Abstract
Abstract New clay mineralogical analyses have been performed on Campanian sediments from the Tethyan and Boreal realms along a palaeolatitudinal transect from 45° to 20°N (Danish Basin, North Sea, Paris Basin, Mons Basin, Aquitaine Basin, Umbria-Marche Basin and Tunisian Atlas). Significant terrigenous inputs are evidenced by increasing proportions of detrital clay minerals such as illite, kaolinite and chlorite at various levels in the mid- to upper Campanian, while smectitic minerals predominate and represented the background of the Late Cretaceous clay sedimentation. Our new results highlight a distinct latitudinal distribution of clay minerals, with the occurrence of kaolinite in southern sections and an almost total absence of this mineral in northern areas. This latitudinal trend points to an at least partial climatic control on clay mineral sedimentation, with a humid zone developed between 20° and 35°N. The association and co-evolution of illite, chlorite and kaolinite in most sections suggest a reworking of these minerals from basement rocks weathered by hydrolysis, which we link to the formation of relief around the Tethys due to compression associated with incipient Tethyan closure. Diachronism in the occurrence of detrital minerals between sections, with detrital input starting earlier during the Santonian in the south than in the north, highlights the northward progression of the deformation related to the anticlockwise rotation of Africa. Increasing continental weathering and erosion, evidenced by our clay mineralogical data through the Campanian, may have resulted in enhanced CO2 consumption by silicate weathering, thereby contributing to Late Cretaceous climatic cooling.
Highlights
The Late Cretaceous is characterised by a long-term global climatic cooling from the Turonian onward, with a marked acceleration during the Campanian (Huber et al, 1995; Pucéat et al, 2003; Friedrich et al, 2012; Linnert et al, 2014)
Combined with previously published data sets, our work provides the first constrains at the Tethyan scale on variations in continental weathering induced by tectonic uplift during the Campanian
New results on clay minerals assemblages of Campanian sediments from six sections and boreholes ranging from the southern Tethyan margin to the Boreal realm, provide the first insights on the evolution of continental weathering at the Tethyan scale during a long underexplored time interval (11 Myr)
Summary
The Late Cretaceous is characterised by a long-term global climatic cooling from the Turonian onward, with a marked acceleration during the Campanian (Huber et al, 1995; Pucéat et al, 2003; Friedrich et al, 2012; Linnert et al, 2014). Continental silicate weathering governs atmospheric CO2 on a multi-million year time scale (Berner, 1990, 2004; Raymo and Ruddiman 1992; Dessert et al, 2003), but this process remains poorly explored for the Late Cretaceous This period was marked by major geodynamic changes, which included the initiation of Tethys Ocean closure (Dercourt et al, 1986). This event, which is linked to the convergence of Africa toward Eurasia, was associated with the development of topographic relief around the Tethys, including lithospheric folds in Morocco (Frizon de Lamotte et al, 2011), and the 5000 km long chain of relief developed across North Africa and the Middle East by the Ayyubid orogeny (Şengör and Stock, 2014). This increased relief might be expected to have induced an increase in continental silicate weathering, enhancing CO2 consumption
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
