Shock attenuation at terrestrial impact structures.
Abstract
Four levels of shock metamorphism have been quantitatively established for up to 50 grains per sample in autochthonous rocks from the central uplifts of two complex craters - the Slate Islands and Charlevoix impact structures - and in drill core samples from the base of one simple crater - Brent, Canada. The levels are distinguished on the basis of the development of planar deformation features in quartz. Average shock pressures and equal-pressure shock contours are characterized. The calculated shock attenuation rate for the simple crater is considered excessively high. An attenuation rate for complex craters was obtained by comparing the inferred and hypothetical excavated cavities for various modelled attenuation rates. The more rapid attenuation of large complex craters implies that the original excavated cavity of a complex crater is shallower, and the zone of autochthonous material beneath the floor is narrower, than is the case in simple craters.
- Publication:
-
Impact and Explosion Cratering: Planetary and Terrestrial Implications
- Pub Date:
- 1977
- Bibcode:
- 1977iecp.symp..687R
- Keywords:
-
- Earth Surface;
- Hypervelocity Impact;
- Impact Loads;
- Meteorite Collisions;
- Shock Wave Attenuation;
- Craters;
- Pressure Distribution;
- Quartz;
- Shock Loads;
- Lunar and Planetary Exploration;
- Meteorite Craters