Paleomagnetic and Geotectonic Investigation of Ophiolite Suites and Surrounding Rocks in South-Central Honshu, Japan

Tonouchi, Shyoji; Kobayashi, Kazuo

doi:10.1007/978-94-009-7102-8_19

Cited by 13 publications

(13 citation statements)

References 31 publications

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“…It has already been postulated by the authors (ToNoudiI andKOBAYASHI, 1982, 1983) that the ophiolite complexes of the Setogawa belt were formed at a mid-oceanic ridge situated further south of the present latitude probably in Eocene or early Oligocene and then drifted northward. Most of the ocean floor may have subducted at a paleotrench which presumably existed along the present suture belt.…”

Section: Summary Of Results and Tectonic Considerationsmentioning

confidence: 83%

Paleomagnetism of alkali basalts occurring in Takakusayama and Ryuso districts, south-central Honshu, Japan.

Tonouchi

Kobayashi

1982

J. geomagn. geoelec

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Directions of stable natural remanent magnetization as well as thermomagnetic and opaque-mineralogical characteristics of alkali basalts occurring in Takakusayama and Ryuso districts immediately east (in the oceanside) of the Setogawa ophiolite belt indicate that the alkali basalts were formed as seamounts or post-spreading volcanics, partly emerged at one time, at a site not far from the present location. The masses of alkali rocks were dissected by the normal faults with a strike of N40 E and then accreted along the outer margin of the Setogawa ophiolite belt.

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Section: Summary Of Results and Tectonic Considerationsmentioning

confidence: 83%

Paleomagnetism of alkali basalts occurring in Takakusayama and Ryuso districts, south-central Honshu, Japan.

Tonouchi

Kobayashi

1982

J. geomagn. geoelec

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“…A southward-tilted high-density layer below the Hayama-Mineoka belt, inferred from gravity and magnetic anomalies (Tonouchi and Kobayashi, 1983), also supports the obducted plate model.…”

Section: Tectonic Implication For Ophiolitic Rocks In the Hayama-minementioning

confidence: 76%

Sulfide minerals as an indicator for petrogenesis and serpentinization of peridotites: An example from the Hayama-Mineoka Belt, central Japan

Sato¹,

Ogawa²

2000

Ophiolites and Oceanic Crust: New Insights From Field Studies and the Ocean Drilling Program

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Assemblages of sulfide minerals ؉ awaruite ؉ native copper are used to estimate conditions for petrogenesis and serpentinization of their host peridotites in the Hayama-Mineoka belt, central Japan. The presence of primary sulfide grains (pentlandite) suggests that they are residual after moderate degrees of partial melting. This idea is supported by spinel and bulk-rock compositions of the peridotites, which indicate 15% to 30% partial melting. Assemblages of secondary sulfide minerals ؉ awaruite ؉ native copper that replace the primary sulfide indicate that the serpentinization of peridotites in the Hayama-Mineoka belt occurred under low f and low f conditions. O S 2 2The suggestion that the ophiolitic rocks in the Hayama-Mineoka belt might be equivalents of those in the Izu-BoninMariana forearcs on the Philippine Sea plate is not supported by the results of our study. As the peridotites of the forearcs are lacking in sulfide minerals because of higher degrees of partial melting and as the characteristics of the peridotites in the two occurrences differ, we conclude that the peridotites in the Hayama-Mineoka belt were originally part of another oceanic plate.

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“…According to Tonouchi & Kobayashi (1983), a heavy and magnetically polarized slab 5 km thick is dipping SW under the present oceanic floor SW of the Mineoka belt, and the northeastern tip appears as the ophiolite belt. They calculate that the part of the Philippine Sea plate, originally formed at lat.…”

Section: Plate Tectonic Considerationsmentioning

confidence: 99%

“…Some part of the ophiolite which was formed at lat. 24~ about 40 Ma was accreted to the Mineoka area (Tonouchi & Kobayashi 1983;Ogawa 1983). Other dismembered ophiolites may have become the 'basement' of the trench slope in the Bonin, Mariana and, possibly, Yap areas (See text).…”

Section: Mineoka Beltmentioning

confidence: 99%

Emplacement of ophiolitic rocks in forearc areas: Examples from central Japan and Izu-Mariana-Yap island arc system

Ogawa

Naka

1984

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Recent results of ocean dredging of ophiolitic rocks in forearc areas in the west Pacific region are summarized and discussed together with the field data in the ophiolitic belts in the Setogawa and Mineoka forearc belts in central Japan. Metamorphism, deformation and sedimentation of the dismembered ophiolites in these regions indicate that they were emplaced at first in transform-fault areas or oceanic fracture zones, and they became the subsequent zones of initiation of subduction. Sometimes the mass of dismembered ophiolite was tectonically and sedimentarily mixed with island-arc materials and incorporated into the forearc belts during subsequent forearc tectonics.

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Paleomagnetic and Geotectonic Investigation of Ophiolite Suites and Surrounding Rocks in South-Central Honshu, Japan

Cited by 13 publications

References 31 publications

Paleomagnetism of alkali basalts occurring in Takakusayama and Ryuso districts, south-central Honshu, Japan.

Paleomagnetism of alkali basalts occurring in Takakusayama and Ryuso districts, south-central Honshu, Japan.

Sulfide minerals as an indicator for petrogenesis and serpentinization of peridotites: An example from the Hayama-Mineoka Belt, central Japan

Emplacement of ophiolitic rocks in forearc areas: Examples from central Japan and Izu-Mariana-Yap island arc system

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