scholarly journals Post-Opening Deformation History of the Japan Sea Back-Arc Basin: Tectonic Processes on an Active Margin Governed by the Mode of Plate Convergence

2018 ◽  
Author(s):  
Yasuto Itoh
Keyword(s):  
Japan Sea ◽  
Deformation History ◽  
Active Margin ◽  
Plate Convergence ◽  
Tectonic Processes ◽  
The Japan Sea ◽  
History Of ◽  
Back Arc

scholarly journals Last stage of the Japan Sea back-arc opening deduced from the seismic velocity structure using wide-angle data

2006 ◽  
Vol 7 (6) ◽  
pp. n/a-n/a ◽  
Author(s):  
Takeshi Sato ◽  
Narumi Takahashi ◽  
Seiichi Miura ◽  
Gou Fujie ◽  
Dong-Hyo Kang ◽  
...  
Keyword(s):  
Velocity Structure ◽  
Seismic Velocity ◽  
Japan Sea ◽  
Wide Angle ◽  
Seismic Velocity Structure ◽  
Angle Data ◽  
The Japan Sea ◽  
Last Stage ◽  
Back Arc

U–Pb ages of Miocene near-trench granitic rocks of the Southwest Japan arc: implications for magmatism related to hot subduction

2019 ◽  
Vol 158 (1) ◽  
pp. 47-71 ◽  
Author(s):  
Hironao Shinjoe ◽  
Yuji Orihashi ◽  
Ryo Anma
Keyword(s):  
Middle Miocene ◽  
Japan Sea ◽  
Wide Distribution ◽  
Granitic Rocks ◽  
Philippine Sea Plate ◽  
Kii Peninsula ◽  
The Japan Sea ◽  
Igneous Activity ◽  
Mariana Arc ◽  
Back Arc

AbstractWe present a new dataset of zircon U–Pb ages that document igneous activity in the SW Japan arc during middle Miocene time and discuss its relationship with the opening of the Japan Sea, Philippine Sea plate migration, and subduction of the young hot lithosphere of the Shikoku Basin. Precursory magmatism, characterized by dike and stock intrusions, started c. 15.6 Ma in both Kyushu and the Kii Peninsula. Most plutonism occurred between 15.5 and 13.5 Ma in an area 600 km long and 150 km wide. No along-arc trend was recognized in the U–Pb ages of igneous activity near the trench. Our data indicate that all near-trench middle Miocene igneous activity occurred immediately after the opening of the Japan Sea ceased, i.e. after 16 Ma, implying that melt extraction and the emplacement of granites in the near-trench region had some influence on the back-arc opening. Our data also imply that the trench–trench–trench-type triple junction between the Japan arc and the Izu–Bonin–Mariana arc must have reached the east side of the Kii Peninsula by 15.6 Ma. The wide distribution of contemporaneous magmatic activity along the arc requires a trench-parallel heat source, such as the subduction of a trench-parallel ridge or a young and highly segmented ridge–fracture zone system in addition to the hot wedge mantle condition related to the opening of Japan Sea.

Neogene deformation of the back-arc shelf of Southwest Japan and its impact on the palaeoenvironments of the Japan Sea

1997 ◽  
Vol 281 (1-2) ◽  
pp. 71-82 ◽  
Author(s):  
Yasuto Itoh ◽  
Takeshi Nakajima ◽  
Atsushi Takemura
Keyword(s):  
Japan Sea ◽  
Southwest Japan ◽  
The Japan Sea ◽  
Back Arc

Zircons to the front: accretionary history of the Rheno-Hercynian active margin (Variscides, Germany)

2019 ◽  
Vol 56 (12) ◽  
pp. 1375-1397 ◽  
Author(s):  
Wolfgang Franke ◽  
Hermann Huckriede ◽  
Paul O’Sullivan ◽  
Klaus Wemmer
Keyword(s):  
Foreland Basin ◽  
Late Devonian ◽  
Metamorphic Belt ◽  
Active Margin ◽  
History Of ◽  
Southern Portugal ◽  
Late Neoproterozoic ◽  
Palinspastic Restoration ◽  
Back Arc ◽  
Detrital Mineral

Our paper reports the detrital zircon record from Late Devonian to late Carboniferous foreland basin deposits in the Rheno-Hercynian (RH) Variscides of Germany. Together with a review of petrography and detrital mineral ages from the literature, the data permit to reconstruct accretion and exhumation along the RH active margin. From Frasnian to latest Carboniferous, the main source (now eroded) was a north-Armorican microcontinent (Franconia) with magmatic rocks representing late Neoproterozoic arc or back-arc, Cambro-Ordovician rift and Silurian–Early Devonian subduction of the Rheic ocean and (or) RH rifting. At ca. 380 Ma, detrital magmatic zircons combined with high- to medium-pressure mica and detrital glaucophane suggest the existence of a paired metamorphic belt at the RH tectonic front. From the Viséan onwards, zircons reveal younging of granitoid debris from ca. 380–360 Ma in Late Devonian sediments to ca. 320–300 Ma in the Westphalian C–D and Stephanian. Greywackes of the Namurian A record a change from dominant magmatic clasts toward meta-arenites associated with Baltoscandian zircons, which document accretion to and exhumation from the base of the orogenic wedge. Their source must be sought in metamorphosed Devonian sandstones of the type presently encountered in parts of the active margin crystallines (Mid-German Crystalline High), but in eroded higher units. Basal accretion implies heating of the lower plate beyond the brittle–ductile boundary and supports the model of a high-temperature regime before and during Variscan collision. Palinspastic restoration of the estimated volume of recycled material yields >100 km of distal shelf deposits lost in the process, which adds to the known shortening of the RH basin. The Variscan geology of southwestern England and southern Portugal and provenance studies in those areas are compatible with a geodynamic evolution similar to that in Germany.

scholarly journals Alkali basalt from the Seifu seamount of the Japan Sea: post-spreading magmatism in the back-arc region

2019 ◽  
Author(s):  
Tomoaki Morishita ◽  
Naoto Hirano ◽  
Hirochika Sumino ◽  
Hiroshi Sato ◽  
Tomoyuki Shibata ◽  
...  
Keyword(s):  
Early Stage ◽  
Japan Sea ◽  
Spinel Peridotite ◽  
Stability Field ◽  
Alkaline Basalt ◽  
Trace Element Pattern ◽  
Low Degree ◽  
Element Pattern ◽  
The Japan Sea ◽  
Back Arc

Abstract. We report geochemical characteristics and Ar-Ar dating of a basalt dredged from the Seifu Seamount (SSM-basalt), located at northeast of the Tsushima Basin in the southwest Japan Sea, which is one of the western Pacific back-arc basin swarm. A plateau age of 8.33 ± 0.15 Ma (2σ) was obtained by the 40Ar-39Ar age spectrum of SSM-basalt. The SSM-basalt (8.3 Ma) was formed at an early stage after the termination of the Japan Sea back-arc opening. The SSM-basalt is high-K to shoshonitic alkaline basalt and is characterized by enrichment of light rare earth element (REE). The trace element pattern of the SSM-basalt is similar to Ocean island-type basalt (OIB) whereas YbPM (= 6) is distinctively higher than that of OIB, indicating of its formation by the low degree melting of the source mantle under spinel peridotite stability field. The Nd-Sr and Pb isotope compositions of the SSM-basalt are offset from the compositional trend of the Japan Sea back-arc basin basalts. The Sr-Nd isotope relationship of the SSM-basalt suggest its source can be formed by deplete MORB mantle source mixing with EM1-like component. The SSM basalt was formed as a post-back-arc spreading magmatism by low degree of partial melting of a portion that is easily melted in the upwelling asthenosphere associated with the main back-arc magmatism.

scholarly journals Taxonomy and palaeobiogeographical significance of four new species of <i>Semicytherura</i> (Ostracoda, Crustacea) from the Early Pleistocene Omma Formation of the Japan Sea coast

2008 ◽  
Vol 27 (2) ◽  
pp. 135-146 ◽  
Author(s):  
Hirokazu Ozawa ◽  
Takahiro Kamiya
Keyword(s):  
New Species ◽  
Benthic Fauna ◽  
Japan Sea ◽  
Early Pleistocene ◽  
Late Cenozoic ◽  
Shallow Sea ◽  
Central Japan ◽  
The Japan Sea ◽  
History Of ◽  
Sea Coast

Abstract. The genus Semicytherura (Ostracoda, Crustacea) is distributed widely in shallow-sea areas of the Northern Hemisphere and occurs commonly in Pliocene and Pleistocene strata along the Japan Sea coasts. Four new species -Semicytherura robustundata sp. nov., Semicytherura subslipperi sp. nov., Semicytherura leptosubundata sp. nov. and Semicytherura tanimurai sp. nov. - are described from the Early Pleistocene Omma Formation, central Japan. These species are palaeobiogeographically significant in the history of species diversity changes in Japan Sea benthic fauna during the Late Cenozoic. The geological and geographical occurrences suggest that these four species originated within the Japan Sea from the Late Pliocene, including one species that diversified by heterochronic evolution, and were endemic to the Japan Sea. They became extinct within this sea during the Early Pleistocene.

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