Production of High-Sr Andesite and Dacite Magmas by Melting of Subducting Oceanic Lithosphere at Propagating Slab Tears

I. Pineda-Velasco, Hiroshi Kitagawa, T. T. Nguyen, Katsura Kobayashi, Eizou Nakamura

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

We present K-Ar ages, major and trace element concentrations, and Sr-Nd-Pb isotope data for late Cenozoic volcanic rocks from the Chugoku district, southwest Japan arc. Andesite and dacite lavas in this region are enriched in Sr (mostly >800 μg g−1) and show geochemical characteristics of volcanic rocks commonly referred to as “adakite.” K-Ar dating of these lavas revealed that the eruption of high-Sr andesitic to dacitic magmas occurred during the last 2 Myr, following or concurrent with the eruption of basalt in adjacent regions. Trace-element characteristics of high-Sr andesites and dacites are consistent with the formation of their parent magmas by partial melting of the basaltic layer of the subducting Shikoku Basin Plate. Mass balance modeling of trace element concentrations and isotopic compositions suggests that the parental magmas of high-Sr andesites and dacites are best explained by mixing of partial melts from oceanic crust (F = 5–15%) and sediment (F = 30%) at 80:20 to 55:45 ratios. Spatial coincidence of the occurrences of high-Sr andesites and dacites and seismic gaps of the subducting slab demonstrates the causal link between slab melting and mantle upwelling at slab tears. We speculate that these tears could have been formed by subduction of ridges on the plate. A warm mantle upwelled through tears, preventing the solidification of the siliceous slab melts in the mantle and facilitating the transportation of these melts to the surface.

Original languageEnglish
Pages (from-to)3698-3728
Number of pages31
JournalJournal of Geophysical Research: Solid Earth
Volume123
Issue number5
DOIs
Publication statusPublished - May 1 2018

Fingerprint

andesite
Trace Elements
oceanic lithosphere
dacite
lithosphere
Volcanic rocks
slab
Melting
slabs
melting
trace elements
Earth mantle
trace element
melt
volcanic eruptions
volcanology
volcanic rock
volcanic eruption
rocks
mantle

Keywords

  • adakite
  • slab melting
  • slab tear
  • subduction zone

ASJC Scopus subject areas

  • Geophysics
  • Geochemistry and Petrology
  • Earth and Planetary Sciences (miscellaneous)
  • Space and Planetary Science

Cite this

@article{169f24c430bc4a4fa8f317f8d6026578,
title = "Production of High-Sr Andesite and Dacite Magmas by Melting of Subducting Oceanic Lithosphere at Propagating Slab Tears",
abstract = "We present K-Ar ages, major and trace element concentrations, and Sr-Nd-Pb isotope data for late Cenozoic volcanic rocks from the Chugoku district, southwest Japan arc. Andesite and dacite lavas in this region are enriched in Sr (mostly >800 μg g−1) and show geochemical characteristics of volcanic rocks commonly referred to as “adakite.” K-Ar dating of these lavas revealed that the eruption of high-Sr andesitic to dacitic magmas occurred during the last 2 Myr, following or concurrent with the eruption of basalt in adjacent regions. Trace-element characteristics of high-Sr andesites and dacites are consistent with the formation of their parent magmas by partial melting of the basaltic layer of the subducting Shikoku Basin Plate. Mass balance modeling of trace element concentrations and isotopic compositions suggests that the parental magmas of high-Sr andesites and dacites are best explained by mixing of partial melts from oceanic crust (F = 5–15{\%}) and sediment (F = 30{\%}) at 80:20 to 55:45 ratios. Spatial coincidence of the occurrences of high-Sr andesites and dacites and seismic gaps of the subducting slab demonstrates the causal link between slab melting and mantle upwelling at slab tears. We speculate that these tears could have been formed by subduction of ridges on the plate. A warm mantle upwelled through tears, preventing the solidification of the siliceous slab melts in the mantle and facilitating the transportation of these melts to the surface.",
keywords = "adakite, slab melting, slab tear, subduction zone",
author = "I. Pineda-Velasco and Hiroshi Kitagawa and Nguyen, {T. T.} and Katsura Kobayashi and Eizou Nakamura",
year = "2018",
month = "5",
day = "1",
doi = "10.1029/2017JB015066",
language = "English",
volume = "123",
pages = "3698--3728",
journal = "Journal of Geophysical Research",
issn = "0148-0227",
publisher = "American Geophysical Union",
number = "5",

}

TY - JOUR

T1 - Production of High-Sr Andesite and Dacite Magmas by Melting of Subducting Oceanic Lithosphere at Propagating Slab Tears

AU - Pineda-Velasco, I.

AU - Kitagawa, Hiroshi

AU - Nguyen, T. T.

AU - Kobayashi, Katsura

AU - Nakamura, Eizou

PY - 2018/5/1

Y1 - 2018/5/1

N2 - We present K-Ar ages, major and trace element concentrations, and Sr-Nd-Pb isotope data for late Cenozoic volcanic rocks from the Chugoku district, southwest Japan arc. Andesite and dacite lavas in this region are enriched in Sr (mostly >800 μg g−1) and show geochemical characteristics of volcanic rocks commonly referred to as “adakite.” K-Ar dating of these lavas revealed that the eruption of high-Sr andesitic to dacitic magmas occurred during the last 2 Myr, following or concurrent with the eruption of basalt in adjacent regions. Trace-element characteristics of high-Sr andesites and dacites are consistent with the formation of their parent magmas by partial melting of the basaltic layer of the subducting Shikoku Basin Plate. Mass balance modeling of trace element concentrations and isotopic compositions suggests that the parental magmas of high-Sr andesites and dacites are best explained by mixing of partial melts from oceanic crust (F = 5–15%) and sediment (F = 30%) at 80:20 to 55:45 ratios. Spatial coincidence of the occurrences of high-Sr andesites and dacites and seismic gaps of the subducting slab demonstrates the causal link between slab melting and mantle upwelling at slab tears. We speculate that these tears could have been formed by subduction of ridges on the plate. A warm mantle upwelled through tears, preventing the solidification of the siliceous slab melts in the mantle and facilitating the transportation of these melts to the surface.

AB - We present K-Ar ages, major and trace element concentrations, and Sr-Nd-Pb isotope data for late Cenozoic volcanic rocks from the Chugoku district, southwest Japan arc. Andesite and dacite lavas in this region are enriched in Sr (mostly >800 μg g−1) and show geochemical characteristics of volcanic rocks commonly referred to as “adakite.” K-Ar dating of these lavas revealed that the eruption of high-Sr andesitic to dacitic magmas occurred during the last 2 Myr, following or concurrent with the eruption of basalt in adjacent regions. Trace-element characteristics of high-Sr andesites and dacites are consistent with the formation of their parent magmas by partial melting of the basaltic layer of the subducting Shikoku Basin Plate. Mass balance modeling of trace element concentrations and isotopic compositions suggests that the parental magmas of high-Sr andesites and dacites are best explained by mixing of partial melts from oceanic crust (F = 5–15%) and sediment (F = 30%) at 80:20 to 55:45 ratios. Spatial coincidence of the occurrences of high-Sr andesites and dacites and seismic gaps of the subducting slab demonstrates the causal link between slab melting and mantle upwelling at slab tears. We speculate that these tears could have been formed by subduction of ridges on the plate. A warm mantle upwelled through tears, preventing the solidification of the siliceous slab melts in the mantle and facilitating the transportation of these melts to the surface.

KW - adakite

KW - slab melting

KW - slab tear

KW - subduction zone

UR - http://www.scopus.com/inward/record.url?scp=85047753036&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85047753036&partnerID=8YFLogxK

U2 - 10.1029/2017JB015066

DO - 10.1029/2017JB015066

M3 - Article

AN - SCOPUS:85047753036

VL - 123

SP - 3698

EP - 3728

JO - Journal of Geophysical Research

JF - Journal of Geophysical Research

SN - 0148-0227

IS - 5

ER -