Identification of geodynamic setting and of folding formation mechanisms using of strain ellipsoid concept for multi-scale structures of Greater Caucasus

Yakovlev, Fedor

doi:10.1016/j.tecto.2012.06.004

Cited by 7 publications

(5 citation statements)

References 59 publications

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“…Prior studies (e.g., Adamia et al, 2011b;Vincent et al, 2018) have documented multiple high-angle faults in the core of the western Greater Caucasus, including the structures that make up the North Georgia fault system. These faults are often considered to have formed as extensional structures during earlier tectonic episodes and to have been reactivated in the current tectonic setting as reverse faults (Yakovlev, 2012;e.g., Vincent et al, 2018). In this view, and given their steep dips, such structures have been proposed to accommodate rock uplift within the orogen with relatively little shortening.…”

Section: Role Of High-angle Structures In the Greater Caucasusmentioning

confidence: 99%

Tectonostratigraphy and major structures of the Georgian Greater Caucasus: Implications for structural architecture, along-strike continuity, and orogen evolution

et al. 2022

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Although the Greater Caucasus Mountains have played a central role in absorbing late Cenozoic convergence between the Arabian and Eurasian plates, the orogenic architecture and the ways in which it accommodates modern shortening remain debated. Here, we addressed this problem using geologic mapping along two transects across the southern half of the western Greater Caucasus to reveal a suite of regionally coherent stratigraphic packages that are juxtaposed across a series of thrust faults, which we call the North Georgia fault system. From south to north within this system, stratigraphically repeated ~5–10-km-thick thrust sheets show systematically increasing bedding dip angles (<30° in the south to subvertical in the core of the range). Likewise, exhumation depth increases toward the core of the range, based on low-temperature thermochronologic data and metamorphic grade of exposed rocks. In contrast, active shortening in the modern system is accommodated, at least in part, by thrust faults along the southern margin of the orogen. Facilitated by the North Georgia fault system, the western Greater Caucasus Mountains broadly behave as an in-sequence, southward-propagating imbricate thrust fan, with older faults within the range progressively abandoned and new structures forming to accommodate shortening as the thrust propagates southward. We suggest that the single-fault-centric “Main Caucasus thrust” paradigm is no longer appropriate, as it is a system of faults, the North Georgia fault system, that dominates the architecture of the western Greater Caucasus Mountains.

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Section: Role Of High-angle Structures In the Greater Caucasusmentioning

confidence: 99%

Tectonostratigraphy and major structures of the Georgian Greater Caucasus: Implications for structural architecture, along-strike continuity, and orogen evolution

et al. 2022

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“…Whole sedimentary cover 5 × 5 km 15 × 15 km Shortening, advection, meso-buckling, other mechanisms in physical experiments (Goncharov, 1979;Yakovlev, 2012bYakovlev, , 2015Yakovlev, , 2017; Method of shortening measurement (Yakovlev, 2017).…”

Section: Structural Cellsmentioning

confidence: 99%

“…Shortening, some mechanisms in experimental modelling, faults vertical displacements; Method of shortening measurement (Yakovlev, 2017). Identification of some mechanisms in experiments and a nature ( [Yakovlev, 2012b[Yakovlev, , 2015, p. 332).…”

Section: × Km 50 × 50 Kmmentioning

confidence: 99%

Balanced cross‐section restoration in a complicated folded hinterland structure: Shilbilisaj profile, Talas ridge, Caledonian Tien Shan

et al. 2022

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Conventional cross-section balancing techniques based on layer length measuring can be applied only for foreland structures. To analyse complicated hinterland structure with numerous small-scale folds, this balancing technique requires the reliable and detailed tracing of the morphology of any layer throughout the cross-section, which is unattainable. We present a special kinematic method of balancing cross sections based "on the geometry of the folded domain" which enables the structural restoration of hinterland regions. We apply the method to restore the detailed structural section along the Shilbilisaj River, having a length of 26 km. We divided this section into 40-60 so-called "domains" each including 2-7 folds. Our method uses the fold's morphology to determine the strain ellipsoid, which describes the deformation of each domain and is used to restore its pre-folded state. By combining the pre-folded states of the domains, we reconstruct the entire profile, and calculate shortening values as K = L 0 /L 1 (initial to final length). The overall shortening value for the profile is 4.49, incrementally varying along the section from 3.79 to 5.53. The comparable results of two independently performed reconstructions emphasize the reliability of the applied balancing method.

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“…В методическом отношении такие модели создава-лись как конкретная интерпретация структуры Кавказа в свете общих теоретических, геодинами-ческих схем; они не могут быть достоверно доказа-ны или опровергнуты в рамках этой методологии. Использование тектонофизических подходов, а именно выявления нескольких иерархических уровней структур и определения для объектов каждого уровня величины и типа их деформаций (кинематики), может дать корректное решение проблемы расшифровки строения и генезиса неко-торых типов крупных объектов в масштабе оса-дочного чехла складчатых сооружений [Yakovlev, 2008a[Yakovlev, , 2012a[Yakovlev, , 2012b.…”

Section: Introductionunclassified

The First Experience in Diagnosing the Geodynamic Mechanisms of Folding by the Factor Analysis of Folded Structure Parameters (Greater Caucasus)

Яковлев

Gorbatov

2017

Geodin. tektonofiz.

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This article is focused on identifying geodynamic mechanisms leading to formation of large crustal blocks in nature. A specific feature of our study is statistical analysis of the data obtained by the methods of tectonophysics and structural geology. The analyzed material included 24 detailed structural sections (almost 500 km in total length) of Greater Caucasus. The Meso-Cenozoic sedimentary cover, that was intensely folded in the Oligocene and Early Miocene, is 10-15 km thick. A structure balanced in strain amounts and sediments volumes was reconstructed for three stages in the development of the studied area: 1 -pre-folded, 2 -post-folded, 3 -modern post-orogenic. The 'geometry of folded domains' method was used. For this purpose, 505 structural domains were identified in the detailed structural sections, the pre-fold state for every domain were reconstructed, and all the domains were aggregated into 78 structural cells. The reconstructions were based on structural indicators measurable in the folds forming the folded domains. Each structural cell was characterized by six parameters: an amount of shortening; depths of the basement top in the prefolded, post-folded, and modern stages (i.e. stages 1, 2, and 3, respectively); a calculated position of the eroded top of the sedimentary cover (i.e. amplitude of orogenic uplifting); and a difference between the basement depths in stages 1 and 3. For 78 structural cells, shortening is about 50 % on average (from 2-10 % to 67 %). An average modern depth of the basement top is 13 km (from 2.2 to 31.7 km). The amplitudes of uplifting and of the erosion of top of the sedimentary cover for large blocks are in a range from 9 to 19 km. Steady combinations of these values forming certain structures have been detected on the studied areas. It was found that the depth of the basement top in stage 3 (modern) has tendency to keep the value similar to the depth acquired in stage 1 (pre-folded) generally. This effect may be caused by an isostasy.. A number of estimated high values of the pair correlations have a genetic meaning. Using the factor analysis (as generalization of pairs correlations), we detected two factors related to the geodynamic mechanisms leading to formation of the structures larger than the cells -of the crust, and the upper mantle. Factor F1 (shortening, 60 % weight) depends on the amount of shortening and is responsible for amplitudes of uplifting. Factor F2 (isostasy, 27 % weight) is related to the initial thickness of the cover; it is responsible for the stability of the depth of the basement top. Isostasy assumes significant changes in the density of rocks in the crust and mantle, including the obtaining of mantle density volumes by the large volumes of the crust rocks. The factor "isostasy" in such kind was not taken into account in geodynamic models earlier.

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Identification of geodynamic setting and of folding formation mechanisms using of strain ellipsoid concept for multi-scale structures of Greater Caucasus

Cited by 7 publications

References 59 publications

Tectonostratigraphy and major structures of the Georgian Greater Caucasus: Implications for structural architecture, along-strike continuity, and orogen evolution

Tectonostratigraphy and major structures of the Georgian Greater Caucasus: Implications for structural architecture, along-strike continuity, and orogen evolution

Balanced cross‐section restoration in a complicated folded hinterland structure: Shilbilisaj profile, Talas ridge, Caledonian Tien Shan

The First Experience in Diagnosing the Geodynamic Mechanisms of Folding by the Factor Analysis of Folded Structure Parameters (Greater Caucasus)

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