Tectonic history of the western Tethys since the Late Triassic

Abstract

The tectonic history of the western Tethys since the Late Triassic is illustrated through a set of computer-generated plate reconstructions, which are based on a rigorous plate motions model of this region. The model is constrained by the Atlantic plate kinematics and on-land geologic evidence and defines 13 tectonic phases, spanning the time interval from the late Ladinian (230 Ma) to the present. The kinematics associated with the Late Triassic western Tethyan rifts produced the detachment of a large composite fragment from the northern margin of Gondwana. It can be considered as the eastern propagation of the central Pangea breakup. During the Early Jurassic these rift zones became inactive, while new zones of extension formed along the southern margin of Eurasia, the eastern margin of Iberia, and within the rifted northern Gondwana fragment itself. Plate motions associated with the first two extensional centers can still be considered as an eastern branch of the central Atlantic plate kinematics. Conversely, the kinematic parameters of the latter rift result from the composition of the Euler rotation describing the central Pangea breakup and the Euler pole of closure of the paleo–Tethys ocean. The Late Triassic–Early Jurassic rifting phases determined the formation of a number of independent microplates at the interface between Africa and Eurasia. Starting from the Early Cretaceous, convergence between Africa and Eurasia triggered further deformation within the dispersed continental fragments and the formation of backarc basins at the active margins, ultimately leading to an increase in the number of tectonic elements that were moving independently in the western Tethyan region during the Late Cretaceous and the Cenozoic. The proposed tectonic evolution of the western Tethys area is compatible with both global-scale plate kinematics and geological constraints from on-land data observed across the present-day mosaic of displaced terranes surrounding the Mediterranean region.