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Research Spending & Results

Award Detail

Awardee:REGENTS OF THE UNIVERSITY OF MICHIGAN
Doing Business As Name:University of Michigan Ann Arbor
PD/PI:
  • Jie Li
  • (734) 615-7317
  • jackieli@umich.edu
Award Date:05/12/2010
Estimated Total Award Amount: $ 116,206
Funds Obligated to Date: $ 116,205
  • FY 2009=$105,065
  • FY 2008=$11,140
Start Date:01/01/2010
End Date:10/31/2011
Transaction Type:Grant
Agency:NSF
Awarding Agency Code:4900
Funding Agency Code:4900
CFDA Number:47.050
Primary Program Source:040100 NSF RESEARCH & RELATED ACTIVIT
Award Title or Description:Constraints on core composition from nuclear resonant scattering and x-ray diffraction studies on Fe-light-element compounds
Federal Award ID Number:1023729
DUNS ID:073133571
Parent DUNS ID:073133571
Program:Geophysics
Program Officer:
  • Robin Reichlin
  • (703) 292-8556
  • rreichli@nsf.gov

Awardee Location

Street:3003 South State St. Room 1062
City:Ann Arbor
State:MI
ZIP:48109-1274
County:Ann Arbor
Country:US
Awardee Cong. District:12

Primary Place of Performance

Organization Name:University of Michigan Ann Arbor
Street:3003 South State St. Room 1062
City:Ann Arbor
State:MI
ZIP:48109-1274
County:Ann Arbor
Country:US
Cong. District:12

Abstract at Time of Award

Constraints on core composition from nuclear resonant scattering and x-ray diffraction studies on iron-light-element compounds The light element composition of the Earth's core has been a long-standing mystery in the study of the Earth's interior. The presence of light elements was first inferred from the density deficit and velocity excess of the core relative to that of pure iron under corresponding conditions. In order to test competing core composition models, we need accurate knowledge of the effects of various light elements on the density and velocities of iron as a function of pressure and temperature. Previous work has placed sulfur and carbon among the leading candidates for the principal light element in the core, even though density and sound velocity data for iron-sulfur and iron-carbon alloys are limited to room temperature and moderate pressures. The investigators will extend the data coverage into the Mbar regime and up to 1700 K, over the same pressure and temperature range of the existing measurements on pure iron. X-ray diffraction and nuclear resonant scattering - both established synchrotron radiation techniques - will be applied to determine the phase stability, equation-of-state, and partial phonon density-of-state of iron-rich compounds containing amounts of sulfur and carbon that are within the estimated range for the Earth's core. The new data will permit the team to explore the effects of sulfur and carbon on the density and sound velocities of iron in a previously uncharted pressure-temperature sector. They will be able to conduct stringent tests of candidate models describing sulfur-bearing or carbon-bearing core scenarios. This research will provide fundamental new knowledge about the properties of iron-rich alloys at high pressures and temperatures and the nature of planetary cores.

Publications Produced as a Result of this Research

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Gao, L., B. Chen, M. Lerche, E. E. Alp, W. Sturhahn, J. Zhao, H. Yavas, and J. Li "Sound velocities of compressed Fe3C from simultaneous synchrotron x-ray diffraction and nuclear resonant scattering measurements" Journal of synchrotron radiation, v.16, 2009, p.714.

Gao, L.;Chen, B.;Zhao, J.;Alp, E. E.;Sturhahn, W.;Li, J.; "Effect of Temperature on Sound Velocities of Compressed Fe" Earth and Planetary Science Letters, v.309, 2011, p.213-220.

Chen, Bin;Gao, Lili;Leinenweber, Kurt;Wang, Yanbin;Sanehira, Takeshi;Li, Jie; "In situ investigation of high-pressure melting behavior in the Fe-S system using synchrotron X-ray radiography" High Pressure Research, v.28, 2008, p.315-326,.

Gao, L.;Chen, B.;Wang, J.;Scott, Henry P.;Lerche, M.;Zhao, J.;Sturhahn, W.;Alp, E. E.;Huang, F.;Sinogeikin, S. V.;Lundstrom, C.;Bass, J.;Li, J; "Magnetic transition and sound velocities of Fe" University of Illinos 7th SESE Annual Research Review, v., 2008, p..

Chen, B; Li, J; Hauck, SA "Non-ideal liquidus curve in the Fe-S system and Mercury's snowing core" GEOPHYSICAL RESEARCH LETTERS, v.35, 2008, p.. doi:10.1029/2008GL03331  View record at Web of Science

Chen B., Gao L., Funakoshi K.-i., and Li J. "Thermal expansion of iron-rich alloys and implications for the Earth's core" Proceedings of the National Academy of Sciences, v.104, 2007, p.9162. doi:10.1073/pnas.0610474104 

Murakami M., Sinogeikin S. V., Hellwig H., Bass J. D., and Li J. "Sound velocity of MgSiO3 perovskite to Mbar pressure" Earth and Planetary Science Letters, v.256, 2007, p.47.

Lakshtanov, D. L., K. D. Litasov, S. V. Sinogeikin, H. Hellwig, J. Li, E. Ohtani, and J. D. Bass "Effect of Al3+ and H+ on the elastic properties of stishovite" American Mineralogists, v.92, 2007, p.1026.

Li, J; Sturhahn, W; Jackson, JM; Struzhkin, VV; Lin, JF; Zhao, J; Mao, HK; Shen, G "Pressure effect on the electronic structure of iron in (Mg,Fe)(Si,Al)O-3 perovskite: a combined synchrotron Mossbauer and X-ray emission spectroscopy study up to 100 GPa" PHYSICS AND CHEMISTRY OF MINERALS, v.33, 2006, p.575. doi:10.1007/s00269-006-0105-  View record at Web of Science

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