Complexes dunaires et tourbeux holocènes du littoral du Nord de la France     

Murielle Meurisse  Brigitte Van Vliet-Lanoë  Brigitte Talon  Philippe Recourt 《Comptes Rendus Geoscience》2005,337(7):675-684

This survey of the coastal dunes of northern France is based on stratigraphy, ¹⁴C dating, sedimentology and morphology applied for palaeoclimatic and palaeodynamic purpose. The dunes rest on a Flandrian prism sealed by Atlantic peats grown backward from a subboreal dune ridge. Two historical building phases are recorded: the late Roman dunes and the 13th century dunes. These events are separated by pedogenesis. Contribution of reworked fluvial sands also records the recent climatic degradation, with an increased storminess (Little Ice Age) associated with more efficient erosion (soil erosion and floods). The dunes of Picardy also record the Global Warming: their morphologies attest a shift from parabolic into longitudinal, by coupling storminess and sea-level rise. To cite this article: M. Meurisse et al., C. R. Geoscience 337 (2005).  相似文献   

Chemical Characterisation of the USGS Reference Glasses GSA-1G, GSC-1G, GSD-1G, GSE-1G, BCR-2G, BHVO-2G and BIR-1G Using EPMA, ID-TIMS, ID-ICP-MS and LA-ICP-MS   总被引：6，自引：2，他引：6  

Klaus Peter Jochum  Matthias Willbold  Ingrid Raczek  Brigitte Stoll  Kirstin Herwig 《Geostandards and Geoanalytical Research》2005,29(3):285-302

The USGS reference glasses GSA-1G, GSC-1G, GSD-1G, GSE-1G, BCR-2G, BHVO-2G and BIR-1G were investigated by different analytical techniques. All these materials have a geological (basaltic) matrix and are therefore useful in igneous geochemistry as matrix-matched reference materials for microanalytical techniques. The new GS glasses have trace elements in groups at concentration levels of about < 0.01, 5, 50 and 500 μg g^-1. Their major element compositions have been determined by EPMA, and trace elements have been analysed by LA-ICP-MS and two isotope dilution techniques using TIMS and ICP-MS. EPMA and LA-ICP-MS analyses indicated that the USGS reference glasses are homogeneous at the μm to mm scale with respect to major (variations < 1-2%) and most trace elements (variations 1-4%). Trace element data obtained from the different analytical techniques agreed within an uncertainty of 1-5%, indicating that between method results are comparable. Therefore, the preliminary working values for the four USGS GS glasses calculated from these data have a low level of uncertainty.  相似文献   

GeoReM: A New Geochemical Database for Reference Materials and Isotopic Standards   总被引：13，自引：2，他引：13  

Klaus Peter Jochum  Uwe Nohl  Kirstin Herwig  Esin Lammel  Brigitte Stoll  Albrecht W. Hofmann 《Geostandards and Geoanalytical Research》2005,29(3):333-338

We have developed a new database named GeoReM ( http://georem.mpch-mainz.gwdg.de ) for reference materials and isotopic standards of geochemical and mineralogical interest. Reference samples include rock powders originating from the USGS, GSJ, GIT-IWG, synthetic and natural reference glasses originating from NIST, USGS, MPI-DING, as well as mineral (e.g., 91500 zircon), isotopic (e.g., La Jolla, E&A, NIST SRM 981), river water and seawater reference materials. GeoReM is a relational database, which strongly follows the concept of the three EARTHCHEM databases. It contains published analytical and compilation values (major and trace element concentrations, radiogenic and stable isotope ratios), important metadata about the analytical values, such as uncertainty, uncertainty type, method and laboratory. Sample information and references are also included. Three different ways of interrogating the database are possible: (1) sample names or material types, (2) chemical criteria and (3) bibliography. Some typical applications are described. GeoReM currently (October 2005) contains more than 750 geological reference materials, 6000 individual sets of results and references to 650 publications.  相似文献   

The REBENT monitoring network, a spatially integrated, acoustic approach to surveying nearshore macrobenthic habitats: application to the Bay of Concarneau (South Brittany, France)     

Ehrhold  Axel; Hamon  Dominique; Guillaumont  Brigitte 《ICES Journal of Marine Science》2006,63(9):1604-1615

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Effects of Oxygen Loss on Carbon Processing and Heterotrophic Prokaryotes from an Estuarine Ecosystem: Results from Stable Isotope Probing and Cytometry Analyses     

Rémy D. Tadonléké  Thomas Pollet  Pieter Van Rijswijk  Brigitte Leberre  Jack J. Middelburg 《Estuaries and Coasts》2016,39(4):992-1005

Many aquatic ecosystems are experiencing a decline in their oxygen (O₂) content and this is predicted to continue. Implications of this change on several properties of bacterioplankton (heterotrophic prokaryotes) remain however are poorly known. In this study, oxic samples (～170 μM O₂?=?controls) from an oligohaline region of the Scheldt Estuary were purged with N₂ to yield low-O₂ samples (～69 μM O₂?=?treatments); all were amended with ¹³C-glucose and incubated in dark to examine carbon incorporation and cell size of heterotrophic prokaryotes, and relationships between organic matter (OM) degradation and phosphate (P) availability in waters following O₂ loss. Stable isotope (¹³C) probing of phospholipid fatty acids (PLFA) and flow cytometry were used. In samples that have experienced O₂ loss, PLFA biomass became higher, prokaryotic cells had significantly larger size and higher nucleic acid content, but P concentrations was lower, compared to controls. P concentration and OM degradation were positively related in controls, but uncoupled in low-O₂ samples. Moreover, the dominant PLFA 16:1ω7c (likely mainly from Gram-negative bacteria) and the nucleic acid content of heterotrophic prokaryotic cells in low-O₂ samples explained (62–72 %) differences between controls and low-O₂ samples in P amounts. Shortly after incubations began, low-O₂ samples had consistently lower bacterial PLFA ¹³C-enrichments, suggesting involvement of facultatively anaerobic metabolism in carbon incorporation, and supporting the view that this metabolic pathway is widespread among pelagic bacteria in coastal nutrient-rich ecosystems. Estimates based on ¹³C-enrichment of PLFAs indicated that grazing by protozoa on some bacteria was stronger in low-O₂ samples than in controls, suggesting that the grazing pressure on some heterotrophic prokaryotes may increase at the onset of O₂ deficiency in nutrient-rich aquatic systems. These findings also suggest that physiological responses of heterotrophic prokaryotes to O₂ loss in such ecosystems include increases in cell activity, high carbon incorporation, and possibly phosphorus retention by cells that may contribute to reduce phosphate availability in waters.  相似文献   

Influence of Hydrological Regime in Determining the Response of Macroalgal Blooms to Nutrient Loading in Two Irish Estuaries     

Sorcha?Ní LongphuirtEmail author  Shane?O’Boyle  Robert?Wilkes  Tomasz?Dabrowski  Dagmar?Brigitte?Stengel 《Estuaries and Coasts》2016,39(2):478-494

Eutrophication and the development of persistent opportunistic macroalgal blooms are recognised as one of the main detrimental effects of increased anthropogenic pressures on estuarine and coastal systems. This study aimed to highlight the interplay between pressures and controlling physical factors on ecosystem functioning. The hypothesis that hydrological regime can control the growth of opportunistic macroalgae was tested with the study of two Irish estuaries, the Argideen and the Blackwater, with similar nutrient loading sources but divergent hydrological regimes. Seasonal monitoring data was initially examination, while the application of a pre-existing box model allowed a further analysis of the influence of residence time and nutrient load modifications on macroalgal growth. Seasonal oscillations in monitored river flow rates altered nutrient transfer from the catchments to the estuaries in both cases, as is shown through differences between winter and summer nutrient concentrations. In the Argideen, however, the relative contribution of phosphorus (P) from adjacent marine waters was high due to the shorter residence times and greater influx of marine water into the estuary. Modelling studies showed that in the Argideen Estuary, P load reduction would have potentially minimal impact on macroalgal growth due to the shorter residence time which increased the influx of P from marine sources. Nitrogen (N) load reduction of 60 % had a significant, albeit limited, impact on macroalgae and was insufficient in achieving the environmental objectives for this waterbody. For the more river-dominated Blackwater Estuary, modelled reductions in P resulted in a considerable decrease in biomass. Any further P decreases would accentuate the existing disparity in estuarine N:P ratios with possible repercussions for N transport to the coastal system. Hence, the hydrological complexity of estuarine systems demonstrated dictates that a portfolio of separate, but complimentary, management approaches may be required to address eutrophication in these estuaries.  相似文献   

Suitability of Mn‐ and Fe‐Rich Reference Materials for Microanalytical Research          下载免费PDF全文

Dorothea S. Macholdt  Klaus Peter Jochum  Stephen A. Wilson  Laura M. Otter  Brigitte Stoll  Ulrike Weis  Meinrat O. Andreae 《Geostandards and Geoanalytical Research》2016,40(4):493-504

Manganese‐ and iron‐rich materials are of major geoscientific and economic interest, many of which contain microscopic features that provide valuable information. To obtain accurate results, a homogeneous microanalytical reference material for calibration is needed. Several researchers have used the Mn‐ and Fe‐rich RMs, JMn‐1, NOD‐A‐1, NOD‐P‐1 and FeMn‐1, for this purpose; therefore, they were tested in this study to determine their suitability for microanalysis. Their homogeneity was investigated by laser ablation‐inductively coupled plasma‐mass spectrometry (LA‐ICP‐MS) with two different types of lasers (nano‐ and femtosecond), with spot and line scan analyses and with different operating parameters, such as spot size, pulse repetition rate and fluence. As the established manganese nodule RMs revealed inhomogeneities for picogram to microgram test portions, we also investigated the new synthetic Fe‐ and Mn‐rich RM, FeMnOx‐1. FeMnOx‐1 was found to be homogeneous for large (ø 40 μm: 2% RSD repeatability) and small (ø 8–10 μm: 10% RSD repeatability) spot sizes. This homogeneity is in the range of the homogeneous NIST SRM 610 and GSE‐1G reference glasses. Furthermore, FeMnOx‐1 revealed a large‐scale homogeneity within uncertainties of a few per cent, using test portions in the ng range, when measuring four individual mounts of this material.  相似文献   

Assessing post-pliocene deformation in a context of slow tectonic deformation: insights from paleoseismology,remote sensing and shallow geophysics in Provence,France     

Thomas  Franck  Rizza  Magali  Bellier  Olivier  Billant  Jérémy  Dussouillez  Philippe  Fleury  Jules  Delanghe  Doriane  Ollivier  Vincent  Godard  Vincent  Talon  Brigitte 《Natural Hazards》2021,105(2):1453-1490

Natural Hazards - The Provence region, located in the south-east of France, has experienced a few destructive earthquakes during the last centuries, such as the 1909 Lambesc earthquake or the 1509...  相似文献   

Nano‐Powdered Calcium Carbonate Reference Materials: Significant Progress for Microanalysis?     

Klaus Peter Jochum  Dieter Garbe‐Schnberg  Marina Veter  Brigitte Stoll  Ulrike Weis  Michael Weber  Federico Lugli  Anna Jentzen  Ralf Schiebel  Jasper A. Wassenburg  Dorrit E. Jacob  Gerald H. Haug 《Geostandards and Geoanalytical Research》2019,43(4):595-609

Homogeneity, mass fractions of about forty trace elements and Sr isotope composition of Ca carbonate reference materials (RMs) between original and nano‐powdered pellets are compared. Our results using nanosecond and femtosecond LA‐(MC)‐ICP‐MS show that the nano‐pellets of the RMs MACS‐3NP, JCp‐1NP and JCt‐1NP are about a factor of 2–3 more homogeneous than the original samples MACS‐3, JCp‐1 and JCt‐1, and are therefore much more suitable for microanalytical purposes. With the exception of Si, the mass fractions of the synthetic RM MACS‐3 agree with its fine‐grained analogue MACS‐3NP. Very small, but significant, differences between original and nano‐pellets are observed in the RMs JCp‐1 and JCt‐1 for some trace elements with very low contents, indicating the need for re‐certification. Strontium mass fractions in the analysed RMs are high (1500–7000 mg kg^?1), and their isotope compositions determined by LA‐MC‐ICP‐MS in the original and the nano‐pellets agree within uncertainty limits.  相似文献   

Quaternary thermokarst and thermal erosion features in northern France: origin and palaeoenvironments     

Brigitte Van Vliet‐Lanoë  Jacques Brulhet  Philippe Combes  Cédric Duvail  Frédéric Ego  Stéphane Baize  Isabelle Cojan 《Boreas: An International Journal of Quaternary Research》2017,46(3):442-461

A thermokarst is a collapse feature resulting from the thawing of ice‐rich permafrost or of massive ice of various origins. Little attention has been paid to the sedimentary fabric resulting from this type of collapse, except for glaciotectonic features. In western Europe, two palaeo‐forms are commonly studied: lithalsas and ice‐wedge casts. Collapsed pingos are much rarer. Very few papers have compiled present‐day and fossil data. Here, field data collected from quarries in the eastern Paris Basin were analysed, providing useful records of thermokarst collapses in alluvial calcareous silts, sands, and gravels. These forms have a circular shape when viewed on satellite images. Permafrost is attested regionally by the recurrent occurrence of meter‐sized pattern grounds at the surface of the chalk and of ice‐wedge casts. Traces of segregation and reticulate ice are common. These features are primarily connected to a major interstadial, c. 150 ka BP, orbitally forced and commonly associated with a major glacial retreat. They occur both in drained and waterlogged situations, resulting in a specific pattern of deformation. They are controlled by the brittle and plastic behaviour of sediments and resemble passive glaciotectonism. Normal and reverse faults, with the offset decreasing downward, are common, and those with local shear are reported. Lithalsas, seasonal frost blisters, spring frost blisters and perhaps pingos seem to have formed. Most of these deformations correspond to thermokarst sinkholes bordered by gravitational collapse faults. The offset of these faults increases towards the surface, and the faults have been recurrently confused with neotectonism triggered by palaeo‐earthquakes. However, there are no faults beneath the observed deformation features, and the region lacks recorded seismic activity over the last century. Our data may be helpful in interpreting similar structures elsewhere.  相似文献