Calcium Stable Isotopes of Tonga and Mariana Arc Lavas: Implications for Slab Fluid-Mediated Carbonate Transfer in Cold Subduction Zones SCIE SCOPUS

Cited 2 time in WEB OF SCIENCE Cited 3 time in Scopus
Title
Calcium Stable Isotopes of Tonga and Mariana Arc Lavas: Implications for Slab Fluid-Mediated Carbonate Transfer in Cold Subduction Zones
Author(s)
Wang, Xia; Wang, Zaicong; Liu, Yongsheng; Park, Jung‐Woo; Kim, Jonguk; Li, Ming; Zou, Zongqi
KIOST Author(s)
Kim, Jonguk(김종욱)
Alternative Author(s)
김종욱
Publication Year
2021-03
Abstract
Carbonation of oceanic lithosphere occurs widely during seawater alteration, and subducted carbonated oceanic lithosphere may play a key role in carbon recycling in subduction zones. Here we investigate the Ca isotopic composition of arc lavas from the Tonga rear arc and Mariana arc, western Pacific, to explore the effect of fluid-mediated carbonate transfer in subduction zones. Fresh basalts (0.84 +/- 0.01 parts per thousand, 2sd, n = 3) and dacites (0.84 +/- 0.10 parts per thousand, 2sd, n = 9) from the Tonga rear arc show indistinguishable delta Ca-44/40, reflecting negligible Ca isotopic fractionation during differentiation of hydrous arc magmas. More importantly, arc lavas from both the Tonga rear arc (0.84 +/- 0.09 parts per thousand, 2sd, n = 12) and Mariana arc (0.79 +/- 0.12 parts per thousand, 2sd, n = 9) display MORB-like delta Ca-44/40 values. The MORB-like delta Ca-44/40 of arc lavas indicates that the carbonates released from altered oceanic lithosphere (AOL) do not significantly modify the Ca isotopic composition of the mantle wedge, although extensive volcanic CO2 degassing at both arcs suggests that slab fluids might introduce abundant carbonate into the depleted mantle wedge. These results could be attributed to a limited Ca budget in the slab fluids added to the mantle wedge and/or homogenization effect of variable delta Ca-44/40 for the slab fluids. At cold subduction zones, a fraction of carbonates from the AOL may survive during slab dehydration and recycle into the deep mantle.
ISSN
2169-9313
URI
https://sciwatch.kiost.ac.kr/handle/2020.kiost/41333
DOI
10.1029/2020JB020207
Bibliographic Citation
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH, v.126, no.3, 2021
Publisher
AMER GEOPHYSICAL UNION
Keywords
carbonate; arc lavas; Ca isotopes; carbon recycling; subduction zone
Type
Article
Language
English
Document Type
Article
Publisher
AMER GEOPHYSICAL UNION
Files in This Item:
There are no files associated with this item.

qrcode

Items in ScienceWatch@KIOST are protected by copyright, with all rights reserved, unless otherwise indicated.

Browse