Recrystallization and chemical changes in apatite in response to hypervelocity impact

Gavin G. Kenny1*, Andreas Karlsson1, Martin Schmieder2,3, Martin J. Whitehouse1,

Alexander A. Nemchin1,4, Jeremy J. Bellucci1

1Department of Geosciences, Swedish Museum of Natural History, SE-104 05 Stockholm,

Sweden

2Lunar and Planetary Institute – USRA, 3600 Bay Area Boulevard, Houston TX 77058, USA

3NASA – Solar System Exploration Research Virtual Institute (SSERVI)

4School of Earth and Planetary Sciences (EPS), Curtin University, Perth, WA 6845, Australia

*[email protected] ABSTRACT

Despite the wide utility of apatite, Ca5(PO4)3(F,Cl,OH), in the geosciences, including tracing volatile abundances on the Moon and Mars, little is known about how the mineral responds to the extreme temperatures and pressures associated with hypervelocity impacts.

To address this deficiency, we here present the first microstructural analysis and chemical mapping of shocked apatite from a terrestrial impact crater. Apatite grains from the Paasselkä impact structure, Finland, display intragrain crystal-plastic deformation as well as pervasive recrystallization – the first such report in terrestrial apatite. A partially recrystallized grain offers the opportunity to investigate the effect of shock recrystallization on the chemical composition of apatite. The recrystallized portion of the fluorapatite grain is depleted in Mg and Fe relative to the remnant non-recrystallized domain. Strikingly, the recrystallized region alone hosts inclusions of (Mg,Fe)2(PO4)F, wagnerite or a polymorph thereof. These are interpreted to be a product of phase separation during recrystallization and to be related to the reduced abundances of certain elements in the recrystallized domain. The shock-induced recrystallization of apatite, which we show to be related to changes in the mineral’s chemical composition, is not always readily visible in traditional imaging techniques (such as backscattered electron imaging of polished interior surfaces), thus highlighting the need for correlated microstructural, chemical, and isotopic studies of phosphates. This is particularly relevant for extra-terrestrial phosphates that may have been exposed to impacts and we urge the consideration of microstructural data in the interpretation of the primary or secondary nature of elemental abundances and isotopic compositions. INTRODUCTION

Apatite, Ca5(PO4)3(F,Cl,OH), is an almost ubiquitous accessory mineral that forms in igneous, metamorphic, sedimentary, hydrothermal, and biological environments. It has applications in, for example, geochronology and thermochronology (e.g., Chew and Spikings,

2015), unravelling metasomatic processes (e.g., Harlov, 2015), and tracing abundances of, and processes related to, water and other volatiles on inner Solar System bodies (e.g.,

McCubbin and Jones, 2015). However, little is known about how the mineral responds to the extreme pressures and temperatures associated with impact cratering and how shock metamorphism may affect its isotopic and chemical composition.

Imaging of shocked apatite from terrestrial impact structures has revealed planar microstructures in grains from the Sante Fe impact structure, USA (Cavosie and Lugo

Centeno, 2014), apparent recrystallization along grain margins at the Carswell impact crater,

Canada (Alwmark et al., 2017), and planar fractures and arrays of micro-vesicles in grains from the Nicholson Lake impact crater, Canada (McGregor et al., 2018). Planar microstructures have also been reported in experimentally shocked apatite (Sclar and

Morzenti, 1972). However, despite these observations there has not previously been any detailed microstructural characterization of terrestrial shocked apatite by electron backscatter diffraction (EBSD) analysis, and unequivocal recrystallization textures have been elusive.

This is in contrast to lunar phosphates (apatite and merrillite) in which EBSD analysis has recently revealed crystal-plastic deformation and recrystallization (Černok et al., 2019).

Despite our limited knowledge of the effects of shock metamorphism on apatite, the mineral has been used to date impacts. On Earth, for example, (U-Th)/He, fission track, and

U–Pb geochronology of apatite grains which have had their age reset by impact-related heat and/or pressure has been applied at a number of impact structures (e.g., Omar et al., 1987; van Soest et al., 2011; Wartho et al., 2012; McGregor et al., 2018). (Note that the temperature windows for isotopic closure for apatite (U-Th)/He, fission track, and U–Pb are approximately 40–80°C, 60–110°C and 350–550°C, respectively; Chew and Spikings, 2015.)

On the Moon, U–Pb analysis of phosphates has also been used to constrain the timing of impacts (e.g., Snape et al., 2016; Thiessen et al., 2017). However, it is uncertain whether some dates for lunar phosphates represent actual impact ages or are disturbed due to incomplete resetting of the U–Pb isotope systematics, an effect that may hamper unequivocal geochronologic interpretations (Thiessen et al., 2017).

In addition, extra-terrestrial phosphates also hold information on the abundance of water and other volatiles, such as the halogens F and Cl, in inner Solar System bodies (e.g.,

Boyce et al., 2014; Bellucci et al., 2017; and overview in McCubbin and Jones, 2015). While phosphates in some lunar lithologies show microtextural evidence for shock deformation

(e.g., Černok et al., 2019), there is impetus to understand whether these textures are associated with chemical changes.

Here we describe the first correlated imaging, microstructural characterization and chemical mapping of shocked apatite from a terrestrial impact structure in order to establish how this mineral responds to extreme temperatures and pressures and ultimately evaluate the effect of shock recrystallization on the mineral’s chemical composition.

SAMPLE

A cobble of clast-rich impact melt rock from the ~10 km-in-diameter Paasselkä impact crater, Finland, was investigated. The allochthonous sample had previously been recovered from the Sikosärkät till pit near the southeastern shore of the eponymous lake filling the structure (Fig. 1). The green-grey rock displays a distinct flow fabric and the melt matrix contains vesicles. Lithic clasts in the rock are predominantly composed of mica schist, granite, and partially melted sandstone and single mineral grains mostly consist of quartz, feldspar, and decomposed mica flakes from the target rocks. The rock displays shocked and toasted quartz grains that have multiple sets of planar deformation features (PDFs) and polycrystalline quartz aggregates that are interpreted to represent recrystallized diaplectic quartz glass, which indicate peak shock pressures ≥35 GPa and post-shock temperatures up to

~1500°C (see Schmieder et al., 2008 for petrography and geochemistry). 40Ar/39Ar analysis of recrystallized feldspar melt in this sample and a band of feldspathic melt in a monomict impact breccia comprised of gneissic fragments indicate a late Triassic age of 231 ± 2 Ma for the impact event (Schmieder et al., 2010; Schwarz et al., 2015).

ANALYTICAL METHODS

Apatite grains were separated from the whole-rock sample by crushing and milling and concentrated by magnetic and heavy liquid separation. Seven apatite grains were identified and their exteriors were imaged in backscatter electron (BSE) mode on a FEI

Quanta FEG 650 scanning electron microscope (SEM) at the Swedish Museum of Natural

History, Stockholm. After the grains were mounted in epoxy, their interiors were imaged in

BSE and secondary electron (SE) mode. Energy-dispersive X-ray (EDS) and EBSD analyses were performed on the same SEM. Full analytical methods can be found in the Data

Repository.

RESULTS

Imaging

Six of the seven apatite grains identified in the sample display granular recrystallization textures on their exteriors (e.g., Fig. 2, Fig. 3A; images of all grains are given in Fig. DR4 in the Supplementary Appendix). However, granular textures are less readily visible on polished grain interiors (e.g., Fig. 4A) and under the petrographic microscope (Fig. DR4 in Supplementary Appendix). Each of the recrystallized apatite grains is composed of several thousand neoblastic crystallites that have a modal long axis length of

~5 µm (and maximum of ~20 µm) and a modal short axis length of ~2 µm (maximum of ~4

µm), as estimated from images such as Fig. 2, and are usually aligned in approximately one direction (e.g., Fig. 2, 3A). Five of the six granular grains host mineral inclusions that are typically ~1x10 µm in size on polished surfaces and occur in two to three apparently crystallographically controlled orientations (Fig. 4), however, these inclusions do not seem to occur in the non-granular grain.

Energy-dispersive X-ray analysis

Energy-dispersive X-ray spot analyses show that the apatite grains approach the fluorine end-member composition, Ca5(PO4)3F, and the elongate inclusions are composed of

(Mg,Fe)2(PO4)F, wagnerite or a polymorph thereof (full data in Supplementary Appendix).

Energy-dispersive X-ray mapping of one grain which displays a granular texture in

BSE imaging of its exterior but not in BSE imaging of its interior (Fig. 4A), shows that it is chemically heterogeneous. It contains an oval-shaped region (60 µm x 15 µm) that is relatively rich in Mg (Fig. 4C) and Fe, which are likely substituting for the Ca cation.

Moreover, EDS mapping suggests that the Mg- and Fe-rich core is enriched in F (Fig. 4D); however, the latter may, in part, be an effect of the spectral interference between the Fe-Lα

(0.704 keV) and F-Kα (0.677 keV) X-ray lines. The Mg- and Fe-rich region is devoid of the

(Mg,Fe)2(PO4)F inclusions that are conspicuous in the rest of the grain (Fig. 4A-D).

Electron backscatter diffraction analysis

Microstructural analysis by EBSD reveals two distinct textures: six of the seven grains are composed of euhedral, relatively strain-free granules which define individual domains that are generally aligned but locally subtly misoriented from each other (e.g., Fig.

3A-C) whereas the other grain appears to be composed of a single domain with up to 20° intragrain misorientation (Fig. 3D-F and Fig. DR2 in the Supplementary Appendix).

One of the granular grains is not entirely recrystallized, with EBSD analysis revealing an oval-shaped, non-granular region near the center of the grain (Fig. 4B) that is coincident with the inclusion-free, and relatively Mg- and Fe-rich domain described above (Fig. 4).

Constraints from other shock-recrystallized phases The sample contains recrystallized zircon with microstructural evidence for the former presence of reidite; the specific microstructural observations include: (i) domains of neoblasts systematically misoriented by 90°, (ii) coincidence among (001) and {110} poles, and (iii) high-angle misorientation axes coincident with poles to {110} (Fig. DR5 in

Supplementary Appendix). This indicates likely shock pressures ≥30 GPa (Kusaba et al.,

1985; Leroux et al., 1999; Wittmann et al., 2006; Cavosie et al., 2018), consistent with previous estimates of ≥35 GPa for clasts and mineral grains in this rock (Schmieder et al.,

2008). Zircon, ZrSiO4, has also partially dissociated into ZrO2 and SiO2, which happens at temperatures >1673°C (Timms et al., 2017, and references therein). Monazite from the sample displays shock recrystallization and deformation twins with ( ) composition planes, i.e. misorientations of 180°/<101> (Fig. DR6 in Supplementary Appendix). This specific twinning is known only from shocked monazite (Erickson et al., 2016, 2017).

DISCUSSION

We present the first microstructural characterization of terrestrial shocked apatite which reveals crystal-plastic deformation and striking recrystallization textures that had not been recognized previously and may not be visible with traditional imaging techniques (such as BSE imaging of polished grain interiors). Moreover, this is the first report of impact- related crystallization of wagnerite (or a polymorph thereof) within apatite grains. Shock- recrystallized domains have been shown to record the age of the impact event in minerals such as zircon (e.g., Cavosie et al., 2015, Kenny et al., 2017, 2019) and monazite (e.g.,

Erickson et al., 2017) and the identification of such textures in apatite may lead to wider use of the mineral as an impact chronometer. McGregor et al. (2018) reported in situ U–Pb data for shocked apatite and zircon from the ~12.5 km diameter Nicholson Lake impact structure,

Canada, and discovered that apatite in direct contact with impact melt was reset to the age of impact whereas apatite within lithic clasts retained pre-impact isotopic compositions and ages. Although petrographic and BSE imaging showed that the apatite grains from Nicholson

Lake displayed planar fractures and arrays of micro-vesicles, McGregor et al. (2018) did not report EBSD microstructural data and so it is not possible to draw a detailed comparison with the textures described here. Future work integrating petrographic context, imaging, microstructural analysis and U–Pb age dating of shocked apatite is therefore necessary to better understand the origin of the deformation and recrystallization described here and how these relate to age resetting. In addition to furthering age dating of terrestrial impact craters, this may also aid interpretation of, for example, U–Pb geochronologic results for lunar phosphates (cf. Thiessen et al., 2017).

One apatite grain in our study was only partially recrystallized (Fig. 4) and therefore offers the opportunity to investigate how recrystallization has affected the mineral’s chemical composition. The recrystallized portion of the grain is depleted in Mg and Fe relative to the non-recrystallized remnant of the original crystal and contains inclusions of (Mg,Fe)2(PO4)F which are absent from the non-recrystallized domain and the single crystal-plastically deformed grain. Regarding the significance of the (Mg,Fe)2(PO4)F inclusions, we note that wagnerite occurs as a relatively rare accessory mineral in igneous and metamorphic rocks and is known to crystallize over a wide range of pressures and temperatures; for example, although most occurrences relate to medium- to high-grade metamorphic conditions (e.g.,

Sheridan et al., 1976; Simmat and Rickers, 2000; Ren et al., 2003; Pitra et al., 2008), it has also been reported from low-temperature carbonate veins (Hegemann and Steinmetz, 1927), anatectic veins (e.g., Grew et al., 2006), and pegmatites (e.g., Staněk, 1965). We are aware of only one other documented occurrence of (Mg,Fe)2(PO4)F inclusions in apatite; in this case, inclusions of wagnerite in fluorapatite in a cataclastically deformed Caledonian granite were interpreted to have formed in response to fluid-induced metasomatism via dissolution- reprecipitation reactions (Seifert et al., 2010). Given the correlated depletion of Fe and Mg in the inclusion-bearing, shock-recrystallized apatite from Paasselkä relative to the inclusion- free, non-recrystallized domain (e.g., Fig. 4C), changes in Mg and Fe abundance appear to have also been related to the formation of (Mg,Fe)2(PO4)F inclusions in this setting.

However, we do not invoke a dissolution-reprecipitation reaction (cf. Seifert et al., 2010) and instead suggest that the inclusions formed by phase separation during shock-induced recrystallization of the phosphate.

As the inclusions of (Mg,Fe)2(PO4)F in the shock-recrystallized apatite at Paasselkä appear to have sequestered Mg and Fe that were relatively enriched in the pre-shock apatite grains, it appears likely that F in the inclusions (~10 wt. % F) was also sourced from apatite

(<4 wt. % F). This supports the suggestion that, in addition to altering Mg and Fe abundances in apatite, shock recrystallization can also alter F concentrations. However, we have not fully quantified this effect as the variation in F observed in the EDS map (Fig. 4D) may be related to spectral overlap in the X-ray spectra.

Shock-related alteration of the chemical composition of apatite is potentially significant given the prominent role that volatile compositions of apatite have played in estimating the volatile compositions of the Moon and Mars. Therefore, future petrologic studies should also take into account the potential effects of shock metamorphism on the chemical composition of terrestrial and extraterrestrial phosphates when assessing their volatile content and isotopic age.

ACKNOWLEDGMENTS

Grants from the Knut and Alice Wallenberg Foundation (2012.0097) and the Swedish

Research Council (VR 621-2012-4370) to Whitehouse and Nemchin supported this work and are gratefully acknowledged. This project also received funding from the European Union’s

Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie

Individual Fellowship Grant Agreement No. 792030, supporting Kenny. Schmieder was supported by NASA Solar System Exploration Research Virtual Institute (SSERVI) contract

NNA14AB07A (D. A. Kring, Principal Investigator). Jarmo Moilanen collected and provided the melt rock sample. We thank Carl Alwmark, Chris Mark, Claire Ansberque, Dan Harlov,

David Chew, Gary O’Sullivan, Thomas Riegler and Timm John for feedback on this study;

Kerstin Lindén for support with sample preparation; Timmons Erickson and two anonymous reviewers for insightful comments; and Dennis Brown for editorial handling. This is Lunar and Planetary Institute (LPI) contribution no. 2221. LPI is operated by Universities Space

Research Association under a cooperative agreement with the Science Mission Directorate of the National Aeronautics and Space Administration.

FIGURES

Figure 1. Satellite image of the Paasselkä impact structure, Finland. The Sikosärkät till pit, from which the impact melt rock sample was retrieved, is marked by the white star. The satellite image is LandsatLook “Natural Color” Image: Landsat 5, Path 187, Row 16, acquired on 8th June 2011.

Figure 2. Backscattered electron (BSE) images of the exterior of shock-recrystallized apatite grain Paass-105ap.

Figure 3. Comparison of recrystallized (left) and crystal-plastically deformed (right) apatite grains. A-C: Grain Paass-107ap; D-F: Grain Paass-106ap. BSE – backscattered electron; BC

– band contrast; Rel. mis. – relative misorientation (to white cross). Additional images of each grain and pole figures are shown in Figs DR2-DR3 in the Supplementary Appendix.

Step sizes: 300 nm (Paass-107ap) and 400 nm (Paass-106ap).

Figure 4. Chemical and microstructural characterization of heterogeneously recrystallized apatite grain Paass-103ap. A: Backscattered electron (BSE) image of polished grain interior. B: Electron backscatter diffraction (EBSD) band contrast (BC) image showing oval domain of non-granular relict apatite. C: Energy-dispersive X-ray spectroscopy (EDS) map show the distribution of magnesium (Mg). White arrows highlight three orientations of

(Mg,Fe)2(PO4)F (wagnerite or a polymorph thereof) inclusions. D: EDS map showing the distribution of fluorine (F). Note that apparent variations in F content may be related to variations in Fe content given the difficulty resolving the F-Kα and Fe-Lα X-ray peaks (see text). E: EBSD map colored according to the inset inverse pole figure (IPF). F: EBSD map showing crystallographic misorientation relative to a reference point (white cross). Rel. mis.

– relative misorientation. G: Pole figures plotted in equal-area, lower hemisphere projection and colored according to the IPF in panel E. Most data points form a single cluster; this is consistent with the <15° misorientation between granules and the close alignment of the recrystallized and non-recrystallized domains. The presence of three clusters (in each of the two rightmost pole figures) reflects the hexagonal crystal system of apatite. Stereonets are equal-area, lower-hemisphere projections. Step size: 150 nm. 1GSA Data Repository item 2020004, full analytical methods (including Figure DR1 and

Tables DR1-DR6), Figures DR2-3 (additional characterization of shocked apatite), Figure

DR4 (images of all shocked apatite grains identified at Paasselkä), Figure DR5

(characterization of shock-recrystallized zircon) and Figure DR6 (characterization of shock- recrystallized monazite) are available online at www.geosociety.org/pubs/ft2017.htm, or on request from [email protected] or Documents Secretary, GSA, P.O. Box 9140,

Boulder, CO 80301, USA. REFERENCES CITED

Alwmark, C., Bleeker, W., LeCheminant, A., Page, L., and Scherstén, A., 2017, An Early

Ordovician 40Ar-39Ar age for the ~50 km Carswell impact structure, Canada: GSA

Bulletin, v. 129, no. 11–12, p. 1442–1449, https://doi.org/10.1130/B31666.1.

Bellucci, J. J., Whitehouse, M. J., John, T., Nemchin, A. A., Snape, J. F., Bland, P. A., and

Benedix, G. K., 2017, Halogen and Cl isotopic systematics in Martian phosphates:

Implications for the Cl cycle and surface halogen reservoirs on Mars: Earth and

Planetary Science Letters, v. 458, p. 192–202,

https://doi.org/10.1016/j.epsl.2016.10.028.

Boyce, J. W., Tomlinson, S. M., McCubbin, F. M., Greenwood, J. P., and Treiman, A. H.,

2014, The Lunar Apatite Paradox: Science, v. 344, p. 400–402,

https://doi.org/10.1126/science.1250398.

Cavosie, A. J., and Lugo Centeno, C., 2014, Shocked apatite from the Sante Fe impact

structure (USA): a new accessory mineral for studies of shock metamorphism, in

Proceedings of the 45th Lunar and Planetary Science Conference, abstract #1691.

Cavosie, A. J., Erickson, T. M., Timms, N. E., Reddy, S. M., Talavera, C., Montalvo, S. D.,

Pincus, M. R., Gibbon, R. J., and Moser, D., 2015, A terrestrial perspective on using

ex situ shocked zircons to date lunar impacts: Geology, v. 43, p. 999–1002,

https://doi.org/10.1130/g37059.1.

Cavosie, A. J., Timms, N. E., Ferrière, L., and Rochette, P., 2018, FRIGN zircon—The only

terrestrial mineral diagnostic of high-pressure and high-temperature shock

deformation: Geology, v. 46, no. 10, p. 891–894, https://doi.org/10.1130/G45079.1.

Černok, A., White, L. F., Darling, J., Dunlop, J., and Anand, M., 2019, Shock‐induced

microtextures in lunar apatite and merrillite: Meteoritics & Planetary Science, v. 54,

p. 1262–1282, doi:10.1111/maps.13278. Chew, D. M., and Spikings, R. A., 2015, Geochronology and thermochronology using

apatite: time and temperature, lower crust to surface: Elements, v. 11, p. 189–194,

https://doi.org/10.2113/gselements.11.3.189.

Erickson, T. M., Cavosie, A. J., Pearce, M. A., Timms, N. E., and Reddy, S. M., 2016,

Empirical constraints on shock features in monazite using shocked zircon inclusions:

Geology, v. 44, no. 8, p. 635–638, https://doi.org/10.1130/G37979.1.

Erickson, T. M., Timms, N. E., Kirkland, C. L., Tohver, E., Cavosie, A. J., Pearce, M. A.,

and Reddy, S. M., 2017, Shocked monazite chronometry: integrating microstructural

and in situ isotopic age data for determining precise impact ages: Contributions to

Mineralogy and Petrology, v. 172, no. 2, p. 11, https://doi.org/10.1007/s00410-017-

1328-2.

Grew, E. S., Yates, M. G., Shearer, C. K., Hagerty, J. J., Sheraton, J. W. and Sandiford, M.,

2006, Beryllium and other trace elements in paragneisses and anatectic veins of the

ultrahigh-temperature Napier Complex, Enderby Land, East Antarctica: the role of

sapphirine: Journal of Petrology, 47, 859–882,

https://doi.org/10.1093/petrology/egi098.

Harlov, D. E., 2015, Apatite: A fingerprint for metasomatic processes: Elements, v. 11, p.

171–176, https://doi.org/10.2113/gselements.11.3.171.

Hegemann, F. and Steinmetz, H., 1927, Die Mineralgänge von Werfen im Salzkammergut:

Centralblatt für Mineralogie, Geologie und Paläontologie. Abteilung A: Mineralogie

und Petrographie, 45–56.

Kenny, G. G., Morales, L. F., Whitehouse, M. J., Petrus, J. A., and Kamber, B. S., 2017, The

formation of large neoblasts in shocked zircon and their utility in dating impacts:

Geology, v. 45, p. 1003–1006, https://doi.org/10.1130/G39328.1.

Kenny, G. G., Schmieder, M., Whitehouse, M. J., Nemchin, A. A., Morales, L. F. G.,

Buchner, E., Bellucci, J. J., and Snape, J. F., 2019, A new U-Pb age for shock- recrystallised zircon from the Lappajärvi impact crater, Finland, and implications for

the accurate dating of impact events: Geochimica et Cosmochimica Acta, v. 245, p.

479–494, https://doi.org/10.1016/j.gca.2018.11.021.

Kusaba, K., Syono, Y., Kikuchi, M., and Fukuoka, K., 1985, Shock behavior of zircon: Phase

transition to scheelite structure and decomposition: Earth and Planetary Science

Letters, v. 72, no. 4, p. 433–439, https://doi.org/10.1016/0012-821X(85)90064-0.

Leroux, H., Reimold, W. U., Koeberl, C., Hornemann, U., and Doukhan, J. C., 1999,

Experimental shock deformation in zircon: a transmission electron microscopic study:

Earth and Planetary Science Letters, v. 169, no. 3–4, p. 291–301,

https://doi.org/10.1016/S0012-821X(99)00082-5.

McCubbin, F. M., and Jones, R. H., 2015, Extraterrestrial apatite: Planetary geochemistry to

astrobiology: Elements, v. 11, p. 183–188,

https://doi.org/10.2113/gselements.11.3.183.

McGregor, M., McFarlane, C. R. M., and Spray, J. G., 2018, In situ LA-ICP-MS apatite and

zircon U–Pb geochronology of the Nicholson Lake impact structure, Canada: Shock

and related thermal effects: Earth and Planetary Science Letters, v. 504, p. 185–197,

https://doi.org/10.1016/j.epsl.2018.10.006.

Omar, G., Johnson, K. R., Hickey, L. J., Robertson, P. B., Dawson, M. R., and Barnosky, C.

W., 1987, Fission-track dating of Haughton astrobleme and included biota, Devon

Island, Canada: Science, v. 237, no. 4822, p. 1603–1605,

https://doi.org/10.1126/science.237.4822.1603.

Pitra, P., Boulvais, P., Antonoff, V., and Diot, H., 2008, Wagnerite in a cordierite-gedrite

gneiss: Witness of long-term fluid-rock interaction in the continental crust (Ile d’Yeu,

Armorican Massif, France): American Mineralogist, v. 93, no. 2–3, p. 315–326,

https://doi.org/10.2138/am.2008.2597. Ren, L., Grew, E. S., Xiong, M. and Ma, Z., 2003, Wagnerite-Ma5bc, a new polytype of

Mg2(PO4)(F,OH), from granulite-facies paragneiss, Larsemann Hills, Prydz Bay, East

Antarctica: The Canadian Mineralogist, 41, 393–411,

https://doi.org/10.2113/gscanmin.41.2.393.

Schmieder, M., Moilanen, J., and Buchner, E., 2008, Impact melt rocks from the Paasselkä

impact structure (SE Finland): Petrography and geochemistry: Meteoritics &

Planetary Science, v. 43, no. 7, p. 1189–1200, https://doi.org/10.1111/j.1945-

5100.2008.tb01122.x.

Schmieder, M., Schwarz, W. H., Buchner, E., Trieloff, M., Moilanen, J., and Öhman, T.,

2010, A Middle-Late Triassic 40Ar/39Ar age for the Paasselkä impact structure (SE

Finland): Meteoritics & Planetary Science, v. 45, no. 4, p. 572–582,

https://doi.org/10.1111/j.1945-5100.2010.01041.x.

Schwarz, W. H., Schmieder, M., Buchner, E., Trieloff, M., Moilanen, J., and Öhman, T.,

2015, A Carnian 40Ar/39Ar age for the Paasselkä impact structure (SE Finland)—an

update: Meteoritics & Planetary Science, v. 50, no. 1, p. 135–140,

https://doi.org/10.1111/maps.12407.

Sclar, C. B., and Morzenti, S. P., 1972, Electron microscopy of some experimentally shocked

counterparts of lunar minerals, in Proceedings of the 3rd Lunar and Planetary Science

Conference Proceedings, p. 1121–1132.

Seifert, W., Thomas, R., Rhede, D. and Förster, H. J., 2010, Origin of coexisting wüstite,

Mg–Fe and REE phosphate minerals in graphite-bearing fluorapatite from the

Rumburk granite: European Journal of Mineralogy, 22, 495–507,

https://doi.org/10.1127/0935-1221/2010/0022-2034.

Sheridan, D. M., Marsh, S. P., Mrose, M. E. and Taylor, R. B., 1976, Mineralogy and

geology of the wagnerite occurrence on Santa Fe Mountain, Front Range, Colorado:

U.S. Geological Survey Professional Paper, 955, 23 p., https://doi.org/10.3133/pp955. Simmat, R. and Rickers, K., 2000, Wagnerite in high-MgAl granulites of Anakapalle, Eastern

Ghats Belt, India: European Journal of Mineralogy, 12, 661–666,

https://doi.org/10.1127/0935-1221/2000/0012-0661.

Snape, J. F., Nemchin, A. A., Grange, M. L., Bellucci, J. J., Thiessen, F., and Whitehouse, M.

J., 2016, Phosphate ages in Apollo 14 breccias: Resolving multiple impact events with

high precision U–Pb SIMS analyses: Geochimica et Cosmochimica Acta, v. 174, p.

13–29, https://doi.org/10.1016/j.gca.2015.11.005.

Staněk, J., 1965, První výskyt wagneritu v Československu (First occurrence of wagnerite in

Czechoslovakia): Časopis Moravského musea v Brně (Acta Musei Moraviae), 50, 67–

70 (in Czech with English abstract).

Thiessen, F., Nemchin, A. A., Snape, J. F., Whitehouse, M. J., and Bellucci, J. J., 2017,

Impact history of the Apollo 17 landing site revealed by U-Pb SIMS ages: Meteoritics

& Planetary Science, v. 52, no. 4, p. 584–611, https://doi.org/10.1111/maps.12814.

Timms, N. E., Erickson, T. M., Pearce, M. A., Cavosie, A. J., Schmieder, M., Tohver, E.,

Reddy, S. M., Zanetti, M. R., Nemchin, A. A., and Wittmann, A., 2017, A pressure-

temperature phase diagram for zircon at extreme conditions: Earth-Science Reviews,

v. 165, p. 185–202, https://doi.org/10.1016/j.earscirev.2016.12.008. van Soest, M. C., Hodges, K. V., Wartho, J. A., Biren, M. B., Monteleone, B. D., Ramezani,

J., Spray, J. G., and Thompson, L. M., 2011, (U-Th)/He dating of terrestrial impact

structures: The Manicouagan example: Geochemistry, Geophysics, Geosystems, v.

12, no. 5, https://doi.org/10.1029/2010GC003465.

Wartho, J. A., van Soest, M. C., King, D. T., and Petruny, L. W., 2012, An (U-Th)/He age for

the shallow-marine Wetumpka impact structure, Alabama, USA: Meteoritics &

Planetary Science, v. 47, no. 8, p. 1243-1255, https://doi.org/10.1111/j.1945-

5100.2012.01381.x. Wittmann, A., Kenkmann, T., Schmitt, R., and Stöffler, D., 2006, Shock-metamorphosed

zircon in terrestrial impact craters: Meteoritics & Planetary Science, v. 41, no. 3, p.

433-454, https://doi.org/10.1111/j.1945-5100.2006.tb00472.x. SUPPLEMENTARY APPENDIX

Contents  Full analytical methods (including Figure DR1 and Tables DR1-DR6)  Figure DR2 (imaging and EBSD of apatite grain Paass-106ap)  Figure DR3 (imaging and EBSD of apatite grain Paass-107ap)  Figure DR4 (images of shocked apatite from Paasselkä)  Figure DR5 (imaging and EBSD of zircon grain Paass-202z)  Figure DR6 (imaging and EBSD of monazite grain Paass-213m) FULL ANALYTICAL METHODS Apatite, monazite and zircon grains were separated from a sample of clast-rich impact melt rock from Paasselkä by crushing the rock in a jaw crusher and milling the resulting chips in a ring-and-puck-style mill. The heavy minerals were concentrated by magnetic separation with a hand magnet and Frantz magnetic separator, and heavy liquid density separation using methylene iodide diluted to a density of approximately 3.1 g/cm3. The grains were picked and placed on conductive carbon tabs. These were coated in carbon and the exteriors of the grains were imaged in backscattered electron (BSE) mode on an FEI Quanta FEG 650 scanning electron microscope (SEM) at the Swedish Museum of Natural History, Stockholm. The instrument was operated with an electron beam accelerating voltage of 20 kV and a working distance of 10 mm. The grains were subsequently mounted in 2.5 cm- diameter epoxy mounts and polished with a diamond suspension to expose their interiors. A final polish with colloidal silica prepared the grains for microstructural analysis. The interiors of the grains were imaged in BSE and secondary electron (SE) mode on the SEM described above. Zircon grains were also imaged in cathodoluminescence (CL) mode with a Gatan ChromaCL2 system attached to the SEM. The chemical compositions of the apatite grains and their inclusions were determined using the FEI Quanta FEG 650 SEM described above. The SEM is fitted with an 80mm2 X- MaxN Oxford Instruments energy-dispersive X-ray (EDS) detector. Beam current was calibrated against Co-metal, which in turn was calibrated against metal and mineral standards. The apatite was analysed with an operating voltage of 20 kV, beam size of ~2.6 nm, and a working distance of 10 mm. All apatite analyses were conducted in a single session in which analyses repeated a pattern of three to four spots on Durango standard apatite, followed by three to four spots targeting the relict core domain of grain Paass-103ap, in turn followed by three to four spots on neoblasts in the recrystallized region of the grain (Fig.

DR1). Due to the minute size of the of (Mg,Fe)2(PO4)F inclusions, these were analysed with an operating voltage of 10 kV and a beam size of ~1 nm. This reduced the interaction volume of the electron beam. The instrument was recalibrated against Co-metal in order to accommodate the change in beam current. The full chemical data as shown in Tables DR1-4. It is important to note that measuring F abundance in apatite by EDS and electron probe microanalysis (EPMA) has well-documented issues (e.g., McCubbin et al., 2011; Goldoff et al., 2012; Ketcham, 2015; and summarised by Webster and Piccolli, 2015). The primary problem for EDS analysis is that it is difficult to confidently separate the line on which F is measured (F-Kα, 0.677 keV) from a nearby Fe line (Fe-Lα, 0.705 keV). Although it is difficult to ascertain whether a measured F abundance has been affected by overlapping Fe, Fe itself can be confidently measured as this is done on a separate, interference-free peak (Fe-Kα, 6.405 keV). In addition to Fe, Mg can also be confidently measured in apatite by EDS as it is measured on the Mg-Kα peak (1.254 keV). Electron backscatter diffraction (EBSD) analysis was performed with an Oxford Instruments Nordlys detector attached to the FEI Quanta FEG 650 SEM. The settings and protocols largely followed established routines for this detector and processing software (Table DR3) (e.g., Timms et al., 2017, and references therein). Well-established match units were used for the analysis of monazite and zircon (Table DR5) (e.g., Erickson et al., 2015; Timms et al., 2017, and references therein). Given the lack of a single match unit for apatite, a range of match units were made in the Twist module of Oxford Instruments’ HKL Channel 5 software and used on the apatite grains from Paasselkä. Data for a range of fluorapatite compositions listed in the American Mineralogist crystal structure database (AMCSD) came from Hughes et al. (1989, 1990, 1991, 2004), Fleet and Pan (1995), Rakovan and Hughes (2000), Comodi et al. (2001), McCubbin et al. (2008) and Luo et al. (2009). Two match units were found to index best (see details in Table DR6). Apatite is generally considered to have the space group P63/m (number 176 of 230) but all hexagonal space groups (numbers 168- 194) were tested here. For the Paasselkä apatite grains and the selected chemical compositions in the match units, the P63 space group (number 173 of 230) resulted in the best indexing.

7-9 18- 2114 - 17 22- 25 10- 1-6 13

20 μm

Figure DR1. Backscatter electron image of heterogeneously shock-recrystallized apatite grain Paass-103ap showing locations of energy-dispersive X-ray (EDS) analysis. Data for spots in the relict core domain are shown in Table DR1 and data for spots in neoblasts in the recrystallized domain are shown in Table DR2. These neoblasts were chosen because their outlines are clearly visible so analyses could be confidently conducted within individual neoblasts. Note that the actual areas analyzed are much smaller than the white circle showing location.

Apatite – relict core in Paass-103ap

20 kV, aperture 3 (50 μm)

Spot # Element 1 2 3 4 5 6 10 11 12 13 22 23 24 25 average F 3.7 3.94 3.58 3.58 3.93 3.96 3.29 3.91 3.54 3.84 3.6 3.59 3.73 4.04 3.73 MgO 1.03 1.05 1.04 1.04 1.03 1.08 1.06 1.11 1.05 1.05 1.06 1.17 1.12 1.07 1.07 P2O5 42.31 42.18 42.36 42.36 42.34 42.23 42.7 42.87 42.77 42.86 42.35 42.47 42.35 42.18 42.45 CaO 52.9 52.55 52.92 52.92 52.79 52.86 53.62 53.75 53.48 53.69 52.94 52.8 52.99 52.94 53.08 MnO 0.18 0.16 0.17 0.17 0.17 0.17 0.17 0.16 0.18 0.16 0.19 0.17 0.2 0.16 0.17 FeO 1.07 1.09 1.03 1.03 1.1 1.05 1.01 1.15 1.05 1.08 1.05 1.08 1.02 1.09 1.06 Sum 101.19 100.97 101.1 101.1 101.36 101.35 101.85 102.95 102.07 102.68 101.19 101.28 101.41 101.48 101.57

O = F -1.56 -1.66 -1.51 -1.51 -1.65 -1.67 -1.39 -1.65 -1.49 -1.62 -1.52 -1.51 -1.57 -1.70 Total 99.63 99.31 99.59 99.59 99.71 99.68 100.46 101.30 100.58 101.06 99.67 99.77 99.84 99.78

Normalised to 8 Cations Spot # APFU 1 2 3 4 5 6 7 8 9 10 11 12 13 14 average F 0.98 1.05 0.95 0.95 1.05 1.05 0.87 1.02 0.93 1.01 0.96 0.95 0.99 1.08 0.99 Mg 0.13 0.13 0.13 0.13 0.13 0.14 0.13 0.14 0.13 0.13 0.13 0.15 0.14 0.13 0.13 P 3.01 3.02 3.02 3.02 3.02 3.01 3.01 3.00 3.01 3.01 3.01 3.02 3.01 3.00 3.01 Ca 4.77 4.76 4.77 4.77 4.76 4.77 4.78 4.77 4.77 4.77 4.77 4.75 4.77 4.77 4.77 Mn 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 0.01 Fe 0.08 0.08 0.07 0.07 0.08 0.07 0.07 0.08 0.07 0.07 0.07 0.08 0.07 0.08 0.07 Sum cations 8.00 8.00 8.00 8.00 8.00 8.00 8.00 8.00 8.00 8.00 8.00 8.00 8.00 8.00

Table DR1. Chemical composition of relict core in heterogeneously shock-recrystallized apatite grain Paass-103ap determined by energy- dispersive X-ray analysis. APFU – atoms per formula unit.

Apatite – neoblasts in recrystallized domain in Paass-103ap

20 kV, aperture 3 (50 μm)

Spot # Element 7 8 9 14 15 16 17 18 19 20 21 average F 3.25 3.12 3.43 3.21 3.13 3.12 3.15 3.65 3.25 3.7 3.46 3.32 MgO 0.34 0.35 0.31 0.31 0.38 0.34 0.34 0.37 0.27 0.32 0.26 0.33 P2O5 41.2 41.49 41.23 40.53 41 40.95 40.87 41.58 41.68 41.56 41.64 41.25 CaO 53.12 53.65 53.51 52.46 52.67 52.8 53.06 53 53.38 53.06 53.5 53.11 MnO 0.21 0.17 0.2 0.18 0.21 0.24 0.2 0.24 b.d.l. 0.19 0.24 0.21 FeO 0.76 0.7 0.74 0.72 0.71 0.61 0.76 0.79 0.65 0.75 0.73 0.72 Sum 98.88 99.48 99.42 97.41 98.1 98.06 98.38 99.63 99.23 99.58 99.83 98.91

O = F -1.37 -1.31 -1.44 -1.35 -1.32 -1.31 -1.33 -1.54 -1.37 -1.56 -1.46 Total 97.51 98.17 97.98 96.06 96.78 96.75 97.05 98.09 97.86 98.02 98.37

Normalised to 8 Cations Spot # APFU 15 16 17 18 19 20 21 22 23 24 25 average F 0.88 0.84 0.93 0.89 0.86 0.85 0.86 0.99 0.88 1.00 0.93 0.90 Mg 0.04 0.04 0.04 0.04 0.05 0.04 0.04 0.05 0.03 0.04 0.03 0.04 P 3.00 2.99 2.99 2.99 3.00 3.00 2.98 3.01 3.02 3.02 3.01 3.00 Ca 4.89 4.90 4.91 4.90 4.88 4.89 4.90 4.86 4.90 4.87 4.89 4.89 Mn 0.02 0.01 0.01 0.01 0.02 0.02 0.01 0.02 b.d.l. 0.01 0.02 0.01 Fe 0.05 0.05 0.05 0.05 0.05 0.04 0.05 0.06 0.05 0.05 0.05 0.05 Sum cations 8.00 8.00 8.00 8.00 8.00 8.00 8.00 8.00 8.00 8.00 8.00

Table DR2. Chemical composition of neoblasts in heterogeneously shock-recrystallized apatite grain Paass-103ap determined by energy- dispersive X-ray analysis. b.d.l. – below detection limit. APFU – atoms per formula unit.

Apatite – Durango standard

20 kV, aperture 3 (50 μm)

Spot # Element 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 average Lit* F 3.32 3.19 3.26 3.34 3.36 3.31 3.41 3.3 3.41 3.24 3.51 3.35 3.51 3.3 3.37 3.35 3.35 Na2O 0.31 0.33 0.28 0.23 0.24 0.24 0.24 0.27 0.26 0.26 0.34 0.18 0.27 0.28 0.25 0.27 0.25 SiO2 0.49 0.52 0.57 0.59 0.63 0.58 0.55 0.65 0.65 0.54 0.55 0.54 0.56 0.55 0.59 0.57 0.26 P2O5 41.1 41.24 41.12 40.91 40.67 40.78 40.34 40.79 40.64 41.08 40.57 40.72 40.17 40.61 40.29 40.74 41.28 SO3 b.d.l. b.d.l. b.d.l. b.d.l. 0.55 b.d.l. 0.48 0.5 b.d.l. b.d.l. b.d.l. b.d.l. 0.48 0.51 0.47 0.50 0.38 Cl 0.38 0.39 0.41 0.43 0.41 0.43 0.42 0.43 0.43 0.43 0.41 0.4 0.43 0.43 0.44 0.42 0.46 CaO 54.51 54.4 54.25 54.55 54.39 54.21 54.02 54 53.83 54.21 54.54 54.18 54.04 54.14 54.04 54.22 54.19 FeO 0.11 0.01 0.06 0.03 0.06 0.03 0.07 0.06 0.1 0.03 0.04 0.04 0.04 0.08 0.02 0.05 0.06 Ce2O3 0.5 0.55 0.64 b.d.l. b.d.l. 0.74 b.d.l. 0.65 b.d.l. 0.68 b.d.l. 0.47 b.d.l. 0.46 0.65 0.59 0.52 Sum 100.72 100.63 100.59 100.08 100.31 100.32 99.53 100.65 99.32 100.47 99.96 99.88 99.5 100.36 100.12 100.16 100.75

O = F -1.40 -1.34 -1.37 -1.41 -1.41 -1.39 -1.44 -1.39 -1.44 -1.36 -1.48 -1.41 -1.48 -1.39 -1.42 O = Cl -0.09 -0.09 -0.09 -0.10 -0.09 -0.10 -0.09 -0.10 -0.10 -0.10 -0.09 -0.09 -0.10 -0.10 -0.10 Total 99.24 99.20 99.12 98.58 98.80 98.83 98.00 99.16 97.79 99.01 98.39 98.38 97.92 98.87 98.60

Normalised to 8 Cations Spot # APFU 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 average F 0.89 0.85 0.87 0.90 0.90 0.89 0.92 0.89 0.92 0.87 0.94 0.91 0.95 0.89 0.91 0.90 Na 0.05 0.05 0.05 0.04 0.04 0.04 0.04 0.04 0.04 0.04 0.06 0.03 0.04 0.05 0.04 0.04 Si 0.04 0.04 0.05 0.05 0.05 0.05 0.05 0.06 0.06 0.05 0.05 0.05 0.05 0.05 0.05 0.05 P 2.94 2.95 2.95 2.94 2.92 2.94 2.92 2.93 2.95 2.95 2.92 2.95 2.91 2.92 2.91 2.94 S b.d.l. b.d.l. b.d.l. b.d.l. 0.04 b.d.l. 0.03 0.03 b.d.l. b.d.l. b.d.l. b.d.l. 0.03 0.03 0.03 0.03 Cl 0.05 0.06 0.06 0.06 0.06 0.06 0.06 0.06 0.06 0.06 0.06 0.06 0.06 0.06 0.06 0.06 Ca 4.94 4.93 4.93 4.97 4.95 4.95 4.95 4.91 4.94 4.93 4.97 4.96 4.96 4.93 4.94 4.94 Fe 0.01 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.00 0.00 0.00 0.01 0.00 0.00 Ce 0.02 0.02 0.02 b.d.l. b.d.l. 0.02 b.d.l. 0.02 b.d.l. 0.02 b.d.l. 0.01 b.d.l. 0.01 0.02 0.02 Sum cations 8.00 8.00 8.00 8.00 8.00 8.00 8.00 8.00 8.00 8.00 8.00 8.00 8.00 8.00 8.00

Table DR3. Chemical composition of Durango apatite standard determined by energy-dispersive X-ray analysis in the same session as data reported in Tables DR1-2. *Literature value from Marks et al. (2012). b.d.l. – below detection limit. APFU – atoms per formula unit.

(Mg,Fe)2(PO4)F inclusions

10 kV, aperture 5 (30 μm)

Spot # Element 1 2 3 4 5 average F 11.22 11.07 11.09 11.03 10.92 11.07 MgO 41.93 40.93 41.67 42.25 41.76 41.71 SiO2 b.d.l. b.d.l. b.d.l. 0.37 b.d.l. 0.37 P2O5 39.57 39.65 40.08 39.67 39.43 39.68 CaO 0.88 1.52 0.64 0.81 1.17 1.00 FeO 6.38 6.12 5.97 6.67 6.30 6.29 SUM 99.98 99.29 99.44 100.80 99.58 99.82

O = F -4.72 -4.66 -4.67 -4.65 -4.60 Total 95.26 94.63 94.77 96.16 94.98

Normalised to 8 Cations Spot # APFU 1 2 3 4 5 average F 1.04 1.04 1.03 1.01 1.01 1.03 Mg 1.83 1.81 1.83 1.83 1.83 1.83 Si b.d.l. b.d.l. b.d.l. 0.01 b.d.l. 0.01 P 0.98 0.99 1.00 0.97 0.98 0.99 Ca 0.03 0.05 0.02 0.03 0.04 0.03 Fe 0.16 0.15 0.15 0.16 0.15 0.15 Sum cations 3.00 3.00 3.00 3.00 3.00

Table DR4. Chemical composition of (Mg,Fe)2(PO4)F (wagnerite or a polymorph thereof) inclusions determined by energy-dispersive X-ray analysis. b.d.l. – below detection limit. APFU – atoms per formula unit.

SEM Make/model FEI Quanta FEG 650 SEM Location Swedish Museum of Natural History, Stockholm EBSD acquisition system Oxford Instruments Nordlys detector EBSD processing software Oxford Instruments HKL Channel 5.12 Accelerating voltage 20 kV Working distance ~18 mm Tilt 70°

EBSD match units Apatite Hughes et al. (1991) (AMCSD: 1377), Fleet and Pan (1995) (AMCSD: 1727) Monazite Ni et al. (1995) Zircon Hazen and Finger (1979); 1 atm Reidite Farnan et al. (2003); 0.69 GPa

Baddeleyite (monoclinic ZrO2) Howard et al. (1988)

EBSP acquisition, indexing and processing Grain ID (Paass-) 103ap 106ap 107ap 202z 213m Figure(s) 4 3, DR2 3, DR3 DR5 DR6 EBSP acquisition speed (Hz) 40 40 40 40 40 EBSP background (frames) 128 128 128 128 128 EBSP binning 1x1 1x1 1x1 2x2 2x2 EBSP gain High High High High High Frame averaging 4 8 8 1 1 Hough resolution 60 60 60 60 60 Band detection (min/max) 6/8 6/8 6/8 6/8 6/8 Map step size (nm) 150 400 300 150 75 X steps 682 205 203 794 1049 Y steps 544 301 211 606 797

EBSD noise reduction routine Wildspike correction Yes Yes Yes Yes Yes Kuwahara Filter No No No No No Nearest neighbour zero solution 6 6 6 6 6 extrapolation

Table DR5. Scanning electron microscopy settings and electron backscatter diffraction (EBSD) analysis acquisition and processing parameters. EBSP – electron backscatter patterns.

Hughes et al., 1991 (AMCSD: 1377) Fleet and Pan, 1995 (AMCSD: 1727)

Space group P63 (number 173)* Space group P63 (number 173)* a (Å) 9.4052 a (Å) 9.4123 b (Å) 9.4052 b (Å) 9.4123 c (Å) 6.9125 c (Å) 6.9080 α (°) 90 α (°) 90 β (°) 90 β (°) 90 γ (°) 120 γ (°) 120 Wyckoff x y z occ. Wyckoff x y z occ. positions positions Ca1 2/3 1/3 -0.0012 0.677 Ca1 2/3 1/3 0.0006 0.888 Na1 2/3 1/3 -0.0012 0.237 Na1 2/3 1/3 0.0006 0.089 Ce1 2/3 1/3 -0.0012 0.086 La1 2/3 1/3 0.0006 0.023 Ca2 0.98860 0.23885 0.25 0.847 Ca2 0.98989 0.24018 0.25 0.907 Ce2 0.98860 0.23885 0.25 0.153 La2 0.98989 0.24018 0.25 0.093 P 0.36881 0.39692 0.25 0.947 P 0.36898 0.39808 0.25 0.952 Si 0.36881 0.39692 0.25 0.053 Si 0.36898 0.39808 0.25 0.048 O1 0.4821 0.3233 0.25 O1 0.4847 0.3268 0.25 O2 0.4671 0.5853 0.25 O2 0.4663 0.5872 0.25 O3 0.2557 0.3396 0.0721 O3 0.2568 0.3406 0.0716 F 0 0 0.25 F 0 0 0.25

Table DR6. Match units for apatite used in this study. Data from Hughes et al. (1991) and Fleet and Pan (1995). *note that the space group used in this study, P63 (number 173), is not that quoted in the American Mineralogist crystal structure database (AMCSD), P63/m (number 176).

REFERENCES CITED Comodi, P., Liu, Y., Zanazzi, P. F., and Montagnoli, M., 2001, Structural and vibrational behaviour of fluorapatite with pressure. Part I: in situ single-crystal X-ray diffraction investigation: Physics and Chemistry of Minerals, v. 28, no. 4, p. 219-224, https://doi.org/10.1007/s002690100154. Erickson, T. M., Pearce, M. A., Taylor, R. J. M., Timms, N. E., Clark, C., Reddy, S. M., and Buick, I. S., 2015, Deformed monazite yields high-temperature tectonic ages: Geology, v. 43, no. 5, p. 383-386, https://doi.org/10.1130/g36533.1. Farnan, I., Balan, E., Pickard, C. J., and Mauri, F., 2003, The effect of radiation damage on local 29 structure in the crystalline fraction of ZrSiO4: Investigating the Si NMR response to pressure in zircon and reidite: American Mineralogist, v. 88, no. 11-12, p. 1663-1667, https://doi.org/10.2138/am-2003-11-1205. Fleet, M. E., and Pan, Y., 1995, Site preference of rare earth elements in fluorapatite: American Mineralogist, v. 80, no. 3-4, p. 329-335, https://doi.org/10.2138/am-1995-3-414. Goldoff, B., Webster, J. D., and Harlov, D. E., 2012, Characterization of fluor-chlorapatites by electron probe microanalysis with a focus on time-dependent intensity variation of halogens: American Mineralogist, v. 97, p. 1103–1115, https://doi.org/10.2138/am.2012.3812. Hazen, R. M., and Finger, L. W., 1979, Crystal structure and compressibility of zircon at high pressure: American Mineralogist, v. 64, p. 196-201,

Howard, C. J., Hill, R. J., and Reichert, B. E., 1988, Structures of ZrO2 polymorphs at room temperature by high‐ resolution neutron powder diffraction: Acta Crystallographica Section B, v. 44, no. 2, p. 116-120, https://doi.org/10.1107/S0108768187010279. Hughes, J. M., Cameron, M., and Crowley, K. D., 1989, Structural variations in natural F, OH, and Cl apatites: American Mineralogist, v. 74, no. 7-8, p. 870-876, Hughes, J. M., Cameron, M., and Crowley, K. D., 1990, Crystal structures of natural ternary apatites; solid solution in the Ca5(PO4)3X (X = F, OH, Cl) system: American Mineralogist, v. 75, no. 3-4, p. 295-304, Hughes, J. M., Cameron, M., and Mariano, A. N., 1991, Rare-earth-element ordering and structural variations in natural rare-earth-bearing apatites: American Mineralogist, v. 76, p. 1165-1173, Hughes, J. M., Ertl, A., Bernhardt, H.-J. r., Rossman, G. R., and Rakovan, J., 2004, Mn-rich fluorapatite from Austria: Crystal structure, chemical analysis, and spectroscopic investigations: American Mineralogist, v. 89, no. 4, p. 629-632, https://doi.org/10.2138/am-2004-0417. Ketcham, R. A., 2015, Calculation of stoichiometry from EMP data for apatite and other phases with mixing on monovalent anion sites: American Mineralogist, v. 100, no. 7, p. 1620- 1623, https://doi.org/10.2138/am-2015-5171. Luo, Y., Hughes, J. M., Rakovan, J., and Pan, Y., 2009, Site preference of U and Th in Cl, F, and Sr apatites: American Mineralogist, v. 94, no. 2-3, p. 345-351, https://doi.org/10.2138/am.2009.3026.

Marks, M. A. W. et al., 2012, The volatile inventory (F, Cl, Br, S, C) of magmatic apatite: An integrated analytical approach: Chemical Geology, v. 291, p. 241–255, https://doi.org/10.1016/j.chemgeo.2011.10.026. McCubbin, F. M., Jolliff, B. L., Nekvasil, H., Carpenter, P. K., Zeigler, R. A., Steele, A., Elardo, S. M., and Lindsley, D. H., 2011, Fluorine and chlorine abundances in lunar apatite: Implications for heterogeneous distributions of magmatic volatiles in the lunar interior: Geochimica et Cosmochimica Acta, v. 75, p. 5073–5093, https://doi.org/10.1016/j.gca.2011.06.017. McCubbin, F. M., Mason, H. E., Park, H., Phillips, B. L., Parise, J. B., Nekvasil, H., and Lindsley, D. H., 2008, Synthesis and characterization of low-OH− fluor-chlorapatite: A single-crystal XRD and NMR spectroscopic study: American Mineralogist, v. 93, no. 1, p. 210-216, https://doi.org/10.2138/am.2008.2557. Ni, Y., Hughes, J. M., and Mariano, A. N., 1995, Crystal chemistry of the monazite and xenotime structures: American Mineralogist, v. 80, no. 1-2, p. 21-26, https://doi.org/10.2138/am-1995-1-203. Rakovan, J. F., and Hughes, J. M., 2000, Strontium in the apatite structure: strontian fluorapatite and belovite-(Ce): The Canadian Mineralogist, v. 38, no. 4, p. 839-845, https://doi.org/10.2113/gscanmin.38.4.839. Timms, N. E., Erickson, T. M., Pearce, M. A., Cavosie, A. J., Schmieder, M., Tohver, E., Reddy, S. M., Zanetti, M. R., Nemchin, A. A., and Wittmann, A., 2017, A pressure-temperature phase diagram for zircon at extreme conditions: Earth-Science Reviews, v. 165, p. 185- 202, https://doi.org/10.1016/j.earscirev.2016.12.008. Webster, J. D., and Piccoli, P. M., 2015, Magmatic apatite: A powerful, yet deceptive, mineral: Elements, v. 11, p. 177–182, https://doi.org/10.2113/gselements.11.3.177.

Figure DR2. Shock-recrystallized apatite grain Paass-106ap from the Paasselkä impact structure, Finland. A: Backscattered electron (BSE) image of grain exterior. B: BSE image of grain interior. C: Electron backscatter diffraction (EBSD) band contrast (BC) image. D: Map showing grain reference orientation deviation (GROD) angle (the average orientation is determined for each grain; the deviation angle from this mean orientation is then plotted for each point). E: Map showing crystallographic misorientation relative to a reference point (white cross) F: Pole figures – equal-area, lower-hemisphere projections. G: Misorientation axes binned by misorientation angle and plotted in equal-area projections. Step size = 400 nm.

Figure DR3. Shock-recrystallized apatite grain Paass-107ap from the Paasselkä impact structure, Finland. A: Backscattered electron (BSE) image of grain exterior. B: BSE image of grain interior. C: Electron backscatter diffraction (EBSD) band contrast (BC) image. D: Map showing grain reference orientation deviation (GROD) angle (see definition in caption of Fig. DR1). E: Map showing crystallographic misorientation relative to a reference point (white cross) F: Pole figures – equal-area, lower-hemisphere projections. G: Misorientation axes binned by misorientation angle and plotted in equal-area projections. Step size = 300 nm.

Figure DR4. Images of shocked apatite from Paasselkä. From left to right, columns show backscattered electron (BSE) images of grain exteriors (ext.), reflected light (RL) images of grain interiors (int.), transmitted light (TL) images of grain interiors and BSE images of grain interiors. The black and brown areas around the grains (in TL images) are a result of the electron beam burning the epoxy during the electron backscatter diffraction (EBSD) analyses.

Figure DR5. An example of shock-recrystallized zircon from the Paasselkä impact structure, Finland. A: Backscattered electron (BSE) image. The brighter spots visible in the inset image are ZrO2 cores in the ZrSiO4 granules. Granular zircon grains in this sample of impact melt rock invariably display ZrO2-rich cores in effectively all granules. B: Electron backscatter diffraction (EBSD) band contrast (BC) image. C: Image colored according to the inset inverse pole figure (IPF). Note that the grain is composed of multiple discrete domains of similarly orientated neoblasts. D: Crystallographic orientation in Euler coordinate space. E: Pole figures colored according to IPF map in C. F: Plot showing high-angle (85° to 95°) misorientation axes. The observations of (i) domains of neoblasts systematically misoriented by 90°, (ii) coincidence among (001) and {110} poles, and (iii) high-angle misorientation axes coincident with poles to {110} are consistent with the former presence of reidite in this grain. Stereonets are equal-area, lower-hemisphere projections. Step size = 150 nm.

Figure DR6. An example of shock-recrystallized monazite from the Paasselkä impact structure, Finland. A: Backscattered electron (BSE) image of grain exterior with granular texture readily visible in inset. B: BSE image of grain interior. C: Electron backscatter diffraction (EBSD) band contrast (BC) image. D: Map showing crystallographic orientation in Euler coordinate space and 180°/<101> twins in yellow. E: Pole figure colored according to the Euler map shown in D. The neoblasts (pink-beige color) are misoriented from the host grain (green color) by approximately 100°. Stereonet is equal-area, lower-hemisphere projection. Step size = 75 nm.