Duplex structures in the lewis thrust sheet, crowsnest pass, rocky mountains, Alberta, Canada

McClay, Ken; Insley, Martin

doi:10.1016/0191-8141(86)90036-2

Cited by 25 publications

(1 citation statement)

References 4 publications

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“…The visible structures of the mélange/shear zones exposed in the Pieniny Klippen Belt, Marmarosh Klippen Zone, and Outer Carpathians were studied (Fig. 2) and described according to descriptions of the similar structures given in the works [McClay, Insley, 1986;McClay, 1992;Starzec et al, 2015;Fossen, 2016]. Structural analysis and geological mapping were used to study structural forms.…”

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Characteristics structures of the mélange zones in the Ukrainian Carpathians

Hnylko,

Murovskaya,

Bohdanova

2023

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Mélange is characterized by the block-in-matrix fabric in which rigid blocks of different sizes, lithologies, and ages are distributed in a ductile matrix. Though mélange is a significant component of orogenic belts, in the Ukrainian Carpathians, mélanges of tectonic origin have not been reported. We have described the mélange zones widespread in the Pieniny Klippen Belt, Marmarosh Klippen Zone, and the inner nappes of the Outer Ukrainian Carpathians, as well as the typical deformation structures developed within them. The mélange matrix is characterized by a scaly fabric formed by cleavage surfaces and somewhere arranged in S-C structures. Lenticular clasts within the matrix show their long axis aligned to the tectonic foliation. Rotation of the boudins occurs against the shear direction following the formation of the S-C structures. The rigid clasts somewhere demonstrate sigma-type rotation structures. Some blocks within the mélange are highly fractured up to tectonic breccias. The study of tectonic slicken-sides and other deformation structures within the Pieniny belt demonstrates the presence of regular stress fields correlated with the geodynamics of the Carpatho-Pannonian region. The main stress field indicates the SW-NE regional compression related to the formation of Carpathian nappes and S-N — trending dextral strike-slip faults. Our study in the Priborzhava quarries records the Oash right-lateral strike-slip fault zone. In the Pieniny Klippen Belt some oblique normal faults of the Carpathian direction are related to the Transcarpathian Depression formation. The study showed that the mélange zones in the inner part of the Ukrainian Carpathians were formed largely due to strike-slip movements. In contrast, in the outer part of the Carpathian orogen, they formed mainly due to thrusting.

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Characteristics structures of the mélange zones in the Ukrainian Carpathians

Hnylko,

Murovskaya,

Bohdanova

2023

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The duplex model: Implications from a study of flexural-slip duplexes

Tanner

1992

Thrust Tectonics

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Higher Himalayan Shear Zone, Zanskar Indian Himalaya: microstructural studies and extrusion mechanism by a combination of simple shear and channel flow

Mukherjee

Koyi

2009

Int J Earth Sci (Geol Rundsch)

137

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Thin-section studies of the Zanskar Shear Zone (ZSZ) rocks reveal a top-to-SW and subsequent primary and secondary top-to-NE ductile shearing; brittle-ductile and brittle extensions; top-to-SW brittle shear, steep normal faulting and fracturing. In the proposed two-phase model of ductile extrusion of the Higher Himalayan Shear Zone (HHSZ), a top-to-SW simple shearing during 22-18 Ma was followed by a combination of top-to-SW simple shear and channel flow at 18-16 Ma. The second phase simulates a thin ZSZ characterized by a top-to-NE shearing. The channel flow component ceased around 16 Ma, the extruding HHSZ entered the brittle regime but the topto-SW shearing continued until perturbed by faults and fractures. Variation in the extrusion parameters led to variable thickness of the ZSZ. Shear strain after the extrusion is presumably maximum at the boundaries of the HHSZ and falls towards the base of the ZSZ, which crudely matches with the existing data. The other predictions: (1) spatially uniform shear strain after the first stage, (2) fastest extrusion rate at the base of the ZSZ, and (3) a lack of continuation of the ZSZ along the Himalayan trend are not possible to validate due to paucity of suitable data. Nonparabolic shear fabrics of the ZSZ indicate their heterogeneous deformation.

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Duplex structures in the lewis thrust sheet, crowsnest pass, rocky mountains, Alberta, Canada

Cited by 25 publications

References 4 publications

Characteristics structures of the mélange zones in the Ukrainian Carpathians

Characteristics structures of the mélange zones in the Ukrainian Carpathians

The duplex model: Implications from a study of flexural-slip duplexes

Higher Himalayan Shear Zone, Zanskar Indian Himalaya: microstructural studies and extrusion mechanism by a combination of simple shear and channel flow

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