Supplementary information. Jadeite in Chelyabinsk meteorite and the nature of an impact event on its parent. body

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1 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 , Japan 2 Department of Earth and Planetary Systems Science, Graduate School of Science, Hiroshima University, Higashi-Hiroshima , Japan 3 V. S. Sobolev Institute of Geology and Mineralogy, SB RAS, Novosibirsk, , Russia 4 Institute of Mineralogy Ural Branch RAS, Miass, , Russia 5 Novosibirsk State University, Novosibirsk, , Russia * Corresponding author: Dr. Shin Ozawa Department of Earth Science, Graduate School of Science, Tohoku University, Sendai , Japan Tel: Fax: shin.ozawa@m.tohoku.ac.jp

2 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 wt % mean SD mean SD mean SD mean SD mean SD mean SD mean SD mean SD mean SD mean SD SiO TiO Al 2 O Cr 2 O FeO MnO MgO CaO Na 2 O K 2 O Total Cation Si 1.00 < < < Ti < < < Al < < < Cr < < < < Fe < < Mn 0.01 < < < < < < Mg 1.41 < Ca < Na < K Total 3.00 < < < < Oxygen Fo En Ab Fa Fs An Wo Or 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.

3 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 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

4 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 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 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 ( 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:

5 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 = g/cm 3, c = km/s, and s = obtained from the shock experiments on Jilin ordinary chondrite 9, and substitute the estimated shock pressure of 3 12 GPa, we obtain u p = km/s, U = km/s, and v i = 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 = g/cm 3 and C r = km/s. The obtained C r is slightly faster than shock wave velocity U (=

6 km/s). Using obtained parameters and the estimated shock pressure duration t d > 70 ms, we obtain the diameter of projectile D > km. References 1. Turcotte, D. L. & Schubert, G. Geodynamics: Second Edition (eds Turcotte, D. L. & Schubert, G.) (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, (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, (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.) (Oxford Univ. Press, New York, 1989). 7. Ohtani, E. et al. Formation of high-pressure minerals in shocked L6 chondrite Yamato : constraints on shock conditions and parent body size. Earth Planet. Sci. Lett. 227, (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.) (Wiley-Blackwell, West Sussex, 2013). 9. Chengda, D., Xiaogang, J., Shiqin, F. & Shangchun S. The equation-of-states of Jilin

7 ordinary chondrite and Nandan iron meteorite. Sci. in China (Series D) 40, (1997).