|
Article |
Université de Lille 1, U.F.R. des Sciences de la Terre, Laboratoire de Géologie Stratigraphique, URA 1365 du CNRS 59655 Villeneuve d'Ascq Cedex, France
A detailed stratigraphical study of the Silurian rocks of the Pyrenees and analysis of their graptolite and conodont faunas has allowed the construction of composite lithostratigraphical successions and accurate correlations between them. The lithostratigraphy reflects generally continuous deposition of pelitic and shale sediments across the whole of the Pyrenean range from Rhuddanian to Homerian times. There is, however, some variation eastwards where sandier intercalations appear in the Rhuddanian. Also, carbonate facies were deposited in the Mouthoumet Massif during the latest Telychian and then from Sheinwoodian times spread across the major part of the central and eastern Pyrenees. Pelitic sedimentation persisted during the Gorstian and Ludfordian but with some differentiation into more clastic facies westwards and more carbonate-rich facies to the east. These features of sedimentation became more pronounced during Pridoli times and continued until the Early Devonian. The Silurian lithofacies of the Pyrenees are interpreted as epicontinental deposits formed in low energy, reducing environments on the northern margin of the Gondwanan continent.
