Geology and Earth Systems Vocabulary

Comprehensive practice vocabulary flashcards covering Earth's layers, plate tectonics, seismic activity, minerals, the water cycle, and atmospheric layers based on the geology lecture notes.

Geology

The study of the Earth's structure, history, and processes involved in it.

Geosphere

One of the three parts of the Earth, focused on the solid layers of the planet.

Crust

The outermost layer of the Earth; extends up to $100\,km$ below sea level.

Continental Crust (sial)

The portion of the crust not covered by the ocean.

Oceanic Crust (sima)

The portion of the crust found under the ocean.

Lithosphere

A region made of solid rocks that includes the crust and the upper solid part of the mantle.

Asthenosphere

A region made of semi-solid rocks where rocks begin to melt; divided into a soft upper layer and a hard lower layer.

Mantle

The layer of the Earth under the crust extending to $2900\,km$ into the center; made mostly of molten rocks.

Outer Core

A layer of the Earth made mostly of molten elements, primarily iron and nickel.

Inner Core

A layer of the Earth made of solid light elements like iron and nickel.

Tectonic Plates

Rigid pieces of the Earth's crust and upper mantle.

Plate Tectonics

A scientific theory that describes the large-scale motions of the Earth's lithosphere.

Continental Drift Theory

The theory that the Earth had a single continent through most of geologic time, evidenced by jigsaw-like fits of continental boundaries.

Pangea

The name of the singular super continent that existed according to the Continental Drift Theory.

Panthalassa

The vast ocean that surrounded the singular super continent Pangea.

Sea-floor Spreading

The process in which the ocean floor is extended when two plates move apart.

Divergent Boundary

A boundary where plates move away from each other; it is constructive (new crust is created) and can cause the formation of ridges like the Mid-Atlantic Ridge.

Convergent Boundary

A boundary where plates move towards each other; it is destructive (crust is destroyed as they submerge) and forms trenches, mountain ranges, or volcanoes.

Transform Boundary

A boundary where plates move along or slide past each other; it is conservative as crust is neither created nor destroyed.

Earthquakes

Shaking of the ground caused by the release of tension built up in the plate boundaries.

Focus

The point beneath the Earth's surface where rocks break under stress and plates shift, causing an earthquake.

Epicenter

The center of an earthquake on the surface directly above the focus.

Primary or P waves

Compressional/longitudinal seismic waves that are fast and can travel through all mediums; particles move in the direction of the wave.

Secondary or S waves

Shear/transverse seismic waves that are slower than P waves and can only travel through solid rock; particles move perpendicular to the direction of the wave.

Rayleigh Waves

A type of surface wave known as 'ground roll' that dissipates as it travels farther from the center.

Love Waves

A type of surface wave involving sideways movement that occurs when the ground is composed of multiple layers.

Tsunami

A series of enormous waves caused by the sudden displacement of water, usually due to sudden upward movement of trenches.

Richter Scale

A numerical scale for expressing earthquake magnitude based on seismograph oscillations; it remains constant regardless of the reading location.

Mercalli Scale

An earthquake scale that uses the observations of people who experienced the quake; considered less scientific than the Richter Scale.

Volcano

An opening or rupture in the Earth's surface where hot gases, lava, and rock fragments are released from a magma chamber.

Streak

The color of a mineral in its powdered form, showing the true color of the mineral.

Luster

The way a mineral reflects light.

Cleavage

The tendency of a mineral to break along a plane.

Soil

Fine fragments brought about by weathering composed of mineral fragments, organic matter, water, and air.

Erosion

The transfer of ground materials to another location caused by natural or man-made events.

Angle of Repose

The steepest slope of unconfined material on which the material can be heaped without collapsing.

Hydrosphere

The Earth's system containing all water; $97\%$ is oceanic water and $3\%$ is freshwater.

Zone of Saturation

The region underground where water is always present.

Water Table

The region above the zone of saturation where the water level changes depending on environmental conditions.

Unsaturated Zone

The region above the water table where water only passes through but does not accumulate.

Evaporation

The process where heat from the sun causes water to turn into vapor from oceans, lakes, soil, surfaces, and living bodies.

Condensation

The process where water molecules liquefy and cling to dust particles in the high air to form clouds.

Precipitation

When moisture accumulating in the air becomes too heavy and falls back to Earth as rain, snow, or hail.

Atmosphere

Layers of gases enveloping the Earth, composed mostly of nitrogen ($78\%$) and oxygen ($21\%$).

Exosphere

A thin outer layer of the atmosphere ($690\,km$ to $10000\,km$) made of light gases.

Ionosphere

A layer where ionized particles exist; it is located within the thermosphere and exosphere.