Earth, Atmospheric, and Planetary Sciences Correction for “Oxygen controls on magmatism in rocky exoplanets,” by Yanhao Lin, Wim van Westrenen, and Ho-Kwang Mao, which published November 1, 2021; 10.1073/pnas.2110427118 (Proc. Natl. Acad. Sci. U.S.A. 118, e2110427118).
The authors note: “In our paper we reported the results of three series of experiments focused on the crystallization of a synthetic basalt composition, free of iron and volatile compounds: two of these series were performed at two different low oxygen fugacities (fO2) in a one atmosphere gas mixing furnace (using mixtures of CO and CO2 gas). The third series, consisting of seven experiments at different temperatures, was performed at a high oxygen fugacity (in air) in a second one atmosphere furnace. We reported systematic temperature differences in three parameters of the crystallization behavior of the composition (liquidus temperatures, melt fractions at constant temperature, and the nature and appearance during crystallization of mineral phases) between the three series. We assigned these differences to the differences in oxygen fugacity (fO2). Questioned by Professor Dave Walker, control experiments of the third series with a new thermocouple and temperature calibration of the furnace used indicate that the thermocouple used to measure the temperature of the published third series (in air) was faulty.
The results of the third series of experiments plotted in Fig. 1 (at log fO2 = −0.7) should be discarded, and a corrected Fig. 1 is given here.
Fig. 1.
(A) Liquidus and phase relations of Fe-free basalt as a function of oxygen fugacity at 1 atm. The dashed curves approximate the experimental-constrained location of the liquidus and temperatures at which 35% melt is present in the system as a function of fO2. (B) Representative BSE images of experimental products at 1150 °C illustrating the phases present at different conditions. The experimental conditions are shown in the top right of each BSE image. Abbreviations of phases: Ol, olivine; Opx, orthopyroxene; Cpx, clinopyroxene; Pl, plagioclase; Ru, rutile; Gl, silicate glass (liquid at high-temperature conditions).
While the correction diminishes constraints of our work on fO2-induced effects on liquidus temperatures, the increase in melt percentages at constant temperatures below the liquidus and the differences in minerals formed remain significant, and the central tenet of our work still holds. The error and its correction do not have an impact on the identification of this previously unknown effect of oxygen, nor its implications for magmatism on rocky exoplanets.”
The corrected figure and its legend appear below. The online version has been corrected.