Variety and genesis of the pyroxene-bearing S- and I-type granitoids from the Hidaka Metamorphic Belt, Hokkaido, northern Japan

Abstract

The high-dT/dP-type Hidaka Metamorphic Belt in Hokkaido, northern Japan, represents a tilted crustal section of a magmatic arc of Tertiary age. The highest metamorphic grades reached are granulite facies, and the syn-metamorphic granitic rocks are widely distributed in this metamorphic terrane. The granitic rocks are mainly tonalitic and granodioritic in composition, and are classified into peraluminous (S-type) and metaluminous (I-type) granitoids. A large amount of pyroxene-bearing S-type tonalites (garnet-orthopyroxene tonalite) is distributed in the Niikappu river region in the northern part of the Hidaka Metamorphic Belt. Pyroxene-bearing I-type tonalite (two-pyroxene hornblende tonalite) bodies are also distributed in this area.The pyroxene-bearing tonalites are classified into several sub-types on the basis of their field occurrence, texture, mineral assemblage and geochemical features. Homogeneous IH- and SH-type tonalite are thought to represent original magmas, i.e. those which have been generated by partial melting of mafic metamorphic rocks and pelitic-psammitic metamorphic rocks, respectively. Model calculations assuming batch partial melting indicate that possible restites are garnet-two-pyroxene mafic granulite for IH-type and garnet-orthopyroxene aluminous granulite for SH-type. The unexposed lowermost crust of the ‘Hidaka crust’ is thought to be composed of garnet-two-pyroxene mafic granulite, garnet-orthopyroxene aluminous granulite and metagabbros.

Thermal structure and intermediate-depth seismicity in the Tohoku-Hokkaido subduction zones

“…Kimura (1994) demonstrated that the Kurile fore-arc has been colliding with the NE Japan arc since the Middle Miocene due to the migration to the southwest of the Kuril forearc sliver, forming an arc-arc type collision zone. High temperature metamorphic rocks of Tertiary age are exposed and include materials from the upper and lower crust (e.g., Shimura et al, 2004). Ito (2000) and Iwasaki et al (2004) suggested this region is characterized by delamination of the lower crust, with partial exhumation of the lower crust, and partial subduction along the Pacific slab.…”

Origin of the I- and S-type tonalite magma in the Satsunai-gawa Shichino-sawa river region of the Hidaka metamorphic belt, Hokkaido, northern Japan: Inferences from Sr and Nd isotopic compositions

“…1a -, 1986 , 1983 Kiyokawa, 1992, Ueda et al, 2001Komatsu et al, 1983 Komatsu et al (1986) and Shimura et al (2004). Ni, Niikappu-gawa River region; Os, Oshirabetsu region; Sa, Satsunai-gawa River region.…”

“…1 2 55 Ma 3 , 1992;Toyoshima et al, 1994;Owada et al, 2003 55 Ma Rb-Sr Owada et al, 1991;, 1992 , 1984;Tagiri et al, 1989;Osanai et al, 1991Osanai et al, , 1992Owada et al, 1991;, 1992;Shimura et al, 1992Shimura et al, , 2004Komatsu et al, 1994;, 1994; Whitney and Evans 2010, 1986Fig. 1a -, 1986 , 1983 Kiyokawa, 1992, Ueda et al, 2001Komatsu et al, 1983 Komatsu et al (1986) and Shimura et al (2004).…”

“…, 1985--, 1985, 1986Shimura et al, 1992-Chappell and White 1974S I , 1986Komatsu et al, 1989;Osanai et al, 1991;, 1992;Shimura et al, 1992Shimura et al, , 2004Shimura et al, S I S , 1986Shimura et al, S I , , 1986, 1992;, 1994;Shimura et al, 2004 …”

Isotopic ages of the Pankenushi olivine gabbro complex, Hidaka magmatic belt, central Hokkaido, Japan: implications for the tectonic setting of Hidaka magmatism

“…, , 1997--, , 1986, 1997Komatsu et al, 1994Komatsu et al, 1 , , 1986Komatsu et al, , 1992 P-T 7 kbar, 870°C 20 km , Osanai et al, 1992 , Osanai et al, 1992;Shimura et al, 1992Shimura et al, , 2004 N-MORB Sr Nd Kagami, 1994, 1996;, 1997;Kamiyama et al, 2007Kamiyama et al, -, 1982Kimura, 1986; Ishihara and Terashima, 1985;, 1986;, 1997;Ishihara et al, 1998Owada et al 199155 Ma Maeda and Kagami 1994, 1996 55 . The southern half of the Hidaka magmatic belt coincides with the Hidaka metamorphic belt (or the Hidaka crustal section).…”