Archaean chromitites show constant Fe3+/ΣFe in Earth's asthenospheric mantle since 3.8 Ga

被引：29

作者：

Rollinson, Hugh ^{[1
]}

Adetunji, Jacob ^{[1
]}

Lenaz, Davide ^{[2
]}

Szilas, Kristoffer ^{[3
]}

机构：

[1] Univ Derby, Geosci, Kedleston Rd, Derby DE22 1GB, England

[2] Univ Trieste, Math & Geosci, Via Weiss 8, I-34122 Trieste, Italy

[3] Geol Survey Denmark & Greenland GEUS, Oster Voldgade 10, DK-1350 Copenhagen K, Denmark

来源：

LITHOS | 2017年 / 282卷

关键词：

Archaean; Chromite; Chromitite; Mantle redox; Secular change; SOUTHERN WEST GREENLAND; FERRIC MOSSBAUER FRACTIONS; LAYERED ULTRAMAFIC BODY; CATION DISTRIBUTION; OXIDATION-STATE; OMAN OPHIOLITE; ZIMBABWE; COMPLEX; OXYGEN; SPINELS;

D O I：

10.1016/j.lithos.2017.03.020

中图分类号：

P3 [地球物理学]; P59 [地球化学];

学科分类号：

0708 ; 070902 ;

摘要：

Theoretical and planetary studies show that the Earth's upper mantle is more oxidised than it should be. The mechanism by which this took place and the timing of the oxidation is contested. Here we present new Mossbauer spectroscopy measurements of the ionic ratio Fe3+/(Fe3++Fe2+) in the mineral chromite hosted in mantle-derived melts to show that there is no change in mantle Fe3+/(Fe3++Fe2+) ratio before and after the oxidation of the Earth's atmosphere at ca. 2.4 Ga and over Earth history from 3.8 Ga to 95 Ma. Our finding supports the view that the oxidation of the asthenospheric mantle was very early and that the oxygenation of the Earth's atmosphere was not directly coupled to mantle processes. (C) 2017 Elsevier B.V. All rights reserved.

引用

页码：316 / 325

页数：10

共 58 条

[1] New Mossbauer measurements of Fe3+/ΣFe ratios in chromites from the early Proterozoic Bushveld Complex, South Africa [J].