Search results for "MINERALOGIE"

showing 3 items of 3 documents

In situ Mössbauer spectroscopy: Evidence for green rust (fougerite) in a gleysol and its mineralogical transformations with time and depth

2005

Abstract A miniaturized Mossbauer spectrometer, adapted to the Earth’s conditions from the instrument developed for Mars space missions, has been used for the first time to study in situ variations with depth and transformations with time of iron minerals in a gleysol. The instrument is set into a PVC tube and can be moved up and down precisely (±1 mm) at the desired depth. Mossbauer spectra were obtained from 15 to 106 cm depth and repeated exactly at the same point at different times to follow mineralogical transformations with time. X-ray diffraction (XRD) and selective extraction techniques were performed on soil samples. The piezometric level of the water table was measured and the com…

P33 - Chimie et physique du solSoil test[SDV]Life Sciences [q-bio]Instrument de mesureAnalytical chemistryStructural formulaSol hydromorphe010501 environmental sciencesengineering.material010502 geochemistry & geophysicsFougèrite01 natural sciencesChimie du solhttp://aims.fao.org/aos/agrovoc/c_25315Geochemistry and PetrologyMössbauer spectroscopyhttp://aims.fao.org/aos/agrovoc/c_12457ComputingMilieux_MISCELLANEOUS0105 earth and related environmental sciencesChemistryhttp://aims.fao.org/aos/agrovoc/c_7161FerMINERALOGIEGleysolGEOCHIMIE13. Climate action[SDE]Environmental SciencesSoil waterengineeringSoil horizonhttp://aims.fao.org/aos/agrovoc/c_3950Gleysolhttp://aims.fao.org/aos/agrovoc/c_3276Solid solutionGeochimica et Cosmochimica Acta
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Mise en évidence de corps d'origine cosmique probable au sein de la formation de Carnot (République Centrafricaine)

1992

Resume Deux etudes realisees independamment l'une de l'autre, ont permis de mettre en evidence, au sein de la Formation de Carnot, formation fluviatile mesozoique, d'une part des spherules magnetiques recuperees dans les residus d'un forage (zone de Boyali), d'autre part une anomalie magnetique tres localisee (sur 270 metres de long) traduisant la presence d'un corps decametrique a forte magnetisation remanente (zone de Gambondo). Ces deux elements magnetiques ont une origine cosmique probable. Ils correspondent a des micrometeorites et a une meteorite ayant atteint l'ouest de la Republique Centrafricaine entre l'Albien et le Maastrichtien.

ProvenanceSPHERULE MAGNETIQUEFORMATION DE CARNOTMETEORITEGeochemistryCentral africaPETROLOGIEConglomerateMINERALOGIECOMPOSITION CHIMIQUEMeteoriteANOMALIE MAGNETIQUEClastic rockSedimentary rockMesozoicMagnetic anomalyGeology
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Lead isotopes of the carbonate-hosted Kabwe, Tsumeb, and Kipushi Pb-Zn-CU sulphide deposits in relation to Pan African orogenesis in the Damaran-Lufi…

1999

Lead isotope ratios of galena from the carbonate-hosted massive sulphide deposits of Kabwe (Pb-Zn) and Tsumeb (Pb-Zn-Cu) in Zambia and Namibia, respectively, have been measured and found to be homogeneous and characteristic of upper crustal source rocks. Kabwe galena has average isotope ratios of 206/204Pb = 17.997 ± 0.007, 207/204Pb = 15.713 ± 0.010 and 208/204Pb = 38.410 ± 0.033. Tsumeb galena has slightly higher 206/204Pb (18.112 ± 0.035) and slightly lower 207/204Pb (15.674 ± 0.016) and 208/204Pb (38.276 ± 0.073) ratios than Kabwe galena. The isotopic differences are attributed to local differences in the age and composition of the respective source rocks for Kabwe and Tsumeb. The homog…

[SDE] Environmental SciencesRadiogenic nuclideContinental crust[SDV]Life Sciences [q-bio]DolomiteGeochemistryMineralogyFold (geology)engineering.materialMantle (geology)MINERALOGIE[SDV] Life Sciences [q-bio]chemistry.chemical_compoundGeophysicschemistryGeochemistry and PetrologyGalenaGEOCHIMIE[SDE]Environmental SciencesengineeringCarbonateEconomic GeologyPyriteGeology
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