The role of flexural slip during the development of multilayer chevron folds

Wu, Yuxing; Eckert, Andreas; Liu, Xiaolong; Obrist‐Farner, Jonathan

doi:10.1016/j.tecto.2019.01.008

Cited by 5 publications

(3 citation statements)

References 41 publications

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“…There are some studies related to the flexural mechanisms, such as the role of flexural slip during the development of chevron folds (Wu et al, 2019); lithospheric folding by a flexural slip in subduction zones (Romeo and Álvarez-Gómez, 2018); the mechanisms of flexural flow folding of competent single-layers (Torremans et al, 2014), and non-cylindrical flexural-slip folds (Dubey, 1997). In this study, we provided detailed evidence to analyze the folding mechanisms of the large-scale Khousf folded platform and its smaller-scale folds to figure out the tectonic evolution models of an old ductile splay (Khousf folded platform) in the East Iran orogenic.…”

Section: Folds Flexural-slip Mechanismmentioning

confidence: 99%

Flexural-slip folding in buckling phases of orogenic belts: Insight into the tectonic evolution of fault splays in the East Iran orogen

et al. 2023

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Introduction: The East Iran orogen has experienced multiple buckling phases resulting in the formation of strike-slip fault splays. The geometric and kinematic characteristics of these splays are influenced by folding mechanisms. This study focuses on investigating the structural characteristics and tectonic evolution model of the Khousf splay, located in the northern terminus of the Nehbandan right-lateral strike-slip fault system.Methods: Field visits and geometrical properties from map views were used to analyze the structural features of the Khousf splay. The splay was found to consist of a multi-plunging anticline and syncline, referred to as the Khousf anticline and Khousf syncline, respectively. Flexural slip was identified as a significant mechanism for the formation of these structures. Structural evidence, including parasitic folds, active folds, and strike-slip duplexes, suggested that flexural slip occurred on discrete movement horizons among the rock units.Results: Analysis of the parasitic folds in the cores and limbs of the Khousf anticline and syncline revealed M, W, Z, and S shapes, with complex slicken-line patterns observed on faults parallel to the beds at the limbs. The analysis results indicated strain partitioning and inclined left- and right-lateral transpressional zones. Shortening estimates obtained from profiles in the Shekarab inclined transpressional zone were approximately 33%, 65%, and 68% for NE-SW, N-S, and NW-SE profiles, respectively. In the Arc area, which is the core of the anticline, shortening estimates from NE-SW and N-S profiles ranged from 14% to 10%. Structural analysis of the folds in this area revealed broad, close, semi-elliptical, and parabolic shapes, suggesting that secondary folds with NW-SE axis directions have been superimposed on the first-generation folds with E-W axis directions in the Khousf refolded splay.Discussion: The findings of this study highlight the structural characteristics and tectonic evolution model of the Khousf splay in the northern terminus of the Nehbandan right-lateral strike-slip fault system. The results suggest that flexural slip played a crucial role in the formation of the multi-plunging anticline and syncline in the Khousf splay. The presence of parasitic folds and complex slicken-line patterns on faults indicate the complexity of deformation processes. The observed strain partitioning and inclined transpressional zones suggest a complex tectonic history in the study area. The superimposition of secondary folds with different axis directions on first-generation folds adds further complexity to the structural evolution of the Khousf refolded splay. Overall, this study provides new insights into the structural characteristics and tectonic evolution of the Khousf splay in the East Iran orogen.

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Section: Folds Flexural-slip Mechanismmentioning

confidence: 99%

Flexural-slip folding in buckling phases of orogenic belts: Insight into the tectonic evolution of fault splays in the East Iran orogen

et al. 2023

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“…The development of chevron folds is related to flexural slip initiated during the later stages of folding. The low thickness ratio of incompetent to competent layers (much lower than one) plays an important role in the formation of chevron folds (Wu et al ., 2019). Early marine cementation of lime mud most likely led to the formation of competent layers (lime mudstone), whereas the clay in marl likely prohibited early cementation, and thus resulted in incompetent layers.…”

Section: Facies Observations and Interpretationsmentioning

confidence: 99%

Middle Ordovician mass‐transport deposits from western Inner Mongolia, China: Mechanisms and implications for basin evolution

Chen

Hakim

et al. 2021

Sedimentology

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Subaqueous mass-transport processes are one of the mechanisms for transport of sediment into the deep sea. Internal structures and depositional processes of carbonate mass-transport deposits are relatively poorly understood relative to siliciclastic facies due to their comparative paucity in the rock record. A variety of carbonate mass-transport deposits, including slumps, debrites and deep-channel-confined density flow deposits, occur in Middle-Upper Ordovician slope deposits in western Inner Mongolia (Wuhai), China. These provide a rare opportunity to illustrate the emplacement history of carbonate mass-transport deposits at the outcrop scale. The slumps and debrites host remarkable folds, chaotic beds and imbricated beds that reflect differences in both rheology and position on the slope. Individual slump sheets show gradations between undulating laminae, inclined and recumbent folds, highly deformed folds, and chaotic textures upslope from the toe region. Debrites are commonly interbedded with slump deposits, whereas imbricated beds are present in the middle and lower parts of the toes of slump sheets near the terminal wall. In the study area, thin-bedded limestone with slump deposits of the Kelimoli Formation are overlain by fine-grained, siliciclastic-dominated, slope deposits of the Wulalike Formation. A thick breccia of the Wulalike Formation was deposited in a main feeder channel in south-east Wuhai, but to the west-north-west the breccia was deposited in distributary channels possibly represented as a unique lower-slope pattern of gullies. At the latter locality, the breccia was deposited solely within the channels on a steep west-north-west dipping slope under density-driven flows. The mass-transport deposits documented herein records passive to foreland basin tectonic transitions, and associated platform foundering and steepening of the slope. A slope facies model was constructed to demonstrate the spatial and temporal variations of mass-transport deposits during basin evolution, and as such it provides a template for the interpretation of the deposits of ancient slopes that underwent passive to active tectonic transitions.

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“…These features are not only interesting scientifically and diverse but also very spectacular. For instance, chevron folds are structural features, the formation of which is linked to specific kinematics [41,42]. The lengthy outcrops of the Anisian (Middle Triassic) layered limestones along the Belaya River exhibit chevron folding, which creates a pattern of outstanding aesthetic value (Figure 3).…”

Section: Case Studymentioning

confidence: 99%

Bridges as Geoheritage Viewpoints in the Western Caucasus

2021

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Distant observation of unique geological and geomorphological features facilitates comprehension and tourism of these important resources. Bridges offer an opportunity for such observation, and the idea of bridge-based geoheritage viewpoints is proposed. In the geologically-rich area of the Western Caucasus (southwestern Russia), eleven bridges were assessed semiquantitatively with the newly proposed approach. The results indicated their different but moderate utility as geoheritage viewpoints. The utility of two bridges is high. Bridges differ not only by the quality of the views they offer but also by their accessibility. Mandatory permissions and entrance fees reduce this property in several cases. Although the study area is somewhat specific due to the relatively large number of bridges and their utility, similar situations can be found in other geographical localities. Bridge-based geoheritage viewpoints are important to geotourism development, and, particularly, they contribute to establishing optimal and comfortable routes.

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The role of flexural slip during the development of multilayer chevron folds

Cited by 5 publications

References 41 publications

Flexural-slip folding in buckling phases of orogenic belts: Insight into the tectonic evolution of fault splays in the East Iran orogen

Flexural-slip folding in buckling phases of orogenic belts: Insight into the tectonic evolution of fault splays in the East Iran orogen

Middle Ordovician mass‐transport deposits from western Inner Mongolia, China: Mechanisms and implications for basin evolution

Bridges as Geoheritage Viewpoints in the Western Caucasus

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