Ruth Soto

• PhD
• Researcher at Instituto Geológico y Minero de España-CSIC

The major goal of this work is to provide insight into the structural and geological anatomy of the Pyrenees based on the magnetic anomalies and inferred lineaments from Earth Magnetic Anomaly Grid 2 arcmin resolution (EMAG2v2) magnetic data. We focus on providing qualitative and semi-quantitative evidence of the magnetic signature of the Pyrenees...

A magnetic fabric study was carried out in Permo-Triassic continental sedimentary red beds from the Cadí Basin (Eastern Pyrenees). These rocks were deposited on the top of a volcanic sequence when the regional tectonic regime changed from transtension to extension. Standard paleomagnetic cores (cylinders), cubes and irregular fragments were obtaine...

This work shows the Bouguer and aeromagnetic anomaly maps of the Iberian Chain (NE Spain) and surroundings in relation to its main geological and structural units. In general, both gravity and aeromagnetic anomalies are aligned following the same trends in both maps highlighting the major role played by the structural configuration of the Iberian C...

La zona de estudio, en las inmediaciones de La Seu d’Urgell (Zona Axial pirenaica), está constituida por una serie estratigráfica de rocas Cambro-Ordovícicas, en su mayoría detríticas, donde la discordancia Sarda se identifica claramente entre la Serie de Jujols y la Fm. Conglomerados de la Rabassa. Las principales estructuras son pliegues N-S de p...

The major goal of this work is to provide an insight into the structural anatomy of the Pyrenees based on the magnetic data from the Earth Magnetic Anomaly Grid 2-arc-minute resolution (EMAG2v2). We focused on providing qualitative and semi-quantitative evidence on the magnetic signature of the Pyrenees Mountain Range domains and structures. The in...

Triassic evaporites represent the regional décollement of the Pyrenees and form two salt provinces north and south of the South Pyrenean Central Salient (SPCS). We present an updated Bouguer and residual Bouguer anomaly map built upon the homogenization of available gravity data of the SPCS together with four new and representative cross‐sections,...

In this work, we present results of the application of paleomagnetism and the analysis of synsedimentary structures in order to clarify the age and origin of transversal anticlinal ridges in the northern border of the Central High Atlas (CHA). The results are interpreted in terms of paleogeometry of the main structures. The High Atlas fold-and-thru...

The purpose of this work is to use paleomagnetic data to determine the tectonic evolution of the inverted High Atlas basin in the area of the Taguelft syncline. This syncline shows two well defined rock types of Jurassic age: marly limestones and red beds, and therefore provides the opportunity of comparing paleomagnetic results from rocks with dif...

Este cuento representa un recurso didáctico de Geología para Educación Infantil, es decir, para niños de 3 a 5 años. A través del viaje de Roqui, aprendemos sobre varios procesos geológicos y reforzamos la percepción del entorno natural que tienen los niños y niñas en su etapa infantil.

During the Jurassic, Iberia and western North Africa underwent extensional tectonics conditioned by their position with respect to the African, Eurasian and North American plates and related to the Central and North Atlantic opening and westward expansion of the Tethys. In Iberia, the Jurassic is characterized by the presence of wide shallow marine...

The anisotropy of magnetic susceptibility provides valuable information on the imprint of the different tectonic processes occurred in the Central High Atlas (CHA), complementing the structural analysis and paleomagnetic information. Different types of magnetic ellipsoids, related with extensional, diapiric or intrusive processes occurred during th...

The so-called Henkel's plot (1976) allows relating density and magnetic susceptibility of rocks. In this work we focused on three paramagnetic Pyrenean granites from the Mont Louis-Andorra, Maladeta and Marimanha granitic plutons. In total, 128 sites with 310 density measurements and > 2600 susceptibility readings cover the main range of variabilit...

The Pyrenees constitutes an exceptional example of an Alpine orogenic belt characterized by basement thrust sheets involving Paleozoic rocks and Mesozoic and Cenozoic cover units detached on the Triassic evaporites, the main décollement level. This work is located in the Central Pyrenees, where gravity data help to better constrain the internal arc...

The acquisition and interpretation of gravity and magnetic data represents a cost-effective tool in geophysics since it allows to determine the geometry and distribution of the density and magnetic properties at depth of the subsurface rocks. The study area, where gravity and magnetic data have been interpreted, is the La Cerdanya basin (Eastern Py...

Centrifuge analog modeling incorporating thickness variations of décollement and overlying sedimentary cover is used to study thrust-wedge evolution on salt-detached contractional systems involving tapered sedimentary cover. From simpler, layer-cake to 3D tapered décollement-cover sequences, our models constrain wedge evolution: a more advanced fro...

One of the main challenges facing geological storage is to identify cost-effective methodological workflows for characterizing and monitoring geological storage sites. In the framework of the ALGECO2 project, led by the IGME (Geological and Mining Institute, Spain), a preliminary study of the Lopín site in the NE of Spain indicated conditions were...

The analysis of the Anisotropy of Magnetic Susceptibility (AMS) constitutes a fast and non-destructive technique that has gained the acceptance of structural geologists because it provides valuable information related to the orientation and intensity of the strain ellipsoid of deformed rocks. Part of its strength results from the possibility of (i)...

In this work we establish reliable correlations between density and magnetic susceptibility in three paramagnetic granites from the Pyrenees. In total, 128 sites (310 density measurements and >2600 susceptibility ones) were studied in the Mont Louis-Andorra, Maladeta and Marimanha granitic plutons covering the main range of variability of magnetic...

A new gravity survey (1164 gravity stations and 180 samples for density analysis) combined with two new geological cross sections has been carried out in a sector of the Central Pyrenees in order to improve the characterization of basement and cover architecture. From North to South, the study area comprises the southern half of the Axial Zone and...

The aim of this work is the application of the anisotropy of magnetic susceptibility (AMS) to the study of volcanic materials from the Late Carboniferous-Permian Cadí basin (southern Pyrenees) in order to (i) explore the limits of this technique in ancient volcanic materials that have undergone strong chemical alteration and a complex tectonic evol...

In this work, we present new Bouguer and residual Bouguer anomaly maps of the Central Pyrenees calculated from 3590 stations, of which 1141 are new observations acquired from surveys performed between 2018 and 2019. The most prominent feature of the Bouguer anomaly is the long wavelength elongated minimum in its central part that continues to the W...

Las relaciones geométricas y cinemáticas entre las unidades de basamento de los Pirineos Suroccidentales, específicamente entre la terminación de la Zona Axial y el afloramiento de los Macizos Vascos, son desconocidas y potencialmente muy complejas (Oliva-Urcia, 2018). La gravimetría se ha aplicado con éxito en otras regiones pirenaicas para resolv...

A short video (8 min) allows, on the one hand, to spread information and on the other hand to determine its educational purpose of the Pyrenean geology. The script is based on a dialogue between the Posets Mountain and a geologist who is sampling for studying its deformation. Concepts about geological time and paleogeographic reconstructions (Scote...

Magnetic fabric analyses are a fast and non-destructive method used to determine the fabric in rocks, since the first studies of magnetic fabric, a parallelism between the magnetic fabric and the rock fabric was observed. The mineral distribution in rocks is modified by stress. Magnetic fabric analyses in relation with deformation in folded rocks c...

The characterization of the basement architecture of the Pyrenean Axial Zone, backbone of the chain, is crucial to understand its geodynamic evolution and the interplay between tectonism and magmatism. In this work, a new gravity-constrained cross section was built along the Central Pyrenees, between two of the largest Pyrenean Late Variscan granit...

The South Pyrenean triangle zone represents the southernmost front of the Pyrenees at its central portion deforming the Upper Eocene‐Miocene Ebro Basin deposits. Two main structures characterize its western termination, the Barbastro anticline and the San Román backthrust, which detached on the Barbastro Formation (and lateral equivalents), an Uppe...

The GeoPiri3D project aims to characterize the geometry and kinematics of the Permo-Carboniferous batholiths of the Central Pyrenees through a combination of potential fields and structural data. During 2018 we have acquired 824 new gravity stations and 186 rock samples. The gravity data were processed and integrated into the IGME database and a ne...

Geophysical surveying (both gravity and magnetic) is of great help in 3D modeling of granitic bodies at depth. As in any potential-field geophysics study, petrophysical data (density [r], magnetic susceptibility [k] and remanence) are of key importance to reduce the uncertainty during the modeling of rock volumes. Several works have already demonst...

Shear zones, or their counterparts in near-surface conditions, the brittle fault zones, constitute crustal-scale, narrow, planar domains where deformation is strongly localized. The variation with depth of deformation conditions (P-T), rheology and strain rates entails a wide range of fault rock types, characterized by different petrofabrics and cl...

The aim of this work is to apply the anisotropy of magnetic susceptibility (AMS) to determine the primary and tectonic fabrics of lava flows and volcanoclastic materials in one of the Pyrenean Stephano-Permian basins. The Pyrenean Range is a double vergence orogen located at the northern end of the Iberian Peninsula. During Carboniferous-Early Perm...

In this work we used analogue models in order to better understand how two orthogonal fold-and-thrust belts may interact in the foreland and influence the geometry and kinematics of the resulting structures. Our experimental device has two vertical mobile backstops oriented perpendicular with respect to each other, independent and moving coevally w...

During the Triassic, Iberia and western North Africa displayed a unique situation in relation with the Central and North Atlantic opening and westward expansion of the Tethys. Unravelling the stretching direction in Triassic deposits of the studied area can help in our understanding of this scenario. The tectonic setting is characterized by localiz...

Dating the sedimentary infill of the northern margin of the Ebro foreland basin informs about the orogen-basin evolution. A magnetostratigraphic section of ~5 km-thick combines new magnetostratigraphic results from the syntectonic alluvial Uncastillo Fm (Upper Oligocene-Lower Miocene, 1 km-thick, the Fuencalderas section) with previous (3.3 km-thic...

AMS and structural analysis are here applied to study the deformed zone associated with a large-scale, active normal fault in the central Betic Cordillera (Spain), namely the Baza fault system, to determine: i) the kinematics of structures and their relation with fault zone architecture and segmentation degree, ii) the correlation between deformati...

In the frame of the GEOPIRI3D Project (financed by the Spanish Ministry of Science, Innovation and University), two new gravity-constrained cross sections have been made. The goal of this study is to analyze the Axial Zone of the central part of the Pyrenees to better constrain the geometry of the basement host rocks and genesis of the Late Varisca...

During the Triassic, Iberia and nearby areas of the North-African systems constituted the transition zone between the North Atlantic Ocean opening and the westernmost Tethyan realm. Unravelling the stretching direction (i.e. primary magnetic lineation) during this period can help to understand the tectonic setting of the studied area. In this work,...

The Atlas system is an intracontinental inverted basin located in North Africa. After being subjected to the extensional stage in the Mesozoic, the basin was inverted during the Cenozoic due to the convergence between Africa and Europe. The Central High Atlas is located in the Moroccan Atlas and it is characterized by thick sequences of Jurassic ca...

Magnetic properties of rocks can be useful for determining paleoenvironmental changes. A dramatic climate change that occurred in the Paleocene-Eocene Thermal Maximum (PETM) modified the environment and, hence, the magnetic properties recorded in the sediments. New paleomagnetic data from marine records of the PETM in the Southern Pyrenean zone dis...

This work aims to characterize the Gavarnie thrust, one of the large-scale thrusts that defie the Alpine structure of the west-central sector of the Pyrenees. A detailed comparison of structural analysis and magnetic fabrics is carried out for the Paleozoic phyllonites of the Gavarnie thrust, in order to decipher strain distribution and transport d...

Positive tectonic inversion of sedimentary basins has been recognized as one of the primary mechanisms of mountain building and intraplate deformation. Reconstructing the tectonic history of basins is relatively easy for the inversion stage but becomes more difficult for the basinal stage, especially when strong deformation involving cleavage devel...

The study of the magnetic fabric (AMS) is a quick and effective technique that allows to determine the rock fabric and, in a extensional context, the extension direction at local scale. In this work we present the results of structural analysis and AMS recorded in the Baza Fault, with the aim of characterizing the kinematics of the structure. Five...

Analogue models, help understanding geological processes, in particular deformational ones. However, standard procedures such as surface scanning (at any time) and sectioning at the end of the experiments represent 2D approaches for the analysis of deformation structures. The application of CT scanning techniques helps understanding deformation pat...

Magnetic fabric allows to unravel the petrofabric of sedimentary rocks and to assess their deformational history. The use of this technique, in addition to classical structural field observations in the limbs of seven asymmetric folds in the Pyrenees, helps to determine the differences of internal deformation as well as the folding kinematics. Thre...

River incision into bedrock resulting from the combined effects of tectonic uplift and climate governs long-term regional landscape evolution. We determined spatial and temporal patterns of post-orogenic stream incision from a sequence of well-preserved staircase terraces developed over the last 1 Ma in the Central Pyrenees and its southern forelan...

This work deals with the application of the anisotropy of magnetic susceptibility (AMS), structural analysis and microstructural analysis to the study of shear zones. Mylonitized fault rocks have been sampled in the Gavarnie Trust, one of the main structures of the Pyrenean Axial Zone, which was structured as a south-verging antiformal stack during...

Major discontinuities in the Earth’s crust are expressed by faults that often cut across its whole thickness favoring, for example, the emplacement of magmas of mantelic origin. These long-lived faults are common in intra-plate environments and show multi-episodic activity that spans for hundred of million years and constitute first-order controls...

River incision into bedrock resulting from the combined effects of tectonic uplift and climate governs long-term regional landscape evolution. We determined spatial and temporal patterns of post-orogenic stream incision from a sequence of well-preserved staircase terraces developed over the last 1 Ma in the Central Pyrenees and its southern forelan...

An analysis of Anisotropy of Magnetic Susceptibility was done on Aptian–Albian sediments from the Basque–Cantabrian basin. Samples were collected from 39 sites in the halokinetic sequences of the Bakio, Bermeo, Guernica and Mungia diapirs; 28 sites were sampled close to diapirs, and 11 sites were far from the diapir edges. The magnetic foliation is...

Magnetic fabric studies in sedimentary rocks were firstly focused on strongly deformed tectonic contexts, such as fold-and-thrust belts. As measurement techniques were improved by the introduction of high-resolution equipments (e.g. KLY3-S and more recent Kappabridge susceptometers from AGICO Inc., Czech Republic), more complex tectonic contexts co...

A new gravity survey (almost 900 new sites and more than 4000 sites from previous studies) reveals the existence of Pyrenean-oriented long-wavelength residual gravity anomalies ranging from −18 to 28 mGal, associated with frontal structures, and short-wavelength gravity lows (up to −16 mGal) distributed along an oblique zone in the western sector o...

Resumen: La combinación de 20 nuevas estaciones de paleomagnetismo, con 17 estaciones previas y un modelo geomagnético ha permitido establecer la evolución multiepisódica del edificio volcánico cuaternario de la Isla Decepción (Antártida). Se han analizado tres estaciones en brechas volcánicas y dos estaciones en lavas pertenecientes a los material...

The Barbastro-Balaguer anticline is located in the central sector of the south pyrenean front. In this work we introduce the first paleomagnetic data in this structure seeking to shed light on whether there are vertical axis rotations related to its emplacement. 19 stations were sampled evenly distributed along the anticline, mostly focused on the...

The Uncastillo Fm crops out along the southern boundary of the External Sierras, which represents the southernmost limit of the Pyrenean Range. Three tectosedimentary units related to tectonic pulses have been previously differentiated in this formation. The sedimentary evolution of the Uncastillo Fm is mainly related to the tightening of the WNW-E...

Among the activities of the DR3AM Project it is being carried out a gravimetric study to support the creation of a 3D geological model of the western part of the Barbastro-Balaguer anticline in order to obtain an image of the distribution and thickness variations of the evaporites together with the geometry of the top of the basement. This paper pr...

In this work we present a structural study of the western end of the Barbastro-Balaguer anticline. We elaborated two new cross sections based on a geological map synthesis, new structural data, seismic reflection profiles and the reinterpretation of well log data. These two cross sections together with an already published one allow to describe the...

Despite the lateral continuity of the Eocene evaporites in the core of the Barbastro-Balaguer anticline along 150 km of extension, surface geology depicts, in structural terms, along-strike variations. In this work, we present a synthetized geological map of this structure and three cross sections to illustrate specific zones of the western, centra...

Resumen: El estudio de fábricas magnéticas (mediante la Anisotropía de la Susceptibilidad Magnética, ASM) es un método rápido y eficaz de determinar la petrofábrica de las rocas, pudiendo ser utilizada como indicador de la deformación. En este trabajo se relaciona la orientación del elipsoide de susceptibilidad magnética con la dirección de transpo...

In order to obtain a kinematic model linking the diapir formation and the geometry of the syn-diapir sediments, a paleomagnetic study has been conducted in selected syn-diapiric sequences of the Basque-Cantabrian Basin. The studied diapirs (Bakio, Bermeo, Guernika and Mungia) developed during the Early Cretaceous in relation to the North Iberian ex...

This work shows the results obtained after the analysis of the Anisotropy of Magnetic Susceptibility (AMS) of 29 sites sampled on Aptian-Albian marls, marly limestones, fine sandstones and lutites. The study area is located on the northern part of the central sector of the Basque-Cantabrian basin. Fifteen sites were sampled on syn-diapiric rocks re...

This work shows the results obtained after the analysis of the Anisotropy of Magnetic Susceptibility (AMS) of 29 sites sampled on Aptian-Albian marls, marly limestones, fine sandstones and lutites. The study area is located on the northern part of the central sector of the Basque-Cantabrian basin. Fifteen sites were sampled on syn-diapiric rocks re...

In order to obtain a kinematic model linking the diapir formation and the geometry of the syn-diapir sediments, a paleomagnetic study has been conducted in selected syn-diapiric sequences of the Basque-Cantabrian Basin. The studied diapirs (Bakio, Bermeo, Guernika and Mungia) developed during the Early Cretaceous in relation to the North Iberian ex...

Deception Island shows the most recent exposed active volcanism in the northern boundary of the Bransfield Trough. The succession of the volcanic sequence in the island is broadly divided into pre- and post-caldera collapse units although a well-constrained chronological identification of the well-defined successive volcanic episodes is still neede...

The results of anisotropy of magnetic susceptibility analyses of 19 sites carried out on magnetostrigraphically-dated, Lower to Middle Miocene (20.4 to 13.7 Ma) “non-deformed” mudstones from the central part of the Ebro basin reveal the presence of a subtle tectonic overprint lasting at least until the Langhian (Middle Miocene) in the southern Pyre...

New magnetic fabric data from 48 sites in Upper Triassic red beds from the Argana, Asni and Tizi n’Tichka areas in the western High Atlas, in combination with rock magnetic analyses, SEM observations and qualitative chemical analyses, reveal that mineralization processes can affect the primary (extensional) or secondary (post-depositional) magnetic...

The main objective of this work is to characterize the structures belonging to the Altomira Range and Loranca Basin (SW Iberian Chain, Central Spain) in terms of understanding their present-day orientation, highly oblique with respect to the NW–SE orientation of adjacent structures of the Iberian Chain. The Altomira and Loranca fold and thrust belt...

New magnetostratigraphic results from a 3300 m-thick section across the syntectonicfluvial sediments of the Campodarbe Formation (Upper Eocene-Oligocene) in the Ebro forelandbasin (NE Spain) are presented. The new data allow the top of the Campodarbe Formation tobe correlated to Chron 7r (Chattian), younger than previously stated (C10r), therefore...

The Olvena area (Sierras Marginales, southern Pyrenees) provides an outstanding example for studying the relationships between tectonics and sedimentation related to fold-and-thrust systems having shallow decollements. Stratigraphic and sedimentological features allow infer i) the relationship between Oligocene-Miocene locally-sourced alluvial fans...

Syn-tectonic remagnetizations related to burial processes that occurred during their extensional stage are frequently recognized in inverted sedimentary basins. The incremental fold test is the main analytical tool used to detect these syn-tectonic remagnetizations. However this test gives spurious results when asymmetrical folding occurs (i.e. bot...

The main objective of this work is to characterize the structures belonging to the Altomira Range and Loranca Basin (SW Iberian Chain, Central Spain) in terms of understanding their present-day orientation, highly oblique with respect to the NW–SE orientation of adjacent structures of the Iberian Chain. The Altomira and Loranca fold and thrust belt...

In this work, we test the analysis of anisotropy of magnetic susceptibility (AMS) for the study of diapirs in the Naval salt wall that is located in the western end of the South Pyrenean Central Unit. Two hundred eighty-six specimens from 30 sites were sampled in the mobilized Middle-Upper Triassic evaporites and shales that constitute the core of...

This article focuses on how deformation and displacements are transferred between two décollements located at different stratigraphic levels by means of analogue modeling using brittle/viscous, sand/silicone systems. We present results from ten analogue models, in which we varied key parameters, such as the amount of horizontal offset or overlap be...

We present a source-to-sink environmental magnetic study of a sediment core from Lake Sanabria (north-west Iberian Peninsula) and rocks of its catchment. The results indicate the occurrence of magnetite, and probably also pyrrhotite, in sediments accumulated between ca. 26 and 13 cal ka BP in a proglacial lake environment. These minerals also appea...

The southern Pyrenees provide several examples of diapiric structures linked to migration of Triassic evaporites associated with the movement of thrust sheets. Among them, the Naval diapir, the westernmost diapiric body in the Sierras Marginales unit, is key to understanding the mechanisms controlling salt tectonics in this sector of the Pyrenees....

The Aït Attab syncline, located in the Central High Atlas, displays a curved geometry in plan view, and is considered as one of the most spectacular fold shapes in the Central High Atlasic belt. We conducted a paleomagnetic study in Jurassic-Cretaceous red beds to investigate the origin of this geometry. The Natural Remanent Magnetization (NRM) is...

The Ordesa and Monte Perdido National Park, located in the Southern Pyrenees, constitutes the highest karst system in Western Europe. No previous studies regarding its geochemical and isotopic groundwater characterization are available in this area. This work presents the results of field and sampling campaigns carried out between July 2007 and Sep...

Anisotropy of Magnetic susceptibility (AMS) has been traditionally used as an indirect approach for the characterization of mineral preferred orientation and rock petrofabric. In the Southern Central Pyrenees, a robust data set of magnetic fabrics covering a wide range of ages, structural context, and lithologies has been used for an assessment at...

This work assesses the applicability of the analysis of the anisotropy of magnetic susceptibility (AMS) to rocks associated with salt structures. Magnetic fabrics from 16 sites sampled on Upper Triassic clays (Keuper facies) interbedded within the salt layers of the Bicorb-Quesa and Navarrés salt walls (Prebetic Zone, SE Spain) are mostly character...