Strain Partitioning and Localization Due To Detachment Heterogeneities in Fold‐and‐Thrust Belts of Progressive Arcs: Results From Analog Modeling

Jiménez‐Bonilla, Alejandro; Ramos, Inmaculada Expósito; Azpiroz, Manuel Dı́az; Balanyá, Juan Carlos; Crespo‐Blanc, Ana

doi:10.1029/2021tc006955

Cited by 4 publications

(1 citation statement)

References 71 publications

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“…Triaxial deformation has been documented at various scales: (a) At centimetric scale, rock deformation experiments show polymodal fault patterns under triaxial stresses and bimodal or conjugate faults under plane strain (Ghaffari et al., 2014; Healy et al., 2006a, 2006b). (b) At regional scale, along the typically arcuate front of mountain belts folding and thrusting can be strongly non‐cylindrical manifesting triaxial deformation in consequence of primary or progressive arc (Piedmont glacier‐type) formation or oroclinal bending (Hindle & Burkhard, 1999; Jiménez‐Bonilla et al., 2020, 2022). (c) Finally, on a continental scale, continental plate indentation (Krstekanić et al., 2021, 2022; Schurr et al., 2014) results in the Himalayan‐type escape tectonics as well as lateral extrusion (Ratschbacher et al., 1991).…”

Section: Introductionmentioning

confidence: 99%

Fault Networks in Triaxial Tectonic Settings: Analog Modeling of Distributed Continental Extension With Lateral Shortening

Liu,

Rosenau,

Brune

et al. 2024

Tectonics

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Triaxial deformation is a general feature of continental tectonics, but its controls and the systematics of associated fault networks remain poorly understood. We present triaxial analog experiments mimicking crustal thinning resulting from distributed longitudinal extension and lateral shortening. Contemporary longitudinal extension and lateral shortening are related by the principal horizontal strain ratio (PHSR). We investigate the effect of crustal geometry, rheology and strain rate on deformation localization, faulting regime and pattern, and PHSR in brittle and brittle‐viscous crustal‐scale models. We find that in brittle models the fault networks reflect the basal boundary condition and fault‐density scales inversely with brittle layer thickness. In brittle‐viscous models, as strain rate (ė) decreases, (a) Three fault patterns emerge: conjugate sets of strike‐slip faults (ė > 3 × 10−4 s−1, PHSR > 0.31), sets of parallel oblique normal faults (ė = 0.3–3 × 10−4 s−1, PHSR = 0.15–0.25), horst‐and‐graben system (ė < 0.3 × 10−4 s−1, PHSR < 0.1). (b) The strain localization increases systematically and gradually. We interpret the strain rate dependent of faulting regimes to be controlled by vertical coupling between the model upper mantle and model upper crust resulting in spontaneous permutation of principal stress axes. Rate‐dependency of strain localization can be related to mechanical coupling between the upper and lower crust. We identify the following parameters controlling triaxial tectonic deformation: upper crustal thickness and friction coefficient, lower crustal thickness and viscosity, as well as strain rate. We test our models and predictions against natural prototypes (Tibet, Anatolia, Apennines, and Basin and Range Province) thus providing new perspectives on triaxial deformation.

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Section: Introductionmentioning

confidence: 99%

Fault Networks in Triaxial Tectonic Settings: Analog Modeling of Distributed Continental Extension With Lateral Shortening

Liu,

Rosenau,

Brune

et al. 2024

Tectonics

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Oblique plate convergence along arcuate trenches on a spherical Earth. An example from the Western Sunda Arc

Guzmán-Speziale

2023

Acta Geophys.

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We propose a new definition of oblique plate convergence. Our model considers arc-trench curvature on a spherical Earth, and defines obliquity as the angle between the direction of plate convergence and the azimuth from the central point along the arc to the center of curvature of the arcuate trench. We also show how this model may be extended to multiple-arc trenches.We apply this definition to the Western Sunda Arc, which has been traditionally considered the prime example of oblique plate convergence, particularly the segment corresponding to Sumatra. We define eight arc-like segments along this arc-trench system. Obliquity angles on these arc-like segments vary from 92° in the northernmost (Burmese) arc to 7° offshore the Sunda strait (between Sumatra and Java). The angle of obliquity offshore Sumatra is 31°, almost within the definition of slightly oblique convergence. Given the low angle of obliquity, partitioning along the Sumatran fault, in the southern portion of the Western Sunda Arc, is difficult to explain by oblique plate convergence alone. We suggest that the entire segment (or forearc) inboard of the Western Sunda Arc be dragged from the Burmese arc, where overriding and subducting plates are completely coupled and oblique plate convergence is high.

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Interaction of accretion mechanisms and deep fluids in continental orogenesis

Giacomuzzi,

Chiarabba

2024

Gondwana Research

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Strain Partitioning and Localization Due To Detachment Heterogeneities in Fold‐and‐Thrust Belts of Progressive Arcs: Results From Analog Modeling

Cited by 4 publications

References 71 publications

Fault Networks in Triaxial Tectonic Settings: Analog Modeling of Distributed Continental Extension With Lateral Shortening

Fault Networks in Triaxial Tectonic Settings: Analog Modeling of Distributed Continental Extension With Lateral Shortening

Oblique plate convergence along arcuate trenches on a spherical Earth. An example from the Western Sunda Arc

Interaction of accretion mechanisms and deep fluids in continental orogenesis

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