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Fig. 9. Interpretive cross section of the variscan belt from NW Spain, modified from [75], suggesting that two different domains of underplating (1 in the hinterland, 2 in the foreland) controls the structure of the wedge and the location of uplift related normal sense shear zones.

Figure 9 Interpretive cross section of the variscan belt from NW Spain, modified from [75], suggesting that two different domains of underplating (1 in the hinterland, 2 in the foreland) controls the structure of the wedge and the location of uplift related normal sense shear zones.

Related Figures (8)

Fig. 1. (a) Kinematic setting of continental subduction and (b) Schematic setting used for analogue modeling of thrust wedges. Backstop geometries and rheologies can be modified. Dotted line represents the chosen erosion surface. Sedimentation (when integrated) is performed by sprinkling sand.
Fig. 1. (a) Kinematic setting of continental subduction and (b) Schematic setting used for analogue modeling of thrust wedges. Backstop geometries and rheologies can be modified. Dotted line represents the chosen erosion surface. Sedimentation (when integrated) is performed by sprinkling sand.
Fig. 2. Models without erosion showing the main mechanisms of wedge growth and corresponding critical taper: (a) high basal friction model, (b) low friction, (c) multiple décollements, (d) picture of a model with décollement.
Fig. 2. Models without erosion showing the main mechanisms of wedge growth and corresponding critical taper: (a) high basal friction model, (b) low friction, (c) multiple décollements, (d) picture of a model with décollement.
Fig. 4. Sketch showing four stages of wedge development outlining deformation partitioning and kinematics of thrust units. Sim- plified from models with décollements and submitted to erosion. Notice the passive deformation of upper plate (orogenic lid) resting on top of the former refolded décollement . Early folds are suggested to show evolution of U—P geometry. A possible defor- mation mechanism responsible for vertical shear inducing stretching and thinning of the underplated units is schematized. Resulting strain is shown by the green ellipsoids. U—P-pre-structured upper-plate passively deformed during underplating (parts of the foreland basin can be included in); L—P—basement rocks lower-plate.
Fig. 4. Sketch showing four stages of wedge development outlining deformation partitioning and kinematics of thrust units. Sim- plified from models with décollements and submitted to erosion. Notice the passive deformation of upper plate (orogenic lid) resting on top of the former refolded décollement . Early folds are suggested to show evolution of U—P geometry. A possible defor- mation mechanism responsible for vertical shear inducing stretching and thinning of the underplated units is schematized. Resulting strain is shown by the green ellipsoids. U—P-pre-structured upper-plate passively deformed during underplating (parts of the foreland basin can be included in); L—P—basement rocks lower-plate.
Fig. 5. (a) Interpretive geological section of Taiwan orogenic wedge inspired by (b) experiment with décollement and erosion. Medium-term shortening rates on main active faults are indicated.
Fig. 5. (a) Interpretive geological section of Taiwan orogenic wedge inspired by (b) experiment with décollement and erosion. Medium-term shortening rates on main active faults are indicated.
Fig. 6. (a) Model simulating structural heritage of a continental margin without erosion to be compared to (b) same model with erosion and syntectonic sedimentation applied to the Alps, (c) present day geologic section across the Swiss Alps (from [18]).
Fig. 6. (a) Model simulating structural heritage of a continental margin without erosion to be compared to (b) same model with erosion and syntectonic sedimentation applied to the Alps, (c) present day geologic section across the Swiss Alps (from [18]).
Fig. 7. (a) Location of the Montagne Noire in the French Massif Central. (b) Structural map of the area showing the main tec- tonostratigraphic units: PCB, Permian and Upper-Carboniferous basins; NS, Northern Slope; AZ, Axial Zone; SFN, Southern Fold Nappes; VFB, Visean Foreland Basin. (c) Interpretive cross section of the Montagne Noire showing an alternative hypoth- esis for dome formation and enigmatic normal shear zone and faults observed on its northern flank. The southern recumbent fold nappes emplaced on the foreland basin are passively deformed during development of the Axial Zone antiformal stack.
Fig. 7. (a) Location of the Montagne Noire in the French Massif Central. (b) Structural map of the area showing the main tec- tonostratigraphic units: PCB, Permian and Upper-Carboniferous basins; NS, Northern Slope; AZ, Axial Zone; SFN, Southern Fold Nappes; VFB, Visean Foreland Basin. (c) Interpretive cross section of the Montagne Noire showing an alternative hypoth- esis for dome formation and enigmatic normal shear zone and faults observed on its northern flank. The southern recumbent fold nappes emplaced on the foreland basin are passively deformed during development of the Axial Zone antiformal stack.
Fig. 8. Conceptual model showing the impact of surface processes on deformation partitioning, kinematics and exhumation dur- ing orogenic wedge growth: (a) end of oceanic subduction stage (early exhumation of high pressure rocks in the subduction chan- nel), (b) subduction of the continental margin involving deep stacking of underplated crust units and strong uplift controlled ero- sion of the upper plate, (c) deep underplating continue and a new stage of underplating begins in the foreland involving invertec inherited features of the margin, (d) during the late stage, the foreland basin is involved in frontal accretion whereas major back- thrusting develops at the back of the wedge due to strong thinning of the upper plate lid by erosion.
Fig. 8. Conceptual model showing the impact of surface processes on deformation partitioning, kinematics and exhumation dur- ing orogenic wedge growth: (a) end of oceanic subduction stage (early exhumation of high pressure rocks in the subduction chan- nel), (b) subduction of the continental margin involving deep stacking of underplated crust units and strong uplift controlled ero- sion of the upper plate, (c) deep underplating continue and a new stage of underplating begins in the foreland involving invertec inherited features of the margin, (d) during the late stage, the foreland basin is involved in frontal accretion whereas major back- thrusting develops at the back of the wedge due to strong thinning of the upper plate lid by erosion.
Related topics:
GeologyGeophysicsStructural GeologyFirst-Order LogicEarth Surface ProcessesFirst Order LogicCritical StateForeland BasinSurface Processes
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