[en] On the southern side of the Beausset syncline (southwest Provence), lithostratigraphic and structural propositions are divergent. Since 1978, the available geological map at 1/50 000 has revealed these contradictions. During the recent revision of these maps at 1/10 000 scale and with detailed triasic lithostratigraphy, the authors have proposed a new interpretation of the relationship between the Trias and Santonian in diverse structural units of this area. These facts confirm premature tectonic phases (before Santonian), evoked since 1891 by M. Bertrand in this area (Saint-Jean oratory), where the embryonic structures are taken back in the following phases of the Paleogene. Similarly to the other hills around Toulon (Var), this premature genesis of the provençal folds can be attributed to the diapiric behaviour of the Trias, which seems to be the main engine of these local and initial structures. (Author)

[en] A new tectonic interpretation of the Sainte Victoire Mountain (north of Marseille, south eastern France) is proposed, principally invoking vertical movements and providing evidence which suggests an uplift which may be still active today in the western part. Some new observations confirm our hypothesis. (Author)

[en] A first progress report addresses works performed during the first two months of a programme of cartography of emission potentials of radon gas in metropolitan France. This cartography is based on available data bases of radon measurements and on various criteria which can be various geological criteria (petrographic potential, structural potential, mineral deposit potential). The second progress report comments works performed since November 1990 on these aspects. The third document is the final report. It recalls the objectives and discusses the usage limitations of a map, describes the cartographic method (map grid, combination of the different potentials, localisation). Results are discussed and maps are provided

[en] Within the frame of a contract with the CEC dealing with storage and disposal of radioactive wastes in geological formations, the B.R.G.M. has been involved in a research on process of erosion and denudation. The study is based on a literature survey. It shows that the amplitude of relief is the dominant factor to be considered for ranking erosion rates. Extreme figures of 50 and 500mm per 1,000 years are therefore proposed as mean values of erosion rates, respectively for plains-hills and mountains, for indurated rocks and for non-periglacial climates. Coefficients must correct these values when dealing with softer rocks or periglacial climates. All these factors are liable to change as functions of the surface areas of the morphological units considered

[en] This project deals with NOx biosphere-atmosphere exchanges, NOx being considered as an indirect greenhouse gases (tropospheric O₃ precursor). It relies on four laboratory specialized both on the soil-plant-atmosphere interface, and on the atmospheric chemistry. Methodology used bear on a set of in situ and laboratory measurements aiming at improving existing emission parameterization, or building new ones for the agro-ecosystems encountered in France or Europe. In situ measurements allowed to study the emission phenology in relation with relevant environmental parameters (meteorological, soil characteristics, and agricultural). Laboratory measurements allowed to establish an emission algorithm related to the three main parameters, that is, soil temperature, water and ammonia content. This algorithm has been adapted and simplified to spatialize the emissions at the France level. This spatialization was performed using environmental parameters accessible through data base (ECMWF) or agricultural statistics (such as nitrogen inputs, land use, crops). Spatial and temporal extrapolation allowed reaching the main objective, that is, to build a national inventory for a reference year (2002). This inventory allowed determining the contribution of NOx emitted by soil as compared to total emitted NOx, and the proportion of NOx emitted by soil due to fertilizer use. Our study, based on 57% of the French used agricultural area, and extrapolated to the whole arable surface, shows that soils would be responsible of about 5% of the total NOx emissions. On these 5%, 20%, which finally is a rather low percentage, would be linked to fertilizer use. The impact of these emissions on the atmospheric chemistry has been evaluated using the CHIMERE chemistry-transport model. We found that NOx emissions from soil would be of minor importance when compared to the industrial emissions, being a factor of ten lower in France. As a matter of consequence, the impact of the emissions on the maximum ozone concentration during summer months is relatively limited over Europe, but can reach 2 to 3 ppb for some of the rural French regions. (author)

[en] Arable soils are a significant source of nitric oxide (NO), a precursor of tropospheric ozone, and thereby contribute to ozone pollution. However, their actual impact on ozone formation is strongly related to their spatial and temporal emission patterns, which warrant high-resolution estimates. Here, we combined an agro-ecosystem model and geo-referenced databases to map these sources over the 12 000 km² administrative region surrounding Paris, France, with a kilometric level resolution. The six most frequent arable crop species were simulated, with emission rates ranging from 1.4 kg N-NO ha^-1 yr^-1 to 11.1 kg N-NO ha^-1 yr^-1. The overall emission factor for fertilizer-derived NO emissions was 1.7%, while background emissions contributed half of the total NO efflux. Emissions were strongly seasonal, being highest in spring due to fertilizer inputs. They were mostly sensitive to soil type, crops' growing season and fertilizer N rates. - The use of an agro-ecosystem model at regional scale makes it possible to map the emissions of nitric oxide from arable soils at a resolution compatible with tropospheric ozone models.

[en] Global environmental and climate conditions fluctuate on all kind of spatio-temporal scales. Some fluctuations or change/trends are not only anthropogenic, but have different regional and national signatures. While the frequency of extreme events on smaller scales is changing, the public sector and general opinion become more and more aware and concerned of local impacts from global environmental and climate changes. Indeed, negative effects and feedbacks, might occur on ecosystems, natural resources, buildings and grounds, superstructures, economies, food security, public health. This is how, during 1999, a concerted French initiative led to the research program 'Management and Impacts of Climate Change' (GICC). GICC is essentially managed by the Ministry of Ecology and Sustainable Development in close collaboration with the Inter-Ministerial Mission on Greenhouse Effect (MIES). GICC started in 1999. Its first phase (1999-2006) included four calls for proposal (1999, 2000, 2001, and 2002). In parallel and in 2003-2004, the MIES has been developing the so-called 'Climate Plan' based upon three principles : Insure that France follows agreements from the 'Kyoto Protocol'; Participate in ways and means leading to reduction of greenhouse gases by 75% in 2050; Allow for reduction of pollution from transportation means. Input from GICC Phase One final reports are contributing to 'Climate Plan'. The eight themes proposed by GICC-1 (1999-2002) are as follows: Theme 1: Evolution scenarios of the average and extreme features of the 21. Century climate; Theme 2: Interactions between climate, economy and society; related timescales; Theme 3: Role of carbon forest uptake and agricultural practices on climate policies; Theme 4: Links between national and international activities; Theme 5: Towards new inventories of GHG and aerosols (direct and indirect) emissions; Theme 6: Impacts on terrestrial biosphere; Theme 7: Impacts on hydro-systems; Theme 8: Impacts on public health. A symposium presenting the available results of the GICC first phase has taken place in MEDD, Paris, November 23-24, 2004. A final presentation workshop of the first phase took place in Paris, on May 11-12, 2006. This document is the proceedings of this scientific restitution seminar. It is organized in 9 sessions which follow the 8 themes listed above plus a round table for the status and perspectives of the GICC program. (J.S.)

[en] Recent research in nitrogen exchange with the atmosphere has separated research communities according to N form. The integrated perspective needed to quantify the net effect of N on greenhouse-gas balance is being addressed by the NitroEurope Integrated Project (NEU). Recent advances have depended on improved methodologies, while ongoing challenges include gas-aerosol interactions, organic nitrogen and N₂ fluxes. The NEU strategy applies a 3-tier Flux Network together with a Manipulation Network of global-change experiments, linked by common protocols to facilitate model application. Substantial progress has been made in modelling N fluxes, especially for N₂O, NO and bi-directional NH₃ exchange. Landscape analysis represents an emerging challenge to address the spatial interactions between farms, fields, ecosystems, catchments and air dispersion/deposition. European up-scaling of N fluxes is highly uncertain and a key priority is for better data on agricultural practices. Finally, attention is needed to develop N flux verification procedures to assess compliance with international protocols. - Current N research is separated by form; the challenge is to link N components, scales and issues