Meta-igneous origin of Hercynian peraluminous granites in N.W. French Massif Central: implications for crustal history reconstructions     

Laurent Turpin  Michel Cuney  Marc Friedrich  Jean-Luc Bouchez  Monique Aubertin 《Contributions to Mineralogy and Petrology》1990,104(2):163-172

Seventy samples of Hercynian peraluminous granites (Guéret, Millevaches and Saint Sylvestre massifs) and metamorphic units of the Limousin area were analysed for Rb–Sr and Sm–Nd. The source rocks of the peraluminous granites can be found in the metamorphic rocks of Limousin, among them meta-igneous rocks were largely predominent over meta-sedimentary rocks in the source of the three granites. Millevaches and Guéret granites were generated by the partial melting of rocks comprising meta-volcanics and meta-sediments, whereas the Saint Sylvestre granite was produced exclusively by the melting of late Precambrian granites. This leads to confusing T _DM ^Nd values, the confusion being amplified by the segregation of monazite during the petrogenetic evolution of the peraluminous granites, which leads to dramatic fractionation in Sm/Nd ratios. The data of the present study tend to demonstrate that peraluminous granites do not give a good representation of isotopic mean crustal estimates. Late Precambrian time seems, however, to have been a period of extensive crustal generation in Western Europe.  相似文献   

The influence of trade winds,local air-masses and topographic obstacles on the aeolian movement of sand particles and the origin and distribution of dunes and ergs in the Sahara and Australia     

Monique Mainguet 《Geoforum》1978,9(1):17-28

The Saharan ergs consist of a wide range of aeolian land forms, while in Australia, sand-ridges are the main form. The ergs are situated along major sandflows of continental extent along which sand is transported. These are oriented approximately from NE to SW in the Sahara. In Australia they form an anticlockwise pattern open to the west. The spatial and temporal factors that govern the origin of sand-ridges are reviewed.  相似文献   

Les Rotifères du lac Léman     

Gérard Balvay  Monique Laurent 《Aquatic Sciences - Research Across Boundaries》1981,43(1):126-139

The published literature on the zooplankton of Lake Léman has been reviewed and all specific names were rewritten according to the valid nomenclature. Some dubious species are reinstated in a new systematical position. Four species are new for the Lake Léman.  相似文献   

Identification of data-driven Dutch dietary patterns that benefit the environment and are healthy     

Sander Biesbroek  W. M. Monique Verschuren  Yvonne T. van der Schouw  Ivonne Sluijs  Jolanda M. A. Boer  Elisabeth H. M. Temme 《Climatic change》2018,147(3-4):571-583

More sustainable dietary patterns are needed to mitigate global warming. This study aims to identify data-driven healthy dietary patterns that benefit the environment. In EPIC-NL, diet was assessed using a 178-item FFQ in 36,203 participants aged 20–70 years between 1993 and 1997. The Dutch Healthy Diet index 2015 (DHD15-index) was used to score healthiness of the diet. As proxy for environmental impact, greenhouse gas (GHG) emissions were calculated using life cycle analysis. To determine patterns that are both healthy and environmentally friendly, reduced rank regression was applied. A “Plant-based Pattern” characterized by high consumption of fruits, vegetables, and legumes, and low consumption of fries, red meat, and processed meat and a “Dairy-based Pattern” characterized by high consumption of dairy, and nuts and seeds and low consumption of coffee and tea, sugar-containing sodas, low-fiber bread, and savory sauces were derived. At equal energy intake, the diet of adherents (highest quartile) to the “Plant-based Pattern” were significantly healthier (89.8 points on the DHD15-index, p?<?0.0001) and more sustainable (3.96 kg C0₂-eq/day, p?<?0.0001) compared to the average diet (76.2 points, 4.06 kg C0₂-eq/day), whereas the “Dairy-based Pattern” was somewhat healthier (77.9 points, p?<?0.0001), but less sustainable (4.43 kg C0₂-eq/day, p?<?0.0001). When deriving dietary patterns based on health and environmental aspects of the diets, a “Plant-based” and a “Dairy-based” pattern were observed in our study population. Of these, the plant-based diet benefits health as well as the environment.  相似文献   

An integrative physical,mineralogical and ichnological approach to characterize underfilled lake-basins     

Adriana C. Mancuso  Veronica Krapovickas  Cecilia A. Benavente  Claudia A. Marsicano 《Sedimentology》2020,67(6):3088-3118

Lakes are particularly sensitive to environmental fluctuations, which are recorded in their facies and stratigraphy. Ephemeral lakes reveal their sensitivity to palaeoenvironmental changes in the overprinting of the sedimentary features in every single bed. Tetrapod-track taphonomic-modes and ichnological taphonomic-pathways can be used as sensitive indicators of environmental conditions of the track-bearing beds during deposition and imprinting. The Middle Triassic Cerro de las Cabras succession (Cuyana Basin, Argentina) provides an excellent opportunity to these environmental indicators in an underfilled palaeolake. A model of ichnological preservation for underfilled lake systems is proposed and the role of the ichnology record in the sequence stratigraphy analysis is evaluated, based on the integration of tetrapod-track modes, taphonomic-pathways of playa-lake ichnofauna, mineralogy and physical data. Soft-ground suites include those dominated by invertebrate grazing traces and arthropod locomotion traces (Suite 1), and those overprinted by horizontal-vertical dwelling burrows with tetrapod tracks preserved in taphonomic modes B and C (Suite 2). The firm-ground suite (Suite 3) comprises tetrapod-tracks with the best preservation styles (modes A and B) along less abundant invertebrate dwelling and feeding traces as found in Suite 2. Clay mineralogy (dominated by illite with subordinate smectite) suggests low plasticity of the layers, in agreement with low-relief deformation structures observed in tetrapod-track taphonomic-modes. The well-preserved track tetrapod features documented in the Cerro de las Cabras succession, together with the absence of pedogenic disturbance, trampling obliterating the footprints, and/or evidence of strong disturbance by wind, desiccation and/or precipitation, supports short periods of exposure of the imprinted surface particular to this succession. An integrated multiproxy approach is proposed to evaluate the evolutionary interpretation and identification of autogenic versus allogenic controls in underfilled lake-basin histories. The observed aggradational-trend suggests an equilibrium between rates of accommodation change and sediment supply, and that the basin-centre did not experience prolonged sediment-starved conditions.  相似文献   

Autonomous underwater vehicles     

Monique Chyba 《Ocean Engineering》2009,36(1):1

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Influence of bioturbation by the polychaete Nereis diversicolor on the structure of bacterial communities in oil contaminated coastal sediments   总被引：1，自引：0，他引：1  

Cuny P  Miralles G  Cornet-Barthaux V  Acquaviva M  Stora G  Grossi V  Gilbert F 《Marine pollution bulletin》2007,54(4):452-459

Patterns of change in the structure of bacterial communities monitored by ribosomal intergenic spacer analysis (RISA) in oil contaminated sediments inhabited or not by the marine polychaete Nereis diversicolor were studied during 45 days under laboratory conditions. Results supported by principal component analysis showed a marked response of the bacterial communities to the oil contamination and to the presence of N. diversicolor. Phylogenetic affiliation of specific RISA bands showed that, in the contaminated sediments, the presence of the marine polychaetes favoured the development of bacteria which may play an active role in natural bioremediation processes of oil polluted environments.  相似文献   

Combined Analysis of Ultraviolet and Radio Observations of the 7 May 2004 CME/Shock Event     

Salvatore Mancuso 《Solar physics》2011,273(2):511-523

We report results from the combined analysis of UV and radio observations of a CME-driven shock observed on 7 May 2004 above the southeast limb of the Sun at 1.86 R _⊙ with the Ultraviolet Coronagraph Spectrometer (UVCS) on board the Solar and Heliospheric Observatory (SOHO). The coronal mass ejection (CME) was first detected in white-light by the SOHO’s Large Angle and Spectrometric Coronagraph (LASCO) C2 telescope and shock-associated type II metric emission was recorded simultaneously by ground-based radio spectrographs. The shock speed (∼ 690 km s⁻¹), as deduced from the analysis of the type II emission drift in the radio spectra and the pre-shock local electron density estimated with the diagnostics provided by UVCS observations of the O vi λλ 1031.9, 1037.6 doublet line intensities, is just a factor ∼ 0.1 higher than the CME speed inferred by means of the white-light (and EUV) data in the middle corona. The local magnetosonic speed, computed from a standard magnetic field model, was estimated as high as ∼ 600 km s⁻¹, implying that the CME speed was probably just sufficient to drive a weak fast-mode MHD shock ahead of the front. Simultaneously with the type II radio emission, significant changes in the O vi doublet line intensities and profiles were recorded in the UVCS spectra and found compatible with abrupt post-shock plasma acceleration and modest ion heating. This work provides further evidence for the CME-driven origin of the shocks observed in the middle corona.  相似文献   

Flux-Variance Method for Latent Heat and Carbon Dioxide Fluxes in Unstable Conditions   总被引：4，自引：0，他引：4  

Xiaofeng Guo  Hongsheng Zhang  Xuhui Cai  Ling Kang  Tong Zhu  Monique Y. Leclerc 《Boundary-Layer Meteorology》2009,131(3):363-384

Applied previously to momentum and heat fluxes, the present study extends the flux-variance method to latent heat and CO₂ fluxes in unstable conditions. Scalar similarity is also examined among temperature (θ), water vapour (q), and CO₂ (c). Temperature is adopted as the reference scalar, leading to two feasible strategies to estimate latent heat and CO₂ fluxes: the first one relies on flux-variance similarity relations for scalars, while the second is based on the parameterization of relative transport efficiency in terms of scalar correlation coefficient and a non-dimensional quantity. The relationship between the θ-to-q transport efficiency (λ _{θ q} ) and θ-q correlation coefficient (R _{θ q} ) is used to describe the intermediate hydrological conditions. We also parameterize the θ-to-c transport efficiency (λ _{θ c} ) as a function of the θ-c correlation coefficient (R _{θ c} ) by introducing a new non-dimensional ratio (α). The flux-variance method is a viable technique for flux gap-filling, when turbulence measurements of wind velocity are not available. It is worth noting that the extended method is not exempt from a correction for density effects when used for estimating water or carbon exchange.  相似文献   

A Simple Method of Estimating Scalar Fluxes Over Forests   总被引：1，自引：0，他引：1  

Nelson Luis Dias  Jinkyu Hong  Monique Y. Leclerc  T. Andrew Black  Z. Nesic  P. Krishnan 《Boundary-Layer Meteorology》2009,132(3):401-414

A simple aerodynamic-variance method is proposed to fill gaps in continuous CO₂ flux measurements in rainy conditions, when open-path analysers do not function. The method requires turbulent conditions (friction velocity greater than 0.1 ms^–1), and uses measurements of mean wind speed, and standard deviations of temperature and CO₂ concentration fluctuations to complement, and at times replace, eddy-covariance measurements of friction velocity, sensible heat flux and CO₂ flux. Friction velocity is estimated from the mean wind speed with a flux-gradient relationship modified for the roughness sublayer. Since normalised standard deviations do not follow Monin-Obukhov similarity theory in the roughness sublayer, a simple classification scheme according to the scalar turbulence scale was used. This scheme is shown to produce sensible heat and CO₂ flux estimates that are well correlated with the measured values.  相似文献