Abstract
Olivine is a major component of the mantle of differentiated bodies, including Earth. Howardite, eucrite and diogenite (HED) meteorites represent regolith, basaltic-crust, lower-crust and possibly ultramafic-mantle samples of asteroid Vesta, which is the lone surviving, large, differentiated, basaltic rocky protoplanet in the Solar System1. Only a few of these meteorites, the orthopyroxene-rich diogenites, contain olivine, typically with a concentration of less than 25 per cent by volume2. Olivine was tentatively identified on Vesta3,4, on the basis of spectral and colour data, but other observations did not confirm its presence5. Here we report that olivine is indeed present locally on Vesta’s surface but that, unexpectedly, it has not been found within the deep, south-pole basins, which are thought to be excavated mantle rocks6,7,8. Instead, it occurs as near-surface materials in the northern hemisphere. Unlike the meteorites, the olivine-rich (more than 50 per cent by volume) material is not associated with diogenite but seems to be mixed with howardite, the most common7,9 surface material. Olivine is exposed in crater walls and in ejecta scattered diffusely over a broad area. The size of the olivine exposures and the absence of associated diogenite favour a mantle source, but the exposures are located far from the deep impact basins. The amount and distribution of observed olivine-rich material suggest a complex evolutionary history for Vesta.
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References
Russell, C. T. et al. Dawn at Vesta: testing the protoplanetary paradigm. Science 336, 684–686 (2012)
Beck, A. W. & McSween, H. Y. Diogenites as polymict breccias composed of orthopyroxenite and harzburgite. Meteorit. Planet. Sci. 45, 850–872 (2010)
Gaffey, M. J. Surface lithologic heterogeneity of asteroid 4 Vesta. Icarus 127, 130–157 (1997)
Binzel, R. P. et al. Geologic mapping of Vesta from 1994 Hubble Space Telescope Images. Icarus 128, 95–103 (1997)
Li, J. Y. et al. Photometric mapping of asteroid (4) Vesta’s southern hemisphere with Hubble Space Telescope. Icarus 208, 238–251 (2010)
McSween, H. J. et al. Composition of the Rheasilvia basin, a window into Vesta’s interior. J. Geophys. Res. 118, 335–346 (2013)
De Sanctis, M. C. et al. Spectroscopic characterization of mineralogy and its diversity across Vesta. Science 336, 697–700 (2012)
Ammannito, E. et al. Vestan lithologies mapped by the visual and infrared spectrometer on Dawn. Meteorit. Planet. Sci. http://dx.doi.org/10.1111/maps.12192 (13 September 2013)
De. Sanctis, M. C. et al. Vesta’s mineralogical composition as revealed by the visible and infrared spectrometer on Dawn. Meteorit. Planet. Sci. http://dx.doi.org/10.1111/maps.12138 (8 July 2013)
De Sanctis, M. C. et al. The VIR spectrometer. Space Sci. Rev. 163, 329–369 (2011)
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)
Ruzicka, A., Snyder, G. A. & Taylor, L. A. Vesta as the howardite, eucrite and diogenite parent body: implications for the size of a core and for large-scale differentiation. Meteorit. Planet. Sci. 32, 825–840 (1997)
Barrat, J.-A. et al. Relative chronology of crust formation on asteroid Vesta: insights from the geochemistry of diogenites. Geochim. Cosmochim. Acta 74, 6218–6231 (2010)
Mittlefehldt, D. W. Petrology and geochemistry of the Elephant Moraine A79002 diogenite: a genomict breccia containing a magnesian harzburgite component. Meteorit. Planet. Sci. 35, 901–912 (2000)
Singer, R. B. Near-infrared spectral reflectance of mineral mixtures: systematic combinations of pyroxenes, olivine, and iron oxides. J. Geophys. Res. 86, 7967–7982 (1981)
Cloutis, E. A. et al. Calibration of phase abundance, composition, and particle size distribution for olivine–orthopyroxene mixtures from reflectance spectra. J. Geophys. Res. 91, 11641–11653 (1986)
Adams, J. B. Visible and near-infrared diffuse reflectance spectra of pyroxenes as applied to remote sensing of solid objects in the solar system. J. Geophys. Res. 79, 4829–4836 (1974)
Gaffey, M. J. et al. Mineralogic variations within the S-type asteroid class. Icarus 106, 573–602 (1993)
Delaney, J. S. et al. The polymict eucrites. J. Geophys. Res. 89, C251–C288 (1984)
Beck, A. W. et al. Petrologic and textural diversity among the PCA 02 howardite group, one of the largest pieces of the Vestan surface. Meteorit. Planet. Sci. 47, 947–969 (2012)
Beck, A. W. et al. MIL 03443, a dunite from asteroid 4 Vesta: evidence for its classification and cumulate origin. Meteorit. Planet. Sci. 46, 1133–1151 (2011)
Marchi, S. et al. High-velocity collisions from the lunar cataclysm recorded in asteroidal meteorites. Nature Geosci. 6, 303–307 (2013)
DeMeo, F. et al. An extension of the Bus asteroid taxonomy into the near-infrared. Icarus 202, 160–180 (2009)
Shearer, C. K., Burger, P. & Papike, J. J. Petrogenetic relationships between diogenites and olivine diogenites: implications for magmatism on the HED parent body. Geochim. Cosmochim. Acta 74, 4865–4880 (2010)
Jaumann, R. et al. Vesta’s shape and morphology. Science 336, 687–690 (2012)
Marchi, S. et al. The violent collisional history of asteroid 4 Vesta. Science 336, 690–694 (2012)
Jutzi, M. et al. The structure of the asteroid 4 Vesta as revealed by models of planet-scale collisions. Nature 494, 207–210 (2013)
Watts, A. W. et al. The formation of terrains antipodal to major impacts. Icarus 93, 159–168 (1991)
Sunshine, J. M. & Pieters, C. M. Determining the composition of olivine from reflectance spectroscopy. J. Geophys. Res. 103, 13,675–13,688 (1998)
Burns, R. G. Mineralogical Applications of Crystal-Field Theory (Cambridge Univ. Press, 1970)
Acknowledgements
We gratefully acknowledge the support of the Dawn Instrument, Operations and Science teams, and, in particular, the Dawn Framing Camera team. This work was supported by Italian Space Agency grant I/004/12/0 and by NASA through the Dawn mission and the Dawn at Vesta Participating Scientists Program.
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M.C.D.S., E.A., E.P. and A.L. contributed to the data analysis. M.C.D.S., E.A., S.M., D.W.M., H.Y.M. and C.M.P. contributed to the data interpretation and to writing and improving the manuscript. E.A. and M.C.D.S. provided calibrated VIR data. F.T. provided geometric data. F.Z. and A.F. provided the projected and mosaicked VIR data. All authors contributed to discussion of the results.
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All Dawn data are available at PDS: Small Bodies Node (http://pdssbn.astro.umd.edu/data_sb/missions/dawn/index.shtml), and VIR data are also available at the ASI Data Center (http://www.asdc.asi.it/).
Extended data figures and tables
Extended Data Figure 1 Ternary diagram of orthopyroxene, olivine and clinopyroxene in diogenites.
Proportions of orthopyroxene, olivine and clinopyroxene in diogenites normalized to 100%, with fields for orthopyroxenitic (red), harzburgitic (green) and dunitic diogenites (yellow). Data taken from Extended Data Table 1.
Extended Data Figure 2 Distribution of the band centres for the HED meteorites.
The difference in spectral properties of diogenites, howardites and eucrites can be quantified using a scatter plot of the BI-centre position versus the BII-centre position. We used spectra in the RELAB database to define the different HED meteorite spectral areas9. The HED meteorite distribution map has been derived as explained in refs 6, 8, 9. In this diagram, diogenites and eucrites populate distinct areas because both the BI-centre position and the BII-centre position are sensitive to the pyroxene compositions. Howardites, which are physical mixtures of diogenite and eucrite, plot between, and partly overlap, these fields. By associating a colour indication of composition with every region in the scatter plot (red for diogenite, green for howardite and purple for eucrite, with overlapping fields of yellow for diogenite–howardite and cyan for eucrite–howardite), we constructed the correspondence map in Fig. 1 using the same colour scheme.
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Ammannito, E., De Sanctis, M., Palomba, E. et al. Olivine in an unexpected location on Vesta’s surface. Nature 504, 122–125 (2013). https://doi.org/10.1038/nature12665
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DOI: https://doi.org/10.1038/nature12665
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