Extensional Kinematics and Geometry of the Barcelona Fault - Extensional Fault-bend Folding Seismic Characterization

Abstract

Experimental studies and basin analogues of half graben structures were compared with seismic interpretation of the Barcelona offshore basin. The method of extensional fault-bend folding modelling has not been used at the Barcelona basin before even though suitable information is available. Dip domain, axial surfaces and accommodation space analysis was carried out in order to get insight into the kinematic of the Barcelona Fault. Despite limited seismic reflection data, geometrically and kinematically reasonable interpretations that define intrabasinal structures were generated. Geometric model helped to document how fault shape, fault displacement, depositional and erosional pattern, affects the geometry of extensional fault-bend folds. Result show that the Barcelona fault geometry is relatively constant along strike. A concave geometry on the Barcelona Fault favours slip along a flattening fault segment which is responsible for the structures found at the Barcelona basin. Also intrabasinal highs and lows are controlled by fault slip rate. Higher slip rates are found towards the NE where more accommodation space was developed than in the SW. Thus these regions of greater fault slip rate have a greater volume of sediments than those of less slip rate.