Across-arc geochemical trends in the Izu-Bonin arc: Contributions from the subducting slab
Alfred G. Hochstaedter,James B. Gill,Robert B. Peters,Phil Broughton,Pete Holden,Brian Taylor +5 more
TLDR
In this paper, the authors proposed that across-arc differences in the geochemistry of Izu-Bonin arc magmas are controlled by the addition of fertile-slab fluids to depleted mantle at the volcanic front without slab melting or contemporaneous back arc spreading.Abstract:
[1] We propose that across-arc differences in the geochemistry of Izu-Bonin arc magmas are controlled by the addition of fertile-slab fluids to depleted mantle at the volcanic front, and residual-slab fluids to fertile mantle in the back arc without slab melting or contemporaneous back arc spreading. The arc consists of a volcanic front, an extensional zone, and seamount chains (the Western Seamounts) that trend into the Shikoku Basin. Each province produces a distinct suite of arc-like volcanic rocks that have relative Nb depletions and high ratios of fluid-mobile elements to high field strength elements. The volcanic front has the lowest concentrations of incompatible elements and the strongest relative enrichments of fluid-mobile elements (high U/Nb, Ba/Nb, Pb/Zr, Th/Nb, 206Pb/204Pb, ɛNd, and 87Sr/86Sr). A fluid derived from both sediment and altered oceanic crust explains most of the slab-related characteristics of the volcanic front. The Western Seamounts and some of the extensional zone rocks have lower ɛNd, 87Sr/86Sr, 206Pb/204Pb, Ba/Th, and U/Th; moderate Ba/Nb and U/Nb; and similar or higher Th/Nb and Th/Nd. Although the lower ɛNd and higher Th/Nd tempt a sediment melt explanation, a lack of correlation between the strongest sediment proxies, such as ɛNd, Th/Nb, and Ce/Ce*, precludes sediment melts. The subduction component for the Western Seamounts is probably a fluid dehydrated from a residual slab that was depleted in fluid-mobile elements beneath (as well as trenchward of) the volcanic front. This depleted fluid is added to elementally and isotopically more enriched mantle beneath the Western Seamounts.read more
Citations
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Journal ArticleDOI
Subduction factory: 4. Depth-dependent flux of H2O from subducting slabs worldwide
TL;DR: In this article, a global compilation of the thermal structure of subduction zones is used to predict the metamorphic facies and H 2 O content of downgoing slabs.
Journal ArticleDOI
The chemistry of subduction-zone fluids
TL;DR: In this paper, it was shown that H2O-rich, Cl-poor, alkali-aluminosilicate-bearing fluid is fundamental to element transport in the mantle wedge.
Book ChapterDOI
Origin of Back‐Arc Basin Magmas: Trace Element and Isotope Perspectives
Julian A. Pearce,Robert J. Stern +1 more
TL;DR: The back-arc basin basalts can usefully be viewed as products of four factors: (1) the composition of inflowing mantle and its preconditioning during flow to the site of melting; (2) the influx of a subduction component into the arc-basin system; (3) the nature of the interaction between the mantle and subduction components; (4) the melting of water-rich mantle and the assimilation/ crystallization history of the resulting hydrous magma.
Journal ArticleDOI
Back-arc basin basalt systematics
Brian Taylor,Fernando Martinez +1 more
TL;DR: In this paper, a positive correlation between the average degree and pressure of mantle melting that reflects regional variations in mantle potential temperatures (Lau/Manus hotter than Mariana/Scotia) was found.
Book ChapterDOI
An Overview of the Izu‐Bonin‐Mariana Subduction Factory
TL;DR: The Izu-Bonin-Mariana (IBM) arc system extends 2800km from near Tokyo, Japan to Guam and is an outstanding example of an intra-oceanic convergent margin (IOCM) as mentioned in this paper.
References
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Chemical and isotopic systematics of oceanic basalt : implications for mantle composition and processes
TL;DR: In this article, trace-element data for mid-ocean ridge basalts and ocean island basalts are used to formulate chemical systematics for oceanic basalts, interpreted in terms of partial-melting conditions, variations in residual mineralogy, involvement of subducted sediment, recycling of oceanic lithosphere and processes within the low velocity zone.
Journal ArticleDOI
Chemical and isotopic systematics of oceanic basalts. Implications for Mantle Composition and Processes
Book
Orogenic Andesites and Plate Tectonics
TL;DR: In this article, the authors define Orogenic Andesite and discuss its properties and properties, including the following: 1.1 Topography, gravity, heat flow, and conductivity.
Journal ArticleDOI
A large-scale isotope anomaly in the Southern Hemisphere mantle
TL;DR: The authors showed that the isotopic mantle anomaly is globe-encircling in extent, centred on latitude 30° S. They also showed that this mantle anomaly has been in existence for billions of years and placed severe constraints on mantle convection models.
Journal ArticleDOI
Element transport from slab to volcanic front at the Mariana arc
TL;DR: Agarwal et al. as mentioned in this paper presented a comprehensive geochemical data set for the most recent volcanics from the Mariana Islands, which provides new constraints on the timing and nature of fluxes from the subducting slab.