Anisotropy of magnetic susceptibility of tonalite in the Tanzawa plutonic complex and its implications for emplacement mechanism.

Kanamaru, Tatsuo; Takahashi, Masaki

doi:10.5575/geosoc.111.458

Cited by 9 publications

(7 citation statements)

References 45 publications

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“…On the basis of the age data we deduce that the eastern side of the Tanzawa Tonalite Complex cooled uniformly, despite rock type differences, after the ∼180°C closure temperature of zircon in the (U‐Th)/He system was reached. This supports the conclusion of Kanamaru and Takahashi [2005]. Therefore we accept the average of the reliable ages and their standard error as the typical cooling age of the Tanzawa Tonalite Complex.…”

Section: Discussionsupporting

confidence: 87%

“…That also cooled uniformly through ∼80°C based on the apatite (U‐Th)/He ages. These support the conclusion of Kanamaru and Takahashi [2005]. Therefore we accept the average and standard error of the reliable ages as the typical cooling age of the Tanzawa Tonalite Complex.…”

Section: Discussionsupporting

confidence: 86%

“…At one time, the entire complex was thought to be tilted because Yushin‐type tonalite on the eastern side of the complex was considered to be higher level than the tonalite to the west, based on the presence of roof pendants in the eastern part around Mount Ishitanayama [e.g., Takita , 1974; Arai , 1987]. However, similar roof pendant rocks have since been found around Mount Ishiwariyama [ Kanamaru and Takahashi , 2005], and therefore, they concluded that the complex has not tilted significantly since intrusion based on the roof pendant evidence and new data on anisotropy of magnetic susceptibility and paleomagnetic direction.…”

Section: Geologymentioning

confidence: 99%

“…Geological map and sampling locations of the Tanzawa Tonalite Complex. Modified from Sugiyama [1976] and Kanamaru and Takahashi [2005] © Geological Society of Japan with permission.…”

Section: Geologymentioning

confidence: 99%

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Postcollisional exhumation history of the Tanzawa Tonalite Complex, inferred from (U‐Th)/He thermochronology and fission track analysis

Yamada

Tagami

2008

J. Geophys. Res.

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[1] The Tanzawa Mountains in the South Fossa Magna region, in the middle of the Japan Arc, were formed due to collision of the Izu-Bonin Arc against the Japan Arc during the last several million years. The Tanzawa Tonalite Complex is exposed in the Tanzawa Mountains and is inferred to represent middle crust of the Izu-Bonin Arc. We performed new thermochronometry, consisting of (U-Th)/He dating, fission track dating, and fission track length analysis for the complex to investigate the exhumation history of the Tanzawa Tonalite Complex caused by arc-arc collision. Typical (U-Th)/He ages were 2.0 ± 0.2 Ma on apatite, 3.3 ± 0.2 Ma on zircon, and 4.5 to 6.9 Ma on zircon using the fission track method. The mean fission track length was 9.7 ± 0.6 mm (2 SE). The cooling rate of the tonalite has been calculated to be in the range of 20°-60°C Ma À1 from $7 to 3.3 Ma, $80°C Ma À1 from 3.3 to 2.0 Ma, and $30°C Ma À1 from 2.0 to 0 Ma assuming a surface temperature of 10°C. The exhumation rate has been calculated to be 0.5 to 1.5 mm a À1 from $7 to 3.3 Ma, $2 mm a À1 from 3.3 to 2.0 Ma, and $0.8 mm a À1 from 2.0 to 0 Ma with an assumed geothermal gradient of 40°C km À1 . The exhumation rate has not changed significantly despite the simultaneous tectonic changes around the Tanzawa Mountains after $7 Ma.

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Section: Discussionsupporting

confidence: 87%

Section: Discussionsupporting

confidence: 86%

Section: Geologymentioning

confidence: 99%

“…Geological map and sampling locations of the Tanzawa Tonalite Complex. Modified from Sugiyama [1976] and Kanamaru and Takahashi [2005] © Geological Society of Japan with permission.…”

Section: Geologymentioning

confidence: 99%

See 2 more Smart Citations

Postcollisional exhumation history of the Tanzawa Tonalite Complex, inferred from (U‐Th)/He thermochronology and fission track analysis

Yamada

Tagami

2008

J. Geophys. Res.

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“…4 Ma , 1986;Amano, 1991;Takahashi, 1994;Takahashi and Saito, 1997 1968 1933, 1934 1968 1974, 1980 1976 Kawate and Arima 1998Kitamura et al, 2003, 2004;, 20072005 Sato, T. and Takagi, H., 2010, Paleostress history estimated from preferred orientation of microcracks in the Tanzawa tonalite body, central Japan and its relationship to the Honshu arc-Izu arc collision. Jour.…”

mentioning

confidence: 99%