GLOSSARY – K

GLOSSARY – D

by: Charles O’Dale

Kbar
Kilobar, 1 kbar (1 kb) = 1,000 bar; unit of pressure, frequently replaced by the SI unit Pascal, Pa, and Gigapascal, GPa (1,000 kbar = 1 Mbar = 100 GPa). The hydrostatic pressure in the center of the Earth amounts to about 3,000 kbar (300 GPa). Shock pressures in the contact and compression stage of impact cratering may exceed this value.
[see –  CRATER FORMATION]

KINETIC ENERGY
KE, of a massive falling meteorite is given by the following equation: KE = (½)MV2

KINK BAND
Characteristic pressure deformation in minerals, most common in mica but also observed inquartz and other minerals. Kink bands are formed by pressure-induced gliding in the crystal combined with external rotation of the lattice.

KREEP
An acronym built from the letters K (the atomic symbol for potassium), REE (rare-earth elements) and P (for phosphorus), is a geochemical component of some lunar impact breccia and basaltic rocks.

KUIPER BELT

The Kuiper belt or, sometimes called the Edgeworth–Kuiper belt, is a circumstellar disc in the Solar System beyond the planets, extending from the orbit of Neptune to approximately 50 AU from the Sun.

[see – OORT CLOUD]

 

K/T boundary
Cretacious/Tertiary boundary (the C abbreviation is already assigned to the Cambrian system), at present practically synonymous with marking the giant mass extinction 65 Ma ago. The extinction of the dinosaurs at that time is only a subordinate part of this remarkable event.
[see – CRETACEOUS-TERTIARY/CRETACEOUS-PALEOGENE (K–Pg) BOUNDARY.]
[see –  EXTINCTIONS]