TY - JOUR
T1 - How much potassium is in the Earth's core? New insights from partitioning experiments
AU - Corgne, Alexandre
AU - Keshav, Shantanu
AU - Fei, Yingwei
AU - McDonough, William F.
N1 - Funding Information:
This manuscript benefited from discussions with Gudmundur Gudfinnsson, Valérie Malavergne, Rama Murthy, Bjorn Mysen, Mathieu Roskosz, Julien Siebert, Jon Wade, Heather Watson, Wim van Westrenen and Bernard Wood. We thank Chris Hadidiacos and Norman Pearson for technical assistance. Constructive reviews from John Lassiter and an anonymous reviewer and editorial comments from Richard Carlson are gratefully acknowledged. The Carnegie Institution of Washington (Postdoctoral Fellowships to AC and SK), the NASA (Cosmochemistry Grant NNG04GG09G to YF) and the NSF (Grant EAR0337621 to WFM) supported this work. Funding for the GEMOC electron microprobe comes from ARC LIEF and DEST Systemic Infrastructure Grants, Macquarie University and industry. This is contribution no. 455 from the ARC GEMOC National Key Centre ( www.es.mq.edu.au/GEMOC/ ).
PY - 2007/4/30
Y1 - 2007/4/30
N2 - The presence of potassium in the core is a vexing issue in Earth Science that is of fundamental concern to the energy budget of the Earth. New experimental data reported here for partitioning of potassium (K) between peridotitic silicate melt and Fe-Ni-S-C-O molten alloy at 1650-2200 °C and 1.0-7.7 GPa reveal a negligible effect of pressure on K partitioning, at least up to 7.7 GPa. No evidence for a systematic increase of K solubility in the alloy with temperature or pressure and S or C contents in the alloy was found. However, there is a possible increase in the K partition coefficient with increasing O content in the molten alloy. Our results, which are appropriate to model core formation in a shallow magma ocean, suggest it is unlikely to sequester more than a few tens of ppm of K into Earth's core during a magma ocean event if oxygen is not a major contributor to the light element budget of the core.
AB - The presence of potassium in the core is a vexing issue in Earth Science that is of fundamental concern to the energy budget of the Earth. New experimental data reported here for partitioning of potassium (K) between peridotitic silicate melt and Fe-Ni-S-C-O molten alloy at 1650-2200 °C and 1.0-7.7 GPa reveal a negligible effect of pressure on K partitioning, at least up to 7.7 GPa. No evidence for a systematic increase of K solubility in the alloy with temperature or pressure and S or C contents in the alloy was found. However, there is a possible increase in the K partition coefficient with increasing O content in the molten alloy. Our results, which are appropriate to model core formation in a shallow magma ocean, suggest it is unlikely to sequester more than a few tens of ppm of K into Earth's core during a magma ocean event if oxygen is not a major contributor to the light element budget of the core.
KW - Earth's core
KW - geodynamo
KW - high pressure
KW - metal-silicate partitioning
KW - potassium
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U2 - 10.1016/j.epsl.2007.02.012
DO - 10.1016/j.epsl.2007.02.012
M3 - Article
AN - SCOPUS:34047098779
SN - 0012-821X
VL - 256
SP - 567
EP - 576
JO - Earth and Planetary Sciences Letters
JF - Earth and Planetary Sciences Letters
IS - 3-4
ER -