Paleomagnetic results and K-Ar dating on miocene rocks in the northern part of Fukui Prefecture, Central Japan. With reference to the rotation of southwest Japan.

Nakajima, Tadashi; Sawada, Yoshihiro; Nakagawa, Tomio; Hayashi, Akiyo; Itaya, Tetsumaru

doi:10.2465/ganko.85.45

Cited by 33 publications

(14 citation statements)

References 12 publications

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“…This model, hereafter called the 15-Ma rapid rotation model, is supported by several studies based on data from volcanic rocks (Otofuji et al 1991;Shimada et al 2001). However, this model has been questioned, given the results of a number of paleomagnetic and geochronological studies (e.g., Nakajima et al 1990;Jolivet et al 1995) that cite an absence or lack of data for the rotation of rocks dating from ca. 15 Ma in some areas of Southwest Japan (Hoshi and Sano 2013;Sawada et al 2013; and references therein), thus leading to an alternative view that clockwise rotation occurred before (not at) 15 Ma (e.g., Nakajima et al 1990;Hoshi et al 2000b).…”

Section: Introductionmentioning

confidence: 86%

“…The data from Izumo also suggest that clockwise rotation was complete by 15 Ma. Furthermore, studies conducted in other areas of Southwest Japan have provided timeaveraged mean directions suggesting little or no rotation since 15 Ma (Nakajima et al 1990;Itoh et al 2000;Hoshi et al 2000b;Hoshi and Yokoyama 2001;Tamaki et al 2006;Hoshi and Sano 2013).…”

Section: Paleomagnetic Directions and Tectonic Implicationsmentioning

confidence: 99%

“…However, this model has been questioned, given the results of a number of paleomagnetic and geochronological studies (e.g., Nakajima et al 1990;Jolivet et al 1995) that cite an absence or lack of data for the rotation of rocks dating from ca. 15 Ma in some areas of Southwest Japan (Hoshi and Sano 2013;Sawada et al 2013; and references therein), thus leading to an alternative view that clockwise rotation occurred before (not at) 15 Ma (e.g., Nakajima et al 1990;Hoshi et al 2000b). However, the majority of such data are from volcanic rocks which have been radiometrically dated by conventional K-Ar or fission track methods, which are subject to significant uncertainties.…”

Section: Introductionmentioning

confidence: 99%

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Timing of clockwise rotation of Southwest Japan: constraints from new middle Miocene paleomagnetic results

et al. 2015

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Southwest Japan rotated clockwise during the late stage of the opening of the Japan Sea, although the exact timing of the rotation is controversial. A recent biostratigraphic study has revealed that the Miocene Oidawara Formation in eastern Southwest Japan was deposited just before 15 Ma; consequently, its paleomagnetic direction may help constrain the timing of rotation. For this purpose, we collected fine felsic tuffs and siltstones at 71 stratigraphic sites (horizons) in the Oidawara Formation. An analysis of alternating field and thermal demagnetization results yielded characteristic remanent magnetization (ChRM) directions for 177 samples. Approximately 80 % (142) of the samples exhibit reverse polarity ChRM directions that are thought to be paleofield directions of reverse polarity Chron C5Br. Normal polarity ChRM directions in 35 samples include primary paleofield records as well as records of secondary magnetization. The data suggest that a short normal polarity interval (microchron or cryptochron) at~15.8 Ma is present within the dominantly reverse polarity interval of Chron C5Br. Reliable site-mean directions for 19 sites yield a tilt-corrected formation-mean direction of D = 10.5°, I = 41.1°, α 95 = 7.0°, and k = 23.9, indicating virtually no rotation with respect to a reference paleomagnetic direction for the Asian continent. A rotation versus age plot for Southwest Japan indicates that the clockwise rotation started after 17.5 Ma and ceased largely before 15.8 Ma, yielding a rotation rate of~23°/Myr.

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Section: Introductionmentioning

confidence: 86%

Section: Paleomagnetic Directions and Tectonic Implicationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Timing of clockwise rotation of Southwest Japan: constraints from new middle Miocene paleomagnetic results

et al. 2015

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“…Subsequent paleomagnetic studies, however, have disclosed the onset of the rotation to be Early Miocene or earlier time (Nakajima et al, 1990;Hoshi and Takahashi, 1999).…”

Section: Previous Workmentioning

confidence: 95%

Stratigraphic review of Eocene to Oligocene successions along the eastern Japan Sea: Implication for early opening of the Japan Sea

Kano

Uto

Ohguchi

2007

Journal of Asian Earth Sciences

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“…Northern NE Japan is considered to have rotated before 17 Ma, whereas SW Japan rapidly rotated clockwise at about 15 Ma (Hayashida, 1986;Nakajima et al, 1990;Otofuji et al, 1991). This suggests diachronic differential rotation in the Japan Arc in the opening period of the Japan Sea.…”

Section: Counter-clockwise Rotation Of Northern Ne Japanmentioning

confidence: 99%

Early Miocene paleomagnetic results from the Ninohe area, NE Japan: Implications for arc rotation and intra-arc differential rotations

Hoshi

Matsubara

2014

Earth Planet Sp

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We have carried out a paleomagnetic study on well-dated Early Miocene volcanic rocks from the Ninohe area in northern NE Japan. Dacitic welded tuffs ranging from 24 to 21 Ma possess westerly paleomagnetic directions with normal polarity (formation-mean: D/I = 294.5°/44.2° with α 95 = 8.3°, 8 sites), while the andesite flows formed at 17 Ma exhibit southerly directions with reversed polarity (D/I = 186.6°/-61.9°, 2 sites). A positive conglomerate test assures the stability of high-temperature components of remanent magnetization. Our results demonstrate that northern NE Japan rotated counter-clockwise through more than 60° between 21 and 17 Ma, most likely in association with the opening of the Japan Sea. The rotation of northern NE Japan thus preceded the about 15 Ma rapid clockwise rotation of SW Japan, and was synchronous with the possible pre-16 Ma southward translation of it. In comparison with published data, we further suggest that intra-arc block rotations occurred in the back-arc region of NE Japan during and after the arc rotation.

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Paleomagnetic results and K-Ar dating on miocene rocks in the northern part of Fukui Prefecture, Central Japan. With reference to the rotation of southwest Japan.

Cited by 33 publications

References 12 publications

Timing of clockwise rotation of Southwest Japan: constraints from new middle Miocene paleomagnetic results

Timing of clockwise rotation of Southwest Japan: constraints from new middle Miocene paleomagnetic results

Stratigraphic review of Eocene to Oligocene successions along the eastern Japan Sea: Implication for early opening of the Japan Sea

Early Miocene paleomagnetic results from the Ninohe area, NE Japan: Implications for arc rotation and intra-arc differential rotations

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