Abstract
The hig-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 I H -and S H -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 I H -type and garnet-orthopyroxene aluminous granulite for S H -type. The unexposed lowermost crust of the 'Hidaka crust' is thought to be composed of garnet-twopyroxene mafic granulite, garnet-orthopyroxene aluminous granulite and metagabbros.
| Original language | English |
|---|---|
| Pages (from-to) | 161-179 |
| Number of pages | 19 |
| Journal | Special Paper of the Geological Society of America |
| Volume | 389 |
| DOIs | |
| Publication status | Published - Jan 1 2004 |
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All Science Journal Classification (ASJC) codes
- Geology
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Variety and genesis of the pyroxene-bearing S-and I-type granitoids from the Hidaka Metamorphic Belt, Hokkaido, northern Japan. / Shimura, Toshiaki; Owada, Masaaki; Osanai, Yasuhito; Komatsu, Masayuki; Kagami, Hiroo.
In: Special Paper of the Geological Society of America, Vol. 389, 01.01.2004, p. 161-179.Research output: Contribution to journal › Article
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TY - JOUR
T1 - Variety and genesis of the pyroxene-bearing S-and I-type granitoids from the Hidaka Metamorphic Belt, Hokkaido, northern Japan
AU - Shimura, Toshiaki
AU - Owada, Masaaki
AU - Osanai, Yasuhito
AU - Komatsu, Masayuki
AU - Kagami, Hiroo
PY - 2004/1/1
Y1 - 2004/1/1
N2 - The hig-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 I H -and S H -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 I H -type and garnet-orthopyroxene aluminous granulite for S H -type. The unexposed lowermost crust of the 'Hidaka crust' is thought to be composed of garnet-twopyroxene mafic granulite, garnet-orthopyroxene aluminous granulite and metagabbros.
AB - The hig-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 I H -and S H -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 I H -type and garnet-orthopyroxene aluminous granulite for S H -type. The unexposed lowermost crust of the 'Hidaka crust' is thought to be composed of garnet-twopyroxene mafic granulite, garnet-orthopyroxene aluminous granulite and metagabbros.
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U2 - 10.1130/0-8137-2389-2.161
DO - 10.1130/0-8137-2389-2.161
M3 - Article
AN - SCOPUS:84874978454
VL - 389
SP - 161
EP - 179
JO - Special Paper of the Geological Society of America
JF - Special Paper of the Geological Society of America
SN - 0072-1077
ER -