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

TY - JOUR

T1 - Archaean chromitites show constant Fe3+/ΣFe in Earth´s asthenospheric mantle since 3.8 Ga

AU - Rollinson, Hugh

AU - Adetunji , J.

AU - Lenaz, D.

AU - Szilas, Kristoffer

PY - 2017/6/1

Y1 - 2017/6/1

N2 - 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 Mössbauer 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.

AB - 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 Mössbauer 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.

U2 - 10.1016/j.lithos.2017.03.020

DO - 10.1016/j.lithos.2017.03.020

M3 - Journal article

SN - 0024-4937

VL - 282-283

SP - 316

EP - 325

JO - Lithos

JF - Lithos

ER -