Evolución geodinámica de la fosa del Empordà y las Sierras Transversales

The Emporda basin, together with the half graben system of the Sierras Transversales, form a segment of the European Rift, which is defined here by the NW-SE-trending fault system of northeastern Catalonia.The study area, which partially includes the Sierras Transversales and the southem margin of the Emporda basin, is internally structured by normal faults with listric geometry. Those with measured dip slips of about 1,000 meters are here called main faults; those located in the hanging walls of the main ones are called minor faults, and their dip slips are, at least, lesser in one order of magnitude. The hanging walls of the main faults hold half graben basins, with a sedimentary infill mainly neogene in age in the Emporda, and of quaternay age in the Sierras Transversales. Both areas are geologically bounded by the Camós-Celra fault. This rift segment is also characterized by the occurence of numerous volcanic emission centres. The timing of activity and burial of each fault, constrained by the ages of the associated sediments and vulcanism, suggest a piggy-back sequence of propagation from Miocene to recent times. The geological cross-section constructed from surface data, allowed us the elaboration of a geometric model in clepth for the whole fault system, usiug the inclined shear method. The calculated extension from this method gives us a value of B=1.27. On the other han4 the very high calculated magma ascent rates strongiy constrain the structure in the footwall (crust); subsequently, high angle discontinuities favouring a very fast magmatic ascent have to be definied. These discontinuities would form two imbricate systems (extensional duplexes), with a roof detachment coinciding with the floor detachment of the shallow fault system and a floor detachment located in the MOHO discontinuity. A similar crustal structuration is observed in the neighbouring segment of the Gulf of Lions

Novel ball head screw and screwdriver design for implant-supported prostheses with angled channels: a finite element analysis

The primary objective of this study was to design the optimal geometry of a novel screwdriver, create the grooves on a ball head screw, and demonstrate its resistance to a torque of up to 40 Ncm at angulations of 0°, 15°, and 30° by using nonlinear finite element analysis. A secondary objective was to create a foolproof, easily recognizable system. The grooved ball head screw and geometry of the screwdriver, functioning from an angulation of 0° to 30°, was generated using Pro-ENGINEER Wildfire 5.0 software. Static structural analyses among bodies in contact were performed at different angles of 0°, 15°, and 30° at a torque of 20 Ncm and 40 Ncm using nonlinear finite element simulation by means of ANSYS 12.0. The maximum stress supported by the ball head screw and screwdriver was similar at 20 Ncm and 40 Ncm. Although greater deformations were found at 40 Ncm, these were small and might not affect the performance of the system. Further, the rupture torque value for the M2 connection was 55 Ncm for 0° and 30°, and 47.5 Ncm for 15°. Numerical simulation showed that the ball head system design can achieve the mechanical strength requirements expected for screws used in implant-supported restorations at an angulation of up to 30°. Finite element analysis showed this novel ball head screw and screwdriver system to be a good solution for angled screw channels in implant-supported prostheses

Survival and long-term maintenance of tertiary trees in the Iberian Peninsula during the Pleistocene. First record of Aesculus L.

The Italian and Balkan peninsulas have been places traditionally highlighted as Pleistocene glacial refuges. The Iberian Peninsula, however, has been a focus of controversy between geobotanists and palaeobotanists as a result of its exclusion from this category on different occasions. In the current paper, we synthesise geological, molecular, palaeobotanical and geobotanical data that show the importance of the Iberian Peninsula in the Western Mediterranean as a refugium area. The presence of Aesculus aff. hippocastanum L. at the Iberian site at Cal Guardiola (Tarrasa, Barcelona, NE Spain) in the Lower– Middle Pleistocene transition helps to consolidate the remarkable role of the Iberian Peninsula in the survival of tertiary species during the Pleistocene. The palaeodistribution of the genus in Europe highlights a model of area abandonment for a widely-distributed species in the Miocene and Pliocene, leading to a diminished and fragmentary presence in the Pleistocene and Holocene on the southern Mediterranean peninsulas. Aesculus fossils are not uncommon within the series of Tertiary taxa. Many appear in the Pliocene and suffer a radical impoverishment in the Lower–Middle Pleistocene transition. Nonetheless some of these tertiary taxa persisted throughout the Pleistocene and Holocene up to the present in the Iberian Peninsula. Locating these refuge areas on the Peninsula is not an easy task, although areas characterised by a sustained level of humidity must have played an predominant role

The projects on geological cartography of the Geological Survey of Catalonia

Since the Gravimetric Map on a scale of 1/500 000 was published in 1987, the Geological Survey of Catalonia (SGC) published in 1989 the Geological and the Aeromagnetic maps on a scale of 1/250 000. The publications of the Hydrogeological map on a scale of 1/250 000 (1992) and a crustal-scale cross-section on a scale of 1/200 000 (1993) followed the first maps. Currently the Survey is developping a project of regional geological mapping on a scale of 1/25 000 wich aim is to cover the entire area of Catalonia (about 31 879 sq.km), which is included into 301 sheets. The Survey is also involved in a project of detailed geological mapping of the highly populated, neighbouring area of Barcelona (about 3 180 sq. km.) on a scale of 1/10 000. Other projects the Survey is going on are the Structural Map on a scale of 1/250 000 and a new edition of the Geological Map at the same scale. Either the hardware and software facilities, the topographic bases, and the edition and publication works are supplied by the Cartographic Institute of Catalonia (ICC). The aim of this paper is to give general information about these project

Relations between the sedimentary evolution of the Aren Group and the Boixols thrust (Uppermost CampanianMaastrichtian of South-Central Pyrenees)

The Arén Croup was deposited synchronously to the growth of the Boixols thrust. Sedimentation took place in siliciclastic marine and alluvial environments. The growth of a footwall syncline affected the geometry of the basin fill by adding drowning and uplifting movements. Such a mechanism might be common to those settings where fault propagation folds develop. In the Arén Croup, this differential subsidence mechanism was not able to overprint the identified sedimentary cycle

The Geological Map of Catalonia at 1:25.000 scale

The sheets of the “Mapa Geoldgic de Catalunya 1:25.000" are conceived as selfsufficient documents. Thus, full information for the correct interpretation of the geological data must be included in the sheet. The elements forming the sheets are: 1: Cover, 2: Geological map, 3 : Legend of cartographyc units, 4: Symbols, 5 : Cross-sections, 6: Litho -stratigraphyc logs, 7: Sketch of stratigraphyc relationship s, 8: Stereographyc diagrams, 9: Sketch of tectonic, metamorphyc and igneous processes, 10: Geological sketch 1:100.000 and 11: Authors

A N-S cross-section in the estern Pyrenees: an overstep sequence in the thrust slices forming the lower Pedraforca thrust sheet

We present a N-S geological cross-section in the eastern Pyrenees, starting in the southern margin of the Neogene Cerdanya basin, and ending in the Upper Eocene to Oligocene Ebro foreland basin. The lower Pedraforca thrust sheet, which mainly consists of Mesozoic and Paleocene pre-tectonic sediments, was emplaced during late Lower Lutetian times over the early Lower Lutetian sediments forming the Cadi thrust sheet, and the whole, over the Ebro foreland basin, in a piggy-back thrust-propagation sequence. Once the lower Pedraforca thrust sheet was emplaced, internal deformation processes continued until Upper Eocene to Oligocene times. Subsequently, five thrust slices forming an imbricate system were individualized into this thrust sheet. Field detailed geological mapping allowed us to define four major unconformities in the syntectonic conglomerates. Precise dating of these unconformities constrained the emplacement of the thrust slices. Thus, we conclude that the imbricates formed in an overstep sequence of thrust propagatio

Stratigraphy of the Montgrí Massif

The creiaceous carbonates forming the Montgri massif (Berriasian ? to Santonian) were deposited in the southern, marginal areas of the basin. As they sedimented in shallow platform environments, they were very sensible to sea-level changes. Thus, the section is divided into seven allostratigraphic units (NASC, 1 983), numbered from 1 (o 7. Some of their bounding discontinuities include erosion with subaerial exposure (lower boundaries of the units 2, 4, 5 and 7), paleokarst (2 and 4) and lateritic-soil developments (lower boundary of the unit 2). The units numbered 2, 4 and 6 respectively show onlap relationships over truncated underlying strata, and the lower boundary of the unit number 7 is a disconformity. The unit number 3 is bounded by a discontinuity recording a non-depositional event, and the bottom of the unit 5 is a condensed section. The units 2 (Aptian) and 6 (Coniacian to Santonian I) record the activity of exlensional faulting along two structures known in outcrop; one of them can be observed in its original shape, and the other was inverted during the alpine compression. The uppermost strata in the unit 2 and the unit 7, respectively postdate these extensional structure

Structure of the Catalan Pre-litoral Range between the Llobregat and the Montseny

It has been largely demonstrated that basement thrust-slices were emplaced over the southeastern margin of the Ebro basin during Eocene times (Fontboté, 1954) due to sinistral, convergent wrenching in a north-south regional shortening context (Julia y Santanach ,1984; Guimerà, 1984), and that the deformation migrated from the northern to the southern areas through the active margin (Anadôn et al, 1985). Three groups of compressional structures deform the basin margin in the area between Vacarisses Slice and Montserrat. Subsequently to emplacement, continental syntectonic, sediments were deposited in the adjacent areas o f the basin, which together with the unconformities bounding their depositional sequences, recorded the evolution of the deformation along the time. Thus, in a first step, apile of north-verging thrust slices, involving the basement and the Triassic-Paleocene cover, were emplaced in a piggyback sequence; in a second step, the northwards progression of the system was partially blocked, and the previous structures were deformed by backthrusts involving Triassic and the deposited Eocene cover; and in a third step, as the system was completely blocked, formed a basement-involving fold, which southern limb evolved to a basement-involving thrust, and emplaced, in an overstep sequence, Paleozoic slices over the previously deformed basin margin. The emplacement of such basement slices at different heights in the sedimentary record, together with the trace in map view of the segments forming the Vallès fault, suggest a positive flower geometry for the main original wrench fault. We relate these three steps to the migration of the deformation proposed by the aforementioned authors. During the Neogene, the most internal structures with suitable dips were inverted. As a consequence, the segments forming the old strike-slip fault were transformed in overstepping normal-fault segments, linked by relay ramps. Seismic and field data show that one of these ramps corresponds to the "Llobregat fault

Structure of the upper and lower Pedraforca thrust sheets

The Pedraforca nappe is one of the allochtonous structural units in which the Cover Upper thrust sheets of the southern Pyrenees are organised. Its is internally constituted by two thrust sheets, namely Upper Pedraforca thrust sheet and Lower Pedraforca thrust sheet. As a whole, they were emplaced in a piggyback thrusting sequence. But in the detail, a new, minor structural unit, here named "Intermediate unit", has been found in between them. This newly identified thrust sheet mainly consists of a carbonate breccia series, derived from the Lower Cretaceous sediments forming the Upper Pedraforca thrust sheet, showing an "inverted mountain" internal arrangement of elements. Restoration of a detailed cross-section allows us to interpret the Upper Pedraforca thrust sheet as the result of tectonic inversion of a Lower Cretaceous extensional basin occurred during late Cretaceous times. The sediments forming the Intermediate Unit are syntectonic materials, because they generated synchronously to the tectonic transportation of the Upper Pedraforca thrust sheet (Santonian to Maastrichtian). Further emplacement of the Intermediate unit included piggy back transportation of the Upper Pedraforca thrust sheet, until both structural units were definitively emplaced, and their frontal parts were covered by late Cretaceous to Palaeogene continental redbed