The effects of basement ramps on deformation of the Prebetics (Spain): A combined field and analogue modelling study

作者：Ter Borgh M M^*; Oldenhuis R; Biermann C; Smit J H W; Sokoutis D

来源：Tectonophysics, 2011, 502(1-2): 62-74.

DOI：10.1016/j.tecto.2010.04.013

• Basement ramps
• Betic Cordilerra
• Analogue modelling
• Palaeostress analysis
• Fault reactivation
• Pre-existing faults

In this study we test whether pre-existing basement faults control deformation in the Prebetic zones of the Betic Cordillera. We focus on an area in the northern part of the Prebetics which is dominated by a transpressional fault system consisting of a NNE-SSW striking fault zone and E-W striking small-scale thrusts. Field observations show that both sets of faults formed in a regional NW-SE to NNW-SSE directed compressional stress field during the Miocene. We propose that the faults formed on top of a basement containing basement ramps overlain by a decollement of Late Triassic evaporites and clays. These basement ramps have either an E-W or NNE-SSW orientation and result from extensional faulting prior to the compressional phase. The style of faulting in the overlying sediments is controlled by the variation in orientation of the pre-existing basement ramps in a uniform stress field. Where the ramps have an E-W orientation small-scale thrusting and folding occurs, where the ramps are oriented NNE-SSW the fault zone acts as an oblique-slip fault. The model was tested by analogue tectonic experiments incorporating a ductile layer, representing the decollement, overlain by a brittle layer representing the overlying sediments. The pre-existing basement ramps were represented by rigid material. The close similarity between the structures produced during the analogue experiments and those observed in the field suggests that pre-existing basement faults exert a major role on deformation of the Prebetics.

• 出版日期2011-4-13