The structure and the evolution of rift systems is controlled by the migration and localization of deformation, and the evolution of successive deformation modes linked to tectonic activity. Ultimately these processes are controlled by the regional stress field, the thermal state, lithology and pre-existing structure. A change in stress field or thermal state can result in a failure of the extensional system and lead to the formation of small ocean basins or hyperextended rift basins. Such basins, floored by either oceanic, proto-oceanic or hyper-extended crust with variable amounts of serpentinized mantle and/or magmatic additions, have been extensively documented at some present-day margins, showing different evolutionary stages of extensional processes. At some of these margins, a subsequent change in the stress field has led to compressional reactivation.
This session aims to present and compare the structure and the geodynamic evolution of small ocean basins and failed hyperextended rift basins. Analysis of the crustal structure, the sedimentary infill, the subsidence history and the thermal evolution allows us to understand better the evolution of these basins and the associated rifting, breakup processes and the influence of rift inheritance on their subsequent tectonic and magmatic evolution.
We seek contributions that address one or more of these topics using geological and geophysical data, numerical modelling and/or direct studies of rocks and associated geochemical studies related to the formation of these basins.