A Review of the current knowledge of the crustal and lithospheric structure of the Valencia Trough Basin

In this paper, we review the current geophysical knowledge of the Valencia Trough Basin, and the surrounding areas. For this purpose, we summarize the most significant regional geophysical datasets acquired since the seventies to investigate the trough (seismic, gravity, geoid and heat flow data). We then focus on the discussion regarding the geometry and physical properties of the present day crustal and lithospheric structure derived from seismic images, as well as combined potential field modelling and their relationships with the Alpine geodynamic evolution of the Valencia Trough. Finally, we discuss the differences in the results regarding the geometry of the lithosphere-asthenosphere boundary obtained by different modelling approaches and the features that, in our view, require further investigation to unravel the true nature of the Valencia Trough, including what could have caused the differences between the crustal structure observed in the SW region compared to the NE region, the asymmetric style of thinning across the trough; the origin of the changes in the lower crustal reflectivity across the basin; the fabric of the uppermost mantle, characterized by anomalously low P-wave velocities; and the physical properties of the lithosphere mantle (density, Pwaves velocity, thermal conductivity, temperature distribution, mineralogical composition, etc.)

Geofluid behaviour in successive extensional and compressional events: a case study from the southwestern end of the Vallès-Penedès Fault (Catalan Coastal Ranges, NE Spain)

The structural position of the Upper Jurassic-Lower Cretaceous carbonates located in the central part of the Catalan Coastal Ranges corresponds to the southwestern end of the Vallès-Penedès Fault. This fault was reactivated at different times during successive extensional and compressional events and several generations of fractures and cementations were formed

Estructura del sistema frontal de cabalgamientos en el Pirineo Oriental: control estratigráfico en la geometría y secuencia de emplazamiento de los cabalgamientos

El manto del Cadí, la unidad estructural más extensa del Pirineo Oriental meridional, involucra cerca de 5 km de sucesión paleógena depositada en una cuenca de antepaís. Esta secuencia constituye un sistema petrolífero que ha sido explorado desde el año 1960 y suprayace discordantemente un basamento Paleozoico involucrado en el apilamiento antiforme que caracteriza el centro de la cordillera. En el antepaís, la sucesión paleógena presenta un espesor menor y está constituida por un conjunto de facies diferente, en general más somera. La interpretación de datos sísmicos reprocesados recientemente y su integración con datos de superficie y de sondeos son la base de un nuevo modelo estructural del área. La presencia de un espesor anómalo de una serie de rocas evaporíticas por debajo del sinclinal de Ripoll (2000m perforados en el sondeo El Serrat-1) ha sido interpretada como asociada a un cambio lateral de facies entre una formación turbidítica (Campdevànol) septentrional, la formación evaporítica de Beuda y una formación carbonática meridional (Perafita) y a su apilamiento en un dúplex

Physical modelling of the interplay between salt-detached gravity gliding and spreading across complex rift topography, Santos Basin, offshore Brazil

The Santos Basin, offshore Brazil contains a complex set of salt-tectonic structures, the origins of which are debated, that is, the Albian Gap and the São Paulo Plateau (SPP). The Albian Gap is a ca. 450 km long, 60 km wide feature characterized by a post-Albian, counter-regional rollover overlying depleted Aptian salt, and in which the Albian is largely absent. The SPP, located immediately downdip, is defined by a pre-salt structural high overlain by ca. 2.5 km thick salt. Another prominent feature is the Merluza Graben, a rift-related depocentre that underlies the southern portion of the Albian Gap and displays significant (3-4 km) base-salt relief along its main faults. Two competing hypotheses have been proposed to explain the kinematics of these provinces. One invokes post-Albian extension in the Albian Gap and kinematically-linked contraction in the SPP. The other invokes post-Albian salt expulsion in the Albian Gap and salt inflation in the SPP. Recent studies, however, suggest these processes likely alternate in time and space, contributing nearly equally to the evolution of these domains. We apply 3D physical modelling to (i) test this hypothesis; and (ii) to more generally understand how gravity gliding and spreading over three-dimensionally variable base-salt relief control regional salt tectonics. The results show a similar salt-related evolution and structural styles to those proposed in the most recent studies. They also (i) explain the origin of the ca. 25 km wide diapir precursor of the Albian Gap by early salt inflation against base-salt steps; (ii) show that normal faults with different polarities and rollover types form due to the interplay between gliding and spreading over different base-salt domains and (iii) provide a mechanism for the origin of strata encased within salt structures. This improves our understanding of the distribution and origin of salt-related structural styles in worldwide salt basins

A geological cross-section along the Basque Pyrenees and the Parentis Basin (Western Pyrenees)

A new geological cross- section along the North Iberian Margin shows a complete image of the Western Pyrenees and the Parentis Basin as well as the geometric differences and age constraints between both Pyrenean fronts. The South Pyrenean front, developed during Uppermost Cretaceous- Middle Miocene, is represented by a major thrust which accumulates around 20 km of southward displacement. The Basque- Cantabrian basin is a mesozoic extensional basin which was inverted during Paleogene times as a consequence of the Pyrenean orogeny. A basement- involved thrust wedge with an upper south- directed back- thrust characterizes the North Pyrenean Frontal Thrust. The main thrust, emplaced during Late Eocene- Miocene times, shows a displacement around 2 km whereas the back- thrust detached in Paleocene materials shows a displacement about 1.5 km. Northwards, the Landes High, is interpreted as an uplifted plateau where a thick wedge of Upper Cretaceous- Cenozoic synorogenic deposits overlay unconformably the Hercinian basement. This package corresponds with the North Pyrenean foreland basin. More to the north, the Landes fault is the southern margin of the Mesozoic Parentis Basin, a semigraben infilled with a thick package of Triassic to Albian synrift sequence overlied by Cretaceous and Cenozoic deposits. There, inversion structures were poorly developed

Obtención de vidrio a partir de residuos de la minería del estaño en Bolivia

Manufacturing of glass from tin mining tailings in Bolivia Tailings from mining activities in Bolivia represent an environmental problem. In the vicinity of the tin mines of Llallagua,Potosí department, there are large dumps and tailings. We present a study of the use of these wastes as raw materials for the manufacture of glass. This procedure aims to contribute to environmental remediation of mining areas through the vitrification, a process which offers an alternative for stabilization of hazardous waste. In addition, the marketing of the obtained product would provide an additional income to the mining areas. For this study three samples of mining waste, with grain size between sand and silt, were used. The chemical composition of these raw materials, determined by X-ray fluorescence, is granitic, with high contents of heavy metals. On the basis of its composition, glass were made from silica glass by adding CaCO3 and Na2CO3. The thermal cycle has been determined from TDA. Tg values of glass range from 626º to 709 °C. Leaching tests of the obtained glasses confirm their capacity to retain heavy metals

U-Pb geochronology on zircon and columbite-group minerals of the Cap de Creus pegmatites, NE Spain

The Cap de Creus granitic pegmatites in the eastern Catalan Pyrenees were dated using in situ U-Pb geochronology by laser ablation ICP-MS on zircon and columbite-group minerals (CGM), which are present in the different types of pegmatites from type I (K-feldspar pegmatites, least evolved) to type IV (albite pegmatites, most evolved) and therefore allow dating the different pegmatitic pulses. In a type III pegmatite where zircon and CGM are co-genetically associated in the same sample, both minerals were dated using zircon and tantalite reference materials, respectively, to avoid laser-induced matrix-dependent fractionation. In one sample, xenotime genetically associated with zircon was also dated. Two ages were obtained for type I and three ages for type III pegmatites. Three of these 5 ages range from 296.2 ± 2.5 to 301.9 ± 3.8 Ma and are allocated to the primary magmatic stage of crystallization and therefore to the emplacement event. Two younger ages (290.5 ± 2.5 and 292.9 ± 2.9 Ma) obtained on secondary zircon and xenotime, respectively, are interpreted as late post-solidus hydrothermal remobilization. There is no age difference between type I and type III pegmatites. The mean 299 Ma primary magmatic age allows the main late Carboniferous deformation event to be dated and is also synchronous with other peraluminous and calc-alkaline granites in the Pyrenees. However, the youngest ages around 292 Ma imply that tectonics was still active in Early Permian times in the Cap de Creus area

Quantum memory for photons: I. Dark state polaritons

An ideal and reversible transfer technique for the quantum state between light and metastable collective states of matter is presented and analyzed in detail. The method is based on the control of photon propagation in coherently driven 3-level atomic media, in which the group velocity is adiabatically reduced to zero. Form-stable coupled excitations of light and matter (``dark-state polaritons'') associated with the propagation of quantum fields in Electromagnetically Induced Transparency are identified, their basic properties discussed and their application for quantum memories for light analyzed.Comment: 13 pages, 6 figures, paragraph on photon echo adde