Abstract
We present a compositional and textural analysis of shock-induced microtextures in garnet porphyroblasts in migmatitic garnet–cordierite–biotite paragneisses from the centre of the Vredefort impact structure, South Africa. Detailed imaging and major element analysis of deformation features in, and adjacent to, the garnet porphyroblasts record a complex, heterogeneous distribution of shock effects at the microscale. As the most competent silicate mineral in the assemblage, with the highest Hugoniot Elastic Limit and a wide pressure–temperature stability field, the porphyroblastic garnet preserves a more diverse shock deformation response compared to minerals such as quartz and feldspar, which underwent more comprehensive shock metamorphism and subsequent annealing. The garnet porphyroblasts display pre-impact fractures that are overprinted by later intra-granular Hertzian and distinctive planar fractures associated with the impact event. Shock-induced strain localization occurred along internal slip planes and defects, including pre-existing fractures and inclusion boundaries in the garnet. Symplectitic (kelyphitic) coronas commonly enclose the garnet porphyroblasts, and inhabit intra-granular fractures. The kelyphite assemblage in fractures with open communication beyond garnet grain boundaries is characterized by orthopyroxene—cordierite—sapphirine. Conversely, the kelyphite assemblage in closed-off intra-granular fractures is highly variable, comprising spatially restricted combinations of a secondary garnet phase with a majoritic component, Al-rich orthopyroxene, sapphirine and cordierite. The impedance contrast between garnet porphyroblasts and their inclusions further facilitated the formation of shock-induced features (Al-rich orthopyroxene coronas). Together, the textural and mineralogical data suggest that these features provide a record of oscillatory shock perturbations initiated under confining pressure beneath the transient crater floor. This occurred as the shocked rock volume underwent post-shock expansion, forming the core of the central uplift, and was followed by variable textural re-equilibration. This study thus provides a microtextural and mineralogical perspective of the shock regime within confined crust immediately prior to and during central uplift formation.
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References
Adams M, Sines G (1978) Crack extension from flaws in a brittle material subjected to compression. Tectonophysics 49:97–118
Agarwal A, Reznik B, Alva-Valdivia LM, Srivastava DC (2016) Alternating augite-plagioclase wedges in basement dolerites of Lockne impact structure, Sweden: A new shock wave-induced deformation feature. Meteorit Planet Sci. doi:10.1111/maps.12806
Ashwal LD (2013) Anorthosites. Springer, Heidelberg
Ashworth JR, Sheplev VS (1997) Diffusion modelling of metamorphic layered coronas with stability criterion and consideration of affinity. Geochim Cosmochim Acta 61:3671–3689. doi:10.1016/S0016-7037(97)00190-7
Buchanan PC, Reimold WU (2002) Planar deformation features and impact glass in inclusions from the Vredefort Granophyre, South Africa. Meteorit Planet Sci 37:807–822
Carlson WD (2002) Scales of disequilibrium and rates of equilibration during metamorphism. Am Mineral 87:185–204
Collerson KD, Williams Q, Kamber BS et al (2010a) Majoritic garnet: a new approach to pressure estimation of shock events in meteorites and the encapsulation of sub-lithospheric inclusions in diamond. Geochim Cosmochim Acta 74:5939–5957
Collerson KD, Williams Q, Kamber BS et al (2010b) Majoritic garnet: a new approach to pressure estimation of shock events in meteorites and the encapsulation of sub-lithospheric inclusions in diamond. Geochim Cosmochim Acta 74:5939–5957. doi:10.1016/j.gca.2010.07.005
Collins GS, Melosh JH, Ivanov BA (2004) Modeling damage and deformation in impact simulations. Meteorit Planet Sci 39:217–231
Davision L, Grady DE, Shahinpoor M (eds) (1996) High-pressure shock compression of solids II: dynamic fracture and fragmentation. Springer, New York
Deer WA, Howie RA, Zussman J (1997) Rock-forming minerals: orthoslicates, second. The Geological Society, Great Britain
Dégi J, Abart R, Török K et al (2010) Symplectite formation during decompression induced garnet breakdown in lower crustal mafic granulite xenoliths: mechanisms and rates. Contrib Mineral Petrol 159:293–314. doi:10.1007/s00410-009-0428-z
Fel’dman VI, Sazonova LV, Kozlov EA (2006) Shock metamorphism of some rock-forming minerals: experimental results and natural observations. Petrology 14:540–566. doi:10.1134/S0869591106060038
Field SW, Haggerty SE (1994) Symplectites in upper mantle peridotites: development and implications for the growth of subsolidus garnet, pyroxene and spinel. Contrib Mineral Petrol 118:138–156
Fossen H, Tikoff B, Teyssier C (1994) Strain modeling of transpressional and transtensional deformation. Nor Geol Tiddskrift 74:134–145
French B (1998) Traces of catastrophe: a handbook of shock-metamorphic effects in terrestrial meteorite impact structures. Lunar and Planetary Institute, Houston
French BM, Koeberl C (2010) The convincing identification of terrestrial meteorite impact structures: what works, what does not, and why. Earth-Sci Rev 98:123–170. doi:10.1016/j.earscirev.2009.10.009
Garde AA, Boriani A, Sørensen EV (2015) Crustal modelling of the Ivrea-Verbano zone in northern Italy re-examined: coseismic cataclasis versus extensional shear zones and sideways rotation. Tectonophysics 662:291–311. doi:10.1016/j.tecto.2015.04.003
Georgen ET (2008) Integrating crystallographic data and phase equilibria to quantify P-T-X evolution during reaction texture formation, Abstract number V24C-05
Gibson RL (2002) Impact-induced melting of Archean granulites in the Vredefort Dome, South Africa. I: anatexis of metapelitic granulites. J Metamorph Geol 20(1):57–70
Gibson RL, Reimold WU (2008) Geology of the Vredefort impact structure – a guide to sites of interest. Memoir 97, Council for Geoscience, Pretoria, p 181
Gibson RL, Stevens G (1998) Regional metamorphism due to anorogenic intracratonic magmatism. Geol Soc Lond Spec Publ 138:121–135
Gibson RL, Reimold WU, Stevens G (1998) Thermal-metamorphic signature of an impact event in the Vredefort dome, South Africa. Geology 26:787–790
Hargraves R (1961) Shattercones in the rocks of the Vredefort Ring. Trans Geol Soc South Afr 65:147–161
Hobbs BE, Ord A (2015) Structural geology: the mechanics of deforming metamorphic rocks. Elsevier, Waltham
Holland TJB, Powell R (2011) An improved and internally consistent thermodynamic dataset for phases of petrological interest, involving a new equation of state for solids. J Metamorph Geol 29(3):333–383
Ivanov BA (2005) Numerical modeling of the largest terrestrial meteorite craters. Sol Syst Res 39:381–409
Johnson CD, Carlson WD (1990) The origin of olivine-plagioclase coronas in metagabbros from the Adirondack Mountains, New York. J Metamorph Geol 8:697–717. doi:10.1111/j.1525-1314.1990.tb00496.x
Kamo SL, Reimold WU, Krogh TE, Colliston WP (1996) A 2.023 Ga age for the Vredefort impact event and a first report of shock metamorphosed zircons in pseudotachylitic breccias and Granophyre. Earth Planet Sci Lett 144:369–387. doi:10.1016/S0012-821X(96)00180-X
Kenkmann T, Hornemann U, Stoffler D (2000) Experimental generation of shock-induced pseudotachylytes along lithological interfaces. Meteorit Planet Sci 35:1275–1290
Koeberl C, Reimold WU, Shirey SB (1996) Re-Os isotope and geochemical study of the Vredefort Granophyre: clues to the origin of the Vredefort structure, South Africa. Geology 24:913–916. doi:10.1130/0091-7613(1996)024<0913:ROIAGS>2.3.CO;2
Kranz RL (1979) Crack-crack and crack-pore interactions in stressed granite. Int J Rock Mech Min Sci Geomech 16:37–47
Lana C, Gibson RL, Reimold WU (2003) Impact tectonics in the core of the Vredefort dome, South Africa: implications for central uplift formation in very large impact structures. Meteorit Planet Sci 38:1093–1107
Lana C, Reimold WU, Gibson RL et al (2004) Nature of the Archean midcrust in the core of the Vredefort Dome, central Kaapvaal Craton, South Africa. Geochim Cosmochim Acta 68:623–642
Larikova TL, Zaraisky GP (2009a) Experimental modelling of corona textures. J Metamorph Geol 27:139–151. doi:10.1111/j.1525-1314.2008.00809.x
Larikova TL, Zaraisky GP (2009b) Experimental modelling of corona textures. J Metamorph Geol 27:139–151. doi:10.1111/j.1525-1314.2008.00809.x
Lieger D, Riller U, Gibson RL (2009) Generation of fragment-rich pseudotachylite bodies during central uplift formation in the Vredefort impact structure, South Africa. Earth Planet Sci Lett 279:53–64. doi:10.1016/j.epsl.2008.12.031
Manton WI (1965) The orientation and origin of shattercones in the Vredefort Ring. Geol Probl Lunar Res 123:1017–1048
Martini JEJ (1978) Coesite and stishovite in the Vredefort Dome, South Africa. Nature 272:715–717
Melosh JH (1984) Impact ejection, spallation and the orogin of meteorites. Icarus 59:234–260
Melosh JH (1985) Impact cratering dynamics: relationship between the shockwave and excavation flow. Icarus 62:339–343
Melosh HJ (2015) Acoutsitc fluidization: what it is, and is not. Bridging The Gap III. Abstract number 1004
Melosh JH, Ryan EV, Asphaug E (1992) Dynamic fragmentation in impacts: hydrocode simulation of laboratory impacts. J Geophys Res 97:14735–14759
Milke R, Abart R, Kunze K et al (2009) Matrix rheology effects on reaction rim growth I: evidence from orthopyroxene rim growth experiments. J Metamorph Geol 27:71–82. doi:10.1111/j.1525-1314.2008.00804.x
Mohr-Westheide T, Reimold WU, Thirlwall M (2011) Genesis of the pseudotachylytic breccias from the Vredefort Dome, South Africa: Current state of research. In: Lunar and Planetary Science Conference
Negrini M, Stünitz H, Nasipuri P et al (2014) Semibrittle deformation and partial melting of perthitic K-feldspar: an experimental study: deformation and melting of K-feldspar. J Geophys Res Solid Earth 119:3478–3502. doi:10.1002/2013JB010573
Nesterenko VF (2001) Dynamics of heterogeneous materials. Springer, Heidelberg
Obata M (2011) Chapter 5—Kelyphite and Symplectite: textural and mineralogical diversities and universality, and a new dynamic view of their structural formation. In: Sharkov EV (ed) New frontiers in tectonic research—general problems, sedimentary basins and island arcs. InTech, pp 93–122
Obata M, Ozawa K, Naemura K, Miyake A (2013) Isochemical breakdown of garnet in orogenic garnet peridotite and its implication to reaction kinetics. Mineral Petrol 107:881–895. doi:10.1007/s00710-012-0260-4
Obata M, Ohi S, Miyake A (2014) Experimental synthesis of isochemical kelyphite—a preliminary report. J Mineral Petrol Sci 109:91–96. doi:10.2465/jmps.131022a
Ogilvie P (2010) Metamorphic studies in the Vredefort Dome. PHD thesis, University of the Witwatersrand, South Africa
Ogilvie P, Gibson RL, Reimold WU et al (2011) Experimental investigation of shock metamorphic effects in a metapelitic granulite: the importance of shock impedance contrast between components: Shock metamorphic effects in a pelitic granulite. Meteorit Planet Sci 46:1565–1586. doi:10.1111/j.1945-5100.2011.01250.x
Perchuk LL, Sazonova LV, van Reenen DD, Gerya TV (2003) Ultramylonites and their significance for the understanding of the history of the Vredefort impact structure, South Africa. Petrology 11:128–144
Riller U, Lieger D, Gibson RL et al (2010) Origin of large-volume pseudotachylite in terrestrial impact structures. Geology 38:619–622. doi:10.1130/G30806.1
Schmid DW, Abart R, Podladchikov YY, Milke R (2009) Matrix rheology effects on reaction rim growth II: coupled diffusion and creep model. J Metamorph Geol 27:83–91. doi:10.1111/j.1525-1314.2008.00805.x
Schreyer W, Abraham K (1978) Symplectitic cordieritic-orthopyroxene-garnet assemblages as products of contact metamorphism of pre-existing basement granulites in the Vredefort structure, South Africa, and their relations to pseudotachylite. Contrib Mineral Petrol 68:53–62
Schreyer W, Medenbach O (1981) CO2-rich fluid inclusions along planar elements of quartz in basement rocks of the Vredefort Dome, South Africa. Contrib Mineral Petrol 77:93–100. doi:10.1007/BF00636513
Solorzano IG, Purdy GR (1984) Interlamellar spacing in discontinuous precipitation. Metall Trans A 15:1055–1063
Spacek P, Ackerman L, Habler G et al (2013) Garnet breakdown, symplectite formation and melting in basanite-hosted peridotite xenoliths from Zinst (Bavaria, Bohemian Massif). J Petrol 54:1691–1723. doi:10.1093/petrology/egt028
Spray JG (1998) Localized shock- and friction-induced melting in response to hypervelocity impact. Geological Society, London, Special Publications, vol 140, Issue 1, pp 195–204
Spray JG (2010) Frictional melting processes in planetary materials: from hypervelocity impact to earthquakes. Annu Rev Earth Planet Sci 38:221–254. doi:10.1146/annurev.earth.031208.100045
Spray JG, Thompson LM (2008) Constraints on central uplift structure from the Manicouagon impact crater. Meteorit Planet Sci 43:2049–2057
Stahle V, Altherr R, Nasdala L, Ludwig T (2011) Ca-rich majorite derived from high-temperature melt and thermally stressed hornblende in shock veins of crustal rocks from the Ries impact crater (Germany). Contrib Mineral Petrol 161:275–291. doi:10.1007/s00410-010-0531-1
Stevens G, Gibson RL, Droop GTR (1997) Mid-crustal granulite facies metamorphism in the Central Kaapvaal Craton: the Bushveld Connection. Precambrian Res 82:113–132
Stickle AM, Schultz PH, Crawford DA (2015) Subsurface failure in spherical bodies: a formation scenario for linear troughs on Vesta’s surface. Icarus 247:18–34. doi:10.1016/j.icarus.2014.10.002
Swanson MT (1992) Fault structure, wear mechanisms and rupture processes in pseudotachylyte generation. Tectonophysics 204:223–242
Whitney DL, Evans BW (2010) Abbreviations for names of rock-forming minerals. American Mineral 95(1):185–187
Wieland F, Gibson RL, Reimold WU (2005) Structural analysis of the collar of the Vredefort Dome, South Africa—Significance for impact-related deformation and central uplift formation. Meteorit Planet Sci 40(9–10):1537–1554
Wieland F, Reimold WU, Gibson RL (2006) New observations on shatter cones in the Vredefort impact structure, South Africa, and evaluation of current hypotheses for shatter cone formation. Meteorit Planet Sci Arch 41:1737–1759
Wu X, Meng D, Fan X et al (2008) Defect microstructures in garnet, omphacite and symplectite from UHP eclogites, eastern Dabieshan, China: a TEM and FTIR study. Mineral Mag 72:1057–1069. doi:10.1180/minmag.2008.072.5.1057
Zhang Q, Enami M, Suwa K (1993) Aluminium orthopyroxene in pyrometamorphosed garnet megacrysts from Liaoning and Shiandong provinces, northeast China. Eur J Mineral 5:153–164
Acknowledgements
Natalie Deseta’s Post-Doctoral Fellowship was supported by the Canadian Space Agency through a FAST program Grant awarded to JGS. Additional support came from grants awarded to JGS from the Natural Sciences and Engineering Research Council of Canada and the Canada Research Chairs program, as well as the South African NRF awarded to RG.
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Communicated by Timothy L. Grove.
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Deseta, N., Boonsue, S., Gibson, R.L. et al. Shock-induced kelyphite formation in the core of a complex impact crater. Contrib Mineral Petrol 172, 84 (2017). https://doi.org/10.1007/s00410-017-1399-0
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DOI: https://doi.org/10.1007/s00410-017-1399-0