Preliminary hydrodynamic results of a field experiment on a barred beach, Truc Vert beach on October 2001

A field experiment conducted on a sandy barred beach, situated on the southern part of the French Atlantic coastline, allowed us to investigate the impact of the intertidal bar on the wave-energy dissipation on the beach face in presence of a high-energy long-incoming swell (significant wave height of about 1.7 to 3.0 m in 56 m water depth and significant wave period about 12 s). Data were collected along three parallel cross-shore transects deployed along an intertidal ridge and runnel system. Wave heights in the inner surf zone are depth-limited, consistent with previous works, and the wave-energy dissipation in the inner surf zone appears to be relatively independent of the offshore energy level. On the other hand, the presence of the bar seems to scatter the data. In models of surf-zone hydrodynamics, wave-energy dissipation is often parameterized in terms of , the ratio of the sea-swell significant wave height to the local mean water depth. The observed values of are not constant along a cross-shore transect, and increase onshore. Furthermore, the observed values observed onshore the intertidal bar are higher than those observed outside the influence of the intertidal bar, and this cannot be fully explained by the different local beach slope.Responsible Editor: Iris Grabemann     

Neoproterozoic–Cambrian synsedimentary magmatism in the Central Iberian Zone (Spain): geology,petrology and geodynamic significance

Petrographic, geochemical and field studies in low grade metamorphic areas (Ciudad Rodrigo-Hurdes-Sierra de Gata domain, CRHSG, central-western Spain) show that Neoproterozoic-Lowermost Cambrian series in the Central Iberian Zone (CIZ) record two kinds of provenance sources including: (1) detrital material derived from recycled orogens and (2) a Cadomian coeval juvenile contribution that governs their isotopic signature. Evidence of magmatism contemporaneous with Neoproterozoic-Cambrian sedimentation is provided by the presence of coherent, massive volcanic rocks (metabasalts, metaandesites, and metarhyolites), volcaniclastic shales, sandstones, conglomerates and breccias. The appearance of volcanogenic lithic fragments and crystals mixed in different proportions with siliciclastic constituents and also present within calcareous components in the sedimentary succession, reinforces this evidence. Although most of the selected volcanic and volcaniclastic samples appear to show tholeiitic affinity, some of them display calc-alkaline affinity. Different trace element ratios, such as Sm/Nd, Nb/Yb and Ta/Yb, suggest a magmatic evolution in the same tectonic setting. The geochemical results reported here support the existence of an active geodynamic setting as a direct contributor to the synsedimentary and magmatic content of the Neoproterozoic–Lowermost Cambrian successions in the CIZ. In particular, the relatively high Nd _(T) values and the high range of f ^Sm/Nd ratios are consistent with an active margin during the Neoproterozoic–Early Cambrian. The existence of tectonic activity is also confirmed by the presence of synsedimentary deformation and volcanic rocks. All of these traits favour a geodynamic model in which the Iberian Cadomian segment represented in the CIZ would have been part of an active northern margin of Gondwana, with an associated magmatic arc and related basins during Neoproterozoic–Lower Cambrian times. A proposed link between the Ossa Morena and the Central Iberian Zones might account for late Cadomian pull-apart basins developed on both sides of the magmatic arc, sharing the same scenario and involving similar magmatic activity during the Neoproterozoic–Cambrian transition.

Geological,geophysical and geochemical structure of a fault zone developed in granitic rocks: Implications for fault zone modeling in 3-D

The structure of a fault zone developed in granitic rocks can be established on the basis of the spatial variability of geological, geophysical and geochemical parameters. In the North Fault of the Mina Ratones area (SW Iberian Massif, Spain), fault rocks along two studied traverses (SR-2 and SR-3 boreholes) exhibit systematic changes in mineralogy, geochemistry, fabrics and microstructures that are related to brittle deformation and alteration of granite to form cataclasite and subsequent gouge. The spatial distribution and intensity of these changes suggest a North Fault morphology that is consistent with the fault-core/damage-zone model proposed by Chester et al. (1993) to describe a fault zone architecture. North Fault damage zone thickness can be defined by the development of mechanically related mesoscopic faults and joints, that produce a Fracture Index (FI)>10. High FI values are spatially correlated with relative low seismic velocity zones (V_P<5 km/s and V_S<2.5 km/s in the well-logs), more probably related to a high concentration of fractures and geochemical alteration produced by meteoric water-granite interaction along fault surfaces. This correlation is the base of a geostatistical model proposed in the final part of this study to image the fault zone architecture of a granitic massif.     

Détermination indirecte des limites d'Atterberg par gravimétrie dynamique

This study presents a new method for Atterberg limits measurements using dynamic drying. Indeed, for some polluted clays, or clay mixtures, classical methods cannot be used. The principle of liquid $(W_{\mathrm{L}})$ and plasticity $(W_{\mathrm{P}})$ limits determination by this method is presented. Experimental values for classical clays are close to those obtained with Casagrande's methods, allowing for larger physical mud characterisation. To cite this article: C. Proust et al., C. R. Geoscience 336 (2004).     

On the Dynamic Disconnection of Rising Omega Loops

The tilt-angle variation of solar bipolar magnetic regions (BMRs) in space and time is a probable indicator of large-scale properties of magnetic field distribution, the dynamo and other different processes affecting the rising of magnetic flux tubes. We analyze the tilt-angle distribution and evolution of clearly oriented BMRs using sunspot position and area measurements from the Greenwich Photo-Heliographic Results (GPHR) supplemented by high-quality full-disk sunspot drawings made in the Haynald Observatory in Hungary. Our work is made on the basis of the 14th sunspot cycle and we compare our results with present theories of magnetic flux evolution in the convective zone. Our results support the assumption that the scatter of tilt angles of BMRs around Joy`s law is determined by the convective turbulence. Furthermore, we find that regular BMRs grouped by age generally do not show the phenomenon of toroidal relaxation towards the east–west direction. We interpret this by the disconnection of -loops from the bottom of the convection zone.     

Improvement of pollutant drift forecast system applied to the Prestige oil spills in Galicia Coast (NW of Spain): development of an operational system

An integrated system named METEOMOHID, developed by MeteoGalicia in the first stage of the Prestige accident in November 2002 was used successfully in an operational form to support decision making and assist in recovering tasks. Afterwards, METEOMOHID has been enhanced with the aim of developing an operational oceanography system to be used in the NW of the Iberian Peninsula. The METEOMOHID system includes local area hydrodynamic coastal ocean modelling (MOHID), real time atmospheric forcing from a local meteorological model (ARPS). Using the available data from the Prestige crisis, a set of simulations were designed in order to reproduce the oil spill drift. The implementation of a detailed vertical resolution in the model has allowed obtaining a detailed surface dynamic, improving our knowledge of the behaviour of tarballs into the water column. Thus, the wind-driven Eckman drift, the direct dragging of the wind were detached, and the possible existence of subsurface oil was assessed. In addition, the present work evaluates the effects of introducing climatologic large scale currents in the METEOMOHID system.     

Biomarkers of exposure and effect in the Brazilian flounder Paralichthys orbignyanus (Teleostei: Paralichthyidae) from the Patos Lagoon estuary (Southern Brazil)

Biomarkers of exposure (liver metallothionein-like proteins content and catalase and glutathione S-transferase activities) and effect (liver lipoperoxidation and blood cell DNA damage) of contaminants were analyzed in the Brazilian flounder Paralichthys orbignyanus from the Patos Lagoon estuary (Southern Brazil). Flounders were collected for a year in two sites: "Coroa do Boi" (polluted site) and "Saco do Justino" (non-polluted site). Results indicated that micronucleated cells frequency was the best biomarker to distinguish flounders from the two sites. Taken together, data from DNA damage analyses (micronucleus test and comet assay) indicated that flounders from the non-polluted site efficiently repaired the DNA breaks, contrary to those from the polluted site, which probably had their DNA repair system inhibited or exhausted. Furthermore, data from enzyme activities (catalase and GST) and lipid peroxidation indicated that flounders from the polluted site were under oxidative stress in summer and autumn.     

An exotic Cretaceous kimberlite linked to metasomatized lithospheric mantle beneath the southwestern margin of the Francisco Craton,Brazil

We present major and trace element compositions of mineral concentrates comprising garnet xenocrysts,ilmenite,phlogopite,spinel,zircon,and uncommon minerals (ti...     

Mental maps and travel behaviour: meanings and models

In this paper, the “mental map” concept is positioned with regard to individual travel behaviour to start with. Based on Ogden and Richards’ triangle of meaning (The meaning of meaning: a study of the influence of language upon thought and of the science of symbolism. International library of psychology, philosophy and scientific method. Routledge and Kegan Paul, London, 1966) distinct thoughts, referents and symbols originating from different scientific disciplines are identified and explained in order to clear up the notion’s fuzziness. Next, the use of this concept in two major areas of research relevant to travel demand modelling is indicated and discussed in detail: spatial cognition and decision-making. The relevance of these constructs to understand and model individual travel behaviour is explained and current research efforts to implement these concepts in travel demand models are addressed. Furthermore, these mental map notions are specified in two types of computational models, i.e. a Bayesian Inference Network (BIN) and a Fuzzy Cognitive Map (FCM). Both models are explained, and a numerical and a real-life example are provided. Both approaches yield a detailed quantitative representation of the mental map of decision-making problems in travel behaviour.