Recycled Carbonate‐Bearing Silicate Sediments in the Sources of Circum‐Mediterranean K‐Rich Lavas: Evidence From Mg‐Zn Isotopic Decoupling

Објеката

Тип

Рад у часопису

Верзија рада

објављена верзија

Језик

енглески

Креатор

Zi‐Tan Shu, Sheng‐Ao Liu, Dejan Prelević, Yu Wang, Stephen F Foley, Vladica Cvetković, Shuguang Li

Извор

Journal of Geophysical Research: Solid Earth

Издавач

American Geophysical Union

Датум издавања

2023

Сажетак

The high flux of subaerial volcanic CO2 emissions around the circum-Mediterranean region requires the involvement of an unusually carbon-rich reservoir, but the origin of which is still unclear. Here, we aim to resolve this problem by analyzing Mg and Zn isotopes for the widely distributed mafic potassic to ultrapotassic lavas in this region. These K-rich lavas have lower δ 26Mg but similar δ 66Zn compared to mid-ocean ridge basalts (MORB). No known magmatic processes can explain the isotopic data, which must therefore be characteristics of the mantle sources. Recycled carbonate sediments are capable of explaining the low δ 26Mg, but they typically also have high δ 66Zn. Thus, the low δ 26Mg but unfractionated δ 66Zn of these K-rich lavas define “Mg-Zn isotopic decoupling” which has not yet been observed for other types of mantle-derived lavas. The carbonate-bearing silicate sediments analyzed here possess low δ 26Mg and MORB like δ 66Zn, which can account for the Mg-Zn isotopic decoupling. Therefore, the nature of recycled materials (carbonates vs. carbonate-bearing silicate sediments) in the mantle can be distinguished by the coupling or decoupling of Mg and Zn isotopes of mantle-derived magmas. The input flux of carbon from the sediments to the lithospheric mantle is estimated to be ∼8.1 Mt/yr, and ∼22.4 Mt/yr of CO2 emissions are predicted, which fit well with the observed output flux of 20.1 ± 13.4 Mt/yr. Our results demonstrate that recycled crustal carbon stored in the lithospheric mantle is an important source for the extensive subaerial volcanic CO2 emissions in the circum-Mediterranean region.

doi

10.1029/2022JB025135

issn

2169-9356

Subject

Mg i Zn izotopski sistemi i njihovo razdvajanje, Circum-Mediteranske K-bogate lave, carbonatitski metasomatizam omotača, recikliranje sedimenata

Шира категорија рада

M20

Ужа категорија рада

М21

Је дио

RECON TETHYS - 7744807

Права

Отворени приступ

Лиценца

All rights reserved

Формат

.pdf

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Медија

320188445.pdf

Zi‐Tan Shu, Sheng‐Ao Liu, Dejan Prelević, Yu Wang, Stephen F Foley, Vladica Cvetković, Shuguang Li. "Recycled Carbonate‐Bearing Silicate Sediments in the Sources of Circum‐Mediterranean K‐Rich Lavas: Evidence From Mg‐Zn Isotopic Decoupling" in Journal of Geophysical Research: Solid Earth, American Geophysical Union (2023). https://doi.org/10.1029/2022JB025135

This item was submitted on 14. јануар 2025. by [anonymous user] using the form “Рад у часопису” on the site “Радови”: http://drug.rgf.bg.ac.rs/s/repo