Intrusion of granitic magma and uplift tectonics of the Hidaka metamorphic belt, Hokkaido.

Shimura, Toshiaki

doi:10.5575/geosoc.98.1

Cited by 26 publications

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“…The mylonites often display deformation fea tures such as intrafolial folds, asymmetric boudins and pressure shadows indicating dex tral horizontal slip (Shimura, 1992).…”

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confidence: 99%

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K-Ar geochronological constraints on tectonics and exhumation of the Hidaka metamorphic belt, Hokkaido, northern Japan.

Arita

Shingu

Itaya

1993

J. Min. Petr. Econ. Geol.

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“…The mylonites often display deformation fea tures such as intrafolial folds, asymmetric boudins and pressure shadows indicating dex tral horizontal slip (Shimura, 1992).…”

mentioning

confidence: 99%

“…The amphibolites are medium-grained, and contain brown hornblende and plagioclase along with minor pyroxenes (Shimura, 1992).…”

mentioning

confidence: 99%

K-Ar geochronological constraints on tectonics and exhumation of the Hidaka metamorphic belt, Hokkaido, northern Japan.

Arita

Shingu

Itaya

1993

J. Min. Petr. Econ. Geol.

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“…The Hidaka metamorphic belt (HMB) is an exhumed crustal section of an island arc formed during early Paleocene to Miocene (e.g., Komatsu et al, 1994;Owada et al, 1997), where relatively fresh fault zones formed within the deep crust are exposed (e.g., Toyoshima et al, 1994). A huge volume of S-type tonalite was intruded along largescale shear zones in preexisting metamorphic rocks subsequent to peak metamorphism (e.g., Toyoshima, 1991;Shimura, 1992;Toyoshima et al, 1994). This paper describes the occurrences and the meso-to microstructures of mylonites and pseudotachylytes in these tonalitic rocks.…”

Section: Introductionmentioning

confidence: 99%

Occurrence of mylonite zones and pseudotachylyte veins around the base of the upper crust: An example from the southern Hidaka metamorphic belt, Samani area, Hokkaido, Japan

et al. 2014

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Geological studies on exhumed pseudotachylyte-bearing mylonite zones in S-type tonalite were carried out in the southern Hidaka metamorphic belt, Hokkaido, Japan. Mylonitization is characterized by (1) development of composite planar fabrics, (2) grain size reduction, and (3) change in modal composition an increase in mica content and a decrease in quartz content from protolith to mylonite. Mylonite zones are heterogeneously concentrated in the host rocks. At microscopic scales, shear deformation is concentrated heterogeneously in finegrained layers along C-surfaces. Most of the pseudotachylyte layers are subparallel to the C-surface, and tend to overprint thick mylonite zones. The heterogeneous development of mylonite zones, which may be activated as layers of co-seismic slip, should be incorporated into numerical modeling of seismogenic zones.

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“…roof thrusts of a duplex structure (Shimura, 1992). Two giant intrusive sheets are formed as the basal and middle tonalities along the decollement and roof thrust in the later phase of the D 2 -stage ( Fig.…”

Section: Geology and Tectonics Of The Hidaka Metamorphic Beltmentioning

confidence: 99%

“…1. Simplified geological map and pseudotachylyte distribution of the Hidaka metamorphic belt, compiled from Osanai et al (1986a), Owada (1989), Toyoshima (1990), Shimura (1992), Toyoshima et al (1994), Komatsu et al (1994), Obara (1997), and Niizato and Toyoshima (2000).…”

Section: Geology and Tectonics Of The Hidaka Metamorphic Beltmentioning

confidence: 99%

Pseudotachylytes, related fault rocks, asperities, and crustal structures in the Hidaka metamorphic belt, Hokkaido, northern Japan

et al. 2014

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Many pseudotachylytes and their related fault rocks are found in the Hidaka metamorphic belt representing an ancient crustal section. On the basis of field observations of the pseudotachylytes and related fault rocks, nature of seismogenic faulting in the Hidaka crust is examined. The field observations suggest the following conclusions.(1) Two structural types of pseudotachylytes are distinguished: layer-parallel and layer-oblique. The latter are scattered in the metamorphic belt, but the former occur only in the southern part of the metamorphic belt. (2) An abundance of the layer-parallel pseudotachylytes suggests that earthquakes occurred repeatedly and frequently in the southern part, where complicated and duplicated crustal structures occur with many lowtemperature thin mylonite zones. The southern part with such crustal structures was an ancient seismogenic area containing asperities and having a radius of a few tens of kilometers in the Hidaka crust. In the seismogenic area, the layer-parallel pseudotachylytes resulted from seismic slip on the mylonitic foliation within the lowtemperature mylonite zones with strong preferred orientation of micas. (3) The layer-parallel pseudotachylytes and the subsequent layer-oblique pseudotachylytes post-date the latest and very-low-temperature mylonitization in the metamorphic belt. The former pseudotachylytes formed just above the upper side of the brittle-plastic transition zone.

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Intrusion of granitic magma and uplift tectonics of the Hidaka metamorphic belt, Hokkaido.

Cited by 26 publications

References 0 publications

K-Ar geochronological constraints on tectonics and exhumation of the Hidaka metamorphic belt, Hokkaido, northern Japan.

K-Ar geochronological constraints on tectonics and exhumation of the Hidaka metamorphic belt, Hokkaido, northern Japan.

Occurrence of mylonite zones and pseudotachylyte veins around the base of the upper crust: An example from the southern Hidaka metamorphic belt, Samani area, Hokkaido, Japan

Pseudotachylytes, related fault rocks, asperities, and crustal structures in the Hidaka metamorphic belt, Hokkaido, northern Japan

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