The Spin Deep Within

Intermediate-Spin Ferrous Iron in Lowermost Mantle Post- Perovskite and Perovskite

Jung-Fu Lin1, Heather Watson2, György Vankó3, Esen E. Alp4, Vitali B. Prakapenka5, Przemek Dera5, Viktor V. Struzhkin6, Atsushi Kubo5, Jiyong Zhao4, Catherine McCammon7, William J. Evans2

1Department of Geological Sciences, Jackson School of Geosciences, The University of Texas at Austin, TX 78758 , USA 2Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94550, USA 3KFKI Research Institute for Particle and Nuclear Physics, P.O. Box 49, H-1525 Budapest, Hungary 4Advanced Photon Source, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 5Consortium for Advanced Radiation Sources, The University of Chicago, Chicago, IL 60637, USA 6Geophysical Laboratory, Carnegie Institution of Washington, 5251 Broad Branch Rd. NW, Washington, DC 20015, USA 7Bayerisches Geoinstitut, Universität Bayreuth, D-95440 Bayreuth, Germany

About the cover image: The cover illustrates an artist’s interpretation of the deep-mantle mineral physics research, where two opposing diamond anvils force electrons of iron in lower-mantle silicate perovskite and post- perovskite to be partially paired under high pressures and temperatures. The occurrence of the intermediate-spin ferrous iron is expected to profoundly affect our understanding on the geodynamic, geophysical, and geochemical properties of the planet’s interior. Reference: Lin et al., Nature Geoscience, 1, 688-691, 2008; Image credit: David M. Stephens.

News and Views “The spin deep within”

“The electronic configuration of iron impurities in lower-mantle minerals influences their physical properties, but it is not well-constrained. New studies reported in Nature Geoscience in October 2008 by the teams of Lin et al., and McCammon et al., suggest that ferrous iron in silicate phases exist mainly in an intermediate spin state.” [S. Stackhouse, Nature Geoscience, 1, 648-650, 2008].

ACKNOWLEDGEMENTS We acknowledge GSECARS and XOR-3, APS, ANL for the use of the synchrotron and laser facilities; operation of the SMS facilities at XOR-3 is partially supported by COMPRES as an infrastructure development project under EAR 01-35554 and 06-49658. We thank J. Nalibof, E. J. Garnero, B. Maddox, W. Sturhahn, J. Lassiter, and S. Grand for helpful discussions. Use of the Advanced Photon Source was supported by U.S. Department of Energy, Office of Science, Basic Energy Sciences, under contract No. DE-AC02-06CH11357. GSECARS is supported by NSF Earth Sciences (EAR-0622171) and DOE Geosciences (DE-FG02-94ER14466). This work at Lawrence Livermore National Laboratory was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52- 07NA27344. J.F.L. was partially supported by the Lawrence Livermore Fellowship. G.V. acknowledges financial support from the Hungarian Research Fund (OTKA) under contract No. K72597, and from the Bolyai Fellowship. V.V.S. acknowledges financial support from DOE.

REFERENCES McCammon, C., I. Kantor, O. Narygina, J. Rouquette, U. Ponkratz, I. Sergueev, M. Mezouar, V. Prakapenka, and L. Dubrovinsky, Stabe intermediate-spin ferrous iron in lower-mantle perovskite, Nature Geoscience, 1, 684-687, 2008. Stackhouse, S., The spin deep within, Nature Geoscience, 1, 648-650, 2008.

PUBLICATION Lin, J. F., H. Watson, G. Vanko. E. E. Alp, V. B. Prakapenka, P. Dera, V. V. Struzhkin, A. Kubo, J. Zhao, C. McCammon, and W. J. Evans, Intermediate-spin ferrous iron in lowermost mantle post- perovskie and perovskite, Nature Geoscience, 1, 688-691, 2008.