Analogue modelling of the Ainsa oblique zone in the Southern Central Pyrenees, Spain
Abstract
The Pyrenees are a collisional orogen striking WNW-ESE. However, in the Ainsa oblique zone in the south-central part of the Pyrenees, faults and folds rotate to ∼N–S over a westward thinning evaporitic layer. The influence of lateral change in basal friction due to declining evaporitic layer thickness in a fold-and-thrust belt is studied by analogue modelling simulating the Ainsa oblique zone. In the experiments the transition zone is simulated by a viscous silicone mixture sheet that laterally changes in thickness adjacent to frictional-plastic quartz-sand. The models confirm that a transition between weak and strong basal friction causes oblique structures to develop. Weak detachment zones are prone to fault propagation whereas strong detachment zones are prone to imbrication. At the transition zone those structural styles are combined, resulting in a complex domain. The differences in deformation style cause dextral shear and clockwise rotation in the transition zone and larger horizontal deformation propagation in the weak basal friction zone. Structures produced in the analogue models are compared to structures in the Ainsa oblique zone and found to be representative. Therefore, this study shows that transition between weak and strong detachment layers can explain the regional structural deformation style in the Ainsa oblique zone. Show more
Permanent link
https://doi.org/10.3929/ethz-b-000640134Publication status
publishedExternal links
Journal / series
Journal of Structural GeologyVolume
Pages / Article No.
Publisher
ElsevierSubject
Analogue modelling; Oblique faulting; Ainsa oblique zone; Continent-continent collision; Transition zone; Basal frictionMore
Show all metadata