Essentials of Geology - Prologue Vocabulary Flashcards

A set of vocabulary flashcards defining key geologic concepts, Earth system realms, time scales, structural layers, and scientific principles covered in the Prologue.

Geology

The science that focuses on the Earth's composition and evolution.

Geoscience

A term used to discuss the broad overlaps found between geology, physics, chemistry, and biology.

Earth's Compositional Layers

The distinct internal divisions of the Earth separated by composition and density: the crust, mantle, outer core, and inner core.

Magnetosphere

The magnetic field that surrounds the Earth.

Geosphere

The solid Earth realm.

Atmosphere

The envelope of mixed gases that surround the Earth.

Hydrosphere

The realm consisting of the Earth's liquid water.

Cryosphere

The realm consisting of the Earth's frozen water.

Biosphere

All of the Earth's living organisms and the regions they occupy.

Earth System

The dynamic, interconnected system made up of Earth's six realms: magnetosphere, geosphere, atmosphere, hydrosphere, cryosphere, and biosphere.

Ka (kilo-annum)

An abbreviation for one thousand years ago ($1\text{ Ka} = 1,000\text{ years ago}$).

Ma (mega-annum)

An abbreviation for one million years ago ($1\text{ Ma} = 1,000,000\text{ years ago}$).

Ga (giga-annum)

An abbreviation for one billion years ago ($1\text{ Ga} = 1,000,000,000\text{ years ago}$); geologic data indicates Earth formed between $4.57\text{ Ga}$ and $4.54\text{ Ga}$.

Lithosphere

The outer shell of the Earth formed by the crust and uppermost part of the mantle, which is broken into plates that move slowly over the asthenosphere.

Asthenosphere

The warmer mantle layer located beneath the lithosphere over which lithospheric plates move.

Plate Boundaries

The margins along which tectonic plates interact, producing earthquakes, volcanoes, and mountain belts.

Hypothesis

An idea, involving only natural processes, that might explain a feature or phenomenon.

Theory

An idea that has been supported by an abundance of evidence, has passed definitive tests, and has not yet failed a test.

Scientific Law

Statements that apply without exception for a given range of conditions (such as Newton's law of gravity).

Shatter Cones

Cone-shaped rock structures produced by the shock of a meteorite impact that open in the direction away from the impact.