Tectonic implications of Early Miocene OIB magmatism in a near-trench setting: The Outer Zone of SW Japan and the northernmost Ryukyu Islands

Kiminami, Kazuo; Imaoka, Teruyoshi; Ogura, Kazuki; Kawabata, Hiroshi; Ishizuka, Hiroki; Mori, Yasushi

doi:10.1016/j.jseaes.2016.12.033

Cited by 15 publications

(18 citation statements)

References 110 publications

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“…The rollback and back‐arc rifting may have also extended into central Sabah, forming the Late Miocene Tongod‐Telupid BAB‐type ophiolite. The IAB‐OIB‐transitional Jelai basaltic‐andesites likely reflects possible near‐trench entrainment of deeper and more‐enriched mantle during the slab rollback, or slab‐tearing/fracturing similar to the northernmost Miocene Ryukyu arc (Kiminami et al., 2017).…”

Section: Tectonomagmatic Evolution Of Sulu Sea Arc‐basin Systemmentioning

confidence: 99%

Cenozoic Evolution of the Sulu Sea Arc‐Basin System: An Overview

et al. 2021

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Section: Tectonomagmatic Evolution Of Sulu Sea Arc‐basin Systemmentioning

confidence: 99%

Cenozoic Evolution of the Sulu Sea Arc‐Basin System: An Overview

et al. 2021

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“…In detail, S9 pumice samples have relatively higher 87 Sr/ 86 Sr ratios (0.70480-0.70502) and lower 143 Nd/ 144 Nd ratios (0.51272-0.51274; εNd = 1.67-2.05) compared with the MOT basalt [57], andesite and type I rhyolite [26] (Table 1). Additionally, these pumice samples have Sr-Nd isotope ratios similar to those of the central Ryukyu basalts [50,53] and plot within the overlapping fields of Indian Ocean MORB and Philippine Sea sediment [57][58][59][60] in the Sr-Nd isotope diagrams ( Figure 6). Figure 7).…”

Section: Sr-nd-pb Isotopesmentioning

confidence: 80%

“…Additionally, all these pumice samples lie distinctly above the Northern Hemisphere reference line (NHRL) [62] and are compositionally within the field of southern Kyushu and Indian Ocean MORB (Figure 7). [17,24,26,27,57], basalts from the northern West Philippine Basin [55,56], basalts from the northern Ryukyu volcanic front [37,50,51], basalts from the central Ryukyu arc [37]. Indian MORB, Pacific MORB and Philippine Sea sediments (PetDB database; http://www.earthchem.org/petdb) are also shown for comparison.…”

Section: Sr-nd-pb Isotopesmentioning

confidence: 99%

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Origin of Pumice in Sediments from the Middle Okinawa Trough: Constraints from Whole-Rock Geochemical Compositions and Sr-Nd-Pb Isotopes

Fang

Zeng

et al. 2019

JMSE

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Frequent volcanic activity has occurred in the Okinawa Trough (OT) during the late Quaternary, which attracted much attention to the origin of volcanic rocks. Pumice collected from the seafloor has been extensively investigated, whereas few studies paid attention to the pumice in the sediment. The geochemical compositions of pumice preserved in sediments generally provide insight into past volcanic activity and regional magmatism. Here, we present major and trace element compositions and Sr-Nd-Pb isotope data, together with the established age framework for pumice samples recovered from sediment core S9 in the middle OT (MOT) to investigate their possible formation. Compositionally, the S9 pumice samples are dacite and are characterized by relatively higher Sr (87Sr/86Sr = 0.70480–0.70502) and Pb (206Pb/204Pb = 18.321-18.436, 207Pb/204Pb = 15.622–15.624, and 208Pb/204Pb = 38.52–38.63) and lower Nd (143Nd/144Nd = 0.51272–0.51274) isotope compositions than basalts from the MOT. The geochemical compositions of pumice clasts from different layers of core S9 display no temporal variation trends and vary within narrow ranges. On the basis of the geochemical characteristics of S9 pumice samples, we infer that the parent magma of these samples might generate from hybrid magma through an extensive fractional crystallization process. The Indian Ocean MORB-type mantle was first metasomatized by the subducted Philippine Sea sediments to form the primitive magma; then, followed by assimilation of a small amount of lower crustal component occurred in the lower crust. The long-term magmatism and relatively consistent isotopic compositions indicate that a magma chamber might have existed in the lower crust of the MOT between 11.22 and 12.96 cal. ka BP.

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“…The gabbros in this study, which show OIB-like or transitional OIB/E-MORB-like geochemical characteristics, have been dated to the Early Silurian. Previous researches have demonstrated that the intraplate-type mafic rocks with OIB-like or E-MORB-like affinities can form in various tectonic settings, such as mantle plume-related oceanicislands/seamounts [24,37], continental rifts [86] and large igneous province [88], and slab window settings associated with ridge subduction [4] and slab tearing [9,103] during oceanic subduction stage and slab break-off at postcollision stage [104].…”

Section: Tectonic Implicationsmentioning

confidence: 99%

Age and Petrogenesis of the Gabbros from Tajik South Tianshan: Implications for Early Paleozoic Geodynamic Evolution of the Southwestern Central Asian Orogenic Belt

et al. 2020

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Identification of slab window process is important for understanding the nature of the accretionary orogenesis. In this study, we report detailed petrological, geochronological, geochemical, Sr–Nd isotopic, and mineral chemical data for two dyke-like gabbroic intrusions from the South Tianshan belt of Tajikistan, southwestern margin of the Central Asian Orogenic Belt. Both intrusions are composed of coarse- and fine-grained gabbros. U–Pb zircon dating shows that they were emplaced at 431±5 Ma. The gabbroic rocks show relatively large variation in elemental and isotopic compositions, with SiO2 of 40.62–53.97 wt.%, Sr of 333–1261 ppm, and εNdt of +2.5 to +5.8. Especially, the fine-grained gabbros show lower SiO2 and higher MgO but more evolved isotopes than the coarse-grained gabbros for each of the intrusions. All the rocks display OIB-like or transitional OIB-/E-MORB-like geochemical characteristics with no obvious Nb-Ta depletion, indicative of an intraplate affinity. Combined with their mineral chemical compositions, we suggest that these gabbroic rocks were generated by partial melting of asthenospheric mantle in the transitional spinel-garnet stability field, followed by different degrees of fractional crystallization of olivine, clinopyroxene, and plagioclase and mixing with carbonatitic melts. The available data indicate that roll-back of the subducting Turkestan oceanic slab occurred during the Late Ordovician to Early Silurian period. Asthenosphere upwelling due to the opening of slab window resulted from localized slab tearing during slab roll-back may have been responsible for the generation of the studied dyke-like gabbroic intrusions.

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Tectonic implications of Early Miocene OIB magmatism in a near-trench setting: The Outer Zone of SW Japan and the northernmost Ryukyu Islands

Cited by 15 publications

References 110 publications

Cenozoic Evolution of the Sulu Sea Arc‐Basin System: An Overview

Cenozoic Evolution of the Sulu Sea Arc‐Basin System: An Overview

Origin of Pumice in Sediments from the Middle Okinawa Trough: Constraints from Whole-Rock Geochemical Compositions and Sr-Nd-Pb Isotopes

Age and Petrogenesis of the Gabbros from Tajik South Tianshan: Implications for Early Paleozoic Geodynamic Evolution of the Southwestern Central Asian Orogenic Belt

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