Disentangling magnetic subfabrics and their link to deformation processes in cleaved sedimentary rocks from the Internal Sierras (west central Pyrenees, Spain)

摘要: Abstract Here we present a detailed study of the magnetic fabrics and subfabrics remagnetized Upper Cretaceous limolites that crop out in Internal Sierras (west central Pyrenees) affected by penetrative pressure-solution cleavage. The bulk these rocks (RT-AMS) show variable orientations do not conform to what is typically reported for cleaved sedimentary rocks. In contrast, paramagnetic (LT-AMS) remarkably constant directional properties, so their K max min axes cluster parallel intersection lineation poles bedding, respectively. These LT-AMS indicate preferred orientation phyllosillicates consistent with syn-sedimentary (Late Cretaceous) period NNE-oriented layer-parallel shortening. Noticeably, phyllosillicate are further altered subsequent formation cleavage Late Eocene–Early Oligocene. ferrimagnetic (AARM) also orientation, strikingly shortening direction area. We interpret this grains as being caused subhorizontal shear associated formation, which age mechanisms (authigenic growth rotation pre-existing magnetite grains) proposed pervasive remagnetization affects studied