Search results for "Minéralogie"
showing 6 items of 6 documents
Late Cretaceous continental weathering evolution on the southern Atlantic margins of Africa and South America : contributions of a new geochemical tr…
2022
The late Cretaceous records a pronounced decrease in temperatures on a global scale between 90 and 65 million years that marks the first step of the progressive climatic decline ultimately leading to our modern climate mode. This first cooling step is concomitant to a major tectonic uplift of the east South American and west African margins. Relief formation on the African ans South American continent, enhancing continental weathering, can have induced a climatic cooling at a global scale through atmospheric CO2 consumption linked to silicate weathering reactions. The main objective of this project is to explore the potentially determinant impact of this tectonic uplift on the long-term coo…
The sedimentary series of upper Bajocian-lower Bathonian age and their organization in the Burgundy threshold and its surroundings. Stratigraphy, sed…
1981
Three fundamental features concerning the organization of the bio-sedimentary series of the upper Bajocian-lower Bathonian of the Burgundy threshold environment are retained:- the formations are organized in a bio-sedimentary platform, composed of three sets: a deep SW platform with clay sedimentation, a superficial NE platform, a transition zone- the geochemical characteristics are consistent with the reconstitution of the NE-NW polarized platform- this device has changed over time: a migration and extension of the surface platform to the SW, development of the transition zone, a slight displacement of the deep platform correlated with a more and more opening towards the SW.
Changements climatiques et océanographiques au cours du Campanien – approche couplée minéralogie et géochimie
2018
The origin of the Late Cretaceous (~100 – 65 Ma) global cooling is not yet well understood. The evolution of sea surface and bottom temperatures shows an acceleration of the cooling during the Campanian stage (~84 Ma). The main goal of this study was to explore the processes driving this cooling, focusing on Campanian sediments from the Tethyan, Boreal and Atlantic realms.The clay mineralogical assemblages of several (hemi)pelagic sites, selected along a S-N transect, from 5° to 45°N, reveal an increase in continental weathering during the Campanian, expressed by enhanced kaolinite inputs. The detrital input related to the uplift of new continental areas seems to evolve from south to north.…
Minéralogie de la mine du Prabis (Villapourçon, Nièvre, France)
2011
Territorial and socio-economic organisation in Le Grand-Pressigny
2012
In and around Le Grand-Pressigny (Indre-et-Loire, France), a petrographic study was implementedon 92 ceramic samples from the Final Neolithic sites of Le Petit-Paulmy and Bergeresse (Abilly).Analyses showed that the sediments used were extracted from local sources: Claise and Creusealluvium, local substrate and loessic silts. Quantitatively, the study showed that almost all the ceramicmaterials in Bergeresse and more than half of those in Le Petit-Paulmy come from the valley of theCreuse. The mineralogical compositions of three samples from Le Petit-Paulmy, including one ofunusual form, indicate sources from an exogenous region, the Massif Central (perhaps the alluviumof the Loire or the Al…
La collection historique d’échantillons de sols de l’essai patrimonial des ‘42 parcelles’ (INRAE, Versailles) : une machine à remonter le temps...
2020
Following three previous papers (van Oort et al., 2016, 2017, 2020) dealing with current soil characteristics and geochemical budgets in surface horizons, as well as the impacts of fertilization in subsurface horizons in soils of INRAE’s long term bare fallow experiment (the 42-plots trial), we now present some chronological aspects of soil evolution at the soil’s surface since 1928. For that, we analyzed several series of about 15 samples from the historical sample archive for 10 representative treatments: fertilizers with acidifying effects (ammonium sulphate, ammonium phosphate), fertilizers with dispersive effects (sodium nitrate, sylvinite, and potassium chloride), superphosphate, amen…