Evolution of water quality in the abandoned iron mines of Lorraine: towards a semi-distributed modelling approach     

Pauline Collon  Robert Fabriol  Michel Bus 《Comptes Rendus Geoscience》2005,337(16):77

In Lorraine, flooding of the iron mines leads to a degradation of groundwater quality. Based on a global approach, a numerical simulator has been built that can reproduce and predict the evolution of water quality at the overflow point of the mining basin. In order to specify the spatial distribution of these pollutant concentrations, a new model has been developed. The basin is represented as a network of homogeneous reservoirs. Although encouraging, the results show the need to specify the spatial organisation of water flow in order to reproduce the pollutant concentrations in the different monitored wells. To cite this article: P. Collon et al., C. R. Geoscience 337 (2005).  相似文献   

Planktonic and whole system metabolism in a nutrient-rich estuary (the Scheldt estuary)     

Frédéric Gazeau  Jean-Pierre Gattuso  Jack J. Middelburg  Natacha Brion  Laure-Sophie Schiettecatte  Michel Frankignoulle  Alberto Vieira Borges 《Estuaries and Coasts》2005,28(6):868-883

Planktonic gross primary production (GPP), community respiration (CR), and nitrification (NIT) were measured monthly in the Scheldt estuary by the oxygen incubation method in 2003. No significant evolution of planktonic GPP was observed since the 1990s with high rates in the freshwater area (salinity 0; 97±65 mmol C m⁻² d⁻¹) decreasing seaward (22–37 mmol C m⁻² d⁻¹). A significant decrease of NIT was observed with regard to previous investigations although this process still represents up to 20% of total organic matter production in the inner estuary. Planktonic CR was highest in the inner estuary and seemed to be mainly controlled by external organic matter inputs. Planktonic net community production was negative most of the time in the estuary with values ranging from −300 to 165 mmol C m⁻² d⁻¹. Whole estuary net ecosystem production (NEP) was investigated on an annual scale using the results mentioned above and published benthic metabolic rates. A NEP of −39±8 mmol C m⁻² d⁻¹ was estimated, which confirms the strong heterotrophic status of this highly nutrified estuary. NEP rates were computed from June to December 2003 to compare with results derived from the Land-Ocean Interaction in the Coastal Zone budgeting procedure applied to dissolved inorganic phosphorus and carbon (DIP and DIC). DIP budgets failed to provide realistic estimates in the inner estuary where abiotic processes account for more than 50% of the nonconservative DIP flux. DIC budgets predicted a much lower NEP than in situ incubations (−109±31 versus −42±9 mmol C m⁻² d⁻¹) although, as each approach is associated with several critical assumptions, the source of this discrepancy remains unclear.  相似文献   

Caractérisation des ignimbrites néogènes du bassin d'Arequipa,Pérou     

Perrine Paquereau  Jean-Claude Thouret  Gerhard Wörner  Michel Fornari  Orlando Macedo  Pierrick Roperch 《Comptes Rendus Geoscience》2005,337(5):477-486

Four ignimbritic units have filled the Arequipa Basin and outcrop around the Chachani Volcano. (1) The oldest Río Chili ignimbrite is 13.33 Ma old; (2) the most widespread La Joya ignimbrite is 4.9 Ma old; (3) the Arequipa Airport ignimbrite (1.65 Ma) flowed from an area buried beneath Chachani; (4) the Yura Tuffs, 1.02 Ma old, are restricted to the west of Chachani. All are calc-alkaline rhyolites with plagioclase, biotite, quartz, sanidine, and opaques, but the Río Chili and La Joya ignimbrites also contain amphibole. Trace elements of the older ignimbrites reflect stronger crustal influence. To cite this article: P. Paquereau et al., C. R. Geoscience 337 (2005).  相似文献   

Mise en évidence d'une discontinuité émersive majeure au sein de la plate-forme récifale plio-pléistocène de l'avant-arc des Petites Antilles     

Jean-Len Léticée  Auran Randrianasolo  Jean-Jacques Cornée  Philippe Münch  Jean-Frédéric Lebrun  Jean-Paul Saint-Martin  Michel Villeneuve 《Comptes Rendus Geoscience》2005,337(6):617-624

A major emersion surface (S1) reveals at least a 60-m relative sea-level fall within the ‘Calcaires supérieurs’ of Grande-Terre (Lesser Antilles fore-arc), an Upper Pliocene–Lower Pleistocene reefal unit. We thus divide the ‘Calcaires supérieurs’ into 2 units. S1, together with the transgresssive calcarenitic and the Acropora-rich reefal units on top of it, corresponding to the record of a complete eustatic cycle by the carbonate platform of this active margin. A comparison with the carbonate platform of the Bahama Bank stable margin, allows us to relate S1 to the major emersive event of 1.66 Ma and to infer that its origin is glacio-eustatic. To cite this article: J.-L. Léticée et al., C. R. Geoscience 337 (2005).  相似文献   

From partial melting to retrogression in the Pointe Geologie migmatitic complex: a history of heterogeneous distribution of fluids     

Anne Pelletier  Michel Guiraud  Ren-Pierre Menot 《Lithos》2005,81(1-4):153-166

In the Pointe Géologie area (66°40 S; 140°00 E; Terre Adélie, East Antarctica), the Paleoproterozoic basement consists in a migmatitic complex of metasedimentary origin. Metasediments underwent a thermal event, leading to the high-grade amphibolite facies assemblages biotite–cordierite–sillimanite and to dehydration melting reactions at 4–6 kbar and 700±50 °C, followed by retrogression in greenschist facies.

In most of the archipelago, K-feldspar gneisses (KFG) are characterized by a Sil+Crd+Kfs+Bt assemblage and many K-feldspar-rich leucosomes. Locally, a spectacular rock type occurs as North dipping bands of about 10 m thick and consists in nodular gneisses (NG) that display less abundant, K-feldspar-poor leucosomes.

Commonly, the retrograde imprint facies is quite weak in KFG and only expressed by sporadic Bt–Ms±And equilibrium assemblage, whereas it developed more extensively in NG. A pseudosection calculated at constant P=4 kbar shows that the differences between NG and KFG assemblages can be considered to be mainly driven by difference in H₂O proportions and much less by differences in FeO/MgO or K₂O/MgO ratios. The hydrated assemblage (Bt–Ms nodules) in NG requires at least 10–20% more H₂O than the Crd+Kfs+Sil/And assemblage does in KFG. Parageneses and mineral compositions indicate that this difference in H₂O occurred early in the history, at least as early as the anatectic stage. Therefore, differences between NG and KFG are related to the variation in partial melting features (water distribution, proportion of melt extraction), which appears to be spatially controlled by cryptic tectonic structures. The particular shape and orientation of NG bands are interpreted as a complex history of melt extraction in the Pointe Géologie area which could involve a two stage melting process.  相似文献   

Late Cenozoic geodynamic evolution of eastern Indonesia   总被引：2，自引：0，他引：2  

Florent Hinschberger  Jacques-Andr Malod  Jean-Pierre Rhault  Michel Villeneuve  Jean-Yves Royer  Safri Burhanuddin 《Tectonophysics》2005,404(1-2):91-118

This paper presents an internally and globally consistent model of plate evolution in eastern Indonesia from Middle Miocene to Present time. It is centered on the Banda Sea region located in the triple junction area between the Pacific–Philippine, Australia and South–East Asia plates. The geological and geophysical data available from Indonesia were until recently insufficient to define a unique plate tectonic model. In this paper, the new data taken into account clearly restrict the possible interpretations. Owing to a great number of geological, geophysical and geochemical studies, the major plate boundaries (the Sunda–Banda subduction zone to the south, the Tarera–Aiduna Fault zone and the Seram Thrust to the east, and the Sorong Fault zone and Molucca Sea collision zone to the north) are now clearly identified. The age of the major tectonic structures is also better known. Geodetic measurements well constrain the Present time plate kinematics. We also consider the deformation history within eastern Indonesia, where numerous short-lived microplates and their related microcontinents successively accreted to the Asiatic margin. Moreover, magnetic anomalies identification of the North and South Banda Sea basins allows a precise kinematic reconstruction of the back-arc opening. We used the Plates software to test the coherency of our model, presented as a series of 4 plate reconstruction maps from 13 Ma to the present. Finally, the origin of oceanic domains restored by our reconstruction is discussed.  相似文献   

Stratigraphie et paléoenvironnement des dép?ts volcano-détritiques à dinosauriens du Jurassique inférieur de Toundoute (Province de Ouarzazate, Haut-Atlas – Maroc)     

Christian Montenat  Michel Monbaron  Ronan Allain  Najat Aquesbi  Jean Dejax  Jean Hernandez  Dale Russell et Philippe Taquet 《Eclogae Geologicae Helvetiae》2005,98(2):261-270

Resume. Le gisement de dinosauriens du Jurassique inférieur de Toundoute, à sauropode primitif (Tazoudasaurus naimi), est examiné sous ses aspects stratigraphiques, sédimentologiques et paléoenvironnementaux. Les couches continentales détritiques à dinosaures, succédant en continuité à des niveaux marins carbonatés trés peu épais du Lias inférieur (Hettangien-Sinémurien probables), sont rapportées au Lias moyen-supérieur. Les dép?ts continentaux contiennent une part importante de produits volcanoclastiques différents des basaltes triasiques. Les centres d’émission, non connus, étaient sans doute proches. La sédimentation continentale, de type chenaux fluviatiles – plaine d’inondation, refléte un climat chaud à périodes alternativement humides et séches, ces derniéres étant fortement marquées. Les deux niveaux à ossements correspondent à des coulées boueuses ayant charrié des ossements et portions de carcasses (os en connexion) sur de courtes distances. Ce mode de transport a préservé les ossements de l’érosion et favorisé un enfouissement rapide permettant leur conservation. Manuscrit re?u le 16 juillet 2004 Révision acceptée le 17 mars 2005  相似文献   

Révision stratigraphique de l’Ile de Timor (Indonésie orientale)     

Michel Villeneuve  Jean-Jacques Cornée  Agus Harsolumakso  Rossana Martini et Louisette Zaninetti 《Eclogae Geologicae Helvetiae》2005,98(2):297-310

Resume. De nombreuses échelles stratigraphiques de l’?le de Timor ont vu le jour car les corrélations stratigraphiques étaient rendues difficiles par la complexité tectonique de l’?le et par la variété des faciès. Dès les premiers travaux, plusieurs séries ont été distinguées, regroupées en trois unités litho-structurales principales: unité allochtone, sub-autochtone et autochtone. Les données stratigraphiques et géodynamiques récentes montrent que l’?le de Timor est en fait constituée par six unités litho-structurales, chacune témoignant d’un épisode majeur de l’histoire géologique de l’Ile. Cette histoire consiste d’abord à la séparation, au Jurassique, d’un bloc issu du continent de Gondwana (unité para-allochtone) qui est entré en collision avec l’arc volcanique asiatique à l’Oligo-Miocène (unités allochtone et sub-allochtone). Cet ensemble a ensuite été séparé de l’Asie lors de l’ouverture de la mer de Banda sud, au Miocène supérieur (unité sub-autochtone) pour finalement entrer en collision avec la marge nord australienne au cours du Pliocène moyen (plateforme australienne et groupe de Kolbano). Timor est depuis incorporée à la marge nord australienne (unité autochtone). Ce travail présente les différentes échelles stratigraphiques de chaque nouvelle unité, des propositions de corrélations et une comparaison avec les ?les voisines de Sumba et de Sulawesi pour aboutir à une proposition d’évolution géodynamique. Manuscrit re?u le 13 février 2004 Révision acceptée le 14 février 2005  相似文献   

Tectonic evolution of the Dabieshan orogen: In the view from polyphase deformation of the Beihuaiyang metamorphic zone   总被引：1，自引：0，他引：1  

LIN Wei    Faure Michel  WANG Qingchen & Arnaud Nicolas . LTE  Institute of Geology  Geophysics  Chinese Academy of Sciences  Beijing  China  . Department of Earth  Planetary Sciences  Graduate School of Science  Nagoya University  Japan  . ISTO  UMR CNRS  Batiment Géosciences  Orléans Université d’Orléans  Orléans Cedex  France  . UMR "Magmas et Volcans"  Rue Kessler  Clermont-Ferrand  France 《中国科学D辑(英文版)》2005,48(7)

The Dabieshan and its geological counterpart in the Sulu area represent the eastern part of the Qinling-Dabie orogenic belt in Eastern China. This Orogen corresponds to the collision zone between the North and South China blocks (denoted as NCB and SCB, respectively) during the Early Mesozoic. Since the discovery of ultra-high-pressure (UHP) metamor- phism[1?3], research of the Dabieshan has made great progress from petrological work (e.g. Cong and Wang, 1999 and enclosed references)[…  相似文献   

Does sediment resuspension by storms affect the fate of polychlorobiphenyls (PCBs) in the benthic food chain? Interactions between changes in POM characteristics, adsorption and absorption by the mussel Mytilus galloprovincialis   总被引：1，自引：0，他引：1  

Franois Charles  Susanna Lopez-Legentil  Antoine Grmare  Jean Michel Amouroux  Martin Desmalades  Gilles Vtion  Karine Escoubeyrou 《Continental Shelf Research》2005,25(19-20):2533

Environmental parameters and gross sedimentation rates (GSR) were monitored at a fixed site located in the Bay of Banyuls-sur-Mer (NW Mediterranean), between March 1997 and April 1998, together with the main biochemical characteristics of both sedimenting and sedimented particulate organic matter (POM). Three storms which occurred during this time period resulted in natural sediment resuspension. This is indicated by the corresponding increase in GSR and a decrease in the enzymatically hydrolysable amino acids/totally hydrolysable amino acids ratio (EHAA/THAA), within the sedimenting POM. Only the strongest storm resulted in (1) a transitory increase in fine-grained particles, (2) concomitant increases in organic carbon, carbohydrates, lipids and THAA, and (3) a decrease in the EHAA/THAA ratio in surficial sediments. For most of the assayed parameters, the values recorded after the December 1997 storm corresponded to extremes for the whole period under study. This emphasises the role of storms in controlling the characteristics of sedimented and sedimenting POM.Ten sediment types, with contrasting biochemical characteristics, were selected for experiments; these were based on the results of the monitoring survey and were used during adsorption and absorption experiments involving ¹⁴C tetrachlorobiphenyl (TCB). Adsorption rates differed significantly between the sediment types, but did not correlate with any of the assayed biochemical parameters. Absorption efficiency by the mussel Mytilus galloprovincialis also differed between the sediment types; it correlated positively with all the assayed biochemical parameters, except lipids. Comparison between the magnitudes of the increase in GSR, together with the decrease in absorption efficiency during resuspension events, suggests that resuspension tends to enhance the transfer of organic pollutants in the benthic food chain.  相似文献