Jump to ContentJump to Main Navigation
Show Summary Details
More options …

American Mineralogist

Journal of Earth and Planetary Materials

Ed. by Baker, Don / Xu, Hongwu / Swainson, Ian

IMPACT FACTOR 2017: 2.645

CiteScore 2017: 2.31

SCImago Journal Rank (SJR) 2017: 1.440
Source Normalized Impact per Paper (SNIP) 2017: 1.059

See all formats and pricing
More options …
Volume 101, Issue 9


The effects of shear deformation on planetesimal core segregation: Results from in-situ X-ray micro-tomography

Kasey A. Todd
  • Geology and Environmental Geosciences, Northern Illinois University, Davis Hall, Normal Road, Dekalb, Illinois 60115, United States of America
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
/ Heather .C Watson
  • Corresponding author
  • Department of Earth and Environmental Science, Rensselaer Polytechnic Institute, Troy, New York 12180, United States of America
  • Email
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
/ Tony Yu
  • Center for Advanced Radiation Sources, University of Chicago, 9700 South Cass Avenue, Argonne, Illinois 60439, United States of America
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
/ Yanbin Wang
  • Center for Advanced Radiation Sources, University of Chicago, 9700 South Cass Avenue, Argonne, Illinois 60439, United States of America
  • Other articles by this author:
  • De Gruyter OnlineGoogle Scholar
Published Online: 2016-09-01 | DOI: https://doi.org/10.2138/am-2016-5474


It is well accepted that the Earth formed by the accretion and collision of small (10–100 km), rocky bodies called planetesimals. W-Hf isotopic evidence from meteorites suggest that the cores of many planetesimals formed within a relatively short time frame of ~3 My. While a very hot, deep magma ocean is generally thought to have been the driving mechanism for core formation in large planetary bodies, it inadequately explains differentiation and core formation in small planetesimals due to temperatures potentially being insufficient for wide-scale silicate melting to occur. In order for these planetesimals to differentiate within such a relatively short time without a magma ocean, a critical melt volume of the metallic (core-forming) phase and sufficient melt connectivity and grain size must have existed to attain the required permeability and lead to efficient core formation. Shear deformation may increase the connectedness of melt and the permeability, and thus could have been a major contributing factor in the formation of planetesimal cores. This deformation may have been caused by large impacts and collisions experienced by the planetesimals in the early solar system. The purpose of this work is to test the hypothesis that shear deformation enhances the connectivity and permeability of Fe-S melt within a solid silicate (olivine) matrix, such that rapid core formation is plausible. A rotational Drickamer apparatus (RDA) was used to heat and torsionally deform a sample of solid olivine + FeS liquid through six steps of large-strain shear deformation. After each deformation step, X-ray microtomographs were collected in the RDA to obtain in situ three-dimensional images of the sample. The resulting digital volumes were processed and permeability simulations utilizing the lattice Boltzmann method were performed to determine the effect of shear deformation on connectivity and permeability within the sample. The resulting permeabilities of the sample at various steps of deformation are the same within uncertainty and do not exhibit a change with increasing deformation. Additionally, the migration velocity calculated from the permeability of the sample is not high enough for segregation to take place within the time frame of ~3 My. In addition to further constraining the mechanism of core formation in planetesimals, the image processing techniques developed in this study will be of great benefit to future studies utilizing similar methods.

Keywords: Core formation; microtomography; permeability; lattice Boltzmann

Special collection papers can be found online at http://www.minsocam.org/MSA/AmMin/special-collections.html.

References cited

  • Alexander, C.O.D., Boss, A.P., and Carlson, R.W. (2001) The early evolution of the inner solar system: A meteoritic perspective. Science, 293(5527), 64–68.Google Scholar

  • Bagdassarov, N., Solferino, G., Golabek, G.J., and Schmidt, M.W. (2009a) Centrifuge assisted percolation of Fe–S melts in partially molten peridotite: time constraints for planetary core formation. Earth and Planetary Science Letters, 288(1), 84–95.Google Scholar

  • Bagdassarov, N., Golabek, G.J., Solferino, G., and Schmidt, M.W. (2009b) Constraints on the Fe–S melt connectivity in mantle silicates from electrical impedance measurements. Physics of the Earth and Planetary Interiors, 177, 139–146.Google Scholar

  • Ballhaus, C., and Ellis, D.J. (1996) Mobility of core melts during Earth’s accretion. Earth and Planetary Science Letters, 143(1), 137–145.Google Scholar

  • Bizzarro, M., Baker, J.A., Haack, H., and Lundgaard, K.L. (2005) Rapid timescales for accretion and melting of differentiated planetesimals inferred from 26Al-26Mg chronometry. The Astrophysical Journal Letters, 632(1), L41.Google Scholar

  • Bosl, W.J., Dvorkin, J., and Nur, A. (1998) A study of porosity and permeability using a lattice Boltzmann simulation. Geophysical Research Letters, 25(9), 1475–1478.Google Scholar

  • Bourbie, T., and Zinszer, B. (1985) Hydraulic and acoustic properties as a function of porosity in Fontainebleau sandstone. Journal of Geophysical Research, 90(B3) 11524–11532.Google Scholar

  • Bruhn, D., Groebner, N., and Kohlstedt, D.L. (2000) An interconnected network of core-forming melts produced by shear deformation. Nature, 403(6772), 883–886.Google Scholar

  • Bulau, J.R., Waff, H.S., and Tyburczy, J.A. (1979), Mechanical and thermodynamic constraints on fluid distribution in partial melts, Journal of Geophysical Research: Solid Earth, 84(B11), 6102–6108.Google Scholar

  • Burkhardt, C., Kleine, T., Bourdon, B., Palme, H., Zipfel, J., Friedrich, J.M., and Ebel, D.S. (2008) Hf–W mineral isochron for Ca, Al-rich inclusions: age of the solar system and the timing of core formation in planetesimals. Geochimica et Cosmochimica Acta, 72(24), 6177–6197.Google Scholar

  • Chen, S., and Doolen, G.D. (1998) Lattice Boltzmann method for fluid flows. Annual Review of Fluid Mechanics, 30(1), 329–364.Google Scholar

  • Degruyter, W., Burgisser, A., Bachmann, O., and Malaspinas, O. (2010) Synchrotron X-ray microtomography and lattice Boltzmann simulations of gas flow through volcanic pumices. Geosphere, 6(5), 470–481.Google Scholar

  • Faul, U.H. (1997) Permeability of partially molten upper mantle rocks from experiments and percolation theory. Journal of Geophysical Research, 102(B5), 10,299–10,311.Google Scholar

  • Gaetani, G.A., and Grove, T.L. (1999) Wetting of mantle olivine by sulfide melt: implications for Re/Os ratios in mantle peridotite and late-stage core formation. Earth and Planetary Science Letters, 169(1), 147–163.Google Scholar

  • Gotou, H., Yagi, T., Iizuka, R., and Suzuki, A. (2015) Application of X-ray radiography to study the segregation process of iron from silicate under high pressure and high temperature. High Pressure Research, 35(2), 130–138.Google Scholar

  • Groebner, N., and Kohlstedt, D.L. (2006) Deformation-induced metal melt networks in silicates: Implications for core–mantle interactions in planetary bodies. Earth and Planetary Science Letters, 245(3), 571–580.Google Scholar

  • Holzheid, A., Schmitz, M.D., and Grove, T.L. (2000) Textural equilibria of iron sulfide liquids in partly molten silicate aggregates and their relevance to core formation scenarios. Journal of Geophysical Research, 105(B6), 13555–13513.Google Scholar

  • Hustoft, J.W., and Kohlstedt, D.L. (2006) Metal-silicate segregation in deforming dunitic rocks. Geochemistry, Geophysics, Geosystems, 7(2), Q02001.Google Scholar

  • Kleine, T., Münker, C., Mezger, K., and Palme, H. (2002) Rapid accretion and early core formation on asteroids and the terrestrial planets from Hf–W chronometry. Nature, 418, 952–955.Google Scholar

  • Kleine, T., Touboul, M., Bourdon, B., Nimmo, F., Mezger, K., Palme, H., and Halliday, A.N. (2009) Hf–W chronology of the accretion and early evolution of asteroids and terrestrial planets. Geochimica et Cosmochimica Acta, 73(17), 5150–5188.Google Scholar

  • Kohlstedt, D.L., and Holtzmann, B.K. (2009) Shearing melt out of the earth: An experimentalist’s perspective on the influence of deformation on melt extraction. Annual Reviews in Earth and Planetary Science, 37, 561–593.Google Scholar

  • Kohlstedt, D.L., and Mackwell, S.J. (1987) High-temperature stability of San Carlos olivine. Contributions to Mineralogy and Petrology, 95(2), 226–230.Google Scholar

  • Kono, Y., Kenney-Benson, C., Shibazaki, Y., Park, C., Shen, G., and Wang, Y. (2015) High-pressure viscosity of liquid Fe and FeS revisited by falling sphere viscometry using ultrafast X-ray imaging. Physics of the Earth and Planetary Interiors, 241, 57–64.Google Scholar

  • Kruijer, T.S., Touboul, M., Fischer-Gödde, M., Bermingham, K.R., Walker, R.J., and Kleine, T. (2014) Protracted core formation and rapid accretion of protoplanets. Science, 344, 1150, doi:.CrossrefGoogle Scholar

  • Latt, J. (2009) Palabos, Parallel Lattice Boltzmann Solver, http://www.Palabos.com. Accessed May 2011.

  • LeBlanc, G.E., and Secco, R.A. (1996) Viscosity of an Fe-S liquid up to 1300 °C and 5 GPa. Geophysical Research Letters, 23(3), 213–216.Google Scholar

  • Miller, K.J., Zhu, W., Montesi, L.G.J., and Gaetani, G. (2014) Experimental quantification of permeability of partially molten mantle rock. Earth and Planetary Science Letters, 388, 273–282.Google Scholar

  • Rivers, M.L., and Gualda, G.A.R. (2009) ‘tomo_display’ and ‘vol_tools’: IDL VM packages for tomography data reconstruction, processing, and visualization, Eos Transactions of AGU, Joint Assembly Supplement.Google Scholar

  • Roberts, J.J., Kinney, J.H., Siebert, J., and Ryerson, F.J. (2007) Fe-Ni-S melt permeability in olivine: Implications for planetary core formation. Geophysical Research Letters, 34(14), doi:.CrossrefGoogle Scholar

  • Rubie, D.C., Nimmo, F., and Melosh, H.J. (2007) Formation of Earth’s core. Treatise on Geophysics, 9, 51–90.Google Scholar

  • Rushmer, T., Petford, N., Humayun, M., and Campbell, A.J. (2005) Fe-liquid segregation in deforming planetesimals: Coupling core-forming compositions with transport phenomena. Earth and Planetary Science Letters, 239(3), 185–202.Google Scholar

  • Scherstén, A., Elliott, T., Hawkesworth, C., Russell, S., and Masarik, J. (2006) Hf–W evidence for rapid differentiation of iron meteorite parent bodies. Earth and Planetary Science Letters, 241(3), 530–542.Google Scholar

  • Shannon, M.C., and Agee, C.B. (1996) High pressure constraints on percolative core formation. Geophysical Research Letters, 23(20), 2717–2720.Google Scholar

  • Shi, C.Y., Zhang, L., Yang, W., Liu, Y., Wang, J., Meng, Y., Andrews, J.C., and Mao, W.L. (2013) Formation of an interconnected network of iron melt at Earth’s lower mantle conditions. Nature Geoscience, 6, 971–975.Google Scholar

  • Speziale, S., Zha, C., Duffy, T.S., Hemley, R.J., and Mao, H.K. (2001) Quasihydrostatic compression of magnesium oxide to 52 GPa: Implications for the pressure-volume-temperature equation of state. Journal of Geophysical Research, Solid Earth, 106, B, 1, 515–528.Google Scholar

  • Takafuji, N., Hirose, K., Ono, S., Xu, F., Mitome, M., and Bando, Y. (2004) Segregation of core melts by permeable flow in the lower mantle. Earth and Planetary Science Letters, 224(3), 249–257.Google Scholar

  • Terasaki, H., Frost, D.J., Rubie, D.C., and Langenhorst, F. (2008) Percolative core formation in planetesimals. Earth and Planetary Science Letters, 273(1), 132–137.Google Scholar

  • Turcotte, D.L., and Schubert, G. (2002) Geodynamics, 2nd ed. Cambridge University Press.Google Scholar

  • von Bargen, N., and Waff, H.S. (1986) Permeabilities, interfacial areas and curvatures of partially molten systems: Results of numerical computations of equilibrium microstructures. Journal of Geophysical Research: Solid Earth (1978–2012), 91(B9), 9261–9276.Google Scholar

  • Walte, N.P., Becker, J.K., Bons, P.D., Rubie, D.C., and Frost, D.J. (2007) Liquiddistribution and attainment of textural equilibrium in a partially-molten crystalline system with a high-dihedral-angle liquid phase. Earth and Planetary Science Letters, 262(3), 517–532.Google Scholar

  • Walte, N.P., Rubie, D.C., Bons, P.D., and Frost, D.J. (2011) Deformation of a crystalline aggregate with a small percentage of high-dihedral-angle liquid: Implications for core-mantle differentiation during planetary formation. Earth and Planetary Science Letters. 305, 124–134.Google Scholar

  • Walter, M.J., and Trønnes, R.G. (2004) Early earth differentiation. Earth and Planetary Science Letters, 225(3), 253–269.Google Scholar

  • Wang, Y., Uchida, T., Westferro, F., Rivers, M.L., Nishiyama, N., Gebhardt, J., and Sutton, S.R. (2005) High-pressure X-ray tomography microscope: Synchrotron computed microtomography at high pressure and temperature. Review of Scientific Instruments, 76(7), 073709.Google Scholar

  • Wang, Y., Lesher, C., Fiquet, G., Rivers, M.L., Nishiyama, N., Siebert, J., and Guyot, F. (2011) In situ high-pressure and high-temperature X-ray microtomographic imaging during large deformation: A new technique for studying mechanical behavior of multiphase composites. Geosphere, 7(1), 40–53.Google Scholar

  • Watson, H.C., and Roberts, J.J. (2011) Connectivity of core forming melts: Experimental constraints from electrical conductivity and X-ray tomography. Physics of the Earth and Planetary Interiors, 186(3), 172–182.Google Scholar

  • Watson, H.C., Roberts, J.J., and Tyburczy, J.A. (2010) Effect of conductive impurities on electrical conductivity in polycrystalline olivine. Geophysical Research Letters, 37(2), L02302, doi:.CrossrefGoogle Scholar

  • White, J.A., Borja, R.I., and Fredrich, J.T. (2006) Calculating the effective permeability of sandstone with multi-scale lattice Boltzmann/finite element simulations. Acta Geotechnica, 1, 195–209.Google Scholar

  • Wood, B.J., Walter, M.J., and Wade, J. (2006) Accretion of the Earth and segregation of its core. Nature, 441(7095), 825–833.Google Scholar

  • Yoshino, T., Walter, M.J., and Katsura, T. (2003) Core formation in planetesimals triggered by permeable flow. Nature, 422, 154–157.Google Scholar

  • Yoshino, T., Walter, M.J., and Katsura, T. (2004) Connectivity of molten Fe alloy in peridotite based on in situ electrical conductivity measurements: implications for core formation in terrestrial planets. Earth and Planetary Science Letters, 222(2), 625–643.Google Scholar

  • Zhu, W., Gaetani, G., Fusseis, F., Montesi, L.G.J., and De Carlo, F. (2011) Microtomography of partially molten rocks: Three dimensional melt distribution in mantle peridotite. Science, 332, 88–91.Google Scholar

About the article

Present address: Department of Physics and Astronomy, Union College, Schenectady, New York 12308, U.S.A.

Received: 2015-06-20

Accepted: 2016-05-06

Published Online: 2016-09-01

Published in Print: 2016-09-01

Citation Information: American Mineralogist, Volume 101, Issue 9, Pages 1996–2004, ISSN (Online) 1945-3027, ISSN (Print) 0003-004X, DOI: https://doi.org/10.2138/am-2016-5474.

Export Citation

© 2016 by Walter de Gruyter Berlin/Boston.

Comments (0)

Please log in or register to comment.
Log in