Supplementary information Jadeite in Chelyabinsk meteorite and the nature of an impact event on its parent body Shin Ozawa 1*, Masaaki Miyahara 1, 2, Eiji Ohtani 1, 3, Olga N. Koroleva 4, Yoshinori Ito 1, Konstantin D. Litasov 3, 5 and Nikolai Pokhilenko 3 1 Department of Earth Science, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan 2 Department of Earth and Planetary Systems Science, Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526, Japan 3 V. S. Sobolev Institute of Geology and Mineralogy, SB RAS, Novosibirsk, 630090, Russia 4 Institute of Mineralogy Ural Branch RAS, Miass, 456317, Russia 5 Novosibirsk State University, Novosibirsk, 630090, Russia * Corresponding author: Dr. Shin Ozawa Department of Earth Science, Graduate School of Science, Tohoku University, Sendai 980-8578, Japan Tel: +81-22-795-6664 Fax: +81-22-795-6662 E-mail: shin.ozawa@m.tohoku.ac.jp
Supplementary Table S1 Chemical compositions of constituent phases in Chelyabinsk meteorite. Phase Ol (host) Ol (vein) En (host) En (vein) Di (host) Di (vein) Fsp (host) Jd-bearing grain (vein) Bulk Jd Gl n 6 19 10 7 3 3 14 16 16 16 wt % mean SD mean SD mean SD mean SD mean SD mean SD mean SD mean SD mean SD mean SD SiO 2 38.35 0.77 38.70 0.28 55.80 1.01 56.65 0.33 55.71 1.77 55.81 0.20 66.30 0.92 66.13 0.59 66.97 1.07 68.27 0.92 TiO 2 - - - - 0.21 0.07 0.16 0.11 0.53 0.20 0.50 0.14 - - - - - - - - Al 2 O 3 - - - - 0.13 0.05 0.19 0.08 0.44 0.09 0.70 0.20 20.87 0.64 20.79 0.25 20.73 0.55 20.34 0.52 Cr 2 O 3 - - - - 0.10 0.05 0.22 0.12 0.85 0.11 0.78 0.14 - - - - - - - - FeO 26.96 0.56 26.94 0.58 16.40 0.37 16.71 0.67 5.78 0.21 5.80 0.55 0.76 0.23 0.95 0.24 0.86 0.23 0.71 0.18 MnO 0.45 0.05 0.46 0.12 0.42 0.10 0.50 0.16 0.26 0.15 0.31 0.08 - - - - - - - - MgO 36.56 0.66 36.55 0.51 27.96 0.50 28.16 0.25 16.70 0.46 16.59 0.06 - - - - - - - - CaO - - - - 0.76 0.15 0.74 0.15 22.28 0.47 22.01 0.71 2.18 0.35 2.15 0.18 2.24 0.11 1.79 0.23 Na 2 O - - - - - - - - 0.54 0.03 0.64 0.10 9.46 0.97 9.38 0.38 8.48 0.95 6.28 0.45 K 2 O - - - - - - - - - - - - 0.85 0.20 1.56 0.49 1.15 0.18 2.19 0.35 Total 102.32 1.93 102.65 0.83 101.78 1.87 103.33 1.06 103.08 2.84 103.14 0.51 100.43 2.07 100.95 0.54 100.42 1.18 99.59 1.10 Cation Si 1.00 < 0.01 1.00 < 0.01 1.98 < 0.01 1.98 0.01 1.99 0.01 1.99 0.01 2.91 0.02 2.90 0.02 2.93 0.03 2.99 0.03 Ti - - - - 0.01 < 0.01 0.00 < 0.01 0.01 0.01 0.01 < 0.01 - - - - - - - - Al - - - - 0.01 < 0.01 0.01 < 0.01 0.02 < 0.01 0.03 0.01 1.08 0.02 1.08 0.01 1.07 0.02 1.05 0.02 Cr - - - - 0.00 < 0.01 0.01 < 0.01 0.02 < 0.01 0.02 < 0.01 - - - - - - - - Fe 2+ 0.58 < 0.01 0.58 0.01 0.49 0.01 0.49 0.01 0.17 < 0.01 0.17 0.02 0.03 0.01 0.03 0.01 0.03 0.01 0.03 0.01 Mn 0.01 < 0.01 0.01 < 0.01 0.01 < 0.01 0.02 < 0.01 0.01 < 0.01 0.01 < 0.01 - - - - - - - - Mg 1.41 < 0.01 1.41 0.01 1.48 0.01 1.47 0.01 0.89 0.01 0.88 0.01 - - - - - - - - Ca - - - - 0.03 0.01 0.03 < 0.01 0.85 0.01 0.84 0.02 0.10 0.02 0.10 0.01 0.10 0.01 0.08 0.01 Na - - - - - - - - 0.04 < 0.01 0.04 0.01 0.81 0.08 0.80 0.03 0.72 0.08 0.53 0.04 K - - - - - - - - - - - - 0.05 0.01 0.09 0.03 0.06 0.01 0.12 0.02 Total 3.00 < 0.01 3.00 < 0.01 4.01 < 0.01 4.01 0.01 4.00 < 0.01 4.00 0.01 4.97 0.06 5.00 0.02 4.92 0.06 4.81 0.04 Oxygen 4 6 8 Fo 70.7 0.2 70.8 0.6 En 74.1 0.2 74.0 0.7 46.4 0.2 46.5 0.5 Ab 84.2 2.3 80.9 2.7 80.8 2.3 72.2 2.5 Fa 29.3 0.2 29.2 0.6 Fs 24.4 0.3 24.7 0.6 9.0 0.2 9.1 0.9 An 10.8 2.0 10.2 0.7 11.9 1.2 11.3 0.9 Wo 1.5 0.3 1.3 0.2 44.5 0.2 44.4 1.2 Or 5.0 1.3 8.9 2.8 7.3 1.3 16.5 2.3 n = number of analyses, SD = standard deviation, Ol = olivine, En = enstatite, Di = diopside, Fsp = Albitic feldspar, Bulk = bulk composition of jadeite-bearing grains, Jd = jadeite-bearing part, Gl = feldspathic glass part coexisting with jadeite, Fo = forsterite, Fa = fayalite, Fs = ferrosilite, Wo = wollastonite, Ab = albite, An = anorthite, Or = orthoclase.
Supplementary Note Solidification time of a shock-melt vein A shock-melt vein can be regarded as a hot slab bounded by two semi-infinite half spaces. Initially, the slab is molten at its melting temperature T m or higher, and the surrounding material on both sides is solid at a temperature T 0. As time passes, the slab cools and solidifies by conduction of heat from the slab to the surrounding material. In this model, the time for complete solidification of the slab t s is given by: t s = w 2 4κλ 2 where w is the half-width of the slab, κ is the thermal diffusivity of the solidified slab and surrounding material, and λ is a dimensionless coefficient 1,2. λ is obtained by solving the transcendental equation: π C p T m T 0 = e -λ λ 1 + erf λ where L is the latent heat of solidification, C p is the specific heat at constant pressure, and erf is the error function 1,2. The temperature at the boundary between the slab and surrounding material (= T b ) stays constant until the slab completely solidifies, and the value is given by 1,2 : T b = T 0 + T m T 0 1 + erf λ In the case of shock-melt veins in Chelyabinsk meteorite, T 0 corresponds to the shock temperature of the host-rock under the shock pressure of 3 12 GPa. Shock temperature is a sum of initial temperature before shock and shock-induced temperature increase during shock. Although the pre-shock initial temperature for Chelyabinsk meteorite is unknown, it might be lower than 100 C based on the cooling model 2
calculation for H5 ordinary chondrite in a parent body later than 4460 Ma ago 3. Stöffler et al. 4 suggested the shock-induced temperature increase can be 20 100 C when ordinary chondrite is shocked at 5 15 GPa. Thus, the shock temperature of the host-rock of Chelyabinsk meteorite might be less than 120 200 C. Here, we adopt T 0 = 100 C for this calculation. This assumption seems to be comparable with the shock temperature of 432 K (= ~159 C) calculated by Sharp et al. 5 for Tenham L6 chondrite shocked to 25 GPa, although the ambient temperature before shock is unknown in their calculations. T m is assumed to be 2000 C, according to the estimated liquidus temperature of a bulk LL chondrite (1700 2000 C). The maximum width of the shock-melt vein containing jadeite was 2w = 1 mm in our observations. If we take typical values of L = 320 kj/kg, C p = 1.2 kj/kg, and κ = 10-6 m 2 /s (ref. 1), we find λ = ~0.9, t s = ~70 ms, and T b = ~1100 C. When the vein completely solidifies, the temperature within the vein is still high (> 1100 C). If pressure release occurs at this time, jadeite might vitrify or back-transform to low-pressure phases due to the ambient pressure and high-temperature conditions. Thus, the shock pressure duration could be longer than 70 ms.. Impact velocity and size of impactor From the Rankine-Hugoniot equations, shock pressure P is given by: P P = ρ 0 u p U where P 0 and ρ 0 are pressure and density of material before impact, u p is the particle velocity, and U is the shock wave velocity 6 8. If P is high enough compared with P 0, we can assume P 0 = 0. A relation between shock wave velocity and particle velocity can be given as:
U = c + su p where c and s are empirical constants depending on materials 6 8. If we assume that the projectile and target are composed of the same material, particle velocity is expressed as: u p = v i / 2 where v i is the impact velocity 6 8. When we take the values of ρ 0 = 3.469 g/cm 3, c = 3.7237 km/s, and s = 1.2822 obtained from the shock experiments on Jilin ordinary chondrite 9, and substitute the estimated shock pressure of 3 12 GPa, we obtain u p = 0.21 0.74 km/s, U = 4.0 4.7 km/s, and v i = 0.4 1.5 km/s. The duration of shock pressure t d can be considered as a sum of the time required for shock wave and rarefaction wave to travel through the projectile. It can be expressed as: t d = t c + t r = D U + ρ 0 ρ D C r where t c is the travel time for shock wave, t r is the travel time for rarefaction wave, D is the diameter of projectile, ρ is the density of shocked material and C r is the rarefaction wave velocity 6 8. On the basis of the Murnaghan equation, C r is given by: C r = K 0 + np ρ where K 0 = ρ 0 c 2 is the bulk modulus of projectile, n = 4s 1 is a dimensionless constant 8. The density of shocked material ρ is calculated with the following equation in ref. 9: P = ρ 0 c 2 1 ρ 0 /ρ 1 s 1 ρ 0 /ρ 2 Substituting the estimated pressure of 3 12 GPa, we find ρ = 3.7 4.1 g/cm 3 and C r = 4.1 4.9 km/s. The obtained C r is slightly faster than shock wave velocity U (= 4.0 4.7
km/s). Using obtained parameters and the estimated shock pressure duration t d > 70 ms, we obtain the diameter of projectile D > 0.15 0.19 km. References 1. Turcotte, D. L. & Schubert, G. Geodynamics: Second Edition (eds Turcotte, D. L. & Schubert, G.) 132 194 (Cambridge Univ. Press, Cambridge, 2002). 2. Langenhorst, F. & Poirier, J-P. Anatomy of black veins in Zagami: clues to the formation of high-pressure phases. Earth Planet. Sci. Lett. 184, 37 55 (2000). 3. Henke, S. et al. Thermal evolution and sintering of chondritic planetesimals. Astron. Astrophys. 537, A45 (2012). 4. Stöffler, D., Keil, K. & Scott, E. R. D. Shock metamorphism of ordinary chondrites. Geochim. Cosmochim. Acta 55, 3845 3867 (1991). 5. Sharp, T. G., Xie, Z., Aramovich, C. J. & De Carli, P. S. Pressure-temperature histories of shock-induced melt veins in chondrites. Lunar Planet. Sci. 34, #1278 (2003). 6. Melosh, H. J. Impact Cratering: A Geological Process (ed. Melosh, H. J.) 29 59 (Oxford Univ. Press, New York, 1989). 7. Ohtani, E. et al. Formation of high-pressure minerals in shocked L6 chondrite Yamato 791384: constraints on shock conditions and parent body size. Earth Planet. Sci. Lett. 227, 505 515 (2004). 8. Melosh, H. J. The contact and compression stage of impact cratering. In Impact Cratering: processes and products (eds Osinski, G. R. & Pierazzo, E.) 32 42 (Wiley-Blackwell, West Sussex, 2013). 9. Chengda, D., Xiaogang, J., Shiqin, F. & Shangchun S. The equation-of-states of Jilin
ordinary chondrite and Nandan iron meteorite. Sci. in China (Series D) 40, 403 410 (1997).