Microstructures of Deformed Grains and Kinematic Analysis in the Gneiss Rocks of Qazzaz Metamorphic Core Complex, Northwestern Arabian Shield, Saudi Arabia.
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| Title: | Microstructures of Deformed Grains and Kinematic Analysis in the Gneiss Rocks of Qazzaz Metamorphic Core Complex, Northwestern Arabian Shield, Saudi Arabia. |
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| Authors: | Kassem, O. M. K.1 (AUTHOR) kassemo1@yahoo.com, Al-Hashim, M. H.2 (AUTHOR) |
| Source: | Geotectonics. 2025 Suppl 1, Vol. 59, pS36-S53. 18p. |
| Subject Terms: | *Microstructure, *Kinematics, *Gneiss, *Deformations (Mechanics) |
| Geographic Terms: | Saudi Arabia |
| Abstract: | The granitic mylonites of the Qazzaz metamorphic core complex in the northwest region of the Arabian Shield, Saudi Arabia were subjected to a through fabric, kinematic and microstructural analyses. The deformed grains (gneisses rocks) enclose a blasto-mylonitic texture that is distinguished by enormous retort-shaped porphyroclasts grains, which are deflected by the ductile, fine to medium grains matrix of biotite, muscovite, feldspar, and quartz. Feldspars exhibit both brittle and ductile behavior, due to reduction processes such as grain boundary migration, subgrain rotation, and fracture. The microstructural of the feldspars, quartz, and mica are generally compatible with fabric formation in greenschist to amphibolite-facies conditions in the mylonitic gneisses for the Qazzaz metamorphic core complex. The kinematic vorticity is measured by using the RGN and the Passchier techniques. Furthermore, in mylonitic gneisses, the kinematic vorticity number (Wm) ranges from 0.68 to 0.86 for felsic minerals and between 0.69 and 0.85 for hornblende. For metavolcano-sedimentary and schist rocks, the range is between 0.68 and 0.89 for felsic minerals and between 0.66 and 0.90 for hornblende. The present data for mean kinematic vorticity number (Wm) are the same for different type of rocks. The long axes (X axis) direction shows a WNW trend with minimal dipping. For finite strain data, the short axes (Z axes) direction is represented as vertical with a corresponding horizontal foliation. The findings of the strain investigations and kinematic vorticity are illustrated by simple shear with various deformations. [ABSTRACT FROM AUTHOR] |
| Database: | Energy & Power Source |
| FullText | Text: Availability: 0 |
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| Header | DbId: enr DbLabel: Energy & Power Source An: 188854479 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Microstructures of Deformed Grains and Kinematic Analysis in the Gneiss Rocks of Qazzaz Metamorphic Core Complex, Northwestern Arabian Shield, Saudi Arabia. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Kassem%2C+O%2E+M%2E+K%2E%22">Kassem, O. M. K.</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> kassemo1@yahoo.com</i><br /><searchLink fieldCode="AR" term="%22Al-Hashim%2C+M%2E+H%2E%22">Al-Hashim, M. H.</searchLink><relatesTo>2</relatesTo> (AUTHOR) – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Geotectonics%22">Geotectonics</searchLink>. 2025 Suppl 1, Vol. 59, pS36-S53. 18p. – Name: Subject Label: Subject Terms Group: Su Data: *<searchLink fieldCode="DE" term="%22Microstructure%22">Microstructure</searchLink><br />*<searchLink fieldCode="DE" term="%22Kinematics%22">Kinematics</searchLink><br />*<searchLink fieldCode="DE" term="%22Gneiss%22">Gneiss</searchLink><br />*<searchLink fieldCode="DE" term="%22Deformations+%28Mechanics%29%22">Deformations (Mechanics)</searchLink> – Name: SubjectGeographic Label: Geographic Terms Group: Su Data: <searchLink fieldCode="DE" term="%22Saudi+Arabia%22">Saudi Arabia</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: The granitic mylonites of the Qazzaz metamorphic core complex in the northwest region of the Arabian Shield, Saudi Arabia were subjected to a through fabric, kinematic and microstructural analyses. The deformed grains (gneisses rocks) enclose a blasto-mylonitic texture that is distinguished by enormous retort-shaped porphyroclasts grains, which are deflected by the ductile, fine to medium grains matrix of biotite, muscovite, feldspar, and quartz. Feldspars exhibit both brittle and ductile behavior, due to reduction processes such as grain boundary migration, subgrain rotation, and fracture. The microstructural of the feldspars, quartz, and mica are generally compatible with fabric formation in greenschist to amphibolite-facies conditions in the mylonitic gneisses for the Qazzaz metamorphic core complex. The kinematic vorticity is measured by using the RGN and the Passchier techniques. Furthermore, in mylonitic gneisses, the kinematic vorticity number (Wm) ranges from 0.68 to 0.86 for felsic minerals and between 0.69 and 0.85 for hornblende. For metavolcano-sedimentary and schist rocks, the range is between 0.68 and 0.89 for felsic minerals and between 0.66 and 0.90 for hornblende. The present data for mean kinematic vorticity number (Wm) are the same for different type of rocks. The long axes (X axis) direction shows a WNW trend with minimal dipping. For finite strain data, the short axes (Z axes) direction is represented as vertical with a corresponding horizontal foliation. The findings of the strain investigations and kinematic vorticity are illustrated by simple shear with various deformations. [ABSTRACT FROM AUTHOR] |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1134/S0016852125700359 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 18 StartPage: S36 Subjects: – SubjectFull: Microstructure Type: general – SubjectFull: Kinematics Type: general – SubjectFull: Gneiss Type: general – SubjectFull: Deformations (Mechanics) Type: general – SubjectFull: Saudi Arabia Type: general Titles: – TitleFull: Microstructures of Deformed Grains and Kinematic Analysis in the Gneiss Rocks of Qazzaz Metamorphic Core Complex, Northwestern Arabian Shield, Saudi Arabia. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Kassem, O. M. K. – PersonEntity: Name: NameFull: Al-Hashim, M. H. IsPartOfRelationships: – BibEntity: Dates: – D: 02 M: 10 Text: 2025 Suppl 1 Type: published Y: 2025 Identifiers: – Type: issn-print Value: 00168521 Numbering: – Type: volume Value: 59 Titles: – TitleFull: Geotectonics Type: main |
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