Search results for "Crétacé supérieur"
showing 2 items of 2 documents
Flore turonienne des silex fossilifères de Châtellerault (Ouest de la France)
2018
International audience; Three new localities yielding fossiliferous flints are reported from the Châtellerault area (Vienne, western France). They include one archaeological site (La Grande Vallée) and two zones with alterite deposits (L’Aunas and Les Bariollières). Broken surfaces of flint nodules show co-occurrence of marine invertebrates such as bryozoans, echinoids (Micraster Agassiz, Orthopsis Cotteau), gastropods (Acteonella d’Orbigny), rudists, and sponges. The association of Acteonella, Micraster and Orthopsis confirms the Turonian age (Upper Cretaceous) of the fossil assemblage. The marine invertebrates co-occur with plant macroremains including fragments of conifer leafy axes such…
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…