Thorium isotope evidence for melting of the mafic oceanic crust beneath the Izu arc

Freymuth, Heye; Ivko, Ben; Gill, James B.; Tamura, Yoshihiko; Elliott, Tim

doi:10.1016/j.gca.2016.04.034

Cited by 30 publications

(52 citation statements)

References 108 publications

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“…50°C in the northern part of the arc (Syracuse et al, 2010). Alternatively, melting of the sediment section of the slab beneath the northern Lesser Antilles could be inhibited by a low supply of H2O, as suggested to explain variable degrees of slab melting beneath the Izu arc (Freymuth et al, 2016).…”

Section: Tracing Subducted Black Shales With Mo Isotopesmentioning

confidence: 99%

Tracing subducted black shales in the Lesser Antilles arc using molybdenum isotope ratios

Freymuth

Elliott

Soest

et al. 2016

Geology

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Lesser Antilles arc lavas have trace element and radiogenic isotope characteristics indicative of a continent-derived contribution. It is hotly debated whether this continental signature represents terrigenous sediment that has been subducted with the Atlantic plate and added to the magma sources in the mantle wedge or portions of the sub-arc crust that are assimilated during magma ascent. Here we present Mo isotope data for Lesser Antilles arc lavas and sediments off-board the Lesser Antilles trench. Sequences of black shales, present in the subducting sediment piles, are highly enriched in Mo and have unusually high 98 Mo/ 95 Mo. Despite their low mass fraction in the sediment package (<10 % in DSDP Site 144), they dominate the Mo content and isotopic composition of the bulk sediment subducting at the Lesser Antilles trench. We show that lavas from the southern part of the Lesser Antilles arc also have high 98 Mo/ 95 Mo ratios, implicating the addition Manuscript Click here to download Manuscript G38344-Freymuth-eXtyled_revised.doc

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Section: Tracing Subducted Black Shales With Mo Isotopesmentioning

confidence: 99%

Tracing subducted black shales in the Lesser Antilles arc using molybdenum isotope ratios

Freymuth

Elliott

Soest

et al. 2016

Geology

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“…In summary, the geochemical difference between the southern Yanbian and northern LHZR mafic intrusions can be interpreted as a result of input of compositionally distinct subducted sediments into the mantle source through the arc magmatic belt. Such geochemical variations of arc basalts can also be found in modern subduction zones, for example, the Kamchatka‐Honshu‐Izu‐Bonin‐Mariana arc systems in the western Pacific (e.g., Bergal‐Kuvikas et al, ; Elliott et al, ; Freymuth et al, ; Hoang et al, ). The continental arc mafic rocks (e.g., in the Kamchatka and Honshu arcs) derived from a mantle wedge enriched by addition of predominantly subducted terrigenous sediments also have higher Th/La and Th/Yb and lower Lu/Hf ratios than those oceanic arc basalts (e.g., in the Izu‐Bonin‐Mariana arcs), which originate from a mantle source metasomatized by subducted pelagic sediments (Figures c and d).…”

Section: Discussionmentioning

confidence: 94%

Roles of Subducted Pelagic and Terrigenous Sediments in Early Jurassic Mafic Magmatism in NE China: Constraints on the Architecture of Paleo‐Pacific Subduction Zone

Zhao

Guo

et al. 2019

JGR Solid Earth

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The role of subducted sediments in arc magmatism has been widely documented. However, identifying the sedimentary provenance (e.g., pelagic vs. terrigenous) input in subduction systems is difficult because of the wide compositional range of sedimentary components and the complex magmatic evolution of arcs. Here we report zircon U‐Pb‐Hf‐O isotopes and whole‐rock elemental and Sr‐Nd‐Hf isotopic compositions of four Early Jurassic subduction‐related mafic intrusions from the Yanbian area, NE China. These rocks show typical trace element and isotopic features of arc magmas. In combination with the published data, we discover two distinct elemental‐isotopic arrays of the Early Jurassic mafic rocks across the arc magmatic belt. Such geochemical variations are mainly attributed to variable subducted sediment input into the mantle wedge instead of crustal contamination or assimilation during magmatic evolution. The mantle source for the southern Yanbian mafic rocks was enriched by addition of a crustal component dominated by terrigenous sediments, whereas that for the northern Lesser Hinggan‐Zhangguangcai Range, mafic rocks was modified by another crustal component comprising mainly pelagic sediments. The results can be best interpreted if the southern part was a continental arc as opposed to an oceanic arc in the north, which is analogous to the modern Kamchatka‐Honshu‐Izu‐Bonin‐Mariana arc systems in the western Pacific. Our reconstructed architecture, based mainly on the geochemical data, further suggests that the Khanka‐Jiamusi‐Buleya Massif was probably sinistrally and northwardly displaced to the present position after Mesozoic subduction of the Paleo‐Pacific Ocean.

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“…Symbols and mixing lines as in Figures 4–6 using isotope ratios and element concentrations from Table 2. Comparison data sources: Izu arc Volcanic Front (VF), Active Rifts (AR), Backarc Knolls (BAK), and Rear Arc Seamount Chains (RASC): (Freymuth et al, ; Hochstaedter et al, ; Ishizuka et al, ; Taylor & Nesbitt, ); ODP Sites 1149 and 52, and IODP Site C0011 are bulk sediments (Plank et al, ; Saitoh et al, ; Scudder et al, ). Bulk leached loess data are from Chen and Li ().…”

Section: Resultsmentioning

confidence: 99%

“…The same also is true of <6.5 Ma bulk sediment at ODP Site 1149 just east of the Izu‐Bonin Trench, although the glacial stage muds at Site U1437 are even more loess‐like than the eolian‐dominated ash‐bearing clays at Site 1149 (Chauvel et al, ; Plank et al, ). Second, three of the least loess‐like tuffaceous mud(stones) have Hf isotope ratios as high as at the Izu volcanic front at about the same latitude (Hachijo‐jima: Freymuth et al, ) and Unit VII hyaloclastites (Miyazaki et al, ). However, the Hf in two others (B12F3 and D68R2) is more like rear arc lavas and tuffs, including Manji seamount (Figure b; Tollstrup et al, ).…”

Section: Resultsmentioning

confidence: 99%

“…In summary, many incompatible and compatible trace elements, radiogenic isotopes, grain size characteristics, and the amount of quartz relative to glass, all indicate binary mixing, and all correlate with the Th content of the tuffaceous mud(stone)s. Sometimes another element concentration or isotope ratio correlates Table 2. Comparison data sources: Izu arc Volcanic Front (VF), Active Rifts (AR), Backarc Knolls (BAK), and Rear Arc Seamount Chains (RASC): (Freymuth et al, 2016;Hochstaedter et al, 2001;Ishizuka et al, 2003;Taylor & Nesbitt, 1998); ODP Sites 1149 and 52, and IODP Site C0011 are bulk sediments (Plank et al, 2007;Saitoh et al, 2015;Scudder et al, 2014). Bulk leached loess data are from Chen and Li (2013).…”

Section: Evidence Of Binary Mixingmentioning

confidence: 99%

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Tuffaceous Mud is a Volumetrically Important Volcaniclastic Facies of Submarine Arc Volcanism and Record of Climate Change

Gill

Bongiolo

Miyazaki

et al. 2018

Geochem Geophys Geosyst

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The inorganic portion of tuffaceous mud and mudstone in an oceanic island arc can be mostly volcanic in origin. Consequently, a large volume of submarine volcaniclastic material is as extremely fine‐grained as products of subaerial eruptions (<100 µm). Using results of IODP Expedition 350 in the Izu rear arc, we show that such material can accumulate at high rates (12–20 cm/k.y.) within 13 km of the nearest seamount summit and scores of km behind the volcanic front. The geochemistry of bulk, acid‐leached mud, and its discrete vitriclasts, shows that >75% of the mud is volcanic, and that most of it was derived from proximal rear arc volcanic sources. It faithfully preserves integrated igneous geochemical information about arc evolution in much the same way that terrigenous shales track the evolution of continental crust. In addition, their high sedimentation rate enables high resolution study of climate cycles, including the effects of Pleistocene glaciation on the behavior of the Kuroshio Current in the Shikoku Basin south of Japan.

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Thorium isotope evidence for melting of the mafic oceanic crust beneath the Izu arc

Abstract: General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above. Full terms of use are available: http://www.bristol.ac.uk/pure/about/ebr-terms

Cited by 30 publications

References 108 publications

Tracing subducted black shales in the Lesser Antilles arc using molybdenum isotope ratios

Tracing subducted black shales in the Lesser Antilles arc using molybdenum isotope ratios

Roles of Subducted Pelagic and Terrigenous Sediments in Early Jurassic Mafic Magmatism in NE China: Constraints on the Architecture of Paleo‐Pacific Subduction Zone

Tuffaceous Mud is a Volumetrically Important Volcaniclastic Facies of Submarine Arc Volcanism and Record of Climate Change

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