Spatial and temporal variation in penetrative strain during compression: Insights from analog models

Burberry, Caroline M.

doi:10.1130/l454.1

Cited by 18 publications

(43 citation statements)

References 57 publications

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“…The geometric evolution and related interpretations of the six experiments are shown in Figures 4 and S1-S6. With progressive shortening, the foreland propagating sequence of thrusts forms a wedge-like geometry in all models, and the length and wedge slope angle fluctuate with episodes of thrust nucleation in a style similar to that observed in previous analogue experiments (e.g., Burberry, 2015;Koyi & Vendeville, 2003;Liu et al, 1992;McClay & Whitehouse, 2004;Mulugeta, 1988).…”

Section: Resultssupporting

confidence: 78%

Low basal friction‐controlled geometry and kinematics of accretionary wedges from analogue experiments

Deng

Fan

et al. 2019

Geological Journal

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Cohesion and friction coefficients are fundamental parameters of granular materials used in analogue experiments. Our six models, comprising two sets of quartz sand with a 0-3 mm thickness of basal glass beads, illustrate that accretionary wedges with high basal friction have relatively larger slope angles and heights, shorter wedge lengths, and larger numbers of faults with smaller spacings and displacements than wedges with low basal friction. It should be noted that the differences in the geometry and evolution of the two sets of homogeneous quartz sands are not distinct; however, the differences are substantial when the models have low basal friction of the glass beads. In particular, there are two different tendencies of growth in wedge height with progressive shortening, that is, progressive growth of wedge height with high basal friction and steady-state growth of wedge height with basal glass beads.We thus infer that the wedge geometries in our experiments are preferentially controlled by the low basal friction achieved with glass beads. In particular, the basal décollement (even when thin) has a significant influence on the location and development of accretionary wedges, in contrast to the physical properties of brittle materials (e.g., friction coefficient and cohesion). KEYWORDS accretionary wedge, analogue modelling, basal décollement, Longmenshan fold-and-thrust belt, Mohr-Coulomb brittle rheology

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Section: Resultssupporting

confidence: 78%

Low basal friction‐controlled geometry and kinematics of accretionary wedges from analogue experiments

Deng

Fan

et al. 2019

Geological Journal

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“…Hence, the estimations of extension and compression represent minima values, since the strain analysis methods capture only seismic-scale deformation (cf. Kautz & Sclater, 1988;Marrett & Allmendinger, 1992;Walsh, Watterson, Childs, & Nicol, 1996;Burberry, 2015;Dalton, Paton, Oldfield, Needham, & Wood, 2017).…”

Section: Sub-seismic Strainmentioning

confidence: 99%

“…Penetrative strain typically accommodates between 2%-30% of overall shortening in horizontal shorteningrelated analogue models (Burberry, 2015;Koyi, Sans, Teixell, Cotton, & Zeyen, 2004). The amount of penetrative strain decreases away from thrust belts (Craddock & van der Pluijm, 1989), with the magnitude of layer-parallel shortening increasing with depth (Koyi, 1995).…”

Section: Sub-seismic Strainmentioning

confidence: 99%

“…Thus, a strain mismatch of 2%-60% may be ascribed to variables that cannot be identified using seismic data; we discuss later potential ways in which we can mitigate these (1) e = L 1 − L 0 ∕L 0 F I G U R E 4 (a) Dip seismic Section 1, used for structural restoration, note the well-defined extensional and contractional domains, and inset sections highlighting the overriding debrite, (b) Dip seismic Section 2 used for structural restoration located more centrally within the MTC note bulking towards the contractional domain, (c) Strike seismic section highlighting distinct lateral margins, megaclasts and incision of the top surface, HTS: hummocked top surface; LM: lateral margins. Amplitudes have been compressed to account for washout from very high amplitude gas charged sediment above the study interval uncertainties (Burberry, 2015;Marrett & Allmendinger, 1992). Structural restoration and strain analysis also carry interpretation errors, with our interpretation of structures being subjective and non-unique, and likely biased towards our previous geological experiences and concepts (see Bond, Gibbs, Shipton, & Jones, 2007).…”

Section: Decompaction and Strain Analysismentioning

confidence: 99%

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Strain analysis of a seismically imaged mass‐transport complex, offshore Uruguay

et al. 2019

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Strain style, magnitude and distribution within mass‐transport complexes (MTCs) are important for understanding the process evolution of submarine mass flows and for estimating their runout distances. Structural restoration and quantification of strain in gravitationally driven passive margins have been shown to approximately balance between updip extensional and downdip contractional domains; such an exercise has not yet been attempted for MTCs. We here interpret and structurally restore a shallowly buried (c. 1,500 mbsf) and well‐imaged MTC, offshore Uruguay using a high‐resolution (12.5 m vertical and 15 × 12.5 m horizontal resolution) three‐dimensional seismic‐reflection survey. This allows us to characterise and quantify vertical and lateral strain distribution within the deposit. Detailed seismic mapping and attribute analysis shows that the MTC is characterised by a complicated array of kinematic indicators, which vary spatially in style and concentration. Seismic‐attribute extractions reveal several previously undocumented fabrics preserved in the MTC, including internal shearing in the form of sub‐orthogonal shear zones, and fold‐thrust systems within the basal shear zone beneath rafted‐blocks. These features suggest multiple transport directions and phases of flow during emplacement. The MTC is characterised by a broadly tripartite strain distribution, with extensional (e.g. normal faults), translational and contractional (e.g. folds and thrusts) domains, along with a radial frontally emergent zone. We also show how strain is preferentially concentrated around intra‐MTC rafted‐blocks due to their kinematic interactions with the underlying basal shear zone. Overall, and even when volume loss within the frontally emergent zone is included, a strain difference between extension (1.6–1.9 km) and contraction (6.7–7.3 km) is calculated. We attribute this to a combination of distributed, sub‐seismic, ‘cryptic’ strain, likely related to de‐watering, grain‐scale deformation and related changes in bulk sediment volume. This work has implications for assessing MTCs strain distribution and provides a practical approach for evaluating structural interpretations within such deposits.

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“…The restored sections in Figures 6 and 7 show differences in restored line lengths between the subpolymer and suprapolymer units. To explain the differential line length, the actual geologic processes that have been described in nature and are replicated by sandbox models include (1) internal shear and readjustment of particles because of the ongoing deformation regime; and (2) out-of-section movement due to salt tectonics and transpression (Casas et al, 1996;Koyi, 2000;Koyi and Sans, 2006;Burberry, 2015). Consequently, we consider internal shear as the main factor to take into account when it comes to considering bed length and area conservation in the restoration of compressional structures.…”

Section: Modeling Limitationsmentioning

confidence: 99%

Tectonic inversion of salt-detached ramp-syncline basins as illustrated by analog modeling and kinematic restoration

Roma

Vidal-Royo²,

McClay

et al. 2018

Interpretation

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Salt-detached ramp-syncline basins are developed in extensional settings and are characterized by wide synclinal sedimentary basins detached on salt and formed above the hanging wall of active ramp-flat-ramp extensional faults. They are rarely fault bounded; instead, they are bounded by salt structures that are in general parallel to the major subsalt structures. As such, the formation of these extensional systems requires the presence of (1) a subsalt extensional fault with significant dip changes and (2) an evaporitic unit above the extensional fault, which partially or completely decouples the basin from a subsalt extensional fault. Saltdetached ramp-syncline basins have a significant exploration potential when their extensional geometry is preserved and when they have undergone positive tectonic inversion and consequent uplift and fold amplification. However, in some cases, their subsalt geometry may not be fully recognizable, especially when subsalt seismic imaging is poor. To obtain a deeper understanding of the geometry and kinematic evolution of these salt-detached ramp-syncline basins, we performed a series of analog modeling experiments, in which the models' cross sections had been sequentially restored. Analog models and restoration results reveal that the kinematic evolution of the salt-detached ramp-syncline basins during extension and inversion depends on the interaction of different factors that may function simultaneously. Our results are used to improve the interpretation of seismic sections in inverted Mesozoic salt-detached ramp-syncline basins on the Atlantic margins, where subsalt faults are not well-imaged, and thus the suprasalt geometries must be used to infer the subsalt structure.

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Spatial and temporal variation in penetrative strain during compression: Insights from analog models

Abstract: Burberry, Caroline M., "Spatial and temporal variation in penetrative strain during compression: Insights from analog models" (2015).

Cited by 18 publications

References 57 publications

Low basal friction‐controlled geometry and kinematics of accretionary wedges from analogue experiments

Low basal friction‐controlled geometry and kinematics of accretionary wedges from analogue experiments

Strain analysis of a seismically imaged mass‐transport complex, offshore Uruguay

Tectonic inversion of salt-detached ramp-syncline basins as illustrated by analog modeling and kinematic restoration

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