U-Pb geochronology on zircon and columbite-group minerals of the Cap de Creus pegmatites,NE Spain     

Van Lichtervelde  Marieke  Grand’Homme  Alexis  de Saint-Blanquat  Michel  Olivier  Philippe  Gerdes  Axel  Paquette  Jean-Louis  Melgarejo  Joan Carles  Druguet  Elena  Alfonso  Pura 《Mineralogy and Petrology》2017,111(1):1-21

Mineralogy and Petrology - The Cap de Creus granitic pegmatites in the eastern Catalan Pyrenees were dated using in situ U-Pb geochronology by laser ablation ICP-MS on zircon and columbite-group...  相似文献   

A grassed waterway and earthen dams to control muddy floods from a cultivated catchment of the Belgian loess belt     

Olivier Evrard  Karel Vandaele  Bas van Wesemael  Charles L. Bielders 《Geomorphology》2008,100(3-4):419-428

Muddy floods, i.e. runoff from cultivated areas carrying large quantities of soil, are frequent and widespread in the European loess belt. They are mainly generated in dry zero-order valleys and are nowadays considered as the most likely process transferring material eroded from cultivated hillslopes during the Holocene to the flood plain. The huge costs of muddy flood damages justify the urgent installation of control measures. In the framework of the ‘Soil Erosion Decree’ of the Belgian Flemish region, a 12 ha-grassed waterway and three earthen dams have been installed between 2002–2004 in the thalweg of a 300-ha cultivated dry valley in the Belgian loess belt. The measures served their purpose by preventing any muddy flood in the downstream village, despite the occurrence of several extreme rainfall events (with a maximum return period of 150 years). The catchment has been intensively monitored from 2005–2007 and 39 runoff events were recorded in that period. Peak discharge (per ha) was reduced by 69% between the upstream and the downstream extremities of the grassed waterway (GWW). Furthermore, runoff was buffered for 5–12 h behind the dams, and the lag time at the outlet of the catchment was thereby increased by 75%. Reinfiltration was also observed within the waterway, runoff coefficients decreasing by a mean of 50% between both extremities of the GWW. Sediment discharge was also reduced by 93% between the GWW's inflow and the outlet. Before the installation of the control measures, specific sediment yield (SSY) of the catchment reached 3.5 t ha^− 1 yr^− 1 and an ephemeral gully was observed nearly each year in the catchment. Since the control measures have been installed, no (ephemeral) gully has developed and the SSY of the catchment dropped to a mean of 0.5 t ha^− 1 yr^− 1. Hence, sediment transfer from the cultivated dry valley to the alluvial plain should dramatically decrease. Total cost of the control measures that are built for a 20 year-period is very low (126 € ha^− 1) compared to the mean damage cost associated with muddy floods in the study area (54 € ha^− 1 yr^− 1). Similar measures should therefore be installed to protect other flooded villages of the Belgian loess belt and comparable environments.  相似文献   

Meteoric ions in the atmosphere of Mars   总被引：1，自引：0，他引：1  

Gregorio J. Molina-Cuberos  Olivier Witasse 《Planetary and Space Science》2003,51(3):239-249

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Effects of building materials on UHF ranging signals     

Richard?KlukasEmail author  Olivier?Julien  Lei?Dong  Elizabeth?Cannon  Gerard?Lachapelle 《GPS Solutions》2004,8(1):1-8

Positioning and tracking inside buildings using wireless location methods has recently received considerable attention. One method is the estimation of the time of arrival of satellite or terrestrial-based radio frequency signals in order to produce ranges from the transmitter to the receiver. This paper investigates the effect of walls made of various construction materials on the penetration of ranging signals. In the tests conducted, a GPS pseudo-satellite transmits a pseudorandom noise code at a carrier frequency of 1.57542 GHz. After penetrating walls made of plywood, gyprock and cinder blocks, the signal is received by a GPS receiver which measures the carrier phase and the pseudorange between the transmitter and receiver using code correlation. Compared to measurements obtained with no walls present, the effect on the measurements is determined. The results indicate that the carrier phase measurement is superior to the pseudorange in terms of noise, stability, and the magnitude of the effect of the walls on the range obtained. Ranges based on the carrier phase only change by a few centimeters. Given that the integer number of cycles of the phase can be determined and phase lock is maintained, the carrier phase measurement shows considerable promise for indoor ranging.  相似文献   

Author Index     

Olivier Fouché  Jean Diebolt 《Mathematical Geology》2004,36(8):993-994

Authors Index

Author Index  相似文献   

Recent temporal change in the stress state and modern stress field along the North Anatolian Fault Zone (Turkey)     

Olivier Bellier  Semir Över  ré Poisson  Jean Andrieux 《Geophysical Journal International》1997,131(1):61-86

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Minor changes in surface-water fertility across the oceanic anoxic event 1d (latest Albian,SE France) evidenced by calcareous nannofossils     

Fabienne?GiraudEmail author  Davide?Olivero  Fran?ois?Baudin  Stéphane?Reboulet  Bernard?Pittet  Olivier?Proux 《International Journal of Earth Sciences》2003,92(2):267-284

The latest Albian sediments deposited in the Vocontian basin in south-eastern France record the oceanic anoxic event (OAE) 1d, locally named the Breistroffer interval. They are represented by argillaceous marls and marls, containing organic matter (total organic carbon varying from 0.8 to 1%). Changes in calcareous nannofossil abundance and assemblage composition as well as macrofauna abundance, ichnofossil assemblage, and bioturbation intensity were analysed in order to evaluate the main palaeoenvironmental factors controlling the deposition of the OAE 1d sediments in this area. The pelagic carbonate production is limited and the carbonate fraction is predominantly of nektonic/benthic, and of allochthonous origin from carbonate platforms. The enrichment in organic carbon within the Breistroffer interval is weak and not associated with high surface-water productivity. The organic matter is mainly terrigenous. Its record is due to (1) a good preservation under dysoxic conditions within the sediments, and (2) a weak input of allochthonous carbonates. Eustatic fluctuations strongly influenced the variations of nannofossil and macrofauna abundances. Distinctive patterns in nannofossil assemblages and macrofauna abundances within the Breistroffer interval are also recognized, reflecting changes from mesotrophic to more oligotrophic conditions which are probably controlled by climate.  相似文献   

On the composition of ices incorporated in Ceres     

Olivier Mousis  Yann Alibert 《Monthly notices of the Royal Astronomical Society》2005,358(1):188-192

We use the clathrate hydrate trapping theory and gas drag formalism to calculate the composition of ices incorporated in the interior of Ceres. Utilizing a time-dependent solar nebula model, we show that icy solids can drift from beyond 5 au to the present location of the asteroid and be preserved from vaporization. We argue that volatiles were trapped in the outer solar nebula in the form of clathrate hydrates, hydrates and pure condensates prior to having been incorporated in icy solids and subsequently in Ceres. Under the assumption that most of volatiles were not vaporized during the accretion phase and the thermal evolution of Ceres, we determine the per mass abundances with respect to H₂O of CO₂, CO, CH₄, N₂, NH₃, Ar, Xe and Kr in the interior of the asteroid. The Dawn space mission, scheduled to explore Ceres in August 2014, may have the capacity to test some predictions. We also show that an in situ measurement of the D/H ratio in H₂O in Ceres could constrain the distance range in the solar nebula where its icy planetesimals were produced.  相似文献   

Landslide risk management in Switzerland   总被引：1，自引：2，他引：1  

Olivier Lateltin  Christoph Haemmig  Hugo Raetzo  Christophe Bonnard 《Landslides》2005,2(4):313-320

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Hydromechanical behaviour of a compacted swelling soil over a wide suction range     

Olivier Cuisinier 《Engineering Geology》2005,81(3):204-212

A study of the hydromechanical behaviour of a compacted swelling material in the range of suctions comprised between 0 and 40 MPa was performed. This study has required the development of two kinds of suction controlled oedometer devices based on two different suction control techniques. In the range of suctions higher than 8.5 MPa, the saturated salt solutions method was used and a new oedometer using this suction control technique was developed. For suctions lower than 8.5 MPa an osmotic oedometer was used. Despite the differences between the applied suction components (matric and total), the correlation between the two methods was verified for the tested material. The second part of the paper presents a set of oedometer tests conducted under various suctions. The effect of the applied suction on the hydromechanical parameters was studied. First, two swelling phases were highlighted: a low swelling phase above a suction of 4 MPa and a high swelling one below this value. These phases were considered as being related to the microstructure of compacted swelling clays. Secondly, it was shown that the slopes of the elastic part and of the plastic part of the consolidation curves were not influenced significantly by the applied suctions. In opposition, the preconsolidation pressure is affected by the decrease of the applied suctions even in the low swelling phase. Such a behaviour could be explained by the effects of wetting on the microstructure.  相似文献