Abstract
A large impact by a comet or meteorite releases an enormous amount of energy, which evaporates, melts and fractures the surrounding rocks1,2,3,4. Distinctive features of such impacts are ‘shatter cones’, deformed rocks characterized by hierarchical striated features5,6. Although such features have been used for decades as unequivocal fingerprints of large-body impacts, the process by which shatter cones form has remained enigmatic. Here we show that the distinctive shatter-cone striations naturally result from nonlinear waves (front waves) that propagate along a fracture front7,8,9,10. This explains the observed systematic increase of striation angles with the distance from the impact. Shatter-cone networks, typically spanning many scales, can be understood as hierarchical bifurcations of the fracture front, which is generated by the immense energy flux carried by the initial, impact-generated, shock waves. Our quantitative predictions based on this theory are supported by field measurements at the Kentland and Vredefort impact sites. These measurements indicate that shatter cones near to the impact site were formed by fractures propagating at nearly the Rayleigh wave speed of the host rocks, whereas the furthest shatter cones observed (about 40 km from the impact site) were formed by fronts moving more slowly. These results provide insight into impact dynamics as well as dissipative mechanisms in solids subjected to sudden, extremely intense fluxes of energy.
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References
Melosh, H. J. Impact ejection, spallation, and the origin of meteorites. Icarus 59, 234–260 (1984)
Melosh, H. J. Impact Cratering: A Geologic Process (Oxford Univ. Press, New York, 1989)
French, B. M. Traces of Catastrophe. Handbook of Shock-metamorphic Effects in Terrestrial Meteorite Impact Structures (Lunar and Planetary Institute, Houston, 1998)
Turtle, E. P. & Pierazzo, E. Constraints on the size of the Vredefort impact crater from numerical modeling. Meteorit. Planet. Sci. 33, 483–490 (1998)
Dietz, R. S. in Shock Metamorphism of Natural Materials (eds French, B. M. & Short, N. M.) 267–285 (Mono Book Corp., Baltimore, 1969)
Sharpton, V. L., Dressler, B. O., Herrick, R. R., Schnieders, B. & Scott, J. New constraints on the Slate Islands impact structure, Ontario, Canada. Geology 24, 851–854 (1996)
Morrissey, J. W. & Rice, J. R. Crack front waves. J. Mech. Phys. Solids 46, 467–487 (1998)
Morrissey, J. W. & Rice, J. R. Perturbative simulations of crack front waves. J. Mech. Phys. Solids 48, 1229–1251 (2000)
Ramanathan, S. & Fisher, D. S. Dynamics and instabilities of planar tensile cracks in heterogeneous media. Phys. Rev. Lett. 79, 877–880 (1997)
Sharon, E., Cohen, G. & Fineberg, J. Propagating solitary waves along a rapidly moving crack front. Nature 410, 68–71 (2001)
Milton, D. J. in Impact and Explosion Cratering; Planetary and Terrestrial Implications (eds Roddy, D. J., Pepin, R. O. & Merrill, R. B.) 703–714 (Pergamon, New York, 1977)
Roy, D. W. Shatter cone geometry and description procedure. Tectonophysics 60, T37–T42 (1979)
Albat, H. M. & Mayer, J. J. Megascopic planar shock fractures in the Vredefort Structure; a potential time marker? Tectonophysics 162, 265–276 (1989)
Nicolaysen, L. O. & Reimold, W. U. Vredefort shatter cones revisited. J. Geophys. Res. B 104, 4911–4930 (1999)
Johnson, G. P. & Talbot, R. J. A Theoretical Study of the Shock Wave Origin of Shatter Cones Thesis (Air Force Inst. Technol., Wright-Patterson Air Force Base)
Gash, P. J. S. Dynamic mechanism for the formation of shatter cones. Nature 230, 32–35 (1971)
Shibuya, T. & Nakahara, I. The semi-infinite body subjected to a concentrated impact load on the surface. Bull. Jpn Soc. Mech. Eng. 11, 983–992 (1968)
Asphaug, E. et al. Mechanical and geological effects of impact cratering on Ida. Icarus 120, 158–184 (1996)
Camacho, G. T. & Ortiz, M. Computational modelling of impact damage in brittle materials. Int. J. Solids Struct. 33, 2899–2938 (1996)
Melosh, H. J., Ryan, E. V. & Asphaug, E. Dynamic fragmentation in impacts — Hydrocode simulation of laboratory impacts. J. Geophys. Res. E 97, 14735–14759 (1992)
Field, J. E. Brittle fracture: its study and application. Contemp. Phys. 12, 1–31 (1971)
Ahrens, T. J. & Rubin, A. M. Impact-induced tensional failure in rock. J. Geophys. Res. E 98, 1185–1203 (1993)
Polanskey, C. A. & Ahrens, T. J. Impact spallation experiments; fracture patterns and spall velocities. Icarus 87, 140–155 (1990)
Arakawa, M., Shirai, K. & Kato, M. Shock wave and fracture propagation in water ice by high velocity impact. Geophys. Res. Lett. 27, 305–308 (2000)
Sharon, E. & Fineberg, J. Microbranching instability and the dynamic fracture of brittle materials. Phys. Rev. B 54, 7128–7139 (1996)
Sagy, A., Reches, Z. & Roman, I. Dynamic fracturing; field and experimental observations. J. Struct. Geol. 23, 1223–1239 (2001)
Freund, L. B. Dynamic Fracture Mechanics (Cambridge Univ. Press, Cambridge, 1990)
Henkel, H. & Reimold, W. U. Integrated geophysical modelling of a giant, complex impact structure; anatomy of the Vredefort Structure, South Africa. Tectonophysics 287, 1–20 (1998)
Dally, J. W. Dynamic photoelastic studies of fracture. Exp. Mech. 19, 349–361 (1979)
Therriault, A. M., Grieve, R. A. F. & Reimold, W. U. Original size of the Vredefort Structure; implications for the geological evolution of the Witwatersrand Basin. Meteorit. Planet. Sci. 32, 71–77 (1997)
Acknowledgements
We thank W. U. Reimold and E. G. Charlesworth for information and hospitality at the Vredefort site; the Rogers Group's Newton County quarry for their hospitality at the Kentland site; and G. Cohen for assistance. This work was supported by the United States–Israel Binational Fund.
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Sagy, A., Reches, Z. & Fineberg, J. Dynamic fracture by large extraterrestrial impacts as the origin of shatter cones. Nature 418, 310–313 (2002). https://doi.org/10.1038/nature00903
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DOI: https://doi.org/10.1038/nature00903
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