Terrestrial Impact: The Record in the Rocks
Abstract
The terrestrial impact craters are mostly recognized not by their morphology but by the occurrence of the characteristic shock metamorphic effects. The recognition of the diagnostic shock metamorphic effects and the signature of the projectile contamination through geochemical anomalies in impact lithologies provide the basis for recognizing the impact signature in K/T boundary samples and for testing hypothesis of periodic cometary showers. It is emphasized, however, that, in evaluating and making interpretations based on the overall cratering record, it is important to realize that one of the basic characteristics of the terrestrial impact record is its bias to geologically young craters on the better known cratonic areas and the fact that the sample of the currently known (about 130) terrestrial craters is deficient in small (D less than 20 km) craters.
- Publication:
-
Meteoritics
- Pub Date:
- September 1991
- DOI:
- 10.1111/j.1945-5100.1991.tb01038.x
- Bibcode:
- 1991Metic..26..175G
- Keywords:
-
- Geochronology;
- Hypervelocity Impact;
- Lithology;
- Meteorite Collisions;
- Meteorite Craters;
- Structural Properties (Geology);
- Breccia;
- Cretaceous-Tertiary Boundary;
- Earth Surface;
- Impact Melts;
- Metamorphism (Geology);
- Sedimentary Rocks;
- Geophysics;
- Broadly Focused Reviews