The challenge of dating early pleistocene fossil teeth by the combined uranium series–electron spin resonance method: the Venta Micena palaeontological site (Orce,Spain)     

Mathieu Duval  Christophe Falguères  Jean‐Jacques Bahain  Rainer Grün  Qingfeng Shao  Maxime Aubert  John Hellstrom  Jean‐Michel Dolo  Jordi Agusti  Bienvenido Martínez‐Navarro  Paul Palmqvist  Isidro Toro‐Moyano 《第四纪科学杂志》2011,26(6):603-615

The palaeontological site of Venta Micena (Orce, Andalusia, Spain) lies in the eastern sector of the Guadix–Baza basin, one of the best documented areas in Europe for Plio‐Pleistocene biostratigraphy. The combination of biochronological and palaeomagnetic results, combined with the radiometric data obtained for Atapuerca Sima del Elefante, indicated that the Venta Micena stratum was formed between the Jaramillo and Olduvai palaeomagnetic events, most likely between 1.22 and 1.77 Ma. Five fossil teeth from two outcrops (sites A and B) were selected to assess the potential of combined uranium series–electron spin resonance (US‐ESR) dating of Early Pleistocene sites. Although the US‐ESR results of the first outcrop showed a large scatter between the three teeth, the mean age of 1.37 ± 0.24 Ma can be considered a reasonable age estimate for Venta Micena. The mean ESR age of 0.62 ± 0.03 Ma obtained for site B seems to be a severe underestimation when compared with the independent age control. This underestimation is attributed to a relative recent U‐mobilization event that led to some U‐leaching. The results show that any ESR age calculations of old samples are extremely sensitive to variations in the measured ²³⁰Th/²³⁴U ratios in dental tissues. Although the results demonstrate that ESR can in principle be applied to Early Pleistocene sites, they also reveal the complexity of dating such old teeth. It is necessary to continue research in several directions, such as study of the behaviour of ESR signals in old teeth and understanding recent U‐mobilization processes, to improve the reliability of the combined US‐ESR dating method applied to Early Pleistocene times, a period for which the number of available numerical dating techniques is very limited. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

Factors and processes of permanent gully evolution in a Mediterranean marly environment (Cape Bon,Tunisia)     

A. El Khalili  H. Habaeib  J. M. Lamachère 《水文科学杂志》2013,58(7):1519-1531

Abstract

Gully erosion is considered to be one of the most important soil erosion processes in Mediterranean marly environments, but its actual contribution to total soil loss is still under discussion. The objectives of this paper are: (a) to acquire the distributed value of erosion rate in a permanent gully developed on a marly substratum in a Mediterranean environment; and (b) to quantify the key factors responsible for the spatial and temporal differences in erosion rates observed within the gully. A permanent gully located in Cap Bon (northeastern Tunisia) has been intensively and regularly monitored over a 7-year period with electronic survey equipment (total station) to give five field topographic surveys, as well as hydrological measurements at the gully outlet. The net soil loss for the 7-year period comprised a denudation of 51 m³ of sediment on the gully bank slopes, which corresponds to a mean soil loss of 61 m³ ha^?1 year^?1 or 6.1 mm year^?1. Denudation was observed on bed units with a slope gradient greater than 20%, while the remainder showed deposition. By confirming the factors involved in gully evolution, and by refining the statistical link between factors and erosion rates within the gully, the results provide important information to predict gully erosion rates in Mediterranean marly environments.

Editor Z.W. Kundzewicz; Associate editor G. Mahé

Citation El Khalili, A., Raclot, D., Habaieb, H., and Lamachère, J.M., 2013. Factors and processes of permanent gully evolution in a Mediterranean marly environment (Cape Bon, Tunisia). Hydrological Sciences Journal, 58 (7), 1519–1531.  相似文献   

A 20cm 2 CCD mosaic camera for a dark matter search part II : Electronics,data acquisition and performance     

Arnaud  M.  Aubourg  E.  Bareyre  P.  Br';ehin  S.  Caridroit  R.  de Kat  J.  Dispau  G.  Djidi  K.  Gros  M.  Lachièze-Rey  M.  Laigneau  Y.  Laurent  B.  Lesquoy  E.  Lavocat  Ph.  Magneville  C.  Mazeau  B.  Milsztajn  A.  Moscoso  L.  Pasquaud  J.  Paul  B.  Perrin  P.  Petibon  J.  Piret  Y.  Queinnec  F.  Rich  J.  Spiro  M.  de Trogoff  J.  Vigroux  L.  Zylberajch  S.  Ansari  R.  Cavalier  F.  Moniez  M.  Beaulieu  J. P.  Ferlet  R.  Grison  Ph.  Vidal-Madjar  A.  Adrianzyk  G.  Berger  J. P.  Burnage  R.  Delclite  J. C.  Kohler  D.  Magnan  R.  Richaud  A.  Guibert  J.  Moreau  O.  Tajahmady  F.  Baranne  A.  Maurice  E.  Prévôt  L.  Gry  C. 《Experimental Astronomy》1994,4(3-4):279-296

Conclusion To summarize, the readout and the control system of the CCD mosaic camera are running since December 1991 at the La Silla Observatory (ESO). The overall performance of the camera has been good. About 12000 pictures (data and flat-fields) have been successfully registered up to now. We will report in the near future preliminary scientific results of the EROS experiment.  相似文献   

Surfaces of section in the Miranda-Umbriel 3:1 inclination problem     

Michèle Moons  Jacques Henrard 《Celestial Mechanics and Dynamical Astronomy》1994,59(2):129-148

The recent numerical simulations of Tittemore and Wisdom (1988, 1989, 1990) and Dermottet al. (1988), Malhotra and Dermott (1990) concerning the tidal evolution through resonances of some pairs of Uranian satellites have revealed interesting dynamical phenomena related to the interactions between close-by resonances. These interactions produce chaotic layers and strong secondary resonances. The slow evolution of the satellite orbits in this dynamical landscape is responsible for temporary capture into resonance, enhancement of eccentricity or inclination and subsequent escape from resonance. The present contribution aims at developing analytical tools for predicting the location and size of chaotic layers and secondary resonances. The problem of the 3:1 inclination resonance between Miranda and Umbriel is analysed.  相似文献   

Continual long-term monitoring of methane in wells above the Utica Shale using total dissolved gas pressure probes     

Roy  James W.  Bordeleau  Genevi&#;ve  Rivard  Christine  Ryan  M. Cathryn  Malet  Xavier  Brown  Susan J.  Tremblay  Vincent 《Hydrogeology Journal》2022,30(3):1005-1019

Hydrogeology Journal - Monitoring of dissolved methane concentrations in groundwater is required to identify impacts from oil and gas development and to understand temporal variability under...  相似文献   

Properties and Comparison of Some Kriging Sub-model Aggregation Methods     

Bachoc  François  Durrande  Nicolas  Rullière  Didier  Chevalier  Clément 《Mathematical Geosciences》2022,54(5):941-977

Mathematical Geosciences - Kriging is a widely employed technique across computer experiments, machine learning and geostatistics. An important challenge for kriging is its high costs when dealing...  相似文献   

Origin and variability of resource-grade marine ferromanganese nodules and crusts in the Pacific Ocean: A review of biogeochemical and physical controls     

Philomène A. Verlaan  David S. Cronan 《Chemie der Erde / Geochemistry》2022,82(1):125741

Marine ferromanganese nodules and crusts containing Mn, Cu, Ni and Co in the most promising resource-grade concentrations and quantities, together with Fe and Zn (all elements of biogeochemical importance) are found far from land on the deep seafloor of the Pacific Ocean. The biogeochemical, chemical and physical mechanisms contributing to their formation, distribution, abundance and – for these six elements – variability in their concentrations in these deposits, are the main focus of the present review. The mechanisms addressed include biological productivity, sedimentation types and rates, bottom water characteristics, the Calcium Carbonate Compensation Depth, the depth and intensity of the oxygen minimum zone, and biogeochemical characteristics of the six focal elements. Particular attention is given to comparisons between the deposits found in the north and the south Pacific, in order to present an overarching view of our current understanding of the mechanisms that apply to both nodules and crusts in both oceanic hemispheres, including examination of the possible existence of a marine ferromanganese oxide continuum. The renewed interest in the commercial exploitation of these deposits has stimulated a welcome increase in scientific research that is essential to informing the public discourse on seabed mining. We briefly reflect on the work addressed in this review in that context.  相似文献   

Climate and climate change in western canada as simulated by the Canadian regional climate model     

Rene Laprise  Daniel Caya  Michel Giguere  Guy Bergeron  Hélène Côté  Jean‐Pierre Blanchet 《大气与海洋》2013,51(2):119-167

Abstract

A þrst climate simulation performed with the novel Canadian Regional Climate Model (CRCM) is presented. The CRCM is based on fully elastic non‐hydrostatic þeld equations, which are solved with an efþcient semi‐implicit semi‐Lagrangian (SISL) marching algorithm, and on the parametrization package of subgrid‐scale physical effects of the second‐generation Canadian Global Climate Model (GCMII). Two 5‐year integrations of the CRCM nested with GCMII simulated data as lateral boundary conditions are made for conditions corresponding to current and doubled CO₂ scenarios. For these simulations the CRCM used a grid size of 45 km on a polar‐stereographic projection, 20 scaled‐height levels and a time step of 15 min; the nesting GCMII has a spectral truncation of T32, 10 hybrid‐pressure levels and a time step of 20 min. These simulations serve to document: (1) the suitability of the SISL numerical scheme for regional climate modelling, (2) the use of GCMII physics at much higher resolution than in the nesting model, (3) the ability of the CRCM to add realistic regional‐scale climate information to global model simulations, and (4) the climate of the CRCM compared to that of GCMII under two greenhouse gases (GHG) scenarios.  相似文献   

Impact of climate change on the hydrogeology of two basins in northern France     

Florence Habets  Julien Boé  Michel Déqué  Agnès Ducharne  Simon Gascoin  Ali Hachour  Eric Martin  Christian Pagé  Eric Sauquet  Laurent Terray  Dominique Thiéry  Ludovic Oudin  Pascal Viennot 《Climatic change》2013,121(4):771-785

This study presents an analysis of climate-change impacts on the water resources of two basins located in northern France, by integrating four sources of uncertainty: climate modelling, hydrological modelling, downscaling methods, and emission scenarios. The analysis focused on the evolution of the water budget, the river discharges and piezometric heads. Seven hydrological models were used, from lumped rainfall-discharge to distributed hydrogeological models, and led to quite different estimates of the water-balance components. One of the hydrological models, CLSM, was found to be unable to simulate the increased water stress and was, thus, considered as an outlier even though it gave fair results for the present day compared to observations. Although there were large differences in the results between the models, there was a marked tendency towards a decrease of the water resource in the rivers and aquifers (on average in 2050 about ?14 % and ?2.5 m, respectively), associated with global warming and a reduction in annual precipitation (on average in 2050 +2.1 K and ?3 %, respectively). The uncertainty associated to climate models was shown to clearly dominate, while the three others were about the same order of magnitude and 3–4 times lower. In terms of impact, the results found in this work are rather different from those obtained in a previous study, even though two of the hydrological models and one of the climate models were used in both studies. This emphasizes the need for a survey of the climatic-change impact on the water resource.  相似文献   

Impact of justice and solidarity variables on the acceptability of managed realignment     

Bénédicte Rulleau  Hélène Rey-Valette  Valérie Clément 《Climate Policy》2013,13(3):361-377

Sea-level rise due to climate change will have significant effects on coastal areas and populations. Adaptation policies recommend the managed realignment of the most vulnerable assets and activities. Despite their medium- and long-term benefits, these policies face significant friction due to social acceptability in the communities where they are implemented.

This article investigates the hypothesis that respecting principles of justice in the implementation of managed realignment should increase its acceptability. We compare preferences of those people who are exposed to the risk of climate-change-induced flooding and those who are not, as regards funding managed retreat policies and defining compensation criteria for assets at risk. The main theories of social justice provide the four principles included in the analysis: efficiency, need, responsibility and priority assigned to property rights.

A choice experiment survey was conducted with 258 residents of coastal and hinterland communities in the south of France. Four attributes were selected to define the managed realignment policy: the dialogue arrangements, the implementation period, the policy implementation schedule and the cost. The results show support for a relatively fast launch of these policies (within 15 years) but in stages and through a process of dialogue with the population. People's perceptions of the funding criteria reveal a preference for national solidarity. Finally, national funding of managed retreat policies and compensation criteria based on market prices have a significant positive influence on the acceptability of managed realignment policies, whereas introducing responsibility-based compensation criteria tends to favour the status quo over the adaptation policy.

Policy relevance

Prioritization of the funding criteria reveals the preference for national solidarity. Preferences for the justice criteria underpinning compensation reveal a great diversity of values. Besides implantation modalities, preferences for managed realignment policies depend on which level they are implemented at, on the expropriation criteria (the emphasis given to property rights, i.e. market price), on the attachment (people perceived as worst off, i.e. the property is their main residence rather than a second home or they have lower levels of income) and on the degree of responsibility (related to the date of purchase, i.e. on the information given at the time on the risk).  相似文献