Melt droplet formation in energetic impacts
Abstract
Impacts between rocky bodies at velocities exceeding about 15 km/sec are capable of melting or vaporizing both the impacting object and a portion of the target. Geological materials initially shocked to high pressure approach the liquid-vapor phase boundary from the liquid side as they decompress, breaking up into an expanding spray of liquid droplets. A simple theory is presented for estimating the sizes of these droplets as a function of impactor size and velocity. It is shown that these sizes are consistent with observations of microtektites and spherules found in the Cretaceous-Tertiary boundary layer, the Acraman impact structure, Archean beds in South Africa and lunar regolith. The model may also apply to the formation of chondrules.
- Publication:
-
A Bibliography of Planetary Geology and Geophysics Principal Investigators and their Associates, 1990 - 1991
- Pub Date:
- June 1991
- Bibcode:
- 1991pggp.rept..362V
- Keywords:
-
- Cretaceous-Tertiary Boundary;
- Drops (Liquids);
- Geomorphology;
- Hypervelocity Impact;
- Impact Melts;
- Mathematical Models;
- Melting;
- Vaporizing;
- High Pressure;
- Impactors;
- Lunar Rocks;
- Precambrian Period;
- Projectiles;
- Regolith;
- Spherules;
- Spraying;
- Tektites;
- Lunar and Planetary Exploration