Shear deformation bands in clastic dikes: a case study from the Miocene Pohang Basin, SE Korea.
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| Title: | Shear deformation bands in clastic dikes: a case study from the Miocene Pohang Basin, SE Korea. |
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| Authors: | Yun, Donghwa1 (AUTHOR), Han, Raehee1 (AUTHOR) raeheehan@gnu.ac.kr, Kim, Chang-Min2 (AUTHOR), Woo, Sangwoo1,3 (AUTHOR), Park, Hyeon-Je1,4 (AUTHOR), Gu, Dohee1 (AUTHOR), Son, Moon5 (AUTHOR), Song, Cheol Woo5,6 (AUTHOR), Lee, Hakyung1 (AUTHOR) |
| Source: | Geosciences Journal. Dec2025, Vol. 29 Issue 6, p815-830. 16p. |
| Subject Terms: | *Dikes (Geology), *Sedimentary basins, *Structural geology, *Shear strain, *Miocene Epoch, *Strains & stresses (Mechanics), *Shear (Mechanics) |
| Geographic Terms: | Korea |
| Abstract: | Clastic dikes and deformation bands are common geological structures in the shallow parts of sedimentary basins. Although their co-occurrence is relatively rare, some cases have been reported, but their detailed characteristics and formation mechanisms remain unclear. This study investigates a clastic dike in the Pohang Basin, southeastern Korea, where deformation bands are prominently developed, using structural observations and material analysis from outcrop to microscopic scales. At the outcrop scale, 1–2 mm-thick shear bands with normal displacement up to 1.3 cm were observed within the dikes. Some bands terminate within the dike, while others propagate into the surrounding mudrock, forming wedge structures. Microscopically, the bands in the dike show cataclastic textures in quartz and feldspar clasts, whereas those in the mudrock consist of well-aligned platy minerals with ultrafine quartz and feldspar grains, accompanied by fold structures. Stress conditions inferred from these structures indicate formation during crustal extension, with a subvertical maximum principal stress (σ1) and a subhorizontal, E–W-trending minimum principal stress (σ3). The nucleation and propagation of shear deformation bands in the dike and their termination in the mudrock are attributed to the lower shear strength of the sand in the dike compared to the mudrock, as well as the shear hardening behavior of the mudrock. Notably, shear deformation bands terminating in the mudrock display asymmetric bifurcation near their tips, similar to synthetic branch faults. These findings provide insights into shear deformation in sedimentary strata composed of alternating sediments with different physical properties. [ABSTRACT FROM AUTHOR] |
| Database: | Energy & Power Source |
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| Header | DbId: enr DbLabel: Energy & Power Source An: 189211064 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Shear deformation bands in clastic dikes: a case study from the Miocene Pohang Basin, SE Korea. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Yun%2C+Donghwa%22">Yun, Donghwa</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Han%2C+Raehee%22">Han, Raehee</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> raeheehan@gnu.ac.kr</i><br /><searchLink fieldCode="AR" term="%22Kim%2C+Chang-Min%22">Kim, Chang-Min</searchLink><relatesTo>2</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Woo%2C+Sangwoo%22">Woo, Sangwoo</searchLink><relatesTo>1,3</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Park%2C+Hyeon-Je%22">Park, Hyeon-Je</searchLink><relatesTo>1,4</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Gu%2C+Dohee%22">Gu, Dohee</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Son%2C+Moon%22">Son, Moon</searchLink><relatesTo>5</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Song%2C+Cheol+Woo%22">Song, Cheol Woo</searchLink><relatesTo>5,6</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Lee%2C+Hakyung%22">Lee, Hakyung</searchLink><relatesTo>1</relatesTo> (AUTHOR) – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Geosciences+Journal%22">Geosciences Journal</searchLink>. Dec2025, Vol. 29 Issue 6, p815-830. 16p. – Name: Subject Label: Subject Terms Group: Su Data: *<searchLink fieldCode="DE" term="%22Dikes+%28Geology%29%22">Dikes (Geology)</searchLink><br />*<searchLink fieldCode="DE" term="%22Sedimentary+basins%22">Sedimentary basins</searchLink><br />*<searchLink fieldCode="DE" term="%22Structural+geology%22">Structural geology</searchLink><br />*<searchLink fieldCode="DE" term="%22Shear+strain%22">Shear strain</searchLink><br />*<searchLink fieldCode="DE" term="%22Miocene+Epoch%22">Miocene Epoch</searchLink><br />*<searchLink fieldCode="DE" term="%22Strains+%26+stresses+%28Mechanics%29%22">Strains & stresses (Mechanics)</searchLink><br />*<searchLink fieldCode="DE" term="%22Shear+%28Mechanics%29%22">Shear (Mechanics)</searchLink> – Name: SubjectGeographic Label: Geographic Terms Group: Su Data: <searchLink fieldCode="DE" term="%22Korea%22">Korea</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Clastic dikes and deformation bands are common geological structures in the shallow parts of sedimentary basins. Although their co-occurrence is relatively rare, some cases have been reported, but their detailed characteristics and formation mechanisms remain unclear. This study investigates a clastic dike in the Pohang Basin, southeastern Korea, where deformation bands are prominently developed, using structural observations and material analysis from outcrop to microscopic scales. At the outcrop scale, 1–2 mm-thick shear bands with normal displacement up to 1.3 cm were observed within the dikes. Some bands terminate within the dike, while others propagate into the surrounding mudrock, forming wedge structures. Microscopically, the bands in the dike show cataclastic textures in quartz and feldspar clasts, whereas those in the mudrock consist of well-aligned platy minerals with ultrafine quartz and feldspar grains, accompanied by fold structures. Stress conditions inferred from these structures indicate formation during crustal extension, with a subvertical maximum principal stress (σ1) and a subhorizontal, E–W-trending minimum principal stress (σ3). The nucleation and propagation of shear deformation bands in the dike and their termination in the mudrock are attributed to the lower shear strength of the sand in the dike compared to the mudrock, as well as the shear hardening behavior of the mudrock. Notably, shear deformation bands terminating in the mudrock display asymmetric bifurcation near their tips, similar to synthetic branch faults. These findings provide insights into shear deformation in sedimentary strata composed of alternating sediments with different physical properties. [ABSTRACT FROM AUTHOR] |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1007/s12303-025-00060-1 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 16 StartPage: 815 Subjects: – SubjectFull: Dikes (Geology) Type: general – SubjectFull: Sedimentary basins Type: general – SubjectFull: Structural geology Type: general – SubjectFull: Shear strain Type: general – SubjectFull: Miocene Epoch Type: general – SubjectFull: Strains & stresses (Mechanics) Type: general – SubjectFull: Shear (Mechanics) Type: general – SubjectFull: Korea Type: general Titles: – TitleFull: Shear deformation bands in clastic dikes: a case study from the Miocene Pohang Basin, SE Korea. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Yun, Donghwa – PersonEntity: Name: NameFull: Han, Raehee – PersonEntity: Name: NameFull: Kim, Chang-Min – PersonEntity: Name: NameFull: Woo, Sangwoo – PersonEntity: Name: NameFull: Park, Hyeon-Je – PersonEntity: Name: NameFull: Gu, Dohee – PersonEntity: Name: NameFull: Son, Moon – PersonEntity: Name: NameFull: Song, Cheol Woo – PersonEntity: Name: NameFull: Lee, Hakyung IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 12 Text: Dec2025 Type: published Y: 2025 Identifiers: – Type: issn-print Value: 12264806 Numbering: – Type: volume Value: 29 – Type: issue Value: 6 Titles: – TitleFull: Geosciences Journal Type: main |
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