Non-rotation of garnet porphyroblasts and 3-D inclusion trail data: an example from the Imjingang belt, South Korea

Jung, Won Sun; Ree, Jin-Han; Park, Y

doi:10.1016/s0040-1951(99)00105-5

Cited by 32 publications

(31 citation statements)

References 24 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).…”

Section: Geological Backgroundsupporting

confidence: 64%

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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 Backgroundsupporting

confidence: 64%

“…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 Backgroundmentioning

confidence: 99%

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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“…South-vergent structure with top-up-to-the-south (reverse) shearing in the Jingok Unit (Fig. 1b) has resulted from the contractional deformation (D n−1 and D n ) (Ree et al, 1996;Jung et al, 1999). On the other hand, top-down-tothe-north (normal) shearing overprinted the reverse shear sense in the Samgot Unit, indicates the contractional deformation followed by extensional deformation (D n+1 ).…”

Section: Geological Backgroundsmentioning

confidence: 97%

“…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: 99%

“…This paper presents an approach that can be used to determine P−T−d history based on; (1) the isopleths of garnet components (X Fe , X Mn , X Ca ) plotted on P−T pseudosection to determine P−T conditions for garnet growth, (2) FIA within the porphyroblasts to reveal the bulk shortening direction during garnet and staurolite growth. The approach has applied to metapelites in the Jingok Unit of the Imjingang belt, South Korea, because the garnet porphyroblasts not only preserved curved inclusion trails, but also did not rotate during growth (Jung et al, 1999). Furthermore, the Imjingang belt in the central Korean peninsula is a candidate to represent the extension of the DabieSulu collision belt in China (Cho et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

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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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Refined tectonic evolution of the Betic-Rif orogen through integrated 3-D microstructural analysis and Sm-Nd dating of garnet porphyroblasts

Aerden

Farrell

Baxter

et al. 2022

Preprint

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The detailed deformation history of the Betic-Rif orogen (Figure 1) and its relationship with distinct metamorphic events recognized in this belt are still ambiguous as is reflected in disparate tectonic models that still differ on such fundamental aspects as the timing and polarity of subduction zones, the role of crustal extension versus compression, or the emplacement history of several peridotite massifs exposed in the belt (e.g.

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Non-rotation of garnet porphyroblasts and 3-D inclusion trail data: an example from the Imjingang belt, South Korea

Cited by 32 publications

References 24 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

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

Refined tectonic evolution of the Betic-Rif orogen through integrated 3-D microstructural analysis and Sm-Nd dating of garnet porphyroblasts

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