GLOSSARY – B
by: Charles O’Dale
Microscopic shock-deformation feature in quartz. Oval quartz with rims of tiny vugs filled with amorphous material.
BALLISTIC EROSION AND SEDIMENTATION
(Oberbeck 1975) Emplacement of ballistically transported impact ejecta, and ejecta-surface interaction.
A dark coloured igneous rock. commonly extrusive, composed primarily of calcic plagioclase and pyroxene; the fine-grained equivalent of gabbro.
The solid rock that underlies gravel, soil, or other surficial material.
[see – METEORITE]
BRECCIA – from Italian indicating both loose gravel and stone made by cemented gravel
A clastic sedimentary rock composed of angular clasts in a consolidated matrix. Breccias can be produced in several geologic processes: tectonic breccia, volcanic breccia (eruption breccia, vent breccia), sedimentary breccia (e.g., rock fall breccia), collapse breccia (e.g., in karst areas). Breccias may be distinguished depending on the origin of the clasts, monomictic (monogenetic, monolithologic) and polymictic (polygenetic, polylithologic).
Dyke formed in the (par)autochthonous basement or in displaced megablocks of impact craters consisting of impact breccia (polymict breccias such as impact melt rock, suevite, lithic breccia or more rarely monomict breccia).
(Bunte Breccie or Bunte Brekzie or Bunte Bresche, Loc. Ries impact crater, Germany) Local term for polymict lithic breccia forming the continuous ejecta blanket at the Ries impact crater, Germany; first detailed description as “Kalkbreccie” by C. W. von Gümbel in 1870.