Basic concepts of the crystallization from aqueous solutions: The example of aluminum oxy(hydroxi)des and aluminosilicates     

Jean-Pierre Jolivet  Corinne Chanéac  David Chiche  Sophie Cassaignon  Olivier Durupthy  Julien Hernandez 《Comptes Rendus Geoscience》2011,343(2-3):113-122

This overview features the chemical background on condensation phenomena of the aluminum cation in aqueous solution. The formation of polycationic molecular clusters and nanosized solid phases of aluminum oxy(hydroxi)des is interpreted with illustrative mechanisms, building a bridge between solution chemistry and solid-state chemistry. The formation of the main structural types of aluminosilicates (zeolites, clays, imogolite) is also illustrated through the aqueous chemistry of aluminum and silicates.  相似文献   

Manufactured metal and metal-oxide nanoparticles: Properties and perturbing mechanisms of their biological activity in ecosystems     

Jean-Yves Bottero  Mélanie Auffan  Jérôme Rose  Catherine Mouneyrac  Céline Botta  Jérôme Labille  Armand Masion  Antoine Thill  Corinne Chaneac 《Comptes Rendus Geoscience》2011,343(2-3):168-176

The inorganic manufactured nanoparticles as TiO₂, Ag°, the iron oxides and CeO₂ are more and more present in various manufactured products and in the aqueous media (TiO₂). Their dispersion in the ecosystems during their life cycle will be associated with interactions with biota (plants, bacteria, fishes). The present work shows strong relations between particular physical chemical properties of very small nanoparticles (size < 30 nm) and biological activity perturbations. It is shown that Ag° and CeO₂ act at very low concentrations. TiO₂ act via the ROS production due to their photo-reactivity.  相似文献   

The extremely reduced silicate‐bearing iron meteorite Northwest Africa 6583: Implications on the variety of the impact melt rocks of the IAB‐complex parent body     

Agnese Fazio  Massimo D'Orazio  Luigi Folco  Jérôme Gattacceca  Corinne Sonzogni 《Meteoritics & planetary science》2013,48(12):2451-2468

Northwest Africa (NWA) 6583 is a silicate‐bearing iron meteorite with Ni = 18 wt%. The oxygen isotope composition of the silicates (?′¹⁷O = ?0.439 ‰) indicates a genetic link with the IAB‐complex. Other chemical, mineralogical, and textural features of NWA 6583 are consistent with classification as a new member of the IAB‐complex. However, some unique features, e.g., the low Au content (1.13 μg g^?1) and the extremely reducing conditions of formation (approximately ?3.5 ?IW), distinguish NWA 6583 from the known IAB‐complex irons and extend the properties of this group of meteorites. The chemical and textural features of NWA 6583 can be ascribed to a genesis by impact melting on a parent body of chondritic composition. This model is also consistent with one of the most recent models for the genesis of the IAB‐complex. Northwest Africa 6583 provides a further example of the wide lithological and mineralogical variety that impact melting could produce on the surface of a single asteroid, especially if characterized by an important compositional heterogeneity in space and time like a regolith.  相似文献   

High-pressure Raman spectroscopic study of Mn2GeO4, Ca2GeO4, Ca2SiO4, and CaMgGeO4 olivines     

Bruno Reynard  Corinne Remy  Fouzia Takir 《Physics and Chemistry of Minerals》1997,24(2):77-84

We present a Raman spectroscopic study of the structural modifications of several olivines at high pressures and ambient temperature. At high pressures, the following modifications in the Raman spectra are observed: 1)?in Mn₂GeO₄, between 6.7 and 8.6?GPa the appearance of weak bands at 560 and 860?cm^?1; between 10.6 and 23?GPa, the progressive replacement of the olivine spectrum by the spectrum of a crystalline high pressure phase; upon decompression, the inverse sequence of transformations is observed with some hysteresis in the transformation pressures; this sequence may be interpreted as the progressive transformation of the olivine to a spinelloid where Ge tetrahedra are polymerized, and then to a partially inverse spinel; 2)?in Ca₂SiO₄, the olivine transforms to larnite between 1.9 and 2.1?GPa; larnite is observed up to the maximum pressure of 24?GPa and it can partially back-transform to olivine during decompression; 3)?in Ca₂GeO₄, the olivine transforms to a new structure between 6.8 and 8?GPa; the vibrational frequencies of the new phase suggest that the phase transition involves an increase of the Ca coordination number and that Ge tetrahedra are isolated; this high pressure phase is observed up to the maximum pressure of 11?GPa; during decompression, it transforms to a disordered phase below 5?GPa; 4)?in CaMgGeO₄, no significant modification of the olivine spectrum is observed up to 15?GPa; between 16 and 26?GPa, broadening of some peaks and the appearance of a weak broad feature at 700–900?cm^?1 suggests a progressive amorphization of the structure; near 27?GPa, amorphization is complete and an amorphous phase is quenched down to ambient pressure; this unique behaviour is interpreted as the result of the incompatibilities in the high pressure behaviour of the Ca and Mg sublattices in the olivine structure.  相似文献   

Drivers of afforestation in Northern Vietnam: Assessing local variations using geographically weighted regression   总被引：2，自引：0，他引：2  

Floriane Clement  Didier Orange  Meredith Williams  Corinne Mulley  Michael Epprecht 《Applied geography (Sevenoaks, England)》2009,29(4):561-576

This article identifies drivers of forest transition in a province of Northern Vietnam between 1993 and 2000 by applying geographically weighted regression (GWR) analysis to remotely sensed and statistical data. The regression model highlighted the spatial variation of the relationship between the percentage of land afforested and its proximate causes. Factors identified as having a major impact on afforestation are: the presence or proximity of a wood-processing industry, the distance to highways, and land allocation to households. Whereas the two former variables are in most areas of the province positively correlated with afforestation, an unexpected negative correlation was observed for the latter. The analysis of these results, supported by an in-depth knowledge of the area and of the political context, leads to the conclusion that, during the time period considered, afforestation was largely driven by state organisations on protected state-owned land, and forestry was not a significant component of household economic activities.  相似文献   

A novel nuclear forensic tool involving deposit type normalized rare earth element signatures   总被引：1，自引：0，他引：1       下载免费PDF全文

Tyler L. Spano  Antonio Simonetti  Thomas Wheeler  Grace Carpenter  Devonee Freet  Enrica Balboni  Corinne Dorais  Peter C. Burns 《地学学报》2017,29(5):294-305

Identifying the provenance of uranium‐rich materials is a critical objective of nuclear forensic analysis. Rare earth element (REE) distributions within uranium ores are well‐established forensic indicators, but quantifying and correlating trace element signatures for U ores to known deposits has thus far involved intricate statistical analyses. This study reports average chondrite normalized (CN)‐REE signatures for important U deposit types worldwide, which are then employed to evaluate U ore paragenesis using a simple linear regression analysis. This technique provides a straightforward method that can aid in determining the deposit type of U ores based on their REE abundances, and combined with other forensic indicators (e.g. radiogenic isotope signatures) can provide essential provenance information for nuclear materials.  相似文献   

Oxygen isotope analyses of fine silica grains using laser-extraction technique: Comparison with oxygen isotope data obtained from ion microprobe analyses and application to quartzite and silcrete cement investigation   总被引：1，自引：0，他引：1  

Anne Alexandre  Isabelle Basile-Doelsch  Corinne Sonzogni  Claude Parron  Fabrice Colin 《Geochimica et cosmochimica acta》2006,70(11):2827-2835

The laser fluorination technique reported here for analyzing the oxygen isotope composition (δ¹⁸O) of fine quartz size fractions 50-20, 20-10, 10-5, 5-2, 2-1 and <1 μm has been validated by comparison with the ion microprobe technique. It yields accurate δ¹⁸O data with an external precision better than 0.15‰. This is a significant methodological improvement for isotopic studies dealing with materials such as soil or biogenic oxides and silicates: particles are often too small and recovered in insufficient amount to be easily handled for ion microprobe analysis. Both techniques were used to investigate δ¹⁸O composition of a Cretaceous quartzite and silcrete sequence from the South-East of France. Quartzite cements average 31.04 ± 1.93‰. They formed from Mid-Cretaceous seawater. Higher in the series, silcretes cements average 26.66 ± 1.36‰. They formed from Upper- or post-Upper-Cretaceous soil water and groundwater. Oxygen isotope data show that the silicification steps from one mineralogical phase to another and from one layer to another (including from an upper pedogenic silcrete to a lower groundwater silcrete) occurred in a closed or weakly evaporating hydrological system.  相似文献   

Ceilometer observations of aerosol layer structure above the Petit Lubéron during ESCOMPTE's IOP 2     

Marcel Zphoris  Hubert Holin  Franck Lavie  Nadine Cenac  Michel Cluzeau  Olivier Delas  Franoise Eideliman  Jacqueline Gagneux  Alain Gander  Corinne Thibord 《Atmospheric Research》2005,74(1-4):581-595

A modified ceilometer has been used during the second Intensive Observation Period (IOP) of the “Expérience sur Site pour COntraindre les Modèles de Pollution atmosphériques et de Transport d'Émission” (ESCOMPTE) to perform continuous remote observations of aerosol accumulations in the first 3 km of the atmosphere. These observations encompassed an episode of intense particulate and photochemical pollution. The submicronic particles density, measured at an altitude of 600 m, went from a very low point of a few tens of particles per cubic centimeter (at the end of a Mistral episode in the free atmosphere) to a high point of more than 4500 particles per cubic centimeter (when pollutants were trapped by thermal inversions).The main result is that this instrument enables a fine documentation of the mixing layer height and of aerosol particles stratifications and circulation. Airborne aerosol measurements have been made above the mountainous region of Mérindol in order to validate in situ the remote sensing measurements. Ozone measurements near the summit of the mountains as well as in the valley were performed in order to correlate aerosol accumulation and ozone concentration. As a notable example, the two-layer aerosol stratification seen in the first 2 days of IOP 2b in that part of the ESCOMPTE domain confirms the results of another team which used backtrajectories. The low-altitude pollution for this timeframe had a local origin (the Fos industrial area), whereas above 500 m, the air masses had undergone regional-scale transport (from north-eastern Spain).The second major result is the highlighting of a pattern, in sea breeze conditions and in this part of the ESCOMPTE experiment zone, of nocturnal aerosol accumulation at an altitude of between 500 and 2000 m, followed by high ozone concentration the next day.  相似文献   

Domains of spit evolution in the Goro area, Po Delta, Italy   总被引：2，自引：0，他引：2  

Umberto Simeoni  Giorgio Fontolan  Umberto Tessari  Corinne Corbau 《Geomorphology》2007,86(3-4):332-348

Goro lagoon was formed during the 19th century in the southern part of the Po Delta. Its origin is related to the growth of a spit system, which progressively occluded the southernmost interdistributary bay from the sea. The development of the spits is due to the morphological prominence of the Po Delta which causes a divergent littoral drift, enhanced by wave refraction over the delta front. During the last century the spit was abandoned, destroyed, and re-constructed several times because of the development of newer spits seawards. Using historical maps and aerial photographs, three different periods are recognised, featuring distinctive spit growth styles: parallel, fan-shaped and branched. The different domains of spit evolution are related to several factors, mainly to the mutual influence of sediment discharge, sand mining along the Po river, wave action over the delta front, human-induced subsidence and direct human interventions along the spits and for flood-control.  相似文献   

Compartmentalization of physical and chemical properties in hard-rock aquifers deduced from chemical and groundwater age analyses     

Virginie Ayraud  Luc Aquilina  Thierry Labasque  Hélène Pauwels  Jérôme Molenat  Anne-Catherine Pierson-Wickmann  Véronique Durand  Olivier Bour  Corinne Tarits  Pierre Le Corre  Elise Fourre  Philippe Merot  Philippe Davy 《Applied Geochemistry》2008

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