Figure DR1. Examples of typical shocked zircon from sample 13GGK029, Sudbury impact crater, Ontario, Canada. A-D: Backscatter electron (BSE) images of grain exteriors. A: Zircon 13GGK029-Z156, exhibiting multiple sets of planar fractures (PFs), many small (<5 µmindimension) apparent neoblasts and a larger, elongate neoblast in the center of the grain which appears to be aligned with a PF orientation. Apparently referring to what we here term “neoblasts” as “crystallites”, Moser et al. (2011; p. 133) described a similar phenomenon at Vredefort whereby “some crystallites nucleate on microtwin lamellae, adopting their orientation relative to the master grain, during intense post-shock heating by the enveloping norite impact melt.” B: Zircon 13GGK029-Z134, again exhibiting PFs, small neoblasts and a single larger, elongate neoblast apparently aligned with a PF orientation. C: Zircon 13GGK029-Z128, showing multiple sets of PFs. D: Zircon 13GGK029-Z18, showing conspicuously non-planar fractures. E: Cathodoluminescence (CL) image of interior of grain 13GGK029-Z18, showing a ‘stock-work’-like pattern of CL-bright fractures typical of shock-related curviplanar fractures (CFs; e.g., Moser et al., 2011).

GSA Data Repository 2017340

Kenny et al., 2017, The formation of large neoblasts in shocked zircon and their utility in dating impacts: Geology, doi:10.1130/G39328.1.

Figure DR2. Additional electronbackscatterdiffraction(EBSD)mapsforzircongrain13GGK029‐Z25showingeffectofdatacleanup. A: Cathodoluminescence image. B: Phase map showing that only zircon was indexed with no evidence for baddeleyite or reidite. C: Map of confidence index (CI) prior to data cleanup. D: Map colored for inset inverse pole figure (IPF), using uncleaned data. E: Map of CI after application of ‘grain CI standardization’ and ‘neighbor CI correlation’ (see Full Analytical Methods). F: Map colored for inset IPF after data cleanup showing that the overall substance of the orientation data is unaffected by the cleanup process. BlackcircularfeaturesinB‐Frepresentlaserablationpitsforrareearthelementanalysesnotreportedhere.

Figure DR3. Additional electron backscatter diffraction (EBSD) data for zircon 13GGK029-Z25. A: EBSD map showing kernel average misorientation (KAM; see fully analytical methods for details on how this is calculated). B: Misorientation profile for the white line shown in A. The red line shows misorientation relative to starting point X and the blue line shows the KAM at a given point. C: Stereographic projection of crystallographic data for area inside white box in A. Pole figure shows dispersion of poles around <001> rotation axis. Data plotted as lower hemisphere equal area projections. The linear misorientation bands observed at the top of the grain and traversed by the profile are interpreted as planar deformation bands (PDBs) – crystallographically-controlled planar microstructures which occur parallel to {100} planes and most commonly having <100> misorientation axes (Timms et al., 2012). PDBs in shocked lunar zircon have a very similar appearance to this; e.g. lunar zircon 72215.195 described by Nemchin et al. (2009; their Fig. 1), Timms et al. (2012; their Fig. 5) and Grange et al. (2013b; their Fig. 10B). ADDITIONAL REFERENCES CITED

Grange, M. L., Pidgeon, R. T., Nemchin, A. A., Timms, N. E., and Meyer, C., 2013b, Interpreting U–Pb data from primary and secondary features in lunar zircon: Geochimica et Cosmochimica Acta, v. 101, p. 112-132, doi:10.1016/j.gca.2012.10.013.

Nemchin, A. A., Timms, N. E., Pidgeon, R. T., Geisler, T., Reddy, S. M., and Meyer, C., 2009,

Timing of crystallization of the lunar magma ocean constrained by the oldest zircon: Nature Geoscience, v. 2, no. 2, p. 133-136, doi:10.1038/ngeo417.

TableDR1Secondaryionmassspectrometry(SIMS)U‐Pbdata

Ratios (PbC corrected) Ages (PbC corrected)Sample ID* Session ID Spot size [U] [Th] [Pb] Th/U 207Pb ± 206Pb ± 207Pb ± Discordance** 207Pb ± 206Pb ± 207Pb ± f206% ***

um ppm ppm ppm calc 235U % 238U % 206Pb % % 235U 238U 206Pb13GGK029‐25a 1 15 196 149 95 0.75 6.226 1.2 0.3615 1.1 0.87 0.1249 0.61 1.9 2008 11 1989 19 2028 11 0.0613GGK029‐25b  1 15 135 128 68 0.88 6.182 1.2 0.3616 1.1 0.87 0.1240 0.61 1.3 2002 11 1990 19 2015 11 0.1313GGK029‐25c (neoblast) 1 15 102 54 44 0.51 5.435 1.7 0.3410 1.2 0.67 0.1156 1.27 ‐0.1 1890 15 1891 19 1889 23 0.3213GGK029‐25d (neoblast) 2 10 124 101 55 0.82 5.092 1.9 0.3341 1.7 0.90 0.1112 0.77 ‐2.8 1835 16 1858 27 1808 14 0.0913GGK029‐25e (neoblast) 2 10 120 64 52 0.55 5.301 1.9 0.3382 1.7 0.88 0.1137 0.93 ‐1.0 1869 17 1878 28 1859 17 {0.03}13GGK029‐25f (neoblast) 2 10 142 68 60 0.48 5.242 1.8 0.3361 1.7 0.92 0.1131 0.70 ‐1.0 1859 16 1868 27 1850 13 {0.00}13GGK029‐25g (neoblast) 2 10 179 92 76 0.52 5.272 1.8 0.3368 1.7 0.93 0.1143 0.63 ‐0.8 1864 15 1871 27 1857 12 0.1113GGK029‐25h 2 10 114 94 59 0.76 7.084 2.0 0.3777 1.8 0.89 0.1367 0.87 5.1 2122 18 2065 31 2177 15 0.0913GGK029‐25i 2 10 154 133 68 0.80 5.097 1.8 0.3234 1.6 0.90 0.1185 0.66 3.3 1836 16 1806 26 1869 14 0.5913GGK029‐25j 2 10 192 152 93 0.77 6.056 1.8 0.3609 1.7 0.94 0.1223 0.59 ‐0.2 1984 16 1986 29 1981 11 0.08

*see figure below for analysis locations. Larger pits from session 1 (prior to EBSD analysis) are shown in red and smaller pits from session 2 (after EBSD analysis) and shown in white.**Discordance here refers to the calculated difference between the 206Pb/238U age and the 207Pb/206Pb age, i.e., discordance = (1 ‐ [206Pb/238U age / 207Pb/206Pb age]) x 100. Therefore, positive numbers correspond to normal discordance and negative numbers correspond to reverse discordance.***% of common 206Pb in measured 206Pb, estimated from measured 204Pb, assuming present‐day Stacey and Kramers (1975) common Pb. Figures in parentheses indicate that no correction has been applied because 204Pb counts were insignificant.