Intraplate deformations, topographic evolution and sediment production of Western Europe from 40 to 5 Myrs

Western Europe experienced a major rift system initiated during Bartonian times (41 Ma). This evolution is coeval with long wavelength deformations (several hundreds of kilometers) that control the topography and the sediment production beyond the rift. The climate during this time interval was first increasingly arid and then wetter.

This study is based on both landform and sediment analysis of southern England, France, Belgium and western Germany. The landforms are mainly large pediments, dated by the intersection with sediments deposited in low to high subsiding areas and volcanism. A set of paleogeographic maps with paleotopographic reconstructions, is used to constrain the uplifting and subsiding areas, their wavelength and the critical periods of intraplate deformations.

The main periods of deformations and sedimentary systems changes area as follow.

41Myrs (base Bartonian) was the beginning of a major tilting of Western Europe with subsidence of France and uplift of the Brabant/Ardennes/Rhenish Massif. Even a dense network of basement faults was reactivated, biochemical sedimentation prevailed.

35-31Myrs (Late Priabonian-Early Rupelian) initiated a period of general subsidence even along the Ardennes/Rhenish Massif and the French Massif Central. Two major marine floodings are recorded, with a differential preservation according to the balance between deformation and eustasy.

27-25Myrs (Chattian) was a period of uplift of Western Europe except the Aquitaine Basin, followed by a relaxation favoring eustatic floodings in (very) low subsiding domains. Chattian siliciclastic deposits are preserved as lowstand wedges in the surrounded basins (North Sea, Atlantic Margin).

14-11Myrs (Serravallian-Early Tortonian) initiated the overall uplift of Western Europe, still operating today. This is the beginning of a period of major denudation in southern England, Western Germany (SW Germany flat - “Stufenland”) and along the southern limb of the Franch Massif Central.

The causes and the consequences in term of sediment production are discussed.