Three-dimensional geometries of rifting on a hyperextended margin - Interpretation of seismic reflection profiles from the Deep Galicia Basin, Iberia.

摘要

Our study utilizes a pseudo-3D grid of 2D, depth-migrated seismic profiles in order to provide new constraints on rifting within the Deep Galicia Basin. 3D analysis shows that faults strike within 10° of north, indicating east-west directed rifting. Three distinct structural domains are identified on the east-west oriented profiles. In addition to an exhumed mantle domain, two crustal domains are distinguished by their different faulting styles and thinning. Restored crustal thickness (9-14 km) within the intracrustal fault domain (IFD) is close to the current thickness of the Galicia Bank crust (15-20 km), implying that the observed faults within the IFD were the first to form after the formation of the Galicia Bank. Restored crustal thickness within the detachment fault domain (DFD) is less than in IFD, yielding 3-5 km thickness. This suggests that the DFD either experienced an additional generation of faulting compared to the IFD, or was extended by a different mechanism, e.g. rolling-hinge-style rifting.