Ordovician arc ophiolite, the Hayachine and Miyamori complexes, Kitakami Mountains, Northeast Japan: isotopic ages and geochemistry.

Shibata, Ken; Ozawa, Kazuhito

doi:10.2343/geochemj.26.85

Cited by 31 publications

(21 citation statements)

References 21 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…It emplaced across the Hayachine tectonic belt which separates the north Kitakami belt of Jurassic accretional complex from the south Kitakami belt of pre‐Silurian basements [ Ehiro and Kanisawa , 1999; Ehiro and Suzuki , 2003]. The tectonic belt is defined as two fault zones comprising basic to ultrabasic rocks of an Ordovician arc ophiolite [ Shibata and Ozawa , 1992]. The Ordovician arc ophiolite has been separated by the Hizume‐Kesennuma fault, being displaced to the south in the early Cretaceous by a sinistral strike‐slip fault [ Ehiro , 1977; Ozawa , 1984].…”

Section: Geological Backgroundmentioning

confidence: 99%

Magnetite microexsolutions in silicate and magmatic flow fabric of the Goyozan granitoid (NE Japan): Significance of partial remanence anisotropy

2006

View full text Add to dashboard Cite

[1] Anisotropy of magnetic susceptibility (AMS) has been widely used to infer magmatic flow patterns of granitoids where an appropriate AMS axis is parallel to an alignment of mafic minerals or magnetite. The magmatic flow fabric in Cretaceous granitic plutons from northeastern Japan was verified using an analysis of anisotropy of partial anhysteretic remanent magnetization (ApARM) which further isolates the magnetite subfabrics according to magnetite grain size. The preferred orientation of polysynthetic twins in plagioclase laths and clinopyroxene is discordant with the bulk AMS fabric along outer marginal zones of the granitoid, as shown by image analysis of microphotographs from thin sections cut in orthogonal planes. This suggests that the uncorroborated use of bulk AMS to detect flow fabric in granitoids has risks. Scanning electron microscopy (SEM) reveals that submicroscopic, needle-shaped magnetite inclusions exsolved in anhedral plagioclase and clinopyroxene may explain such anomalous exceptions to the validity of AMS fabrics. Our ApARM measurements show that the ApARM alignment of relatively high-coercive, submicroscopic magnetite inclusions is concordant to the linear orientation of anhedral plagioclase and clinopyroxene. The combination of SEM, AMS, and ApARM was required to confirm the magmatic and submagmatic flow pattern of granitoids in this study and is generally preferable to the use of AMS alone.Citation: Usui, Y., N. Nakamura, and T. Yoshida (2006), Magnetite microexsolutions in silicate and magmatic flow fabric of the Goyozan granitoid (NE Japan): Significance of partial remanence anisotropy,

show abstract

Section: Geological Backgroundmentioning

confidence: 99%

Magnetite microexsolutions in silicate and magmatic flow fabric of the Goyozan granitoid (NE Japan): Significance of partial remanence anisotropy

2006

View full text Add to dashboard Cite

show abstract

“…Thus, we think that the Os isotopic composition of the CSUS peridotite has not been modified by influx of slab -derived carbonate -rich silicate melt because of less oxidized conditions in the incipient arc stage. Os isotopic range of the 73003 harzburgite using previously obtained age (430 -510 Ma; Shibata and Ozawa, 1992;Yoshikawa and Ozawa, 2007). The initial Os isotopic data for chromitites in ophiolites (Walker et al, 2002) and present depleted mid -ocean ridge source mantle (DMM) range (Snow and Reisberg, 1995) are also shown.…”

Section: Os/ 188mentioning

confidence: 99%

“…The HM complex has been interpreted to have been formed in the early Ordovician on the basis of the Sm -Nd crystallization age of gabbro (510 ± 70 Ma; Shibata and Ozawa, 1992), the Nd model age of the ASUS peridotites (430 Ma; Yoshikawa and Ozawa, 2007), and the Sm -Nd isochron age employing the previously reported data of the ASUS lherzolites (Yoshikawa and Ozawa, 2007) Ludwig, 2003). Subchondritic Os isotopic composition of sample 73003 is consistent with melt depletion in the early Ordovician (around 500 Ma) suggested by previous studies.…”

Section: Os/ 188mentioning

confidence: 99%

Geochemical and Os isotopic characteristics of a fresh harzburgite in the Hayachine-Miyamori ophiolite: Evidence for melting under influx of carbonate-rich silicate melt in an infant arc environment

Yoshikawa

Suzuki

Shibata

et al. 2012

Journal of Mineralogical and Petrological Sciences

Self Cite

View full text Add to dashboard Cite

Os isotopic composition ( 187Os/ 188 Os = 0.1235) of a refractory harzburgite in the Hayachine -Miyamori ophiolite is subchondritic, indicating the long -term depletion of Re. Such an unradiogenic Os isotopic signature is consistent with the less oxidized condition at subduction initiation. The major and trace element characteristics of the harzburgite, together with its petrography and relatively high modal abundance of clinopyroxene, suggest an involvement of a carbonate -rich silicate melt during melt extraction in arc setting.

show abstract

“…Data sources for (a) are HM ophiolite hornblende K – A r ages from O zawa et al . () and S hibata and O zawa (), an HM ophiolite clinopyroxene Sm–Nd model age from Y oshikawa and O zawa (), an HM ophiolite whole‐rock Sm–Nd isochron age from S hibata and O zawa (), an HM ophiolite clinopyroxene S m– N d isochron age from Y oshikawa et al . (), and K agura trondhjemite and O guro formation tuff zircon U – P b ages from S himojo et al .…”

Section: A Review On the Hayachine–miyamori Ophiolite And The Kitakammentioning

confidence: 99%

“…Ultramafic and mafic igneous/metamorphic rocks are widely distributed along the boundary zone between the North and South Kitakami massifs (Onuki , , ; Ozawa ; Shibata & Ozawa ; Ehiro & Suzuki ; Yoshikawa & Ozawa ; Yoshikawa et al . ; Kawamura et al .…”

Section: A Review On the Hayachine–miyamori Ophiolite And The Kitakammentioning

confidence: 99%

Evolution processes of Ordovician–Devonian arc system in the South‐Kitakami Massif and its relevance to the Ordovician ophiolite pulse

et al. 2015

Self Cite

View full text Add to dashboard Cite

The South Kitakami Massif is one of the oldest geological domains in Japan having Silurian strata with acidic pyroclastic rocks and Ordovician–Silurian granodiorite–tonalite basement, suggesting that it was matured enough to develop acidic volcanisms in the Silurian period. On the northern and western margin of the South Kitakami Massif, an Ordovician arc ophiolite (Hayachine–Miyamori Ophiolite) and high‐pressure and low‐temperature metamorphic rocks (Motai metamorphic rocks) exhumed sometime in the Ordovician–Devonian periods are distributed. Chronological, geological, and petrochemical studies on the Hayachine–Miyamori Ophiolite, Motai metamorphic rocks, and other early Paleozoic geological units of the South Kitakami Massif are reviewed for reconstruction of the South Kitakami arc system during Ordovician to Devonian times with supplementary new data. The reconstruction suggests a change in the convergence polarity from eastward‐ to westward‐dipping subduction sometime before the Late Devonian period. The Hayachine–Miyamori Ophiolite was developed above the eastward‐dipping subduction through three distinctive stages. Two separate stages of overriding plate extension inducing decompressional melting with minor involvement of slab‐derived fluid occurred before and after a stage of melting under strong influence of slab‐derived fluids. The first overriding plate extension took place in the back‐arc side forming a back‐arc basin. The second one took place immediately before the ophiolite exhumation and near the fore‐arc region. We postulate that the second decompressional melting was triggered by slab breakoff, which was preceded by slab rollback inducing trench‐parallel wedge mantle flow and non‐steady fluid and heat transport leaving exceptionally hydrous residual mantle. The formation history of the Hayachine–Miyamori Ophiolite implies that weaker plate coupling may provide preferential conditions for exhumation of very hydrous mantle. Very hydrous peridotites involved in arc magmatism have not yet been discovered except for in the Cambrian–Ordovician periods, suggesting its implications for global geodynamics, such as the thermal state and water circulation in the mantle.

show abstract

Ordovician arc ophiolite, the Hayachine and Miyamori complexes, Kitakami Mountains, Northeast Japan: isotopic ages and geochemistry.

Cited by 31 publications

References 21 publications

Magnetite microexsolutions in silicate and magmatic flow fabric of the Goyozan granitoid (NE Japan): Significance of partial remanence anisotropy

Magnetite microexsolutions in silicate and magmatic flow fabric of the Goyozan granitoid (NE Japan): Significance of partial remanence anisotropy

Geochemical and Os isotopic characteristics of a fresh harzburgite in the Hayachine-Miyamori ophiolite: Evidence for melting under influx of carbonate-rich silicate melt in an infant arc environment

Evolution processes of Ordovician–Devonian arc system in the South‐Kitakami Massif and its relevance to the Ordovician ophiolite pulse

Contact Info

Product

Resources

About