Glossary :: R

Rare Earth Elements (REE)

Elements with atomic numbers 57 (Lanthanum) to 71 (Lutetium) inclusive plus scandium and yttrium.

Rayleigh Wave

A seismic surface wave which has an elliptical particle motion in the direction of travel. These are the waves that are responsible for the surface movement during an earthquake.

Regional Metamorphism

Metamorphism on a large scale involving heat and pressure.

Regolith

Loose material, such as dust and rock fragments, covering bedrock.

Regression

A lowering of sealevel observed in the geological record. See trangression.

Reinforcement (reproductive)

Evolution of enhanced reproductive isolation between populations due to natural selection.

Relative age

The age of a rock or formation given relative to other rocks or formation, usually defined as a zone fossil name. See also Absolute age.

Relative sea level change

A local sea level change caused by a combination of global (eustatic) and local (isostatic) changes. This is the sea level variation "recorded" by the rock record....More

Reproductive character displacement

Where a character used in species recognition differs more greatly between sympatric than between allopatric populations/species.

Reproductive isolation

The situation where two populations are prevented or restricted from interbreeding by isolating mechanisms.

: 1 : 2 : >>
(2 pages)