“Test” Definition in Paleontology In the field of paleontology, a subsidiary of geology, the term “test” refers to the external hard part of an invertebrate.

Mafic Definition In geology, “mafic” is a term that describes an igneous rock that has an abundance of darker color minerals.

Time Stratigraphic Unit Definition A Time Stratigraphic Unit, or a Chronostratigraphic Unit, is a rock unit that is characterized by geological formations, during a specific period of time. This serves as a reference for all rocks formed during the same time period.

Surface-Wave Magnitude “Surface-Wave Magnitude” is the magnitude of an earthquake that scientists estimate using measurements of the amplitude of surface waves.

Transgression Transgression: In geology, the term transgression is the formation of a specific sequence of sedimentary and metamorphic layers, that are the result of ocean water advancing onto land. To illustrate, when transgression occurs over millions of years, geologists find a layer of sand, overlain by shale, and overlain again by limestone. The opposite of…

Anion Anion: In the fields of chemistry and geochemistry, an anion is a negatively charged ion. The oppositely charged ion is a cation.