×10 –6. Especially, the enrichment rate of Ce content is high, accounting for almost 60% of the total REY. This REE enrichment is controlled mainly by the sorption of ferromanganese oxides and clay minerals in the nodules and crusts. Moreover, the total REY are higher in ferromanganese deposits of hydrogenous origin than of diagenetic origin. Finally, Light REE (LREE) and heavy REE (HREE) oxides of the ferromanganese deposits in the study area can be classified into four grades: non-enriched type, weakly enriched type, enriched type, and extremely enriched type. According to the classification criteria of rare earth resources, the Xisha and Zhongsha platform-central deep basin areas show a great potential for these rare earth metals. Shuhong. 2018. Rare earth elements and yttrium in ferromanganese deposits from the South China Sea: distribution, composition and resource considerations. Acta Oceanologica Sinica, 37(7): 41–54,

Minerals, 2018

Two Fe–Mn crusts among 35 samples, from six seamounts in the Canary Island Seamount Province, wer... more Two Fe–Mn crusts among 35 samples, from six seamounts in the Canary Island Seamount Province, were selected as representatives of the endpoint members of two distinct types of genetic processes, i.e., mixed diagenetic/hydrogenetic and purely hydrogenetic. High-resolution analyses pursued the main aim of distinguishing the critical elements and their association with mineral phases and genetic processes forming a long-lived Fe–Mn crust. The Fe–Mn crust collected on the Tropic Seamount is composed of dense laminations of Fe-vernadite (>90%) and goethite group minerals, reflecting the predominance of the hydrogenetic process during their formation. Based on high-resolution age calculation, this purely hydrogenetic crust yielded an age of 99 Ma. The Fe–Mn crust collected on the Paps Seamount shows a typical botryoidal surface yielding an age of 30 Ma. electron probe microanalyzer (EPMA) spot analyses show two main types of manganese oxides, indicating their origin: (i) hydrogenetic Fe-vernadite, the main Mn oxide, and (ii) laminations of interlayered buserite and asbolane. Additionally, the occurrence of calcite, authigenic carbonate fluor-apatite (CFA) and palygorskite suggests early diagenesis and pervasive phosphatization events. Sequential leaching analysis indicated that Co, Ni, Cu, Ba and Ce are linked to Mn minerals. Therefore, Mn-oxides are enriched in Ni and Cu by diagenetic processes or in Co and Ce by hydrogenetic processes. On the other hand, Fe-oxides concentrate V, Zn, As and Pb. Moreover, the evidence of HREE enrichment related to Fe-hydroxides is confirmed in the mixed hydrogenetic/diagenetic crust.

Geochemistry, Geophysics, Geosystems, 2017

Submarine volcanic eruptions are frequent and important events, yet they are rarely observed. Her... more Submarine volcanic eruptions are frequent and important events, yet they are rarely observed. Here we relate bathymetric and hydroacoustic images from the 2011-2012 2 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. The eruption consisted of two main phases of edifice construction intercalated with collapse events. Hydroacoustic images show that the eruptions ranged from explosive to effusive with variable plume types and resulting deposits, even over short time intervals. At the base of the edifice, ROV observations show large accumulations of lava balloons changing in size and type downslope, coinciding with the area where floating lava balloon fallout was observed. Peaks in eruption intensity during explosive phases generated vigorous bubbling at the surface, extensive ash,vesicular lapilli and formed high-density currents, which together with periods of edifice gravitational collapse, produced extensive deep volcaniclastic aprons. Secondary cones developed in the last stages and show evidence for effusive activity with lava ponds and lava flows that cover deposits of stacked lava balloons. Chaotic masses of heterometric boulders around the summit of the principal cone are related to progressive sealing of the vent with decreasing or variable magma supply. Hornitos represent the final eruptive activity with hydrothermal alteration and bacterial mats at the summit. Our study documents the distinct evolution of a submarine volcano and highlights the range of deposit types that may form and be rapidly destroyed in such eruptions.

Geochemistry, Geophysics, Geosystems, 2017

New seismic profiles, bathymetric data and sediment-rock sampling document for the first time the... more 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 intrusions is imaged on seismic profiles showing saucer-shaped, parallel or inclined geometries. Three main types of structures are related to these intrusions. Type I consists of cone-shaped depressions developed above inclined sills interpreted as hydrothermal vents. Type II is the most abundant and is represented by isolated or clustered hydrothermal domes bounded by faults rooted at the tips of saucer-shaped sills. Domes are interpreted as seabed expressions of reservoirs of CH4- and CO2-rich fluids formed by degassing and contact metamorphism of organic-rich sediments around sill intrusions. Type III are hydrothermal-volcanic complexes originated above stratified or branched inclined sills connected by a chimney to the seabed volcanic edifice. Parallel sills sourced from the magmatic chimney formed also domes surrounding the volcanic cones. Core and dredges revealed that these volcanoes, which must be among the deepest in the world, are constituted by OIB-type, basanites with an outer ring of blue-green hydrothermal Al-rich smectite muds.
Magmatic activity is dated, based on lava samples, at 0.78±0.05 and 1.61±0.09 Ma (K/Ar methods) and on tephra layers within cores at 25-237 ky. The Subvent hydrothermal-volcanic complex constitutes the first modern system reported in deep-water oceanic basins related to intraplate hotspot activity.

El desarrollo de la sociedad moderna y el avance en la investigación tecnológica dependen íntimam... more El desarrollo de la sociedad moderna y el avance en la investigación tecnológica dependen íntimamente de la minería. Éstos están representados por algunos elementos como las tierras raras, el cobalto, el telurio o el platino que son codiciados por los países industrializados por su escasez y por sus propiedades físicas y/o químicas específicas.

Thick ferromanganese (Fe-Mn) crusts from four Cretaceous seamounts (The Paps, Tropic, Echo and Dr... more Thick ferromanganese (Fe-Mn) crusts from four Cretaceous seamounts (The Paps, Tropic, Echo and Drago) at the southern Canary Island Seamount Province (CISP) in the northeastern tropical Atlantic were recovered along the flanks and summits from 1700 to 3000 m water depths. CISP is composed of N 100 seamounts and submarine hills, is likely the oldest hotspot track in the Atlantic Ocean, and is the most long-lived of known hotspots globally. The Fe-Mn crusts grow on basalt-sedimentary rock substrates below the northeastern tropical Atlantic core of the oxygen minimum zone (OMZ) with a maximum thickness of 250 mm at a water depth of 2400 m. The mineral-ogical and chemical composition of these Fe-Mn crusts indicate a hydrogenetic origin. The main Mn minerals are vernadite with minor interlayered todorokite and asbolane-buserite. Fe oxides are essentially ferroxyhyte and goethite. The Fe-Mn crusts show high average contents in Fe (23.5 wt%), Mn (16.1 wt%), and trace elements like Co (4700 μg/g), Ni (2800 μg/g), V (2400 μg/g) and Pb (1600 μg/g). Rare earth elements plus yttrium (REY) averages 2800 μg/g with high proportions of Ce (1600 μg/g). Total platinum group elements (PGEs) average 230 ng/g, with average Pt of 182 ng/g. Two main types of growth layers form the crusts: 1) a dense laminae of oxides with high contents in Mn, Co and Ni associated with vernadite and Cu, Ni, and Zn associated with todorokite; 2) botryoidal layers with high contents in Fe, Ti, V and REY associated with goethite. The Fe-Mn crusts from the CISP region show higher contents in Fe, V, Pb and REY but lower Mn, Co, Ni and PGEs contents than Pacific or Indian ocean seamount crusts. The oldest maximum age of initiation of crust growth was at 76 Ma (Cam-panian, Late Cretaceous). Using a combination of high resolution Co-chronometer and geochemical data along an Electron Probe Micro Analysis (EPMA) transect, four stages in morphology, chemical contents and growth rates can be differentiated in the the Cenozoic crusts since 28 Ma, which we interpret as due to changes in the ventilation of the North Atlantic OMZ and to the increase of Saharian dust inputs. An earliest growth period, characterized by similar contents of Fe and Mn in the interval 27.8–24.45 Ma (late Oligocene-early Miocene) reflects slow precipitation related to a thick OMZ. An intermediate laminated zone with higher contents of Fe, Si and P, high growth rates reaching 4.5 mm/Ma, and precipitation of Fe-Mn oxides during the interval 24.5–16 Ma is related to periods of ventilation of the OMZ by intrusion of deep upwelling currents. Significant increase in Fe contents at ca. 16 Ma correlates with the onset of incursions of Northern Component Waters into the North Atlantic. Finally, since 12 Ma, the very low growth rates (b0.5 mm/Ma) of the crust are related to a thick North Atlantic OMZ, an increase in Sahara dust input and a stable thermohaline circulation.

Marine ferromanganese (Fe-Mn) nodules and crusts are archives of past environmental conditions an... more Marine ferromanganese (Fe-Mn) nodules and crusts are archives of past environmental conditions and potential mineral resources. Over the last 30 years, many have been discovered in the northern South China Sea (SCS). To determine the origin of the Fe-Mn deposits, a comprehensive laboratory analysis of physical properties, mineralogy and geochemistry was conducted on newly collected Fe-Mn nodule/crust samples. The results revealed that there are three types of Fe-Mn deposits: (1) Fe-rich nodules containing essentially goethite occur on the northeastern slope of the SCS, with high Fe, low Mn (Mn/Fe = 0.03) and low trace metals and rare earth elements concentrations; (2) Smooth Fe-Mn nodules and crusts composed of asbolane, todorokite and CFA occur along the northwestern marginal of the SCS that have similar Fe and Mn contents (Mn/Fe = 1.21), moderate trace metal enrichments, and a positive Ce anomaly; (3) Fe-Mn nodules and crusts composed of asbolane, todorokite and birnessite that occur in the central basin of the SCS have higher Mn and lower Fe contents (Mn/Fe = 1.45). This depositional pattern was associated with major changes in oceanographic conditions and tectonic regimes. The northeastern slope deposits occur in a contourite depositional system, are strongly enriched in Fe relative to Mn (average 38.7% and 0.96%, respectively), formed from the combination of hydrogenetic and diagenetic processes. We propose a new genetic model for Fe-Mn nodules, which formed through the oxidation of pyrite and pyrite-barite concretions that formed by rapid early diagenetic growth (average 3320 mm/Myr) on continental margins above the carbonate compensation depth, and dominated by hydrocarbon seep structures and strong erosive action of bottom currents along the northeastern slope. In contrast, the introduction of vigorous deep-water flow from the North Pacific promoted the slow growth (4–7 mm/Myr) of hydrogenetic Fe-Mn nodules and crusts along the northwestern margin. Finally, hydrogenetic growth of Fe-Mn nodules and crusts in the central basin may have been enhanced by volcanic processes. Our data provide new insights into the genesis and province characteristics of the Fe-Mn nodules and crusts of the northern SCS.

High-resolution single channel and multichannel seismic reflection profiles and multibeam bathyme... more 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 (MVs) in the Gulf of Cádiz at 1,050–1,250 m water depth. These MVs vary strongly in morphology and size. The data reveal elongated cone-shaped edifices, rimmed depressions, and scarps interpreted as flank failures developed by collapse, faulting, compaction and gravitational processes. MV architecture is characterised by both extrusive and intrusive complexes, comprising stacked edifices (including seabed cones and up to four buried bicones) underlain by chaotic vertical zones and downward-tapering cones suggesting feeder systems. These intrusive structures represent the upper layer of the feeder system linking the fluid mud sources with the constructional edifices. The overall architecture is interpreted to be the result of successive events of mud extrusion and outbuilding alternating with periods of dormancy. Each mud extrusion phase is connected with the development of an edifice, represented by a seabed cone or a buried bicone. In all four MVs, the stacked edifices and the intrusive complexes penetrate Late Miocene–Quaternary units and are rooted in the Gulf of Cádiz wedge emplaced during the late Tortonian. Major phases of mud extrusion and outbuilding took place since the Late Pliocene, even though in the Yuma and Jesús Baraza MVs mud volcanism started in the Late Miocene shortly after the emplacement of the Gulf of Cádiz wedge. This study shows that fluid venting in the eastern sector of the Gulf of Cádiz promoted the outbuilding of large long-lived mud volcanoes active since the Late Miocene, and which have been reactivated repeatedly until recent times.

This paper presents a combined onshore-offshore morpho-structural characterization of the El Golf... more 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. The geomorphology and the internal architecture of this giant flank collapse are defined in order to determine its multi-event nature. The subaerial headscarp shows a non-continuous arcuate profile formed by two nested semi-circular amphitheaters that extend offshore along a smooth chute, suggesting the occurrence of at least two large
retrogressive events. Channels/gullies and escarpments developed along the submarine sector of the scar also indicate smaller-scale events and predominance of sediment bypass. In the lower slope, two subunits of submarine mass transport deposits (MTDs), debris avalanche, are identified on multichannel seismic reflection profiles with a total estimated volume of 318 km3: ~84 km3 and ~234 km3, for the younger and older MTDs respectively. Data from wells and galleries show abrasion platforms with beach deposits at sea-level (0 masl) formed after the landslide scar and buried by the post-collapse El
Golfo lavas infill, suggesting an age at least older than 23.5-82.5 Ka for the landslide.

The margin of the continental slope of the Volcanic Province of Canary Islands is characterised b... more 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 elevation data are reported here for the first time. The shape and distribution of characteristics features such as volcanic cones, ridges, slides scars, gullies and channels indicate evolutionary differences. Special attention was paid to recent geological processes that influenced the seamounts. We defined various morpho-sedimentary units, which are mainly due to massive slope instability that disrupt the pelagic sedimentary cover. We also studied other processes such as the role of deep bottom currents in determining sediment distribution. The sediments are interpreted as the result of a complex mixture of material derived from a) slope failures on seamounts and submarine hills; and b) slides and slumps on the continental slope.

Marine Geology, 2020

Geological Society London, 2023

World Atlas of Submarine Gas Hydrates in Continental Margins, 2022

World Journal of Engineering, 2021

Geological Society London, 2019

Quaternary Science Reviews, 2020

Marine and Petroleum Geology, 2021

Marine Geology, 2019

Ore Geology Reviews, 2020

Marine Geology, 2019

Acta Oceanologica Sinica, 2018

Minerals, 2018

Geochemistry, Geophysics, Geosystems, 2017

"This doctoral research is focused on the study of deposits of ferromanganese nodules and crusts ... more "This doctoral research is focused on the study of deposits of ferromanganese nodules and crusts in the Gulf of Cadiz and the Scotia Sea (Antarctica), where significant oceanographic, tectonic and sedimentological processes occur. The specific objectives are: 1) the study of submarine outcrops of nodules and crusts, their physical properties, their petrography, their mineralogy and their geochemistry; 2) comparative analyses of these deposits with respect to other ferromanganese deposits in the world; 3) the establishment of genetic models for mineralizations; and 4) the determination and interpretation of paleoceanographic and paleoclimatic proxies in the studied ferromanganese deposits. These goals are achieved by the analysis and interpretation of principally seismic and acoustic geophysical data and submarine photographs. In addition, more than 500 nodule samples, one crust and several samples of surrounding materials were analyzed by different laboratory methods such as microscopy, spectrometry and chromatography.

The nodules from the Gulf of Cadiz are located in a patchy distribution at the base and flanks of the carbonate-mud mounds from the Guadalquivir Diapiric Ridge, at a depth of 850-1000 meters. This area is characterized by the processes and deposits associated with mud volcanism as well as with diapirism and the strong erosive action of the Mediterranean Outflow Water undercurrent over the sea bottom. The nodules show a wide range of sizes, weights and morphologies. They are formed by a continuous succession of layers of Fe-Mn oxyhydroxides in a concentric pattern surrounding the nucleus of the concretion. The most characteristic textural features are laminated, mottled to dendritic, detrital and massive. Quartz and phylosilicates (smectite, illite and kaolinite) are essential minerals, while carbonates, sulphides, oxides and sulphates are accessory to occasional components. The majority of these minerals are authigenic although some of them are detrital in origin. Biofilm textures, related to bacterial activity, are frequent in oxyhydroxides, carbonates and sulphides. The nodules are enriched in Fe (38.6%) and to a lesser degree in Mn (6%), but they are poor in trace metals and rare earth elements respect to the average of oceanic nodules. The contents in Si, Ca, Mg, As, V, Co and Ni, are higher than the average values for Terrestrial Crust. The nodules contain hydrocarbons. The average value for total organic carbon in the nodules is 1.12%, with the occurrence of n-alkanes from bacterial origin (n-C18), mature hydrocarbons (phenanthrene) and other biomarkers (organic sulphur, fatty acids). The carbon preference indexes (CPI= 0.66 - 1.15) are newly indicating an important maturity of hydrocarbon fractions. The carbonate isotopical signatures range between -5.9 and -10‰ PDB for δ13C and -2.8 to 3.8 ‰ PDB for δ18O. The hydrocarbons present values from -20 to -46‰ PDB for δ13C. The isotopical values of δ34S CDT are as low as -41‰ in pyrite. The chronological methods of Co chronometer and U/Th give us an age of about 70,000 years for the studied nodules.
The ferromanganese crusts from the Scotia Sea appear covering tholeiitic basalts on the flanks of one oceanic spreading ridge from the Central Dove Basin. The crusts are porous, up to 2.5 centimeters in width, and have botryoidal surface texture. The crusts are formed by a succession of subparallel micro-layers composed by Fe-rich vernadite and occasionally by goethite and quartz. The most characteristic textural features are laminated and columnar, frequently showing biofilm textures in vernadite. The geochemistry of the crusts is characterized by high contents in Mn (23%), Fe (20%), Co (0.4%), other metals such as Ni, Cu, Zn and rare earth elements. The Co chronomether used to determinate the age for one ferromanganese crust gives us a growth history record for this sample of at least 13.5 million years.

This investigation shows, for the first time, a type of ferromanganese-oxide nodules derived from the anaerobic oxidation of hydrocarbons and organic matter in areas of mud vulcanism and diaprism from the Gulf of Cádiz. This model proposes the genesis of diagenetic Fe-Mn carbonate nodules with the participation of microorganisms close to the redox boundary. The exhumation process of carbonate nodules by the bottom currents gives rise to the replacement of Fe-Mn cabonates by oxyhydroxides. At the same time, the model discusses the spatial and genetic relationships between the nodules and other biomineralization products in the area (carbonate chimneys and crusts as well as sulphide crusts). Moreover, the role of the migration from deep-seated reservoirs of fluids enriched in hydrocarbons and their influence in the genesis of nodules is analized. Finally, the presence of geochemical, textural and mineralogical proxies is proposed as a means to deduce paleoclimatic/paleoceanographic interpretations in the area. Glacial and interglacial cycles in the Northern Hemisphere have determined the distribution and circulation of the Atlantic Deep Water and Mediterranean Outflow Water. These ciclicity patterns observed in the proxies in the nodules may be related to the paleoclimatic/paleoceanographic changes throughout the last 70,000 years. The ferromanganese crusts from the Scotia Sea must have been generated by slow precipitation from the sea water by hydrogenesis with the involvement of microorganisms. As in the Gulf of Cadiz, different proxies observed in the antarctic crusts may be related to climatic models and distribution in addition to paleo-circulation of the Antarctic Circumpolar Current and the Weddell Sea Bottom Water in this area during a time period of at least 13.5 million years."

Geological Society of America, 2017

Seamounts and submarine banks are prominent geomorphic features throughout the global ocean, and ... more Seamounts and submarine banks are prominent geomorphic features throughout the global ocean, and the target of minerals research and exploration with the goal of future exploitation. Polymetallic ferromanganese deposits and phosphorite are common types of mineralization on seamounts. Co-rich ferromanganese crusts are important as potential resources of Mn and Co, but also Ti, Ni, Tl, REEs, PGEs, and other metals. Many seamounts along the Atlantic Spanish continental margin are known to have mineral deposits but are poorly studied.We present preliminary results of the study of these mineral deposits, including ferromanganese nodules and crusts and phosphate pavements and nodules, which can be considered as potential sources of raw materials.
Seamounts and banks in the northern Iberian Atlantic margin (Lat. 42º-44ºN) show extensive areas covered by phosphorite pavements and nodules as well as ferromanganese nodules and crusts from 700 to 1200 m water depths. Ferromanganese nodules
and crusts are composed of a large variety of Fe and Mn oxyhydroxides (e.g., vernadite, asbolane, goethite, todorokite, romanechite) depending on the predominant genetic process (hydrogenetic, diagenetic, hydrothermal).
High concentrations of metals have been measured in some of these ferromanganese deposits: Mn (up to 45 wt%), Co (up to 1.8 wt%) and Ni (up to 0.8 wt%). Other strategic elements such as Ti, Cu, Mo, REEs, Tl, Ga, and Te are also present in high concentrations with respect to seawater and lithospheric concentrations. Phosphorite, composed mostly of carbonate fluorapatite and ferruginous glauconite and formed by diagenetic processes, shows considerable amounts of P (up to 14 wt%), F (up to 4 wt%), and low concentrations of U and Th.
Seamounts and banks from the Central Atlantic margin (Lat. 23º-26ºN) are largely covered with ferromanganese crusts. We studied crust pavements up to 20 cm thick collected from rock outcrops on several seamounts, at 500 to 2500 m water depths. The crusts have a botryoidal surface texture and colloform, laminar, and massive internal structures formed by vernadite, asbolane, and goethite. The chemical composition shows a predominance of Mn (18.6 wt%) and Fe (24.5 wt%) with considerable amounts of Ti (1.2 wt%), Co (0.67 wt%), Ni (0.27 wt%), REEs (0.3 wt%), Tl, Mo, and Te. The geochemical characteristics indicate a hydrogenetic origin or mixed hydrogenetic and hydrothermal origin for some samples.
The flat top of some seamounts and banks studied shows the most favorable conditions for future mining operations. Many of these seamounts are at ideal depths (800-2500 m) for the occurrence of thick crusts enriched in rare and strategic metals. Some of these metals, including those needed for high-technology applications,
may become important by-products of Mn and Co recovery. The selection of mine sites will depend not only on grade, tonnage, and topography of the site but also on the efficiency of the mining system and the impact of the mining activity on the benthic environment, including deep-sea fauna, ecosystems, and the water column. A better understanding of the distribution, abundance, structure, and genesis of these mineral deposits, and their
mineralogical and geochemical characteristics, are essential for the selection of viable mine sites and the design of environmentally sound and efficient mining systems for the future.

A suite of ferromanganese nodules were sampled during the MVSEIS-2008 cruise aboard of the R/V He... more 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 hydrocarbon-derived authigenic carbonate crusts were sampled at same time. The nodules show tabular morphology, up to 20 cm in maximum diameter and 2 kg of weight, brown-reddish external color and they are internally composed by a concentric to complex arrangement of laminae. The results of X-ray diffraction analysis show that these ferromanganese nodules are essentially composed of goethite and lepidocrocite, being Mn-oxides, silicates (quartz and clay minerals) and carbonates (calcite, dolomite and siderite) accessory to occasional minerals. All the samples display micritic to micro-sparitic mosaic under the petrographic microscope which forms massive, laminated or
dendritic-mottled textures. The nodules show a high abundance of Fe, minor Mn and low contents of trace metals and REEs. Mature hydrocarbons, as n-alkanes derived from marine bacterial activity, and phenanthrene have been detected in all the ferromanganese nodules analyzed.
These nodules display analogous characteristics (textural, mineralogical and geochemical) to the nodules studied by González et al (2009) in the carbonate mud-mounds in the
Gulf of Cadiz, offshore Iberian margin. In this way, the same preliminary genetic model proposed for these nodules might be applicable to those find in the Meknes mud volcano. Therefore, the anaerobic oxidation of hydrocarbon-rich fluids within the mud-breccia sediments in the flanks of Meknes mud volcano would induce the formation of early diagenetic Fe-(Mn) carbonate nodules. Thus, the nodules were later exhumed by the erosive action of sea bottom currents generating the replacement of ferromanganese carbonates by Fe-Mn oxy-hydroxides. Thus, the hydrocarbon-rich fluid venting from deep seated reservoirs and erosive action of bottom currents must have been essential actors, as mineralization controls, for ferromanganese nodules generation and evolution.
These findings imply that this type of nodules must be considered as new product as derived from the anaerobic/aerobic oxidation of hydrocarbons in areas of active seepages.

La campaña SUBVENT1-0913 se ha realizado a lo largo del talud inferior del margen continental de ... more La campaña SUBVENT1-0913 se ha realizado a lo largo del talud inferior del margen continental de las Islas Canarias, área que también es conocida en la literatura como Cuenca Canaria. Esta zona se caracteriza por la presencia de una serie de estructuras
geológicas recientes, así se encuentran la parte distal de los depósitos de debris procedentes de las avalanchas volcánicas generadas desde las Islas Canarias, a favor de la pendiente y probablemente en relación con episodios eruptivos. En la parte
meridional se encuentra además un conjunto de montes submarinos, de diversa entidad, de origen volcánico y, en general, aparece todo un conjunto de montículos con desniveles comprendidos entre 30 y 300 m que han constituido el principal
objetivo de esta campaña. Así mismo, en este sector existen numerosos escarpes lineales de orientación subparalela a la del propio talud a los que se encuentran asociados en ocasiones los citados montículos.
La adquisición de nuevos datos geofísicos y el muestreo llevado a cabo durante la campaña permitirá conocer mejor el origen de estos montículos y el proceso de emisión que los ha generado. Por otro lado, el conocimiento de las relaciones entre los sedimentos de debris y hemipelágicos junto con los asociados a las posibles emisiones de la zona permitirá conocer no sólo la evolución sedimentaria de este margen, sino establecer los episodios de emisión que generaron los montículos y conocer sus patrones de crecimiento. Así mismo, se podrá evaluar la tasa de sedimentación de la zona y el papel de la masa de agua de fondo antártica (AABW) en esta evolución.

La campaña DRAGO 0511 forma parte de los trabajos para la extensión de la plataforma continental ... more La campaña DRAGO 0511 forma parte de los trabajos para la extensión de la plataforma continental española al oeste de las islas Canarias conforme a la Convención de Naciones Unidas sobre Derecho del Mar (CONVEMAR). Han participado un total de 19 científicos y técnicos, 4 investigadores del Instituto Español de Oceanografía (IEO) y 4 investigadores del Instituto Geológico y Minero de España (IGME) del Ministerio de Ciencia e Innovación, 2 investigadores de TRAGSA (para la Secretaría General del Mar) del Ministerio de Medio Ambiente, Medio Rural y Marino, y 6 hidrógrafos del Instituto Hidrográfico de la Marina (IHM) del Ministerio de Defensa, así como 5 estudiantes (2 de grado y 3 de postgrado) de la Facultad de Ciencias del Mar y Ambientales de la Universidad de Cádiz, y de la Facultad de Ciencias Geológicas (Titulación de Ingeniería Geológica) de la Universidad Complutense. El objetivo de esta campaña es la adquisición de los datos científicos necesarios para preparar la propuesta de ampliación de la plataforma continental española más allá de las 200 millas marinas del área situada al oeste de las Islas Canarias, conforme al artículo 76 de CONVEMAR. La información que se ha obtenido es fundamentalmente de batimetría multihaz y monohaz, perfiles de la velocidad del sonido, perfiles sísmicos de alta resolución, y muestreo de fondos principalmente mediante dragas de roca. Estos datos permitirán definir desde un punto de vista morfográfico, morfosedimentario y geológico, la región de la base del talud, así como llevar a cabo la localización de los posibles pies de talud (FOS) en esta región,y demostrar la estrecha relación existente entre la zona estudiada y el archipiélago de las Islas Canarias. En este sentido se han estudiado de forma preferente un conjunto de montes submarinos presentes al suroeste de las islas Canarias cuya génesis, de origen magmático, se debe encontrar en los mismos procesos de “punto caliente” que probablemente han debido generar los edificios volcánicos que constituyen las propias islas Canarias. Por otro lado, se ha localizado la presencia de grandes cuerpos sedimentarios constituidos por materiales procedentes de estos montes submarinos y generados por movimientos en masa de tipo gravitacional a favor de la pendiente del talud continental. La presencia tanto de estos montes submarinos, como de las grandes masas de sedimentos gravitacionales y, además la localización de escarpes en el talud, serán puntos clave de gran interés en esta región, siendo argumentos científicos válidos para demostrar la prolongación natural del territorio emergido del archipiélago canario así como para localizar los puntos del pie del talud continental. Durante la campaña DRAGO 0511 se han adquirido un total de 10895.4 km de registros con sonda multihaz EM302, sonda monohaz EA 600 y sonda paramétrica TOPAS PS 18. De dichas líneas, 9647.3 km se han realizado en las dos zonas de trabajo planificadas, 5603.2 km en la zona A y 4044.3 km en la zona B. En la zona A se ha cubierto un área total de 19996 km2 mientras que en la zona B la extensión ha sido de 13545 km2. En total se ha cubierto una extensión de 17795 km2 en el área de posible ampliación de la plataforma continental española. Por otra parte, cabe señalar que además 16471 km2 de líneas se han realizado dentro de la ZEE española del archipiélago canario, que se utilizarán, en algún caso, para demostrar la continuidad de estos cuerpos sedimentarios con las islas Canarias, y más adelante para la cartografía de este sector de la ZEE española. El resto de registros, 1151.5 km. corresponden a los tránsitos. En el total del tiempo de la campaña DRAGO 0511, un 70.5 % se ha trabajado sobre las zonas planificadas A y B localizadas sobre las áreas de ampliación de la plataforma continental española o sobre puntos concretos de la ZEE española que pueden ser utilizados para establecer los FOS, un 16.7 % en tránsitos sobre la ZEE española de las islas Canarias y un 7.1% de recalada en los puertos de Santa Cruz de Tenerife y de La Estaca de la Iila de El Hierro. Los datos obtenidos en la campaña DRAGO 0511 serán usados para elaborar la presentación del trazado del límite exterior de la plataforma continental de España más allá de las 200 millas marinas en el polígono del archipiélago de las islas Canarias conforme a la parte VI y el anexo II de CONVEMAR. Dicha presentación de datos e información científica se deberá realizar ante la Comisión de límites de la plataforma continental de la Organización de las Naciones Unidas en Nueva York, de conformidad con la CONVEMAR y con las directrices científico-técnicas de dicha Comisión, con anterioridad al 9 de mayo del año 2014.

The aim of the MOUNDFORCE cruise aboard research vessel L´ATALANTE have been to obtain a detailed... more The aim of the MOUNDFORCE cruise aboard research vessel L´ATALANTE have been to obtain a detailed catalog of seismic images of distinct types of deep carbonate mounds, coral reefs, mud volcanoes and diapirs associated with hydrocarbon seeps in the Gulf of Cádiz. As result of the MOUNDFORCE cruise a total of 3.050 km. of multichannel seismic and 3250 km of 3.5 kHz CHEOPS high-resolution seismic have been adquired.
The MOUNDFORCE cruise is part of the of the MOUNDFORCE project of the ESFEU within the framework of the ESF-EUROCORE (EUROropean COllaborative REsearch) EUROMARGINS programme. This project plan out the study of carbonate mounds and deep coral reefs associated with hydrocarbons discovered on Rockall Trough, Porcupine Bight and
Gulf of Cádiz along the Europan Atlantic margins. Along these margins, the periods of
building of the carbonate mounds are related to the main events of palaeo-oceanographic and
climatic changes, and especially due to the interaction between Mediterranean and Artic-type
waters.

Los recursos naturales en general y los mineros en particular forman parte del desarrollo de las ... more Los recursos naturales en general y los mineros en particular forman parte del desarrollo de las naciones. La demanda de metales en el mercado ha ido cambiando a lo largo de la historia hasta llegar a nuestros días donde la demanda de aquellos denominados como de “alta tecnología” empieza a tomar una gran importancia. Éstos se usan para aleaciones de características especiales: para circuitos y “chips” de ordenadores, en teléfonos móviles o la industria militar. Este tipo de metales son escasos en altas concentraciones en las minas en tierra, mientras que en el ámbito marino existen unos determinados accidentes geográficos, los montes submarinos donde se forman depósitos de costras de ferromanganeso, cuya composición en este tipo de metales, resulta muy interesante para la explotación minera. La cantidad de mineral y pureza, y la facilidad para su extracción se pueden deducir en base a una serie de criterios para así obtener la ubicación de zonas con un potencial minero elevado.

Con estas premisas el presente trabajo se centra en la metodología para poder discernir los montes submarinos cuyo potencial minero para costras de ferromanganeso nos indique posibles zonas de exploración en la zona de estudio elegida: el océano Atlántico Central. Esta zona se ha elegido por la influencia que podría tener para Europa debido a su cercanía con el continente, por ser una zona relativamente poco estudiada y por ser muy heterogénea, obteniéndose así más resultados distintos.
Se han utilizado los Sistemas de información Geográfica (SIG) para poder obtener los siguientes resultados:
- Identificación y definición de montes submarinos
- Ponderación de factores en base a la cartografía utilizada para jerarquizar los montes submarinos en función de su potencial minero
- Elección de zonas con alto potencial que servirán para aplicar la normativa dictada por la ISA (International Seabed Authority), organismo independiente que regula la exploración de los fondos submarinos en “La Zona”

Para conseguir estos objetivos se han revisado numerosas publicaciones en las que autores de renombre internacional en la materia exponen las características de las zonas más propicias para encontrar montes submarinos con alto potencial minero, toda esta documentación se ha reflejado y desarrollado mediante SIG con el fin de localizar los montes submarinos del Atlántico Central más interesantes por su potencial minero.

Finalmente se han elaborado mapas de casos de estudio en donde se reflejan los montes submarinos cuyo potencial minero es alto, teniendo en cuenta las divisiones administrativas marinas: la zona económica exclusiva y la posible ampliación de la plataforma continental.
El resultado de todos estos procesos se ha plasmado en un mapa temático donde se aprecian los montes submarinos jerarquizados en base a su potencial minero y las divisiones geográficas según la ISA para su exploración.

"El presente documento trata de exponer la relación existente entre los corales de aguas frías en... more "El presente documento trata de exponer la relación existente entre los corales de aguas frías encontrados en el Golfo de Cádiz (Atlántico NE) con los procesos tectónicos y las estructuras relacionadas con la migración y la emisión de fluidos ricos en hidrocarburos (principalmente metano).
Para ello, desde el año 2000 hasta la actualidad, se han llevado a cabo diversas campañas oceanográficas en las cuales se han obtenido datos y muestras relacionadas con las emisiones de hidrocarburos al fondo marino. Gracias a los datos y las muestras recogidas durante las campañas se han creado una base de datos, en la que se reúnen todos los datos significativos relacionados con las campañas oceanográficas y con el objeto de este trabajo.
Para finalizar, tras la creación de la base de datos, y con las muestras proporcionadas por el IGME recogidas durante la campaña oceanográfica MVSEIS08, se han podido llevar a cabo diversos estudios de laboratorio como la racemización de aminoácidos, análisis de biomarcadores así como la datación de los esqueletos aragoníticos de los corales de aguas frías mediante la técnica de U-Th en un futuro, con el objetivo de esclarecer la relación existente entre estas emisiones de fluidos a través de diversas estructuras y los corales de aguas frías, su edad, y en última instancia determinar los cambios producidos en la composición química de la masa de agua atlántica así como la variación de las corrientes en el Golfo de Cádiz durante el último periodo glaciar."

Los gases hidratados representan una potencial fuente energética para el futuro. Las reservas, di... more Los gases hidratados representan una potencial fuente energética para el futuro. Las reservas, distribuidas en todas las cuencas oceánicas, son tan abundantes que bastarían para satisfacer las necesidades mundiales durante siglos. Al mismo tiempo debemos de evaluar la contribución de la desestabilización de estos depósitos al llamado "efecto invernadero". Nódulos de manganeso Placeres diamantíferos Placeres de Sn, Ti, Cr, REE, Ag y Au Fosforitas Leyenda: MAPA GLOBAL DE OCÉANOS, TERREMOTOS, VOLCANES Y DISTRIBUCIÓN DE RECURSOS MINERALES MARINOS Potencial hidrocarburos Halitas Costras de Fe-Mn ricas en cobalto Sulfuros polimetálicos Fuente datos recursos minerales marinos: Rona (2003)

Report of the polymetallic nodules prospect evaluation parameters that will be employed as a road... more Report of the polymetallic nodules prospect evaluation parameters that will be employed as a road map for the creation of the polymetallic nodules occurrence database This project has been supported by the European Union's Horizon 2020 research and innovation programme, GeoERA (Grant Agreement Nº 731166, project GeoE.171.001). MINDeSEA Seabed Mineral Deposits in European Seas: Metallogeny and Geological Potential for Strategic and Critical Raw Materials Deliverable 6.2: Report of the polymetallic nodules prospect evaluation parameters that will be employed as a road map for the creation of the polymetallic nodules occurrence database

Fe-Mn crusts and phosphorites metallogenic models This project has been supported by the European... more Fe-Mn crusts and phosphorites metallogenic models This project has been supported by the European Union's Horizon 2020 research and innovation programme, GeoERA (Grant Agreement Nº 731166, project GeoE.171.001).

The current report provides a review of European marine exhalative deposits based on their metall... more The current report provides a review of European marine exhalative deposits based on their metallogenic setting. Settings include mid ocean ridge spreading sites, sites related to intra-plate hotspots, and arc/back-arc spreading sites.

MINDeSEA is the flagship project of GeoERA on seabed mineral deposits in the European Seas. http:... more MINDeSEA is the flagship project of GeoERA on seabed mineral deposits in the European Seas. http://geoera.eu/projects/mindesea/

The project MINDeSEA results of the collaboration between eight GeoERA Partners and four Non-funded Organizations at various points of common interest for exploration and investigation on seafloor mineral deposits. This project addresses an integrative metallogenetic study of principal types of seabed mineral resources (hydrothermal sulfides, ferromanganese crusts, phosphorites, marine placers and polymetallic nodules) in the European Seas. The MINDeSEA working group has both knowledge of and expertise in such types of mineralisation, providing exploration results, sample repositories and databases to produce innovative contributions. The importance of submarine mineralisation systems is related to the abundance and exploitation-potential of many strategic metals and Critical Raw Materials (CRM), necessary for the modern society development.
The objectives of this project are the following: 1) Characterise deposit types; 2) Characterise the trace element content of the deposit type including CRM; 3) Identify the principal metallogenic provinces; 4) Develop harmonised mineral maps and datasets of seabed deposits incorporating GSO datasets, along with mineral-potential and prospectivity maps; 5) Demonstrate how the cases study results can be used in off-shore mineral exploration; 6) Analyse present-day exploration and exploitation status in terms of regulation, legislation, environmental impacts, exploitation and future directions. 7) Demonstrate efficiency of a pan-European research approach to understanding seabed minerals and modes of exploration. The methodology will include: procedures for submarine minerals exploration; mineral evaluation and seafloor minerals mapping; a web service that will disseminate procedures, maps and information to the general public, downstream users and decision makers.

En enero de 2014 ha comenzado el proyecto EMODNET, coordinado por el British Geological Survey, t... more En enero de 2014 ha comenzado el proyecto EMODNET, coordinado por el British Geological Survey, tras la creación en diciembre de 2013 del Consorcio de 36 servicios geológicos y otros organismos europeos que participan en el proyecto.

"Los océanos mundiales son un componente mayoritario del sistema Terrestre y los cambios en el co... more "Los océanos mundiales son un componente mayoritario del sistema Terrestre y los cambios en el complejo sistema oceánico de circulación inducen modificaciones ambientales globales. Los océanos polares antárticos juegan un papel importante en esta evolución y en el mantenimiento del sistema climático de la Tierra. La circulación oceánica y el transporte de calor a través de los océanos y la atmósfera son en gran parte debidos a los gradientes latitudinales térmicos, los cuales están muy probablemente ligados a la evolución polar. El intercambio de masas de agua y la producción de aguas frías profundas está controlado por el hundimiento y levantamiento del suelo oceánico durante los procesos de apertura tectónica de portales oceánicos y la formación de cuencas. El establecimiento detallado de la evolución tectónica, geodinámica, petrológica sedimentaría y la evolución geomorfológica de portales y cuencas y oceánicas estratégicas suministrará el encuadre esencial para la realización de modelos que puedan ser contrastados con las observaciones globales que se está recogiendo en el globo terrestre. Este proyecto es una aproximación multidisciplinar basada en estudios tectónico-magmáticos, geodinámicos, sedimentarios y paleoceanográficos, en base a conceptos geológicos y geofísicos y utilizando las tecnología más actuales disponibles en el mar para geofísica y toma de muestras de rocas y sedimentos, además de estudios en tierra. Los objetivos principales incluyen: (1) análisis de la corteza/litosfera de los márgenes continentales y cuencas oceánicas del océano Pacífico sur-oriental, Paso del Drake, y Mares de Scotia y Weddell con el objetivo de desarrollar un buen conocimiento de la cinemática de placas pasada y presente, procesos en el manto, desarrollo de márgenes, subsidencia de la corteza y procesos de levantamiento orogénico; (2) establecimiento de la circulación oceánica pasada en las cuencas y portales oceánicos por medio del estudio de los cambios registrados en los sedimentos y contornitas oceánicas profundas y en base a conceptos de estratigrafía sísmica secuencial y el análisis de técnicas paleoceanográficas y actuales para establecer la evolución de la circulación profunda en los mares del sur y los cambios climáticos asociados; (3) reconstrucción detallada del desarrollo de cuencas oceánicas y la dinámica de apertura del Paso del Drake con el objetivos de acotar los mecanismos de intercambio de masas de agua someras y profundas y el establecimiento de la Corriente Circumpolar Antártica; (4) comprender la historia paleoclimática de la Tierra a largo plazo desde las condiciones de “efecto invernadero” en el Terciario inferior al paso a las condiciones la “Tierra glaciar” durante el Terciario superior-Cuaternario, y (5) establecer el papel jugado por la apertura y cierre de portales oceánicos en el desarrollo del casquete polar Antártico y los cambios climáticos asociados.
Los objetivos de este proyecto están incluidos en el proyecto “Antarctic Climate Evolution Program (ACE)”, el proyecto del Año Polar International (IPY) “Plate Tectonics and Polar Gateways in Earth History (PLATES & GATES)”, y en el proyecto “Circum-Antarctic Paleobathymetry and Stratigraphy Project (CAPS), cuyas actividades están planificadas cooperativamente con la “Antarctic Seismic Data Library System (SDLS)” del SCAR"

"La interacción de una masa de agua con el fondo genera rasgos erosivos y deposicionales que cons... more "La interacción de una masa de agua con el fondo genera rasgos erosivos y deposicionales que constituyen complejos Sistemas Deposicionales Contorníticos (SDC) de grandes dimensiones y espesores sedimentarios. Su estudio ha constituido una de las líneas activas de investigación en Geología Marina en el ámbito internacional durante la última década por su interés estratigráfico, sedimentológico, paleoceanográfico, paleoclimatológico, en procesos de inestabilidad de taludes continentales, como por su relación directa con posibles yacimientos minerales y energéticos. Los Programas de DSDP (Deep Sea Drilling Project), ODP (Ocean Drilling Program) e IODP (Integrated Ocean Drilling Program), han sido esenciales en el desarrollo de la investigación sobre los depósitos contorníticos, y han puesto de manifiesto que son depósitos muy poco conocidos, pero frecuentes en los medios marinos.
La finalidad del Proyecto CONTOURIBER, que es un Proyecto Coordinado, es estudiar los sistemas deposicionales contorníticos generados por las masas de agua mediterráneas alrededor de Iberia, su evolución e implicaciones ambientales. Pretende realizar una investigación del registro estratigráfico Neógeno-Cuaternario en cuatro áreas del talud continental de los márgenes alrededor de Iberia (Ceuta, Golfo de Cádiz, Cabo Ortegal y Banco Le Danois), para estudiar diferentes SDC generados por las mismas masas de agua pero en contextos geológicos diferente. Las masas de agua mediterráneas circulan alrededor de los márgenes sobre el talud inferior y medio en el Mediterráneo Occidental y, tras su salida al Atlántico por el Estrecho de Gibraltar, sobre el talud medio. La circulación de dichas masas de agua ha generado complejos sistemas sedimentarios que están aún por conocer y que contienen un valioso registro de la evolución de nuestros márgenes continentales. Se pretende por tanto, analizar y comparar, por primera vez, dicho registro sedimentario para alcanzar los siguientes objetivos: 1. Caracterizar la influencia y control del margen continental previo y durante al desarrollo de los Sistemas Deposicionales Contorníticos; 2. Establecer la evolución de los sistemas deposicionales contorníticos en diferentes áreas de influencia de las masas de agua mediterráneas; 3. Determinar los procesos sedimentarios y paleoceanográficos recientes en cada uno de los Sistemas Deposicionales Contorníticos; y 4. Identificar la interacción de la dinámica actual de las masas de agua mediterránea con la superficie del margen, y analizar el control los rasgos morfológicos del margen tienen sobre esta dinámica y viceversa, así como la influencia de ambos factores sobre el desarrollo de geohabitats específicos. Por consiguiente, el Proyecto CONTOURIBER, no sólo contempla novedosos objetivos científicos en relación con un registro sedimentario muy poco conocido, sino que pretende promover una investigación multi- e inter-disciplinar de calidad, evidenciada tanto por la internacionalización de las actividades que plantea, como por sus potenciales resultados de alto impacto científico en el ambito de la geología marina, geofísica, oceanografía, y paleoceanografía. Las actividades planteadas están relacionadas con la propuesta aceptada de perforación oceánica en el Golfo de Cádiz y oeste de Portugal dentro del programa internacional Integrated Ocean Drilling Program (IODP), Proposal -644 “GUCADRILL”.
El Proyecto CONTOURIBER se ajusta a los objetivos del VI Plan Nacional de Investigación Científica, Desarrollo e Innovación Tecnológica (2008-2011), así como a la Orden ECI/3354/2007 (BOE, 20 Nov., 2007). Dicha investigación no sería posible sin las instituciones e investigadores que se han involucrado en esta propuesta, que supone una importante masa crítica y un esfuerzo relevante de integración y colaboración entre grupos de probada experiencia en Geología Marina de España. Se propone un esquema de cooperación científica que permitirá sin dudad alguna abordar objetivos difícilmente alcanzables de una manera más restringida.Los antecedentes y resultados previos de los grupos participantes en este Proyecto prueban la eficacia de la integración de investigaciones multidisciplinares para logar un objetivo científico común, así como que constituyen grupos estables de investigación con una muy importante producción científica de calidad internacional.
En cuanto a la aplicabilidad y transferencia de los resultados esperables, se incrementaría la infraestructura geológica y geofísica en áreas donde existe una escasa información previa, sobre unos depósitos muy poco conocidos y que registran la evolución reciente de los márgenes que bordean Iberia. Los modelos deposicionales contorníticos están aún por establecer, y el concretar el inicio de la sedimentación contornítica en el área Atlántico-Mediterráneo, su evolución e interacción lateral con otros depósitos y procesos hacen que el Proyecto CONTOURIBER sea un proyecto novedoso y que los resultados potencialmente esperables puedan tener implicaciones en procesos submarinos activos, cambios ambientales, circulación termohalina intermedia y profunda, y la presencia de recursos minerales y energéticos."

“Este Proyecto está financiado, parcialmente, a través de un proyecto FEDER-CICYT solicitado en J... more “Este Proyecto está financiado, parcialmente, a través de un proyecto FEDER-CICYT solicitado en Junio de 1999 y que fue concedido al IGME en diciembre de ese mismo año. Está asimismo incluido en el marco de un Convenio con la Dirección de Industria de la Comunidad de Extremadura, en el cual se conviene una aportación económica complementaria a la de los fondos FEDER.
El proyecto tiene como objetivo principal la aportación de una infraestructura sistematizada de conocimiento de los recursos minerales (metálicos y minerales industriales) de la región extremeña. Su elaboración se hará a partir de la determinación, tanto en campo como en laboratorio, de los principales atributos geológicos y de los parámetros petrográficos, mineralógicos y geoquímicos de las mineralizaciones y de su encajante inmediato, actividad que se desarrollará de forma sistemática y exhaustiva en todos los indicios de mineralización conocidos actualmente, así como en otros indicios directos como anomalías geoquímicas significativas.
Existe en esta región, que ha sido, por su potencial minero, intensamente explorada en los últimos años, una abundante información de tipo geológico, geoquímico y geofísico de ámbito regional y local, cuya recuperación, ordenación y reinterpretación, junto al estudio más detallado de mineralizaciones representativas, permitirá la definición de las tipologías de mineralizaciones existentes y su caracterización. Todo ello conducirá al establecimiento de sus controles de aparición y distribución a varias escalas, es decir, de la metalotectura regional. La información elaborada en el curso de este proyecto se expresará en el Mapa Metalogenético de Extremadura a escala 1:200.000, y en mapas complementarios de mayor detalle, así como en una base de datos metalogenéticos que será una herramienta fundamental, además de para la búsqueda, consulta y actualización de la información, para los análisis de potencialidad regional mediante la integración, en sistemas de información geográfica, con otras coberturas de datos georeferenciados.
La tendencia actual que expresan las grandes compañías mineras en sus estrategias y programas de exploración, sobre todo en áreas con potencial contrastado pero ya investigadas y con una infraestructura de conocimiento apreciable como es el caso de Extremadura, es la de tender, cada vez más, al reanálisis y reinterpretación de la información regional y, con un enfoque centrípeto, definir zonas más reducidas de interés. Es evidente pues el atractivo de esta infraestructura para las compañías mineras, pero también será de amplia utilidad para las administraciones, a las que permitirá, confrontándola o integrándola con factores positivos, como centros de consumo, núcleos de crecimiento industrial, necesidad de desarrollo de áreas deprimidas, comunicaciones, etc., o negativos, como áreas con problemas medioambientales, parques naturales, etc., establecer programas razonados de investigación de recursos minerales o poner en práctica una ordenación territorial equilibrada. Finalmente, el conocimiento sistemático, implícito en la cartografía metalogenética, de aspectos mineralógicos y geoquímicos de las mineralizaciones, que representan concentraciones locales anómalas de determinados elementos químicos, ya sean naturales o amplificadas e inducidas por la explotación minera, es una infraestructura importante para el análisis y el diagnóstico medioambiental regional.”

Este proyecto de investigación que aquí se presenta para la realización de un trabajo de investig... more Este proyecto de investigación que aquí se presenta para la realización de un trabajo de investigación en el departamento de I+D de la empresa Sociedad de Investigación y Explotación Minera de Castilla y León, S.A. (SIEMCALSA), se enmarca en un amplio estudio que de los Yacimientos de oro primarios en Castilla y León se está llevando a cabo con el Área de Mineralogía de la Universidad de Salamanca, en el marco del Proyecto de Investigación (1FD97-0235) “Estudio Geológico y Metalogenético de las mineralizaciones hidrotermales de Oro y metales asociados de la Comunidad Autónoma de Castilla y León (España)”, del Programa FEDER perteneciente al III Plan Nacional de I+D. El objetivo general del Proyecto es conocer los tipos de yacimientos de oro existentes en Castilla y León, y describir los más representativos a nivel regional.
Por último se establecerán las mineralizaciones de más interés y las posibilidades de explotabilidad de sus recursos.

Se han descubierto minerales estratégicos y raros en concentraciones superiores a los de muchos y... more Se han descubierto minerales estratégicos y raros en concentraciones superiores a los de muchos yacimientos de tierra firme en los montes submarinos canarios de gran interés para la Ciencia y la Sociedad.
Estos descubrimientos son fruto de las investigaciones que, desde el 2011, desarrolla el IGME en las denominadas “Abuelas Canarias”, una antigua cadena de volcanes sumergidos. Los depósitos de óxidos de ferromanganeso de los fondos marinos, a pesar de estar escasamente explorados, ya representan la fuente más importante de elementos de alta tecnología del planeta. Dichos montes submarinos con potenciales yacimientos minerales se encuentran dentro del límite exterior de la Plataforma Continental que presentó España ante la ONU en el 2014. La presentación española ante la ONU inhabilita, de momento, cualquier explotación del monte Tropic por ningún país.

Actualmente, el IGME sigue investigando, con proyectos nacionales de I+D y de cooperación internacional, los minerales marinos en el área de Macaronesia ( Canarias- Azores) para conocer estas importantes mineralizaciones y los procesos de formación y concentración de interés económico.

Nautilus Minerals, Nov 1, 2012

Tribuna de la Ciencia, Jun 2010

El País, Feb 7, 2010

sociedad La gran riqueza en algas verdesazules (cianobacterias) que tiene las islas Canarias es t... more sociedad La gran riqueza en algas verdesazules (cianobacterias) que tiene las islas Canarias es todavía desconocida en gran parte, según los expertos.