Structural styles of the Shuilikeng fault system in the central Taiwan mountain belt

The Shuilikeng fault system in the central Taiwan mountain belt forms the structural boundary between two different tectonostratigraphic zones: the Western Foothills to the W, and the Hsuehshan Range to the E. It comprises a steeply-dipping roughly north-striking transpressive fault zone with splays, folds and bifurcations linked to the main structure. The structural style of the Shuilikeng fault system changes from N to S; while to the N it is defined by diverging splay and non-cylindrical folds branching off the Shuilikeng fault, to the S its structure is dominated by east-striking right-lateral strike-slip faults in the Hsuehshan Range and by a rejoining splay with a composite kinematics in the Western Foothills. At the southernmost tip of the study area, the Shuilikeng fault is defined by a several hundred meters-wide high strain zone and the structural architecture of the Western Foothills is that of a regional anticlinorium branching off the Shuilikeng fault intensely folded and faulted along its limbs.G. Camanni acknowledges the grant JAE-Predoc (CSIC). This research was carried out with the aid of the grant MICINN: CGL2009-11843-BTE.Peer Reviewe

Structural complexities in the Alishan area of the Taiwan fold-and-thrust belt inherited from the margin's shelf-slope transition

This article is subject to a CC Attribution 3.0 License.The Alishan area of Taiwan includes a sector of the fold-and-thrust belt that spans the transition from the platform with full thickness of the Eurasian continental margin in the north to the thinning crust of its slope in the south. This part of the fold-and-thrust belt with the highest elevations includes important along-strike changes in structure, stratigraphy, and seismic velocities. Here we present the results of new geological mapping from which we build geological cross sections both across and along the regional structural trend. Fault contour, stratigraphic cut-off, and branch line maps provide 3-D consistency between the cross sections. Minimum shortening is estimated to be 15 km, with displacement overall to the northwest. A P wave velocity model helps constrain the structure at depth by providing insight into the possible rock units that are present there. P wave velocities of > 5.2 km/s point toward the presence of basement rocks in the shallow subsurface throughout much of the south-eastern part of the area, forming a basement culmination. The changes in strike of thrusts and fold axial traces, the changing elevation of thrusts and stratigraphic contacts, and the growing importance of Middle Miocene sediments that take place from north to south are interpreted to be associated with a roughly northeast striking lateral structure coincident with the northern flank of this basement culmination. These transverse structures appear to be associated with the inversion of Eocene- and Miocene-age extensional faults, deeply rooted in the pre Cenozoic basement that were along what was the shelf-slope transition in the Early Oligocene. Inversion causes uplift of the margin sediments and their higher P wave velocity basement during Pliocene-Pleistocene thrusting.Peer Reviewe

Geophysical data integration for a joint interpretation in a shallow gypsiferous context

As every geophysical technique suffers from its own limitation, a proper survey has to combine different geophysical methods. The integration of different geophysical data in order to derive a joint geological interpretation is complicated beyond qualitative (subjective) correlations. We propose a new numerical method (less subjective) to integrate three separated datasets: seismics, electrics and well logging. The study area is the shallow subsurface of a planned singular facility in Villar de Cañas (Cuenca, Central Spain). Lithology down to 100 m deep consists of a transition from shale to massive gypsum. In 2013, we acquired a3D Traveltime Tomography to characterize this transition. After data processing, the velocity model showed, in general, a good correlation with geological profiles, being able to identify the three main layers: shales, transition gypsum and massive gypsum. The correlation for the massive gypsum limit (high velocity contrast) is very good, but is not that good for the transition shale-gypsum (low velocity contrast).Research supports: CGL2014-56548-P, 2009-SGR-1595 , CGL2013-47412-C2-1-PPeer Reviewe

The Iberian Massif of western Asturias and Lugo: a record of landscape forming processes during 107 time-scales.

El relieve transitorio del occidente Asturiano y Lugo, desarrollado sobre rocas del Macizo Ibérico, contiene información sobre los procesos pasados y recientes que condicionan la topográfica. Un análisis geomorfológico, basado en el uso de Sistemas de Información Geográfica, combinado con técnicas de termocronología de baja temperatura y de análisis de isótopos cosmogénicos, ha permitido identificar varios componentes del paisaje con edades y significados geodinámicos diferentes. Estos son: 1) paleosuperficies de bajo relieve con bajas tasas de denudación, interpretadas como relictos de un periodo entre los 100 y 45 Ma en que se desarrollaron relieves maduros; 2) pequeños ríos costeros que presentan tasas de denudación moderadas asociadas a una lenta elevación del terreno durante el Neógeno; 3) una ancha superficie de abrasión submarina, elevada lentamente (0.07-0.15 mm/a) sobre el nivel del mar desde hace 1.5 Ma. Las rocas de esta región registran tasas de exhumación más altas antes del Cretácico Superior, durante la extensión Mesozoica en el Atlántico y Golfo de Vizcaya. Las tasas de exhumación se redujeron durante el periodo de relativa estabilidad tectónica iniciado después de la ruptura continental en el Cretácico Inferior. El sistema de denudación ha permanecido poco eficiente durante la elevación topográfica iniciada en el Eoceno.Estos estudios han sido financiados a través de los proyectos BTE2002-00330, CGL2005-24204 y CGL2007-60230/BTE de los Ministerios de Educación y Ciencia y de Ciencia e Innovación. Se incluyen en el marco del proyecto “TOPO-Iberia”, Consolider-Ingenio 2010, CSD2006-00041.Peer Reviewe

Seismic structure of the northern continental margin of Spain from ESCIN deep seismic profiles

By the end of the Carboniferous, the crust of the continental shelf in northwestern Spain was made up of deeply rooted structures related to the Variscan collision. From Permian to Triassic times the tectonic setting had changed to mainly extensional and the northern Iberian continental margin underwent rifting during Late Jurassic-Early Cretaceous times, along with sea-floor spreading and the opening of the Bay of Biscay until the Late Cretaceous. Subsequently, the northern Iberian margin was active during the north-south convergence of Eurasia and Iberia in the Tertiary. A multichannel seismic experiment, consisting of two profiles, one north-south (ESCIN-4) crossing the platform margin offshore Asturias, and another (ESCIN-3) crossing the platform margin to the northwest of Galicia, was designed to study the structure of the northern Iberian margin. The ESCIN-4 stacked section reveals inverted structures in the upper crust within the Le Danois Basin. North of the steep continental slope, ESCIN-4 shows a thick sedimentary package from 6 to 9.5 s, two-way travel time (TWT). Within this latter package, a 40-km-long, north-tapering wedge of inclined, mainly south-dipping reflections is thought to represent a buried, Alpine-age accretionary prism. In the north western part of the ESCIN-3 (ESCIN-3-1) stacked section, horizontal reflections from 6.5 to 8.5 s correspond to an undisturbed package of sediments lying above oceanic-type basement. In this part of the line, a few kilometres long, strong horizontal reflection at 11.2 s within the basement may represent an oceanic Moho reflection. Also, a band of reflections dips gently towards the southeast, from the base of the gently dipping continental slope. The part of ESCIN-3 line that runs parallel to the NW-Galicia coast (ESCIN-3-2), is characterized by bright, continuous lower crustal reflections from 8 to 10 s. Beneath the lower crustal reflectivity, a band of strong reflections dips gently toward the southwest from 10 to 13.5 s. The part of ESCIN-3 that parallels the northern margin (ESCIN 3-3), shows good reflectivity in all levels. Upper crustal reflections image the sedimentary fill of probable Mesozoic to recent basins. Mid-crustal reflectivity is characterized by dipping reflections until 8 s that are probably related to compressional Variscan features. The lower crustal level shows 'layered' reflections between 8 and 12 s. Dipping reflections are found below the continental Moho.J. Alvarez-Marrón held a post-doc research grant from the Ministry of Education and Science of Spain. The ESCI-N program was sponsored by the Spanish agencies CICYT (project GEO 90-0660) and FICYT, and STRIDE Program of the EU.Peer Reviewe

Four decades of geophysical research on Iberia and adjacent margins

The dimensions, the geographical position and the complex geological history of the Iberian Peninsula makes it a unique and singular target to study its crustal and upper mantle structure and geodynamical evolution using geophysical methods. The lithospheric structure beneath Iberia has been investigated since the 1970’s using deep multichannel seismic reflection and refraction/wide-angle reflection profiling. Gravimetric and magnetic data were acquired following the deployment of permanent and temporary stations, mostly during the 1990’s. Beginning in the late 1990’s, the progressive use of Global Navigation Satellite Systems (GNSS) instruments contributed to monitor the present-day motions. During the last decades, numerous geological and geophysical surveys have investigated the Iberian lithosphere and upper mantle in the onshore and offshore regions, the most recent ones related to the TopoIberia project. The approach developed in this contribution is twofold. Firstly, we summarize the available geophysical information over Iberia, from focusing on the upper crust to the lithosphere-asthenosphere boundary and the transition zone marking the bottom of the upper mantle. Results of GNSS data, potential fields, controlled source seismic profiles, magnetotelluric data, body and surface wave tomography, receiver functions and 2D and 3D lithospheric modeling are reviewed and compared. Secondly, we focus on the areas of greater geodynamic interest and the regions where inconsistencies within the geophysical results, or contradictions in their tectonic interpretation exist, identifying the major questions that are still under debate. Besides shedding light to the state of knowledge and pointing out present-day research challenges, this review provides a tool for the integration of the diverse geophysical datasets with the surface geology and geodynamical processes that are interpreted to have built the complex geology of the Iberian Peninsula.The authors acknowledge funding from the Generalitat de Catalunya, grant/awards number AGAUR 2017SGR1022, and AGAUR 2017SGR847, the Spanish Ministry of Science, Innovation, and Universities grant numbers RTI2018-095594-B-I00, PGC2018-095154-B-100 and PGC2018-094227-B-I00 and the Spanish Ministry of Economy and Competitiveness grant numbers CGL2017-84901-C2 and PIE-CSIC-201830E039. IP is funded by the Spanish Ministry of Science, Innovation, and Universities and University of Salamanca grant BEAGAL18/00090. AV acknowledges funding from the Spanish government through the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S).Peer reviewe

Pliocene to Holocene structure of the Eastern Alboran Sea (Western Mediterranean)

11 pages, 12 figures.-- Published in: Zahn, R., Comas, M.C., and Klaus, A. (Eds), Proc. ODP, Sci. Results, 161, 345-355. College Station, TX (Ocean Drilling Program, USA).Since the early Pliocene, the active tectonic setting of the Eastern Alboran Sea has been characterized by active strike-slip tectonism, causing the main bathymetric depressions to form in the eastern part of the Alboran Sea, the Eastern Alboran Basin, the Yusuf Basin, the Alboran Channel, and the South Alboran Basin. The Eastern Alboran Basin is a 2000-m-deep, mostly flat-bottomed, triangular-shaped graben developed between the Iberian and African continental margins. Ocean Drilling Program (ODP) Leg 161 data provide the time frame for the late Miocene to Holocene history of the basin. At Site 977, 600 m of Miocene(?)-Pliocene to Holocene marine sediments were drilled, and 700 m of upper Miocene to Pleistocene marine sediments at Site 978. Within the sedimentary package, several unconformities reveal the active strike-slip tectonism that occurred during this time.At the southern border of the Eastern Alboran Basin the active, right lateral strike-slip Yusuf Fault is developing. Reflection seismic profiling shows that, at a right stepover of the Yusuf Fault, a developing negative flower structure is causing the Yusuf Basin to form, in which active tectonic subsidence has been ongoing since at least the late Miocene. Above the interpreted Messinian reflections, the sedimentary fill forms a northeastward-thickening wedge of syntectonic sediments of Pliocene to Holocene age.In the South Alboran Basin, drilling at Site 979 penetrated Pliocene to Holocene syntectonic sediments, which form growth strata geometries related to a south-dipping monocline that evolved above a north-dipping thrust fault in the basement. North of the Alboran Ridge, a narrow strike-slip basin is forming in the Alboran Channel next to the strike-slip fault at the northern flank of the ridge.Funding from the Spanish commission CICYT, project AMB95-1557 is acknowledged.Peer reviewe

Three-dimensional geometry and interference of fault-bend folds: examples from the Ponga Unit, Variscan Belt, NW Spain

12 pages, 11 figures.-- This work forms part of a Ph.D. thesis supervised by A. Pérez-Estaun and and J. L. Alonso.Examples of the three-dimensional geometry and interference patterns between fault-bend folds occur in the Ponga Unit of the Variscan Cantabrian foreland thrust and fold belt of NW Spain. The Ponga Unit consists of several E-directed thrust sheets with a cumulative displacement of 93 km, which were emplaced during Upper Westphalian-Stephanian time. Two major lateral ramps developed in the basal thrust of the Ponga Unit, reaching 15 and 20 km in length, respectively, and some 3 km in height. Lateral structures are also common within the hangingwall thrust sheets.The three-dimensional staircase trajectories of thrust faults, together with the tectonic superposition of thrust sheets, has produced a complex interference pattern of fault-related folds. Most map-scale folds formed as fault-bend folds related to interference between frontal and lateral ramps. Fold geometry and size varies depending on the geometry and size of the associated thrust ramp and flat. The axial traces are grouped into lateral and frontal sets, which are sub-parallel or sub-perpendicular to the tectonic transport direction, respectively. ‘Corner folds’ form with plunging axes at the intersections of frontal and lateral ramps and generally link pairs of frontal-lateral folds. They have relatively short axial traces that are oblique to the tectonic transport direction.Fold plunge varies due to the superposition of lateral and frontal structures of a thrust fault and also depends on the geometry of subsequent thrusts in the footwall. The final geometry of frontal folds in the Ponga Unit are not only the result of the bending mechanism but have been modified by simple shear parallel to the emplacement direction. Major lateral structures have been reactivated as reverse faults and are locally overturned due to post-emplacement north-south compression.This work forms part of a Ph.D. thesis supervised by A. Pérez-Estaun and and J. L. Alonso. The Ph.D. project was funded by the Spanish Ministry of Education and Science.Peer reviewe

Mesa redonda "Mujeres en la investigación científica" en la Facultad de Física de la UB para reflexionar sobre el papel de la mujer en el ámbito científico y los principales retos a superar

La ciencia y la igualdad de género son fundamentales para el desarrollo sostenible. Sin embargo, las mujeres siguen encontrando obstáculos en el campo de la ciencia: menos del 30 % de investigadores científicos en el mundo son mujeres. Ante esta situación, en 2015 la Asamblea General de las Naciones Unidas decidió declarar el 11 de febrero como Día Internacional de la Mujer y la Niña en la Ciencia. El objetivo era reconocer el papel crítico que juegan las mujeres y las niñas en la ciencia y la tecnología. La Universidad de Barcelona, ​​con el impulso del Vicerrectorado de Igualdad y Acción Social y gracias a la labor realizada desde la Unidad de Igualdad, se suma a esta efeméride con diversas actividades que se desarrollarán a lo largo del martes 11 de febrero, y con las que se quiere transmitir un mensaje fundamental: es necesario conseguir el acceso y la participación plena y equitativa en la ciencia para las mujeres y las niñas. El acto central será la instalación expositiva «De gran, vull ser científica!», que se podrá visitar hasta el 20 de febrero en el vestíbulo principal del Edificio Histórico. La iniciativa, que cuenta con la colaboración del Vicerrectorado de Artes, Cultura y Patrimonio, reúne dos exposiciones dedicadas al papel de la mujer en la ciencia: por un lado, la muestra «Dones i física», promovida por el Instituto de Ciencias del Cosmos (ICCUB) —en colaboración con la Sociedad Catalana de Física—, que propone recorrer la historia de la física a través de las aportaciones y vivencias de trece físicas que, pese a haber protagonizado avances científicos importantes, en muchos casos todavía son grandes desconocidas. Por otro, la exposición «Mujeres que cambiaron el mundo», elaborada por el Parque Científico de Barcelona (PCB) —a través del proyecto Ciencia y tecnología en femenino, con la Asociación de Parques Científicos y Tecnológicos de España—, que sigue la trayectoria de diecinueve de las científicas y tecnólogas más célebres de nuestra historia. La instalación se inaugurará el martes 11 de febrero, justo después de la conferencia «Dones i ciència: dades i perspectives», que impartirá la profesora de Ingeniería Electrónica y Biomedicina Sònia Estradé, a las 12 h, en el Aula Magna del Edificio Histórico. Actividades en las facultades de Física y Química Las conmemoraciones con motivo del Día Internacional de la Mujer y la Niña en la Ciencia continuarán el mismo martes 11, por la tarde, en las facultades de Física y Química, con la celebración de la jornada «Mujeres en la investigación científica». En el marco del encuentro, tendrá lugar la conferencia «Quantifying the bias of scientific sucess», que impartirá la profesora de la Universidad de Copenhague Roberta Sinatra, y que irá seguida de un debate al que se sumarán Joaquina Álvarez, del Instituto de Ciencias de la Tierra Jaume Almera (ICTJA-CSIC), y Núria Salan, de la Universidad Politécnica de Cataluña. Las actividades tendrán lugar, de 15 a 18 h, en el Aula Magna Enric Casasses y en el Atrio Solar de las facultades de Física y Química. Asimismo, el ICCUB, a través de su web institucional y en sus páginas de divulgación ServiAstro y ServiPartícules, publicará, a lo largo de la semana, imágenes de cuatro de sus investigadoras (Mercè Romero, Assumpta Parreño, Anna Ferré-Mateu y Licia Verde) acompañadas de niñas, para dar a conocer sus investigaciones