Cratering processes: as interpreted from the occurrence of impact melts.
Abstract
A cratering process model based on field and petrochemical observations of impact melts is described. According to this model, compositional homogeneity is achieved during the excavation stage; at the termination of excavation the bulk of the melt has been ejected, and the remainder forms a lining to the transient crater. Slope failure disrupts the internal structure during modification in simple craters to give rise to a basal melt pool and overlying mixed breccia deposits interspersed with allochthonous basement blocks and clastic breccias derived from the collapse of the transient cavity wall. Base failure in complex structures preserves the original melt stratigraphy, and the major modifications occur due to minor slope failure associated with the development of a central uplift and/or basement rings. As a result, a thin mixed breccia is produced and overlies the melt sheet within the trace of the transient cavity. The genesis of these breccias is considered equivalent to that of the slumped mixed breccias within simple craters.
- Publication:
-
Impact and Explosion Cratering: Planetary and Terrestrial Implications
- Pub Date:
- 1977
- Bibcode:
- 1977iecp.symp..791G
- Keywords:
-
- Cratering;
- Dynamic Models;
- Hypervelocity Impact;
- Impact Damage;
- Melts (Crystal Growth);
- Stratigraphy;
- Breccia;
- Chemical Composition;
- Density Distribution;
- Homogeneity;
- Meteorite Craters;
- Thermophysical Properties;
- Lunar and Planetary Exploration;
- Meteorites;
- Meteorite Craters