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ElGeoPower project is a marine geophsyical study of the Powell Basin area, Bransfield Starit, Scotia Plate and Deception Island. We want to get information from these geographical frame to get a deeper knowledge on the creation of oceanic crust from the very beginning of is onset until it is already formed. To do this we will carry out a marine geophysical cruise using surface magnetometry, marine magnetic deep-tow, swath bathymetry, gravity and refraction seismic

The magnetic anomalies of the Alboran Sea have been modeled along several profiles revealingthe presence of crustal scale, basicigneous intrusionslocated at depths from8 to 14 km. Some ofthem are located under volcanic highs, such as the Djibouti bank,but the most intenseanomalies of central Alboran Seaare related to aNE-SW alignmentof igneous intrusionslocated below the Alboran Channel that runs from the Ibn-Batouta bank to the East Alboran Basin.It is remarkable that these intrusions are northwards displaced with respect to the Alboran Ridge, which is supposed to be the main volcanic high of the Alboran Sea. TheNE-SW elongated anomalyturnseastwardsto NW-SE, parallelingto the Yusuf fault and reachingthe Algerian coast, where it becomes more irregular.According with the geodynamic history of the Alboran Sea, the emplacement of thesebasic igneous intrusions may be related to the rifting of the AlKaPeCa Domain during Oligocene-Early Miocene. This rifting process, which is due to a NW-SE extension associated with slab retreat,led to the spreading of the Algerian basin and the individualization of the Alboran Domain. Thus, the intrusions wouldrepresent the western tip of that rift,since they have the same trend that the rift axis and are also not related with the Miocene volcanic highs. Afterwards, these intrusions were affected by the STEPfault (Subduction Tear Edge Propagator fault)that accommodated the westward displacement of the Alboran Domainalong its southern limit. Since Late Miocene, the tectonic inversion of the Alboran basin curved the STEP fault and originated theYusuf fault, along which some new intrusions could take place. During Pliocene-Quaternary, tectonic indentation was develop as a result of the Eurasia-Africa convergence and the reduction of the Alboran Domain westwards displacement. In this setting, the intrusions act as a backstop that have favored the folding and uplift of the Alboran Ridgein the front of the indenter. Altogether shows that the d

In the Alboran Sea there are a few well exposed Neogene and Quaternary volcanic zones, often geographic highs, that are generally associated with magnetic anomalies. In this paper, we present a characterization of these magnetic anomalies based on a recent and accurate magnetic data compilation for the Abloran Sea area. The anomalies reveal the distribution of magmatism and shed light into the discussion about the origin and evolution of the westernmost Mediterranean. One of the most relevant magnetic anomalies is the Nador dipole, which extends from the Gourougou volcano to the Chafarinas Islands, and is related to an E-W crustal scale intrusion. However, the main NE-SW elongated continuous dipoles of the central Alboran Sea are not related to any surface structure, but they are parallel to the Alboran Ridge, which is the main volcanic high in the Alboran Sea, and are located to the north of it. These anomalies extend discontinuously eastward along the NW-SE dipoles located along the Yusuf fault zone. The results of our 2D magnetic forward modeling suggest that the causative bodies of these main magnetic dipoles are deep igneous bodies. According to the tectonic evolution of the region, and the high magnetic susceptibility values obtained, these igneous bodies probably are made of a basic igneous rocks. Their emplacement may represent the westward tip of the rift axis of the AlKaPeCa Domain, which is related to the Oligocene-Miocene NW-SE extension, and associated with the southern slab retreat stage and oceanic spreading of the Algerian basin. Afterwards, these bodies were displaced toward the west, together with the Alboran Domain, and affected by the STEP fault located at its southern limit. Since the Late Miocene, the north Alboran Ridge elongated intrusions acted as a backstop that conditioned the folding and uplift of the Alboran Ridge in a tectonic indentation setting. In this setting, the STEP fault is deformed and the eastern part of the bodies were segmen

ZEE-2021: Study of the Spanish Economic Zone in the Canary Islands

The Alboran Basin is a Neogene-Quaternary extensional basin located within the Betic-Rif alpine cordillera. The region where the current basin is located holds great oceanographic relevance, as it lies in the area of connection between the western (Atlantic Ocean basin) and eastern seas (ocean basins of the Ligurian Tethys and then Western Mediterranean Sea) of Iberia. The extensional collapse of the Eocene Alpine orogen led to the crustal thinning and formation of the Western Mediterranean basin and the splitting of lithospheric fragments, the Alboran Domain among them, along its margins. The N-S convergence of the African and Eurasian plates, together with the westward escape of the Alboran Domain and its extensional tectonics in the back-arc region linked to the retreat of a subduction zone northwestward has determined the basin’s formation and evolution since the upper Oligocene to Tortonian times. The stretching of the continental crust produced its configuration, creating several sub-basins and tectonic highs, and was accompanied by an important magmatic phase that peaked in the middle-late Miocene. The direction of African-Eurasian convergence evolved to NW-SE in the late Tortonian and is presently WNW-ESE, producing an inversion of the basin in its interior, with the uplift of main reliefs (e.g., the Alboran Ridge), and a progressive elevation of adjacent mountain ranges in southern Iberia (Betic) and northern Africa (Rif), substantially reducing the basin’s width. During this phase, convergence is resolved with an indentation tectonic model in the central Alboran Sea; and to accommodate this deformation, two conjugated sets of dextral WNW-ESE and sinistral NE-SW to NNE-SSW faults are generated. The sedimentary infill of the Alboran Basin consists of unconformable Miocene to Quaternary deposits controlled by the tectonic deformation and paleoceanography. Two important events marked the sedimentary evolution: Messinian desiccation and the opening of the Strai

La zona noroeste de Iberia reúne rasgos geológicos excepcionales relacionados con el desarrollo de un margen continental hiperextendido cerca de un punto triple y la posterior inversión tectónica parcial. Es una zona de gran interés para el estudio del papel de la herencia tectónica y la posterior inversión en márgenes continentales extensionales, pero hay un gran déficit de información. Todo esto sienta las bases del proyecto anfibio MARIBNO (PGC2018-095999-B-I00) donde a lo largo de 2021 y 2022 se adquirirán sísmica marina de reflexión multicanal 2D (~4000 km), sísmica de gran ángulo en 3 transectos tierra-mar (~600 km), batimetría multihaz, grav-mag y sísmica de alta resolución. Se complementará en tierra con adquisición de datos grav-mag y varias campañas de cartografía geológica. Los objetivos se centran en el estudio de la estructura cortical, el control tectónico ejercido por estructuras previas a las etapas alpinas y la cartografía y caracterización de los dominios corticales aunando criterios geológicos y geofísicos.

Rifting of continental lithosphere leading to oceanic basins is a complex process conditioned by different factors such as the rheology and thermal structure of the underlying lithosphere, as well as underlying asthenospheric dynamics. All these processes, which finally lead to oceanic domains, can better be recognized in small oceanic basins. Powell Basin is a small oceanic basin bounded to the north by the South Scotia Ridge, to the east by the South Orkney Microcontinent, and to the west by the Antarctic Peninsula. It was formed between the Oligocene and Miocene, however, its age is not well defined, among other reasons due to the small amplitude of its spreading magnetic anomalies. This basin is an ideal framework to analyze the different rifting and spreading phases, which leads from continental crust to the formation of an oceanic domain through different extensional regimes. To identify the different boundaries during the formation of Powell Basin from the beginning of the rifting until the end of the spreading, we use different data sources: magnetic, gravity, multichannel seismic profiles and bathymetry data. We use seismic and bathymetry data to estimate the Total Tectonic Subsidence. Total Tectonic Subsidence has proven to be useful to delineate the different tectonic regimes present from early rifting to the formation of oceanic seafloor. This result together with magnetic data has been used to delimit the oceanic domain and compare with previous authors’ proposals. This method could be applied in any other basin or margin to help delimiting its boundaries. Finally, we analyze the role that an asthenospheric branch intruding from the Scotia Sea played in the evolution of the magnetic anomaly signature on an oceanic basin.

The northern margin of Hispaniola records the oblique collision/underthrusting of the Bahamas Carbonate Province with the island-arc. Due to the collision, northern Hispaniola has suffered several natural disasters caused by major earthquakes and tsunamis, such as the historic earthquake of 1842, the tsunami caused by earthquake-driven slumping in 1918 in the Mona Passage, the seismic crisis of 1943-1953 with five events of M>7.0 or the seismic crisis of 2003 with a main shock of M6.3 and a large aftershock of M5.3. Using new swath multibeam bathymetry data and vintage single- and multi-channel seismic profiles, we have performed a regional scale analysis and interpretation of the shallow surface and active processes along the northern margin of the Dominican Republic. We have identified three morphostructural provinces: a) the Bahamas Banks, b) the Hispaniola Trench and c) the Insular Margin, which are divided into two tectonic domains, the Collision Domain and Underthrusting Domain. The southern slope of the Bahamas Carbonate Province shows a very irregular morphology produced by active erosive processes and normal dip-slip faulting, evidence of an extensional tectonic regime and margin collapse. This collapse is of major extent in the Oblique Collision Domain where there are erosive and fault escarpments with higher dip-slip fault throws. The Hispaniola Trench, is formed by the Caicos and Hispaniola basins in the underthrusting domain, and by the Santisima Trinidad and Navidad basins in the Oblique Collision Domain. They have a flat seafloor with a sedimentary filling of variable thickness consisting of horizontal or sub-horizontal turbiditic levels. The turbiditic fill mostly proceeds from the island arc through wide channels and canyons, which transports sediment from the shelf and upper slope. The Insular Margin comprises the Insular Shelf and the Insular Slope. The active processes are generated on the Insular Slope where the Northern Hispaniola Deformed Belt, Comunidad de Madrid, Universidad Complutense de Madrid, Depto. de Geodinámica, Estratigrafía y Paleontología, Fac. de Ciencias Geológicas, TRUE, pub

The NW Iberian continental margin has a complex structure, resulting from the succession of several rifting episodes close to a ridge triple junction, and a superimposed partial tectonic inversion stage. The wide-ranging physiography matches the diverse tectonic deformation domains related to its evolution. Each deformation domain has a distinctive gravity signal, so the detailed Bouguer anomaly map presented here is a good first approach to the regional study of the whole margin. Moreover, as the presented chart is a complete Bouguer anomaly map (including terrain corrections), its analysis and interpretation can be done in terms of density, geometry and depth variations below the seafloor. This map is mainly based on the dataset obtained during seven one-month surveys carried out in the frame of the Spanish Economic Exclusive Zone project, and also includes two 2¿+¿3/4D density models illustrating the deep structure of the margin.

The sinking of the ocean sea bottom is produced by thermal cooling of the lithosphere. This evolution is determined by the underlying asthenospheric mantle. Estimation of the Curie Depth variations in the Scotia Sea by using a spectral approach and applied on magnetic anomaly data led us to determine a thermal model and derive a heat flux map. Using multichannel seismic and bathymetry data, we show that the West Scotia Sea reaches thermal equilibrium more quickly than other oceans do and thermally behaves like old oceanic crust in large oceans, following a different empirical age (t, in Ma)-depth (d, in m) relationship, d(t) = 4,480 ¿ 19,380 exp(¿t/4). For oceanic crusts of the same age, underlain by different shallow mantle controlling the heat supply, low heat flux values imply older ages than those predicted for large oceans based on the empirical relationships of the standard plate model. These circumstances, together with the new heat flux map, shed light on the anomalous evolution of the Scotia Sea, a consequence of the present Pacific mantle outflow through the Drake Passage. Two branches of elevated heat flux surround the Shackleton Fracture Zone and extend to the northern and southern boundaries of the Scotia Plate. Most of the heat sources are located in the flanks, whereas the colder parts are centrally located. This signature supports the Drake Passage's role as a main mantle gateway for Pacific outflow toward the Atlantic reservoir favoring the oceanic spreading activity of this ocean. ©2019. American Geophysical Union. All Rights Reserved.

The northern margin of Hispaniola records the oblique collision/underthrusting of the Bahamas Carbonate Province with the island-arc. Due to the collision, northern Hispaniola has suffered several natural disasters caused by major earthquakes and tsunamis, such as the historic earthquake of 1842, the tsunami caused by earthquake-driven slumping in 1918 in the Mona Passage, the seismic crisis of 1943–1953 with five events of M > 7.0 or the seismic crisis of 2003 with a main shock of M6.3 and a large aftershock of M5.3. Using new swath multibeam bathymetry data and vintage single- and multi-channel seismic profiles, we have performed a regional scale analysis and interpretation of the shallow morpho-structure and active processes along the northern margin of the Dominican Republic. We have identified three morphostructural provinces: a) the Bahamas Carbonate Province, b) the Hispaniola Trench and c) the Insular Margin, which are divided into two tectonic domains, the Collision Domain and Underthrusting Domain. The southern slope of the Bahamas Carbonate Province shows a very irregular morphology produced by active erosive processes and normal dip-slip faulting, evidence of an extensional tectonic regime and margin collapse. This collapse is of major extent in the Oblique Collision Domain where there are erosive and fault escarpments with higher dip-slip fault throws. The Hispaniola Trench is formed by the Caicos and Hispaniola basins in the underthrusting domain, and by the Santisima Trinidad and Navidad basins in the Oblique Collision Domain. They have a flat seafloor with a sedimentary filling of variable thickness consisting of horizontal or sub-horizontal turbiditic levels. The turbiditic fill mostly proceeds from the island arc through wide channels and canyons, which transports sediment from the shelf and upper slope. The Insular Margin comprises the Insular Shelf and the Insular Slope. The active processes are generated on the Insular Slope where the Northern H

The acoustic facies analyses have provided an important basis for sedimentary processes in the deep-sea environments. The echo-character mapping, through the interpretation and correlation of very high-resolution seismic profiles, is a very useful tool for the characterization of the recent sedimentary processes and their distribution. This work presents the first echo-character map at 1:800,000 scale of the Galicia Continental Margin and the adjacent abyssal plains elaborated by the Geological Survey of Spain. The map was carried out on the basis of the analysis and interpretation of the bathymetry and reflectivity data from the SIMRAD EM12, EM120 and EM1002 echosounders, and the high-resolution seismic profiles from the SIMRAD TOPAS PS18 parametric echosounder. On the basis of seafloor morphology, surface bedforms, backscatter and sub-bottom acoustic echocharacters, 26 echo-types were identified in the uppermost sedimentary sequence. These echo-types have been grouped into four main echoes: Distinct, Irregular, Hyperbolic and Undulated, according to their main acoustic characteristics. This information has been acquired in the framework of the ‘Scientific Research Program of the Economic Exclusive Zone of Spain’, which is coordinated and leaded by the Defense Ministry of Spain, during the oceanographic cruises carried out on board of the R/V Hesperides in 2001–2003 and 2006–2009.

The ZEE-2018 campaign has as a specific priority, the study of the Exclusive Spanish Economy Zone South of the Canary Islands. Specific objectives: - The systematic bathymetric survey of designated areas with full exploration of the fund, using multibeam probes. - The systematic collection of gravimetry and magnetometry data and of acoustic profiles of the marine subsoil structure. - The systematic collection of oceanographic data and complementary environmental - Vertical Profiles of Celerity of Sound, through Bathtthermographs XBT - Meteorological Data, through instrumentation of the Weather Station -Surface temperature and salinity data, through Thermosalinograph equipment - Current data in the surface layers through acoustic current meters ADCP

The Alboran Sea is located in the convergence area between the Eurasian-African tectonic plates. In the last millions of years, the convergence of these plates has produced the progressive narrowing and closing of the sea anda complex structure. At present, Eurasia and Africa continental collision favors the development and activity of faults with associated crustal earthquakes, in addition to intermediate and deep seismicity related to subduction processes. A band of significant seismicity and tectonic activity is located in the central and eastern part, extending from Campo de Dalías to Alhucemas region. The detailed characterization of these structures is essential to evaluate their impact in the surrounding coastal regions.

The study of the statistical properties of ocean magnetic anomalies could be very important to obtain new understanding on plate tectonics, especially about the past properties of the lithospheric oceanic plates. Here we analyse in terms of statistical distributions the ocean magnetic anomaly data at the global scale covering the crustal oceanic ages from the present to 180 Ma. Our results show that the marine magnetic anomaly data follow the Laplace statistical distribution. This behaviour is observed at global scale and for any time interval within the last 180 Ma. In addition, the statistical parameters of the Laplace distribution are used to define some properties of the crustal oceanic magnetic field, focusing our investigation on the Cretaceous Normal Superchron. Finally, we also provide a physical explanation of this statistical distribution of marine magnetic anomaly data using a test with synthetic data.

One efficient approach to modelling the Earth’s core magnetic field involves the inclusion of crossover marine data which cover areas lacking in observatory and repeat station data for epochs when precise three-component satellite magnetic field measurements were not common. In this study, we show how the Revised Spherical Cap Harmonic Analysis (R-SCHA) can appropriately provide a continuous-time field model for the North Atlantic region by using multilevel sets of geomagnetic data such as marine, repeat station, observatory, and satellite data. Taking advantage of the properties of the R-SCHA basis functions we can model the radial and horizontal variations of the main field and its secular variation with the most suitable spatial and temporal wavelengths. To assess the best compromise between the data fit and the model roughness, temporal and spatial regularization matrices were implemented in the modelling approach. Two additional strategies were also used to obtain a satisfactory regional model: the opportunity to fit the anomaly bias at each observatory location, and constraining the regional model to the CHAOS-6 model at the end of its period of validity, i.e. 1999–2000, allowing a smooth transition with the predictions of this recent model. In terms of the root mean square error, the degree of success was limited partly because of the high uncertainties associated with some of the datasets (especially the marine ones), but we have produced a model that performs comparably to the global models for the period 1960–2000, thus showing the benefits of using this regional technique.

El objetivo principal del proyecto “Physico-chemical, biological and geological study of an underwater volcano in a degassing stage: Island of El Hierro”, (VULCANO-II) es estudiar, desde un punto de vista totalmente interdisciplinar, la fase de desgasificación activa del único volcán submarino monitoreado desde su nacimiento en aguas españolas. De esta forma, se pretende además, dar continuidad a los estudios multidisciplinares realizados sobre el volcán submarino de la isla de El Hierro en el contexto del proyecto del Plan Nacional VULCANO-I, (CTM2012-36317) y VULCANA (Vulcanología Canaria Submarina, IEO). Para ello, se realizará la monitorización de las propiedades físico-químicas, biológicas y geológicas del proceso eruptivo submarino de la isla de El Hierro y otros puntos sensibles, como el volcán de Enmedio entre Gran Canaria y Tenerife

ZEE-2016 cruise : Bathimetry, magnetic field, gravimeter field of Balear Sea. The main objectives will be: - Systematic recognition of study areas with 100% coating, with multi-beam probe, using also single-beam probe, EA-600 and EK60, gravimetry, geomagnetism, sediment penetrator, and oceanographic parameters. The Multi-beam, single-beam and Bathymetry works will be priority, performing simultaneously geomagnetic, gravimetric and high resolution seismic and oceanographic works. Systematic data collection of: - XBT / XSV - Weather Station - Termosalynograph - Doppler

Los estudios de subsidencia tienen como objetivo mostrar la evolución que ha sufrido una cuenca a lo largo de su historia geológica o en un periodo determinado de la misma como consecuencia de la extensión, adelgazamiento y enfriamiento litosférico. El principio básico para entender el fenómeno de subsidencia es el de la isostasia, el cual se refiere a la condición de equilibrio que presentan las diferentes porciones de la litosfera terrestre debido al contraste de densidades basándose en el principio de Arquímedes. A principios del siglo XX, a partir del estudio de propagación de las ondas sísmicas, se concluyó que el interior de la tierra presentaba una estructura basada en capas siguiendo dos modelos: uno estático, según la composición química (corteza, manto y núcleo); y otro dinámico basado en el comportamiento mecánico de los materiales manifestándose de esa manera el comportamiento térmico (Figura 1) (litosfera formada por la corteza y parte del manto superior; astenosfera; mesosfera, formada por el manto inferior; núcleo externo e interno) (Lowrie, 2007).

[ES] El presente estudio realiza una revisión del estado del conocimiento en el Margen Atlántico Ibérico atendiendo a las tres provincias en las que clásicamente se sub-divide éste: margen gallego, planicie abisal suribérica, y planicie abisal del Tagus, utilizando como fuente de información datos de campos potenciales e información derivada de espesor de sedimentos. Se estudian las características de su basamento, estableciendo límites para la extensión de la corteza continental, y la amplitud del dominio denominado transición océano-continente cuyo fin marca el inicio de la corteza oceánica. La corteza continental en el margen gallego ocupa aproximadamente 210 km, la mayor de las tres provincias, mientras que su zona de transición océano- continente varía ligeramente entre los 65 km en su zona sur y los 56 km más al norte, difiriendo de lo propuesto por otros autores que consideran ronda los 30 km. La situación en la planicie abisal sur-ibérica es aproximadamente la contraria. El dominio continental se extiende menos que en el gallego, aproximadamente unos 60 km, mientras que la zona de transición océano-continente lo hace unos 185 km. El estudio de la planicie abisal del Tagus muestra una evolución morfológica más rápida que las otras dos, registrando a partir del análisis de la variación del factor de adelgazamiento ß una zona de transición océano-continente de aproximadamente 100 km. Los resultados obtenidos apoyarían una naturaleza intermedia a la corteza en prácticamente todo el dominio del Tagus, en contra de lo establecido por otros autores., [EN] This study reviews the state of knowledge in the Iberian Atlantic margin. In order to do this, the margin has been divided into three provinces: the Galicia margin, the southern Iberian abyssal plain, and the Tagus abyssal plain. We have used potential field and sediment thickness data. This has allowed us to study the crust, setting limits for the continental crust domain, and the amplitude of the so-called ocean-continent transition, whose end marks the beginning of the oceanic crust. The study shows the continental crust in the Galician margin to be the widest, about 210 km in length, whilst the ocean-continent transition varies slightly in this province: between 65 km wide in the south and 56 km wide in the north. This result shows up some differences with the hypothesis of other authors. The situation in the southern Iberian abyssal plain is nearly the opposite. Its continental crust extends approximately 60 km, whilst the ocean-continent transition zone is 185 km long. The Tagus abyssal plain study shows a faster morphological evolution than the others, according with the amount of crustal thinning ß, the ocean-continent transition domain spanning 100 km. These results support a transitional intermediate character for almost the whole Tagus plain, in contrary to what other authors have stated.

During the cruise, which had as main objective the study of the Exclusive Economic Zone of the North of the Iberian Peninsula, 4,983 nautical miles of sounding, verification of anomalies of the magnetic and gravitational field, and probe with penetration capacity in the subsoil have been made , to study the different layers of sediments. The study area covered by the 'Hespérides' has been 58,682 km², which would roughly equal the size of the territory of Castilla-La Mancha. The 2014 ZEE cruise was directed by the Royal Navy Observatory (ROA), with the support of 45 scientists belonging to the Navy Hydrographic Institute (IHM), the Marine Technology Unit (UTM) of the Spanish National Research Council ( CSIC), the Spanish Oceanographic Institute (IEO), the Geological and Mining Institute of Spain (IGME), and the universities of Cantabria, Cádiz, Oviedo and Complutense de Madrid

Canary Islands ZEE 2011 cruise, Plan for hydrographic and oceanographic Spanish Exclusive Economic Zone

A total of 445 pockmarks were observed on the upper continental slope of the northwest corner of the Iberian Peninsula (the Ortegal Spur area) by swath bathymetric and ultrahigh resolution seismic data. The pockmarks are U-, V- and W-shaped and have terraces or indentations in cross-section, and are dish-shaped (circular to oval) in plan view. They occur on the surface of the seabed and buried within the Plio-Quaternary and Neogene sediments. Four types of pockmarks were identified and mapped on the basis of their plan-view and cross-section morphology: regular, irregular, asymmetric and composite. The concentration of pockmarks is attributed to seepage of fluids migrating up-dip from deeper parts of the sedimentary basin. A linear high-density concentration with a NNW to N, NE and ESE trend of pockmarks is observed above inferred basement faults that do not affect the Quaternary succession. These pockmarks are thus caused by seepage of thermogenic gas and/or other pore fluids from deeper Late Cretaceous units, and their distribution may help to improve our understanding of the fluid system and migration regime in this part of the Galicia continental margin

Exclusive Economic Zone cruise 2008, (Characterization of the Galician Continental Margin). Oceanographic hydrographic study of the Spanish exclusive economic zone

Spanish Exclusive Economic Zone cruise 2007. Hydrography-oceanography research Plan of the Exclusive Spanish Economic Zone

Deception Island is a young, active volcano located in the south-western part of Bransfield Strait, between the Antarctic Peninsula and the South Shetland archipelago. New gravity and magnetic data, from a marine geophysical cruise (DECVOL-99), were analysed. Forty-eight survey lines were processed and mapped around Deception Island to obtain Bouguer and magnetic anomaly maps. These maps show welldefined groups of gravity and magnetic anomalies, as well as their gradients. To constrain the upper crustal structure, we have performed 2+1/2D forward modelling on three profiles perpendicular to the main anomalies of the area, and taking into account previously published seismic information. From the gravity and magnetic models, two types of crust were identified. These were interpreted as continental crust (located north of Deception Island) and more basic crust (south of Deception Island). The transition between these crustal types is evident in the Bouguer anomaly map as a high gradient area trending NE–SW. Both magnetic and gravity data show a wide minimum at the eastern part of Deception Island, which suggests a very low bulk susceptibility and low density intrusive body. With historical recorded eruptions and thermal and fumarolic fields, we interpret this anomaly as a partially melted intrusive body. Its top has been estimated to be at 1.7 km depth using Euler deconvolution techniques., Depto. de Geodinámica, Estratigrafía y Paleontología, Fac. de Ciencias Geológicas, TRUE, pub

Exclusive Economic Zone 2003 cruise

Study of the circulation and bathymetry of the environment of the circumpolar current (DRAKE). Objectives: 1-To study the geographic variations of the differents water masses present in Drake passage, Brandsfield sea and Decepcion Island. 2-To verify the NOAA satellites radiometer formalism comparing in situ measurements simultaneously recorded in the Antartic Ocean and Cadiz Gulf with satellite data. 3-To verify the Topex-Poseidon, ERS-2 altimeters by direct comparation of the geostrophic currents computed from altimetry and local currents simultaneous measurements. 4- To compare satellite altimeter data with gravimeter continous records

Study of Deception Island volcanic complex and its environment from marine geophysical techniques. Partial objectives: - Establishment of models of horizontal and vertical deformation. - Determination of a local geoid. - Analysis of maps of geomagnetic and gravimetric anomalies. - Establishment of a model of the structure of the crust and upper part of the mantle. - Numerical modeling of behavior. of the boilers. - Elaboration of statistical models for the calculation of the return period. - Elaboration of risk and dangerousness maps. - Elaboration of a multidisciplinary scientific support system (SIMAC). -Geodynamic interpretation of the previous models. SOURPROJECTS: GEODEC-GEODESIA: Geodetic studies on Deception Island. GEODEC-MODELS: Modeling of the active geological processes of the Decepción volcano from the integration of geophysical and geodetic data.GEODEC-GEOMAR: Study of the volcanic complex of Deception Island and its surroundings based on marine geophysics techniques