Lattice preferred orientation of quartz inclusions within garnet porphyroblasts from the Imjingang belt, South Korea

Jung, Won Sun; Ree, Jin-Han; Park, Yongjung; Choi, Suna

doi:10.1016/s0191-8141(01)00083-9

Cited by 9 publications

(7 citation statements)

References 26 publications

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“…S n)1 curving asymptotically into S n provides the shear sense of D n consistent with reverse (top-up-to-the-south) movement inferred from microstructural evidence for asymmetric strain shadows around porphyroblasts (Ree et al, 1996;Jung et al, 1999). This thrust movement (D n ) is interpreted as accompanying contractional deformation during the Permo-Triassic collision (Ree et al, 1996;Jung et al, 1999Jung et al, , 2002. The third deformation is associated with an extensional ductile movement prevalent not only in the Imjingang belt, but also in the Gyeonggi shear zone at middlelate Triassic (Kim et al, 2000).…”

Section: Geological Ba Ckgroundsupporting

confidence: 61%

“…This thrust movement (D n ) is interpreted as accompanying contractional deformation during the Permo–Triassic collision (Ree et al. , 1996; Jung et al. , 1999, 2002).…”

Section: Geological Backgroundmentioning

confidence: 99%

“…The Jingok unit was subjected to three episodes of deformation (Ree et al, 1996;Jung et al, 1999Jung et al, , 2002. The first deformation (D n)1 ) was contractional, and is associated with minor structures characterized by weak foliation (S n)1 ) steeper than the main foliation and straight inclusion trails (S i ) oblique to external foliation within garnet porphyroblasts (Ree et al, 1996;Jung et al, 1999).…”

Section: Geological Ba Ckgroundmentioning

confidence: 99%

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Two‐stage growth of porphyroblastic biotite and garnet in the Barrovian metapelites of the Imjingang belt, central Korea

Kim

Cho

2008

Journal Metamorphic Geology

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Porphyroblastic biotite and garnet in the Barrovian metapelites of the Imjingang belt, Korea, were investigated to unravel the sequence and mechanism of mineral growth. Poikiloblastic biotite contains straight inclusion trails (S i ) discontinuous to the major foliation, and develops clear zones at the grain margin. These microstructures suggest an initial growth of biotite between two contractional deformations (D n)1 and D n ) followed by an overgrowth during D n . Although garnet poikiloblasts contain variable S i patterns, their major growth is likely to have occurred during D n on the basis of compositional relationships among variable garnet types. Early poikiloblasts of both minerals were formed by chemical replacement of the matrix that consisted mainly of chlorite, muscovite and quartz. Subsequent growth of biotite was governed by a crack-filling mechanism, and was accompanied by the production of extensional cracks inside or around biotite, providing fluid pathways. The overgrowth of garnet was favoured at the biotite-garnet interface, and the consequence was a partial replacement of inclusion-poor garnet after biotite subsequent to D n . In addition, clear zones and pressure shadows as well as the matrix around biotite porphyroblasts were replaced by garnet, suggesting an inheritance of various pre-existing microstructures in the S i pattern of garnet. Further attention is thus required for any attempt to delineate the microstructural interaction between deformation and metamorphism, particularly in a sample containing early-grown porphyroblasts. Microstructural evidence for the twostage growth of biotite and garnet is present up to the kyanite zone, indicating that this growth mechanism is prevalent during progressive metamorphism of Barrovian metapelites.

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Section: Geological Ba Ckgroundsupporting

confidence: 61%

“…This thrust movement (D n ) is interpreted as accompanying contractional deformation during the Permo–Triassic collision (Ree et al. , 1996; Jung et al. , 1999, 2002).…”

Section: Geological Backgroundmentioning

confidence: 99%

Section: Geological Ba Ckgroundmentioning

confidence: 99%

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Two‐stage growth of porphyroblastic biotite and garnet in the Barrovian metapelites of the Imjingang belt, central Korea

Kim

Cho

2008

Journal Metamorphic Geology

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“…Bell (1981) produced a coaxial strain field diagram that mimicked millipede-shaped inclusion trails in porphyroblasts. All these data demonstrate that SSITs do not form by porphyroblast rotation and are not rotated by subsequent folding at hand sample to outcrop to regional fold scale, or by orocline development due to overprinting deformation at orogen scale, or by shear zone development (Jung et al 2002). The latter strain field diagram produced a realistic crenulation cleavage geometry and revealed that for a deformation history of progressive bulk inhomogeneous shortening, portions of the strain field that did not deform would not rotate in highly non-coaxial deformation.…”

Section: E Alpine Top-to-the-s Shearing During Main Menderes Metammentioning

confidence: 84%

Extensional v. contractional origin for the southern Menderes shear zone, SW Turkey: tectonic and metamorphic implications

Bozkurt

2006

Geol. Mag.

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The southern Menderes Massif in southwest Turkey consists mainly of orthogneisses and overlying Palaeozoic-Middle Paleocene schists and marbles. The contact between the two distinct rock types is almost everywhere structural, herein named the southern Menderes shear zone: a S-facing, high-angle ductile shear zone that separates metamorphic rocks of differing grade. Although there is a consensus that the shear zone was associated with top-to-the-S-SSW shearing and is of Tertiary age, its origin and nature have been highly debated over the last decade. Some claim the contact is a thrust fault, while others have argued for an extensional shear zone. Integration of field and microstructural data (the identification of different fabrics, associated kinematics and overprinting relationships) with fissiontrack thermochronology and the P-T paths of the rocks above and below the shear zone, supports the conclusion that the southern Menderes shear zone is an extensional shear zone and not a thrust. The data are consistent with a model that the exhumation and cooling of the southern Menderes Massif occurred after a period of extensional deformation. Pervasive top-to-the-N-NNE high-temperature-mediumpressure ductile shear structures (D 2 deformation) overprint an early HP event (D 1 deformation). The subsequent top-to-the-S-SSW greenschist shear band foliation (D 3 deformation) developed mostly around the orthogniess-schist contact and forms the most characteristic features of the massif. The topto-the-N-NNE structures are attributed to the main Alpine constructional deformation that developed during back-thrusting of the Lycian nappes during the latest Palaeogene collision between the Sakarya continent and the Anatolide-Tauride platform across the Neotethyan Ocean. The top-to-the-S-SSW structures are interpreted to be the result of the exhumation of the massif during the activity of the southern Menderes shear zone. The presence of these two distinct fabrics with differing kinematics suggests that the southern Menderes shear zone operated as a top-to-the-N-NNE thrust fault during early Alpine contractional deformation but was later reactivated with an opposite sense of movement (top-to-the-S-SSW) during subsequent Oligocene-Miocene extensional collapse.

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“…1b). Three deformation events in the Jingok Unit has been documented by Ree et al (1996) and Jung et al (1999Jung et al ( , 2002. The early two events are initial contractional deformation (D n−1 ) and main contractional deformation (D n ), and the last one is extensional ductile shearing (D n+1 ).…”

Section: Geological Backgroundsmentioning

confidence: 98%

The use of garnet porphyroblasts to resolve the metamorphic pressure-temperature-deformation (P-T-d) path: An example from the Imjingang belts, South Korea

Kim

Jung

2010

Geosci J

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S: Quantitative P−T−deformation path determination for metamorphic rocks can be revealed by an approach combined isopleths intersection of zoned garnet compositions with foliation intersection/inflexion axes (FIAs) preserved within the garnet porphyroblast. The method presented here is applied to metapelites in the Jingok Unit of the Imjingang belt, South Korea. Garnet and staurolite FIA trends are E−W to WNW−ESE (90−120°) and NE−SW to ENE−WSW (50−80°), respectively. The FIA data indicate that garnet porphyroblasts have grown under N−S to NNE−SSW bulk shortening. P−T paths for garnet growth in Grt, St and Ky zone in the Jingok Unit, calculated from geothermobarometers and the intersection of isopleths on P−T pseudosections in the MnO−Na 2 O−CaO−K 2 O−FeO−MgO−Al 2 O 3 −SiO 2 −H 2 O (MnNCK-FMASH) system constructed using program THERMOCALC, are compressional heating from 545°C at 5.3 kbar to 610−640°C at 7.9−8.8 kbar. All compositional and microtextural data and thermodynamic modeling indicate that garnet porphyroblasts have formed during compressional heating under N−S crustal shortening, whereas staurolite porphyroblasts have formed dominantly during sub-isothermal decompression with overgrowing NE/ENE FIA. Consequently, the metapelites in the Jingok Unit have experienced clockwise P−T path derived from Barrovian-type metamorphism belong in amphibolites facies.

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Lattice preferred orientation of quartz inclusions within garnet porphyroblasts from the Imjingang belt, South Korea

Cited by 9 publications

References 26 publications

Two‐stage growth of porphyroblastic biotite and garnet in the Barrovian metapelites of the Imjingang belt, central Korea

Two‐stage growth of porphyroblastic biotite and garnet in the Barrovian metapelites of the Imjingang belt, central Korea

Extensional v. contractional origin for the southern Menderes shear zone, SW Turkey: tectonic and metamorphic implications

The use of garnet porphyroblasts to resolve the metamorphic pressure-temperature-deformation (P-T-d) path: An example from the Imjingang belts, South Korea

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