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31.
Jean-Marie Dautria Delphine Bosch Jean-Michel Liotard 《Comptes Rendus Geoscience》2006,338(8):527-536
Lherzolite xenoliths with calcite-rich microgranular secondary aggregates (0.1–1 mm) have been sampled in a Messinian breccia pipe from the northeastern part of the Languedoc volcanic province (South France). Their study shows that the carbonate crystallized at low pressure from a silico-carbonated melt resulting from partial melting of diopside and spinel at depth. This melting has been induced by injection, shortly before the eruption, of CO2 and H2O-rich fluids, stored probably within the upper lithospheric mantle and reset in motion by the magma ascension. These fluids would derive from decarbonation of levels of deeper lithospheric mantle previously metasomatized by carbonatitic melts. To cite this article: J.-M. Dautria et al., C. R. Geoscience 338 (2006). 相似文献
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Camille Contoux Sophie Violette Raffaella Vivona Patrick Goblet Delphine Patriarche 《Hydrogeology Journal》2013,21(3):545-557
The Albian aquifer of the Paris Basin (France) has been exploited since 1841 and shows drastic drawdown. A three-dimensional (3D) groundwater flow model is used to study the hydrodynamic response of the multi-layered aquifers to pumping activity in the Albian, at basin scale over 167 years. This 3D flow model uses geometry and hydrodynamic parameter distributions that are inherited from a genetic approach through basin modelling, the basin model creating a geometric pattern of hydrodynamic properties constrained by geological history. The paper aims to promote the use of the basin model approach (long time scale, 248 Ma) for the study of deep-aquifer response to anthropogenic perturbation (short time scale, 167 years) in situations for which hydrodynamic data are scarce but geological data are numerous. The results show that parameter distribution is insufficient to reproduce the Albian aquifer behaviour, notably highlighting a different meaning of the specific storage coefficient between basin modelling and groundwater-flow modelling. Dividing the storage coefficient by 100 and including available transmissivity data significantly improved the model/data comparison. The potential impact on a deep aquitard is then discussed. This study sheds light on the advantages and limitations of the basin model approach for groundwater-flow modelling in 3D. 相似文献
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Bruno Malaizé Elsa Jullien Amandine Tisserand Charlotte Skonieczny E. Francis Grousset Frédérique Eynaud Catherine Kissel Jérôme Bonnin Svenja Karstens Philippe Martinez Aloys Bory Vivianne Bout-Roumazeilles Thibaut Caley Xavier Crosta Karine Charlier Linda Rossignol José-Abel Flores Ralph Schneider 《Quaternary Research》2012,77(1):182-191
A high resolution analysis of benthic foraminifera as well as of aeolian terrigenous proxies extracted from a 37 m-long marine core located off the Mauritanian margin spanning the last ~ 1.2 Ma, documents the possible link between major continental environmental changes with a shift in the isotopic signature of deep waters around 1.0–0.9 Ma, within the so-called Mid-Pleistocene Transition (MPT) time period. The increase in the oxygen isotopic composition of deep waters, as seen through the benthic foraminifera δ18O values, is consistent with the growth of larger ice sheets known to have occurred during this transition. Deep-water mass δ13C changes, also estimated from benthic foraminifera, show a strong depletion for the same time interval. This drastic change in δ13C values is concomitant with a worldwide 0.3‰ decrease observed in the major deep oceanic waters for the MPT time period. The phase relationship between aeolian terrigeneous signal increase and this δ13C decrease in our record, as well as in other paleorecords, supports the hypothesis of a global aridification amongst others processes to explain the deep-water masses isotopic signature changes during the MPT. In any case, the isotopic shifts imply major changes in the end-member δ18O and δ13C values of deep waters. 相似文献
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Markus Stoffel Delphine Conus Michael A. Grichting Igor Livre Gilles Maître 《Global and Planetary Change》2008,60(3-4):222-234
Debris-flow activity on the forested cone of the Ritigraben torrent (Valais, Swiss Alps) was assessed from growth disturbances in century-old trees, providing an unusually complete record of past events and deposition of material. The study of 2246 tree-ring sequences sampled from 1102 Larix decidua Mill., Picea abies (L.) Karst. and Pinus cembra ssp. sibirica trees allowed reconstruction of 123 events since AD 1566. Geomorphic mapping permitted identification of 769 features related to past debris-flow activity on the intermediate cone. The features inventoried in the study area covering 32 ha included 291 lobes, 465 levées and 13 well-developed debris-flow channels. Based on tree-ring records of disturbed trees growing in or next to the deposits, almost 86% of the lobes identified on the present-day surface could be dated. A majority of the dated material was deposited over the last century. Signs of pre-20th century events are often recognizable in the tree-ring record of survivor trees, but the material that caused the growth anomaly in trees has been completely overridden or eroded by more recent debris-flow activity.Tree-ring records suggest that cool summers with frequent snowfalls at higher elevations regularly prevented the release of debris flows between the 1570s and 1860s; the warming trend combined with greater precipitation totals in summer and autumn between 1864 and 1895 provided conditions that were increasingly favorable for releasing events from the source zone. Enhanced debris-flow activity continued well into the 20th century and reconstructions show a clustering of events in the period 1916–1935 when warm–wet conditions prevailed during summer in the Swiss Alps. In contrast, very low activity is observed for the last 10-yr period (1996–2005) with only one debris-flow event recorded on August 27, 2002. Since sediment availability is not a limiting factor, this temporal absence of debris-flow activity is due to an absence of triggering events, which not only shifted from June and July to August and September over the 20th century, but also seemed to be initiated primarily by persistent precipitation rather than summer thunderstorms. From the reconstructions, based on RCM simulations, there are indications that debris-flow frequencies might continue to decrease in the future, as precipitation events are projected to occur less frequently in summer but become more common in spring or autumn. 相似文献
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Franck Lavigne Raphaël Paris Delphine Grancher Patrick Wassmer Daniel Brunstein Franck Vautier Frédéric Leone François Flohic Benjamin De Coster Taufik Gunawan Christopher Gomez Anggri Setiawan Rino Cahyadi Fachrizal 《Pure and Applied Geophysics》2009,166(1-2):259-281
This paper presents the results from an extensive field data collection effort following the December 26, 2004 earthquake and tsunami in Banda Aceh, Sumatra. The data were collected under the auspices of TSUNARISQUE, a joint French-Indonesian program dedicated to tsunami research and hazard mitigation, which has been active since before the 2004 event. In total, data from three months of field investigations are presented, which detail important aspects of the tsunami inundation dynamics in Banda Aceh. These include measurements of runup, tsunami wave heights, flow depths, flow directions, event chronology and building damage patterns. The result is a series of detailed inundation maps of the northern and western coasts of Sumatra including Banda Aceh and Lhok Nga. Among the more important findings, we obtained consistent accounts that approximately ten separate waves affected the region after the earthquake; this indicates a high-frequency component of the tsunami wave energy in the extreme near-field. The largest tsunami wave heights were on the order of 35 m with a maximum runup height of 51 m. This value is the highest runup value measured in human history for a seismically generated tsunami. In addition, our field investigations show a significant discontinuity in the tsunami wave heights and flow depths along a line approximately 3 km inland, which the authors interpret to be the location of the collapse of the main tsunami bore caused by sudden energy dissipation. The propagating bore looked like a breaking wave from the landward side although it has distinct characteristics. Patterns of building damage are related to the location of the propagating bore with overall less damage to buildings beyond the line where the bore collapsed. This data set was built to be of use to the tsunami community for the purposes of calibrating and improving existing tsunami inundation models, especially in the analysis of extreme near-field events. 相似文献
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Eric Martin Simon Gascoin Youen Grusson Clément Murgue Mélanie Bardeau François Anctil Sylvain Ferrant Romain Lardy Patrick Le Moigne Delphine Leenhardt Vincent Rivalland José-Miguel Sánchez Pérez Sabine Sauvage Olivier Therond 《Surveys in Geophysics》2016,37(2):223-247
Natural and anthropogenic forcing factors and their changes significantly impact water resources in many river basins around the world. Information on such changes can be derived from fine scale in situ and satellite observations, used in combination with hydrological models. The latter need to account for hydrological changes caused by human activities to correctly estimate the actual water resource. In this study, we consider the catchment area of the Garonne river (in France) to investigate the capabilities of space-based observations and up-to-date hydrological modeling in estimating water resources of a river basin modified by human activities and a changing climate. Using the ISBA–MODCOU and SWAT hydrological models, we find that the water resources of the Garonne basin display a negative climate trend since 1960. The snow component of the two models is validated using the moderate-resolution imaging spectroradiometer snow cover extent climatology. Crop sowing dates based on remote sensing studies are also considered in the validation procedure. Use of this dataset improves the simulated evapotranspiration and river discharge amounts when compared to conventional data. Finally, we investigate the benefit of using the MAELIA multi-agent model that accounts for a realistic agricultural and management scenario. Among other results, we find that changes in crop systems have significant impacts on water uptake for agriculture. This work constitutes a basis for the construction of a future modeling framework of the sociological and hydrological system of the Garonne river region. 相似文献
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Delphine Yeghicheyan Dominique Aubert Martine Bouhnik‐Le Coz Jrme Chmeleff Sophie Delpoux Irina Djouraev Guy Granier Franois Lacan Jean‐Luc Piro Tristan Rousseau Christophe Cloquet Aurlie Marquet Christophe Menniti Catherine Pradoux Rmi Freydier Emmanoel Vieira da Silva‐Filho Krzysztof Suchorski 《Geostandards and Geoanalytical Research》2019,43(3):475-496
The natural river water reference material SLRS‐6 (NRC‐CNRC) is the newest batch of a quality control material routinely used in many international environmental laboratories. This work presents a nine‐laboratory compilation of measurements of major and trace element concentrations and their related uncertainties, unavailable in the NRC‐CNRC certificate (B, Cs, Li, Ga, Ge, Hf, Nb, P, Rb, Rh, Re, S, Sc, Se, Si, Sn, Th, Ti, Tl, W, Y, Y, Zr and REEs). Measurements were mostly made using inductively coupled plasma‐mass spectrometry. The results are compared with equivalent data for the last batch of the material, SLRS‐5, measured simultaneously with SLRS‐6 in this study. In general, very low concentrations, close to the quantification limits, were found in the new batch. The Sr isotopic ratio is also reported. 相似文献
38.
Nicolas Trcera Delphine Cabaret Stéphanie Rossano François Farges Anne-Marie Flank Pierre Lagarde 《Physics and Chemistry of Minerals》2009,36(5):241-257
X-ray absorption spectroscopy at the Mg K-edge is used to obtain information on magnesium environment in minerals, silicate and alumino-silicate glasses. First-principles
XANES calculations are performed for minerals using a plane-wave density functional formalism with core-hole effects treated
in a supercell approach. The good agreement obtained between experimental and theoretical spectra provides useful information
to interpret the spectral features. With the help of calculation, the position of the first peak of XANES spectra is related
to both coordination and polyhedron distortion changes. In alumino-silicate glasses, magnesium is found to be mainly 5-fold
coordinated to oxygen whatever the aluminum saturation index value. In silicate glasses, magnesium coordination increases
from 4 in Cs-, Rb- and K-bearing glasses to 5 in Na- and Li-bearing glasses but remains equal as the polymerization degree
of the glass varies. The variation of the C feature (position and intensity) is strongly related to the alkali type providing
information on the medium range order.
相似文献
| Stéphanie RossanoEmail: |
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