Hiroshi Kawabata

Hiroshi Kawabata
Kochi University · Faculty of Science

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86
Publications
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Publications

Publications (86)
Article
Full-text available
The Samoan mantle plume is thought to host three isotopically (radiogenic) distinct low‐³He/⁴He components including EM2 (enriched mantle 2), dilute HIMU (high μ = ²³⁸U/²⁰⁴Pb), and a depleted mantle (DM) component, which were sampled by shield‐stage lavas from the Malu, Vai, and Upo trend volcanoes, respectively. However, it is unclear whether the...
Article
This study investigates relicts of some granitic Gondwanan basement unexpectedly outcropping in the northwest of Central-East Iranian Microcontinent (CEIM) and incorporated into an ophiolitic mélange. Based on petrographical (e.g. high modal content of muscovite (~10 vol.%), absence of hornblende, inherited zircons (>541 Ma)), geochemical (peralumi...
Article
Magnesium isotopic fractionation during basalt differentiation is commonly thought to be negligible at current levels of analytical precision. However, Mg isotopic variation of ∼0.4 (δ 26 Mg) can be observed in some highly evolved volcanic rocks with MgO contents of <5 wt.%, suggesting that detectable Mg isotopic fractionation may occur during late...
Article
Chemical compositions of Fe-Mg biotite have been used to understand the petrogenesis of metamorphic and igneous rocks. However, biotite is affected by sub-solidus hydrothermal alteration, metamorphism, and chemical exchange with other common coexisting phases such as garnet and muscovite. Therefore, the interpretation of igneous and metamorphic pro...
Article
Ar‐Ar ages, and petrographical and geochemical characteristics of pyroclastics and an overlying lava from Teshima Island, SW Japan are presented. Although previous geological and age data suggested Teshima pyroclastics were products of magmatism >3 my prior to lava flows of Setouchi volcanic rocks generated in association with southward migration o...
Article
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T–prism is a Microsoft–Excel–based tool that visualizes ternary space diagrams (i.e., ternary prisms) in three–dimensional (3D) space. This tool allows us to examine the overall features of a dataset in both three– and two–dimensional spaces by altering the viewing angles. T–prism involves two algorithms that coordinate the transformation and rotat...
Article
Full-text available
The extreme Sr, Nd, Hf, and Pb isotopic compositions found in Pitcairn Island basalts have been labeled enriched mantle 1 (EM1), characterizing them as one of the isotopic mantle end members. The EM1 origin has been vigorously debated for over 25 years, with interpretations ranging from delaminated subcontinental lithosphere, to recycled lower cont...
Article
We investigated the Sr-Nd-Hf-Pb isotope compositions of clinopyroxene separates and strongly leached bulk rock powders from the basalt lavas on Raivavae Island in the South Pacific. These data allowed us to explore the magma chamber processes of the two basalt groups: the high-μ-type (μ= ²³⁸ U/²⁰⁴Pb, HIMU) Rairua basalts erupted at ∼9Ma, and the de...
Article
We explore the element redistribution at mid-ocean ridges (MOR) using a numerical model to evaluate the role of decompression melting of the mantle in Earth's geochemical cycle, with focus on the formation of the depleted mantle component. Our model uses a trace element mass balance based on an internally consistent thermodynamic-petrologic computa...
Article
We quantitatively explore element redistribution at subduction zones using numerical mass balance models to evaluate the roles of the subduction zone filter in the Earth's geochemical cycle. Our models of slab residues after arc magma genesis differ from previous ones by being internally consistent with geodynamic models of modern arcs that success...
Article
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Plutonic suite of Khajeh Morad at southeast of Mashhad includes granodiorites, which are cut across by younger aplite, granitic pegmatite dykes and monzogranites. Aplites are mineralogically including quartz, feldspar (albite to orthoclase and microcline), muscovite, and accessory minerals of garnet (almandine-spessartine), tourmaline, biotite, and...
Article
To investigate the nature and origin of across-arc geochemical variations over time in mantle wedge derived magmas, we have carried out a geochemical study of basalts in the NE Japan arc spanning an age range from 35 Ma to the present. Back-arc basalts erupted at 24–18 Ma, 10–8 Ma, 6–3 Ma and 2·5–0 Ma have higher concentrations of both high field s...
Article
The source mantle of the basaltic ocean crust on the western half of the Pacific Plate was examined using Pb-Nd-Hf isotopes. The results showed that the subducted Izanagi-Pacific Ridge (IPR) formed from both Pacific (180-80Ma) and Indian (80-70Ma) mantles. The western Pacific Plate becomes younger westward and is thought to have formed from the IPR...
Article
Full-text available
Plutonic suite of Khajeh Morad in southeast of Mashhad is including of granodiorites cut across by younger aplite, granitic pegmatite dykes and monzogranites. Aplites are mineralogically including quartz, feldspar (albite to orthoclase and microcline), muscovite, and accessory minerals of garnet (almandine-spessartine), tourmaline, biotite, and ilm...
Article
Full-text available
Plutonic suite of Khajeh Morad in southeast of Mashhad is including of granodiorites cut across by younger aplite, granitic pegmatite dykes and monzogranites. Aplites are mineralogically including quartz, feldspar (albite to orthoclase and microcline), muscovite, and accessory minerals of garnet (almandine-spessartine), tourmaline, biotite, and ilm...
Article
The Yamato Basin in the Japan Sea is a back-arc basin characterized by basaltic oceanic crust that is twice as thick as typical oceanic crust. Two types of ocean floor basalts, formed during the opening of the Japan Sea in the Middle Miocene, were recovered from the Yamato Basin during Ocean Drilling Program Legs 127/128. These can be considered as...
Article
During the Integrated Ocean Drilling Program (IODP), a total of 41.54 m of basement rock, consolidated volcaniclastic sediment, was recovered beneath a thin sediment cover. The drilled site is at the eastern end of the crestal area of Bowers Ridge, a north and westward sweeping offshoot of the Aleutian Arc into the Bering Sea. The volcanic sequence...
Article
We present a new numerical trace element mass balance model for adiabatic melting of a pyroxenite-bearing peridotite for estimating mantle potential temperature, depth of melting column, and pyroxenite fraction in the source mantle for a primary ocean basalt/picrite. The Ocean Basalt Simulator version 1 (OBS1) uses a thermodynamic model of adiabati...
Article
Triassic monzogranites and granodiorites of the Khajeh Morad region in northeastern Iran are cut by two types of garnet-bearing intrusive veins: (1) aplite and (2) granitic pegmatite. The former is composed of quartz, feldspar, muscovite, with minor garnet, biotite, and ilmenite. The latter contains quartz, plagioclase (± quartz and muscovite inclu...
Article
A numerical mass balance calculation model for the adiabatic melting of a dry to hydrous peridotite has been programmed in order to simulate the trace element compositions of basalts from mid-ocean ridges, back-arc basins, ocean islands, and large igneous provinces. The Excel spreadsheet-based calculator, Hydrous Adiabatic Mantle Melting Simulator...
Article
Full-text available
The granitoids of Dehnow in NE Iran are part of a calc-alkaline plutonic series (diorite-tonalite-granodiorite) that intruded the remnants of the Paleo-Tethys oceanic crust during the Triassic. New major and trace element data together with isotopic compositions elucidate their I-type nature and a deep magma origin. P-T calculations based on amphib...
Article
In response to the subduction of the young Shikoku Basin of the Philippine Sea Plate, arc magmas erupted in SW Japan throughout the late Cenozoic. Many magma types are present including ocean island basalt (OIB), shoshonite (SHO), arc-type alkali basalt (AB), typical sub-alkalic arc basalt (SAB), high-Mg andesite (HMA), and adakite (ADK). OIB erupt...
Article
HIMU (high-μ; 238U/204Pb) is a mantle reservoir that has been thought to form by subduction and subsequent storage of ancient oceanic crust and lithosphere in the mantle. In order to constrain the processes that acted on subducted materials over several billion years, we present precise Pb–Sr–Nd–Hf–He isotopic data together with 40Ar/39Ar and K/Ar...
Article
The Triassic Dehnow pluton of NE Iran is a garnet-bearing I-type calc-alkaline metaluminous diorite-tonalite-granodiorite intrusion. The parental magma formed as the result of partial melting of intermediate to felsic rocks in the lower crust. Petrological and geochemical evidence which favors of a magmatic origin for the garnet includes: large siz...
Article
Full-text available
Pagan is one of the largest volcanoes along the Mariana arc volcanic front. It has a maximum elevation of 570 m (Mt. Pagan), but its submarine flanks descend to 2000-3000 m below sea level, and are unexplored. Bathymetric mapping and ROV Hyper-Dolphin dives (HPD1147 and HPD1148) on the submarine NE and SW flanks of Pagan were carried out during cru...
Article
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The Ryozen Formation, which crops out on the trench side of the NE Japan arc, contains middle Miocene rhyodacite with adakite-like trace element geochemical characteristics (Ryozen adakitic rhyodacite) and spatially and temporally related basalt (Ryozen basalt) and andesite (Ryozen andesite). K-Ar age data for the basalt and a zircon U-Pb age for t...
Article
We investigated an appropriate instrumental setup for a laser-ablation multiple-collector inductively coupled plasma mass spectrometer (LA-MC-ICP-MS) and found that a reduced oxide setting allowed accurate and precise analysis of Nd isotope ratios in samples with or without concomitant interfering elements. We used an Aridus II solution-excimer las...
Article
We present analytical protocols and the analytical performance of Pb isotope analysis of silicate minerals and rocks at the Pb = 0.02-15 ppm level using excimer laser ablation (LA) coupled with an enhanced-sensitivity multiple collector-inductively coupled plasma mass spectrometer (MC-ICP-MS). We applied Faraday cups for all the isotopes analysed,...
Article
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Three submarine Diamante cross-chain volcanoes in the southern Mariana arc mark a magma-healed zone of along-arc (north–south) extension that allows either mafic mantle-derived basalts or felsic magmas from the middle of thickened arc crust to erupt. The largest volcano is East Diamante, with a well-developed (5×10 km) caldera that formed via viole...
Article
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Metamorphic rocks of Dehnow area mainly consist of gray to black fine-grained schists. Garnet schists are closer to the tonalitic body than the garnet chloritoid schists. There is a thin layer of staurolite and andalusite bearing hornfels between these schists and the Dehnow tonalitic body. Garnet schists and garnet chloritoid schists of Dehnow are...
Article
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[PUBLISHED IN: IRANIAN JOURNAL OF CRYSTALLOGRAPHY AND MINERALOGY] ****** Hornblende biotite bearing tonalite from the west of Dehnow comprises of quartz, calcic plagioclase (andesine-labradorite), garnet (mostly almandine), biotite (annite to siderophyllite), calcic amphibole (mainly ferrohornblende) and accessory minerals of chlorite, epidote, cal...
Article
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The Sorachi-Yezo belt, central Hokkaido, Japan, is composed of voluminous tholeiitic basaltic volcanics, and has been thought to be accreted fragments of an oceanic plateau formed in the Late Jurassic Pacific Ocean. Picrites have been reported as pillow lava and hyaloclastite from the Sorachi-Yezo belt. These picrites are characterized by very magn...
Article
In the Okoppe area of North Hokkaido, Japan, the eruption of adakitic and calc-alkaline dacites was followed by high-Mg andesite (HMA) and calc-alkaline dacite during the Middle Miocene (12-10 Ma). Adakitic dacite is characterized by high Sr/Y and low Y, with Sr and Nd isotopic compositions identical to those of mid-ocean ridge basalt. It has highe...
Article
Late Oligocene to Middle Miocene adakitic andesites are found in the southern part of Okushiri Island, the northern Noto Peninsula and in the Toyama region in the present-day back-arc margin of the SW and NE Japan arcs. On Okushiri Island, adakitic andesite is accompanied by moderately alkaline basalt, whereas on the Noto Peninsula, adakitic andesi...
Article
The evolution of the microstructure and rheological properties of plate-like particle suspensions subjected to rapid simple shear is studied numerically. In response to the shear-induced strain, particles in the suspensions rearrange to form a steady-state microstructure, and the suspension viscosity reaches a steady value. Under this condition, th...
Article
We have updated the Arc Basalt Simulator numerical model to ver.4 (ABS4). The ABS model (Kimura et al., 2011: G3) was developed to examine the geochemical mass balance among (1) the flux from the subducted slab, (2) open-system flux melting in the mantle peridotite, and (3) primary arc magmas. The new ABS4 model improves the geochemical model of th...
Article
Pagan is an active volcano located in the central island province of the Mariana arc (18°07'N) and is one of the largest volcanoes in the Mariana arc; its main edifice rises from a base ~3,000 m below sea level (b.s.l.) and has a volume of 2,160 km3 (Bloomer et al., 1989). Daon is a small reararc seamount 25 km SW of Pagan (17°58'N). We visited the...
Article
Full-text available
Primitive basalts are rarely found in arcs. The active NW Rota-1 volcano in the Mariana arc has erupted near-primitive lavas, which we have sampled with ROV Hyper-Dolphin (HPD). Samples from the summit (HPD480) and eastern flank (HPD488) include 17 magnesian basalts (51-52 wt % SiO2) with 7 center dot 5-9 center dot 5 wt % MgO and Mg-number of 61-6...
Article
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We present major element, trace element, and petrographic data on alkali basalts from St. Helena, and examine the geochemical charac-teristics of a recycled component involved in the source of HIMU (206 Pb/ 204 Pb 420·5) ocean island basalts. Petrographic and com-positional variations in the St. Helena basalts are best explained by the combined eff...
Article
Combined Pb-Sr-Nd-Hf-Os isotopes, together with major and trace element compositions, were determined from clinopyroxene and olivine phenocrysts, along with whole rocks, for ocean island basalts with high μ (μ = 238U/204Pb) (HIMU) and enriched mantle isotopic characteristics from Cook-Austral Islands. Clinopyroxene and olivine separates record reli...
Article
Primitive basalts are rarely found in arcs. The active NW Rota-1 volcano in the Mariana arc has erupted near-primitive lavas, which we have sampled with ROV Hyperdolphin (HPD). Samples from the summit (HPD480) and eastern flank (HPD488) include 17 magnesian basalts (51-52 wt % SiO2) having 7.5-9.5 wt % MgO and Mg# of 61-67, indicating little fracti...
Article
We have developed the Arc Basalt Simulator version 3 (ABS3), a quantitative calculator to examine the mass balance of (1) slab-dehydration and melting, and (2) slab fluid/melt-fluxed mantle melting, and to quantitatively evaluate magma genesis beneath arcs. Calculation results from the ABS3 model suggest that element re-distribution between the sub...
Article
Felsic lavas may be more abundant than commonly thought in intra-oceanic arcs, but the origins of these magmas remain enigmatic. The Diamante Cross-chain in the southern Mariana arc provides a useful perpective on such felsic magas. This cross-chain comprises three submarine volcanoes: E. Diamante lies along the magmatic front whereas Central Diama...
Article
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We present major, trace element, and Pb-Sr-Nd-Hf isotope data for Quaternary basalt and basaltic andesite lavas from cross-chain volcanoes in the northern Izu (N-Izu) arc. Lavas from Izu-Oshima, Toshima, Udonejima, and Niijima islands show consistent chemical changes with depth to the Wadati-Benioff zone, from 120 km beneath Izu-Oshima to 180 km be...
Article
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The ~50 Myr old Izu-Bonin-Mariana (IBM) arc consists mostly of Oligocene middle and lower crust that underlies the upper crust; these units are in turn covered by Quaternary volcanic rocks. Seismic imaging, forearc geology, Ocean Drilling Program drilling and magnetic anomalies suggest that most IBM arc crust was created in Eocene-Oligocene times....
Conference Paper
Full-text available
Tonalites are mineralogically comprised of quartz, plagioclase (mainly bytownite), garnet (almandine-pyrope), biotite (annite), amphibole (ferro-hornblende), and accessory minerals of chlorite, epidote, calcite, and ilmenite. Based on the geothermobarometrical investigations, the tonalitic melt have had an average temperature and pressure of up to...
Article
We have investigated the process of melt localization and the evolution of microstructures within a crystallizing magma using petrology and numerical simulation. The Miocene Otozan andesitic lava flow in southwestern Japan records the segregation of both melt and vapor in response to flow-induced strain within a lava flow. Crystallization processes...
Article
Whether subducting slab melts or simply dehydrates is a key question for understanding the generation of primary magmas above subduction zones. Chemical composition of the primary magma is the fundamental constraint, both for understanding crust formation and mantle return in subduction zones. There are two endmember ideas about arc primary magma g...
Conference Paper
Full-text available
Garnet schists and garnet chlorotoiid schists of Dehnow are mineralogically composed of quartz, biotite, muscovite, garnet, chlorite, chloritoiid, tourmaline, and opaque minerals. Mineral chemistry show Ti content is up to 0.24 a.p.f.u. and a siderophyllite composition for biotites. Ti in biotite geothermometry indicated that the metamorphic temper...
Article
Full-text available
Convergent margin magmas typically have geochemical signatures that include elevated concentrations of large-ion lithophile elements; depleted heavy rare earth elements and high field strength elements; and variously radiogenic Sr, Pb, and Nd isotopic compositions. These have been attributed to the melting of depleted mantle peridotite by the fluxi...
Article
Full-text available
Numerous geochemical studies have indicated that the Hawaiian mantle plume consists of several distinct components. However, their origin remains controversial, with a number of different interpretations having been proposed. We present new major element, trace element and high-precision Sr-Nd-Pb-He isotope data for a suite of fresh submarine lavas...
Article
Full-text available
Abundant rhyolite has erupted from the Izu–Bonin–Mariana volcanic arc (IBM arc) from its earliest stage (Eocene) to the present. Geochemically, three types of Quaternary rhyolites exist in the Izu–Bonin arc front, and they are closely related to volcano type and crustal structure. The dominantly basaltic islands of the volcanic front produce small...
Article
We have developed a mass balance calculation model for basalt magma genesis in subduction zones. The Arc Basalt Simulator version 2 (ABS2) model includes: 1) calculation of slab fluid composition based on PerpleX (ver.7) metamorphic mineralogy for altered oceanic crust (AOC) and sediment (SED) along the slab P-T trajectory derived by the latest geo...
Conference Paper
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Mineral Chemistry and Petrography of Dehnow Tonalite
Conference Paper
Full-text available
Tonalites are one of the intrusive rocks found in the northwest of Mashhad. They comprise of quartz, plagioclase, garnet, biotite and amphibole. Presence of garnet and application of different calibrations of garnet-biotite geothermometry revealed a temperature of 850-1000 oC for the formation of these garnets. In addition, the pressures under whic...
Article
West Rota Volcano (WRV) is a recently discovered extinct submarine volcano in the southern Mariana Arc. It is large (25 km diameter base), shallow (up to 300 m below sealevel), and contains a large caldera (6 x 10 km, with up to 1 km relief). The WRV lies near the northern termination of a major NNE-trending normal fault. This and a second, paralle...