Covariation of Slab Tracers, Volatiles, and Oxidation During Subduction Initiation
Covariation of Slab Tracers, Volatiles, and Oxidation During Subduction Initiation
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俯冲起始过程中板片示踪剂、挥发物和氧化的协变
DOI：
10.1029/2021gc009823
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发表时间：
2021
期刊：
影响因子：
3.7
通讯作者：
Almeev R.R.
中科院分区：
文献类型：
--
作者：
Brounce M;Reagan M;Kelley K;Cottrell E;Shimizu K;Almeev R.R.
与俯冲作用有关的熔岩比Mirachian脊玄武岩（MORB）具有更高的Fe 3 +/∑Fe。这种偏移的假说包括俯冲板片的印记和加厚地壳的分异作用。这些想法很容易通过检查板片衍生签名的随时间变化的演变，覆盖板块的地壳增厚，以及俯冲开始期间不断变化的氧化还原来检验。在这里，我们提出的Fe 3 +/Fe 3Fe和挥发性元素丰度的火山玻璃回收从国际海洋发现计划（IODP）远征352的伊豆-Bonin-马里亚纳（IBM）的前弧。这些样品包括在地层上被低硅和高硅玻安岩熔岩覆盖的弧前玄武岩（FAB）。FAB玻璃具有0.18-0.85重量%的H2O、75-233 ppm的CO2、通过硫化物相的饱和控制的S含量（602- 1，386 ppm）、3.9 - 10的Ba/La和0.136 - 0.177的Fe 3 +/Fe 3 + Fe比。这些成分与MORB相似，表明干的和还原的地幔的减压熔融主导了俯冲开始的最早阶段。低和高二氧化硅玻安岩玻璃具有1.51-3.19重量%的H2O、低于检测的CO2、低于硫化物饱和所需的S含量（5-235 ppm）、11 - 29的Ba/La和0.181 - 0.225的Fe 3 +/∑Fe。其成分与IBM弧中的现代弧熔岩大致相似。这些数据表明，在俯冲开始后仅0.6-1.2 my内发生的地幔流体熔融的建立与氧化的地幔衍生岩浆的产生同步。在Expedition 352玻璃和现代IBM弧岩中，高Fe 3 +/∑Fe和Ba/La比值与高H2O含量的一致性将氧化弧岩浆的产生与板片脱水的特征紧密联系起来。
Subduction‐related lavas have higher Fe3+/∑Fe than midocean ridge basalts (MORB). Hypotheses for this offset include imprint from subducting slabs and differentiation in thickened crust. These ideas are readily tested through examination of the time‐dependent evolution of slab‐derived signatures, thickening crust of the overriding plate, and evolving redox during subduction initiation. Here, we present Fe3+/ΣFe and volatile element abundances of volcanic glasses recovered from International Ocean Discovery Program (IODP) Expedition 352 to the Izu‐Bonin‐Mariana (IBM) forearc. The samples include forearc basalts (FAB) that are stratigraphically overlain by low‐ and high‐silica boninite lavas. The FAB glasses have 0.18–0.85 wt% H2O, 75–233 ppm CO2, S contents controlled by saturation with a sulfide phase (602–1,386 ppm), Ba/La from 3.9‐10, and Fe3+/ΣFe ratios from 0.136 to 0.177. These compositions are similar to MORB and suggest that decompression melting of dry and reduced mantle dominates the earliest stages of subduction initiation. Low‐ and high‐silica boninite glasses have 1.51–3.19 wt% H2O, CO2below detection, S contents below those required for sulfide saturation (5–235 ppm), Ba/La from 11 to 29, and Fe3+/∑Fe from 0.181 to 0.225. The compositions are broadly similar to modern arc lavas in the IBM arc. These data demonstrate that the establishment of fluid‐fluxed melting of the mantle, which occurs in just 0.6–1.2 my after subduction initiation, is synchronous with the production of oxidized, mantle‐derived magmas. The coherence of high Fe3+/∑Fe and Ba/La ratios with high H2O contents in Expedition 352 glasses and the modern IBM arc rocks strongly links the production of oxidized arc magmas to signatures of slab dehydration.
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DOI：
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发表时间：
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期刊：
影响因子：
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通讯作者：
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影响因子：
3.1
作者：
J. Scholpp;J. Ryan;J. Shervais;C. Stremtan;M. Rittner;A. Luna;Stephen Hill;Z. Atlas;Bradford Mack
通讯作者：
Bradford Mack
影响因子：
2.6
作者：
M. Reagan;J. Pearce;K. Petronotis;R. Almeev;Aaron Avery;C. Carvallo;T. Chapman;G. Christeson
通讯作者：
M. Reagan;J. Pearce;K. Petronotis;R. Almeev;Aaron Avery;C. Carvallo;T. Chapman;G. Christeson
影响因子：
5.3
作者：
William M. Nash;D. Smythe;B. Wood
通讯作者：
William M. Nash;D. Smythe;B. Wood
影响因子：
5.3
作者：
Hongyang Li;R. Taylor;J. Prytulak;M. Kirchenbaur;J. Shervais;J. Ryan;M. Godard;M. Reagan;
通讯作者：
Hongyang Li;R. Taylor;J. Prytulak;M. Kirchenbaur;J. Shervais;J. Ryan;M. Godard;M. Reagan;