Details

Autor(en) / Beteiligte

• Kurosawa, Kosuke
• Genda, Hidenori

Titel

Effects of Friction and Plastic Deformation in Shock‐Comminuted Damaged Rocks on Impact Heating

Ist Teil von

• Geophysical research letters, 2018-01, Vol.45 (2), p.620-626

Ort / Verlag

Washington: John Wiley & Sons, Inc

Erscheinungsjahr

2018

Quelle

Wiley Online Library All Journals

Beschreibungen/Notizen

• Hypervelocity impacts cause significant heating of planetary bodies. Such events are recorded by a reset of 40Ar‐36Ar ages and/or impact melts. Here we investigate the influence of friction and plastic deformation in shock‐generated comminuted rocks on the degree of impact heating using the iSALE shock‐physics code. We demonstrate that conversion from kinetic to internal energy in the targets with strength occurs during pressure release, and additional heating becomes significant for low‐velocity impacts (<10 km s−1). This additional heat reduces the impact‐velocity thresholds required to heat the targets with the 0.1 projectile mass to temperatures for the onset of Ar loss and melting from 8 and 10 km s−1, respectively, for strengthless rocks to 2 and 6 km s−1 for typical rocks. Our results suggest that the impact conditions required to produce the unique features caused by impact heating span a much wider range than previously thought. Key Points We systematically studied the effects of material strength on the degree of impact heating using a shock‐physics code The entropy rise during decompression in targets with strength becomes significant for low‐velocity impacts (<10 km s−1) The impact velocities required for argon loss and incipient melting are much lower than predicted by the entropy matching concept