Shock Melting of the Canyon Diablo Impactor: Constraints from Nickel-59 Contents and Numerical Modeling

• DOI: 10.1126/science.285.5424.85
• Publication Date: 2002-07-27T09:42:20Z
• Authors: C. Schnabel; E. Pierazzo; S. Xue; G. F. Herzog; J. Masarik; R. G. Cresswell; M. L. di Tada; K. Liu; L. K. Fifield
• Keywords: Keywords: nickel; impact structure; melting point; meteorological phenomena; article; shock; iron meteorite; 01 natural sciences; meteorite; United States; spherule; astronomy; nickel; spheroid cell; priority journal; 13. Climate action; shock metamorphism; vaporization; mass spectrometry; 0105 earth and related environmental sciences

Two main types of material survive from the Canyon Diablo impactor, which produced Meteor Crater in Arizona: iron meteorites, which did not melt during the impact; and spheroids, which did. Ultrasensitive measurements using accelerator mass spectrometry show that the meteorites contain about seven times as much nickel-59 as the spheroids. Lower average nickel-59 contents in the spheroids indicate that they typically came from 0.5 to 1 meter deeper in the impactor than did the meteorites. Numerical modeling for an impact velocity of 20 kilometers per second shows that a shell 1.5 to 2 meters thick, corresponding to 16 percent of the projectile volume, remained solid on the rear surface; that most of the projectile melted; and that little, if any, vaporized.