Abstract
Diogenite meteorites are thought to represent mantle rocks that formed as cumulates in magma chambers on 4 Vesta or a similar differentiated asteroid1,2. Northwest Africa 5480 is a harzburgitic diogenite3,4, composed mainly of heterogeneously distributed olivine and orthopyroxene. Here we present a microstructural analysis of olivine grains from Northwest Africa 5480, using electron backscatter diffraction techniques to quantify any preferred orientation of crystallographic lattice. We find that the preferred orientation in the olivine-dominated zones can be explained neither by cumulate formation nor by impact reprocessing near the asteroid’s surface. Rather, they represent high-temperature solid-state plastic deformation by the pencil-glide5 slip system. The detected type of preferred orientation is well known from dry ultramafic rocks on Earth, where it is typically formed by mantle shear5,6,7 at temperatures between 1,273 and 1,523 K. Numerical modelling indicates that our observations can be explained by large-scale downwelling inside the asteroid’s mantle, within the first 50 million years after formation of calcium–aluminium-rich inclusions. The discovery of solid-state plastic deformation in an asteroidal ultramafic rock represents compelling evidence of dynamic planet-like processes in asteroids. We conclude that long-lasting enhanced mass exchange occurred in the dynamic interior of a differentiated asteroid such as Vesta, and enabled accelerated chemical, structural and thermal equilibration.
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References
McSween, H. Y., Mittlefehldt, D. W., Beck, A. W., Mayne, R. G. & McCoy, T. J. HED Meteorites and their relationship to the Geology of Vesta and the Dawn Mission. Space Sci. Rev. 163, 141–174 (2011).
Irving, A. J., Bunch, T. E., Kuehner, S. M., Wittke, J. H. & Rumble, D. Peridotites related to 4 Vesta: Deep crustal igneous cumulates and mantle samples. Lunar Planet. Sci. 40, 2466 (2009).
Beck, A. & McSween, H. Y. Diogenites as polymict breccias composed of orthopyroxenite and harzburgite. Meteorit. Planet. Sci. 45, 850–872 (2010).
Wittke, J. H., Irving, A. J., Bunch, T. E. & Kuehner, S. M. A nomenclature system for diogenites consistent with the IUGS system for naming terrestrial ultramafic rocks. Meteoritics Planet. Sci. 46 (Meteoritical Society LXXIV), Abstr. 5223 (2011).
Carter, N. L. & Avé Lallement, H. G. High temperature flow of dunite and peridotite. Geol. Soc. Am. Bull. 81, 2181–2202 (1970).
Guegen, Y. & Nicolas, A. Deformation of mantle rocks. Annu. Rev. Earth Planet. Sci. 8, 119–144 (1980).
Tommasi, A., Mainprice, D., Canova, G. & Chasatel, Y. Viscoplastic self-consistent and equilibrium-based modeling of olivine lattice preferred orientations: Implications for the upper mantle seismic anisotropy. J. Geophys. Res. 105, 7893–7908 (2000).
Prior, D. J. et al. The application of electron backscatter diffraction and orientation contrast imaging in the SEM to textural problems in rocks. Am. Mineral. 84, 1741–1759 (1999).
Warren, J. M., Hirth, G. & Kelemen, P. B. Evolution of olivine lattice preferred orientation during simple shear in the mantle. Earth Planet. Sci. Lett. 272, 501–512 (2008).
Ismaïl, W. B. & Mainprice, D. An olivine fabric database: An overview of upper mantle fabrics and seismic anisotropy. Tectonophysics 296, 145–157 (1998).
Bystricky, M., Kunze, K., Burlini, L. & Burg, J-P. High shear strain of olivine aggregates: Rheological and seismic consequences. Science 290, 1564–1566 (2000).
Boudier, F. Olivine xenocrysts in picritic magmas. Contrib. Mineral. Petrol. 109, 114–123 (1991).
Frese, K., Trommsdorff, V. & Kunze, K. Olivine [100] normal to foliation: Lattice preferred orientation in prograde garnet peridotite formed at high H2O activity, Cima di Cagnone (Central Alps). Contrib. Mineral. Petrol. 145, 75–86 (2003).
Jung, H., Katayama, I., Jiang, Z., Hiraga, T. & Karato, S. Effect of water and stress on the lattice-preferred orientation of olivine. Tectonophysics 421, 1–22 (2006).
Warren, P. H., Kallemeyn, G. W., Huber, H., Ulff-Møller, F. & Choe, W. Siderophile and other geochemical constraints on mixing relationships among HED-meteoritic breccias. Geochim. Cosmochim. Acta 73, 5918–5943 (2009).
Day, J. M. D., Walker, R. J., Qin, L. & Rumble, D. Late accretion as a natural consequence of planetary growth. Nature Geosci. 5, 614–617 (2012).
Holtzman, B. K. et al. Melt segregation and strain partitioning: Implications for seismic anisotropy and mantle flow. Science 301, 1227–1230 (2003).
Gerya, T. V. & Yuen, D. A. Robust characteristics method for modelling multiphase visco-elasto-plastic thermo-mechanical problems. Phys. Earth Planet. Int. 163, 83–105 (2007).
Ramberg, H. Fluid dynamics of layered systems in the field of gravity, a theoretical basis for certain global structures and isostatic adjustment. Phys. Earth Planet. Int. 1, 63–87 (1968).
Turcotte, D. L. & Schubert, G. Geodynamics 2nd edn (Cambridge Univ. Press, 2002).
Thomas, P. C. et al. Impact excavation on asteroid 4 Vesta: Hubble space telescope results. Science 277, 1492–1495 (1997).
Jutzi, M. & Asphaug, E. Mega-ejecta on asteroid Vesta. Geophys. Res. Lett. 38, L01102 (2011).
Righter, K. & Drake, M. J. Core formation in Earth’s Moon, Mars and Vesta. Icarus 124, 513–529 (1996).
Righter, K. & Drake, M. J. A magma ocean on Vesta: Core formation and petrogenesis of eucrites and diogenites. Meteorit. Planet. Sci. 32, 929–944 (1997).
Greenwood, R. C., Franchi, I. A., Jambon, A. & Buchanan, P. C. Widespread magma oceans on asteroidal bodies in the early Solar System. Nature 435, 916–918 (2005).
Ghosh, A. & McSween, H. Y. A thermal model for the differentiation of asteroid 4 Vesta, based on radiogenic heating. Icarus 134, 187–206 (1998).
Gupta, G. & Sahijpal, S. Differentiation of Vesta and the parent bodies of other achondrites. J. Geophys. Res. 115, E08001 (2010).
Schiller, M. et al. Rapid timescales for magma ocean crystallization on the Howardite-Eucrite-diogenite parent body. Astrophys. J. Lett. 740, L22 (2011).
Misawa, K., Yamaguchi, A. & Kaiden, H. U–Pb and 207Pb–206Pb ages of zircons from basaltic eucrites: Implications for early basaltic volcanism on the eucrite parent body. Geochim. Cosmochim. Acta 69, 5847–5861 (2005).
Fowler, G. W., Shearer, C.K., Papike, J. J. & Layne, G. D. Diogenites as asteroidal cumulates: Insights from orthopyroxene trace element chemistry. Geochim. Cosmochim. Acta 59, 3071–3084 (1995).
Acknowledgements
We thank T. V. Gerya for providing the code 12MART. Funding to G.J.G. was provided by SNF grant PBEZP2-134461.
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B.J.T. and F.E.B. conceived this project. B.J.T. carried out the EBSD measurements on the sample. B.J.T. and F.E.B. analysed and discussed the results of the EBSD measurements. G.J.G. designed and implemented the numerical model. B.J.T., G.J.G. and F.E.B. analysed and discussed the results. B.J.T. prepared the manuscript, which was then jointly edited by B.J.T., G.J.G. and F.E.B.
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Tkalcec, B., Golabek, G. & Brenker, F. Solid-state plastic deformation in the dynamic interior of a differentiated asteroid. Nature Geosci 6, 93–97 (2013). https://doi.org/10.1038/ngeo1710
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DOI: https://doi.org/10.1038/ngeo1710
