Kinematic restoration of the southern North Atlantic and the Alpine Tethys during the Mesozoic

Continental rifting preceding stable seafloor spreading is characterized by a multistage evolution during lithosphere extension. Wide regions of exhumed mantle contain linear magnetic anomalies with a strongly debated nature and origin. Contrasting information used to set up dynamic plate models has resulted in a plethora of alternative interpretations. Structural and stratigraphic records at plate boundaries show indeed variable degree of discrepancies with what expected from computed plate motions during rifting stages. The definition of robust spatial and temporal kinematic constraints using combined offshore and onshore approaches represents a major challenge to unravel rifted margins evolution.   
 
In this study, we address the problem outlined above using the Mesozoic southern North Atlantic and the Alpine Tethys, west and east of the Iberian plate, as a natural laboratory. The two systems are part of the same Africa-Europe kinematic framework and record distinctive Mesozoic rift events and a subsequent Tertiary compression. While in the southern North Atlantic the kinematic framework is still preserved, in the Alpine Tethys, subsequent subduction/collision erased the paleogeographic framework. The study area is among the best investigated but also most debated geological domains on the globe.

In our analysis we (1) integrate rift domains in plate kinematic models and re-consider the nature of the magnetic anomaly J in the southern N-Atlantic; (2) discuss the results of recent studies in the northern part of the Iberian plate; and (3) show new data from the Alpine Tethys realm (Central European Alps and Southern Apennines). We discuss the implications of these observations for the geometry of the rift systems developed around Iberia.

Our robust data network radically reduces the range of possible kinematic solutions. We reconstruct thus the position of Iberia and Adria relative to Europe and Africa and we evaluate the kinematic evolution and the width of the southern North Atlantic and the Alpine Tethys domains during the Mesozoic. The analysis emphasizes (1) the stepping geometry of the plate boundary for the Atlantic-Tethys interaction, (2) the strong partitioning of deformation in time and space, and (3) the large-scale pattern of coeval compression and extension along the Africa-Europe diffuse plate boundary region.