CET - Earth Sci.

Geology

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

Crust

outermost layer of the Earth; up to 100 km below sea level

Continental Crust (sial)

portion of the crust not covered by the ocean

Oceanic Crust (sima)

portion of the crust under the ocean

Lithosphere

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

Asthenosphere

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

Mantle

layer of the Earth under the crust to 2900 km into the center, made mostly of molten rocks

Outer Core

layer made mostly of molten elements, mostly iron and nickel

Inner Core

layer 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

Pangea

the singular super continent existing during geologic time

Panthalassa

the vast ocean surrounding the singular super continent of Pangea

Sea-floor Spreading

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

Divergent Boundary

a constructive plate boundary where plates move away from each other and new crust is created

Convergent Boundary

a destructive plate boundary where plates move towards each other and crust is destroyed as they submerge

Transform Boundary

a conservative plate boundary where plates move along or slide past each other, neither creating nor destroying crust

Earthquakes

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

Focus

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

Epicenter

center of the quake on the surface directly above the focus

Body Waves

seismic/energy waves that travel underground from the focus to the surface

Primary (P) waves

fast, compressional body waves that can travel through all mediums and move particles in the direction of the wave

Secondary (S) waves

shear body waves that are slower than P waves, can only travel through solid rock, and move particles perpendicular to the direction of the wave

Surface Waves

seismic waves that travel along the surface of the earth and are slower than body waves

Rayleigh Waves

surface waves that exhibit a "ground roll" motion and dissipate as they travel farther from the center

Love Waves

surface waves that produce a sideways movement occurring when the ground is composed of multiple layers

Tsunami

a series of enormous waves caused by the sudden displacement of water, usually in oceans or large lakes

Richter Scale

the numerical scale for expressing the magnitude of an earthquake on the basis of seismograph oscillations, holding the same value regardless of reading location

Mercalli Scale

an earthquake intensity scale that uses the observations of the people who experienced the earthquake

Volcano

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

Cinder cones

volcanoes built from particles and blobs of congealed lava ejected from a single vent that solidify and fall as cinders

Composite volcanoes (Stratovolcanoes)

typically steep-sided, symmetrical cones built of alternating layers of lava flows, volcanic ash, cinders, blocks, and bombs

Shield volcanoes

volcanoes built almost entirely of fluid lava flows

Igneous Rocks

rocks formed when magma or lava solidifies

Intrusive Igneous Rocks

rocks that crystallize slowly below the Earth's surface, forming larger crystals

Extrusive Igneous Rocks

rocks that erupt onto the surface and cool quickly, forming an amorphous glass

Sedimentary Rocks

rocks formed from rock residues that accumulate over time and harden

Clastic Sedimentary Rocks

sedimentary rocks formed from mechanical weathering debris

Chemical Sedimentary Rocks

sedimentary rocks formed when dissolved materials precipitate from a solution

Organic Sedimentary Rocks

sedimentary rocks formed from the accumulation of plant or animal debris

Metamorphic Rocks

rocks that undergo physical and chemical changes due to intense pressure and temperature

Minerals

naturally occurring inorganic solids defined by a specific chemical composition

Hardness

the ability of a mineral to resist being scratched

Streak

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

Density

mineral property relating to composition and the geometric pattern in which the mineral's atoms are arranged

Crystalline structure

geometric shapes of minerals determined by the uniform arrangement of their atoms, molecules, or ions

Cleavage

the tendency of a mineral to break cleanly along a flat plane

Luster

the unique way a mineral reflects light from its surface

Soil

fine fragments brought about by weathering that make up the ground, 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

Zone of Saturation

underground region where water is always present

Water Table

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

Unsaturated Zone

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

Evaporation

process where heat from the sun converts water from oceans, soil, leaves, and living bodies into vapor

Condensation

process where water molecules liquify and cling to dust particles in the high air to form clouds

Precipitation

process where moisture accumulating in the air becomes too heavy and falls back to earth as rain, snow, or hail

Atmosphere

a protective blanket made up of layers of gases enveloping the Earth

Troposphere

the atmospheric layer spanning from the surface to 20km where weather conditions occur

Stratosphere

the atmospheric layer spanning from 20km to 50km where the ozone layer is situated

Mesosphere

the atmospheric layer spanning from 50km to 85km characterized by low temperatures and strong winds that slow down meteors

Thermosphere

a very hot atmospheric layer spanning from 85km to 690km where gases are not uniformly mixed due to solar radiation

Exosphere

the thin outer layer of the atmosphere spanning from 690km to 10,000km made of light gases

Ionosphere

atmospheric layer where ionized particles exist, situated within the thermosphere and exosphere

Magnetosphere

region where the Earth's magnetic field exists, bounded below by the ionosphere

Weather

the average atmospheric condition at a certain place at a given time

Sea breeze

diurnal wind movement flowing from sea to land during the day

Land breeze

nocturnal wind movement flowing from land to sea during the night

Cyclones

violent whirling storms characterized by strong winds and rain covering large areas, created by winds converging at a Low-Pressure Area

Thunderstorms

small clusters of storm clouds carrying heavy rain and sometimes lightning

Tornadoes

violent twisting funnels of air

Climate

average atmospheric conditions in a certain area over a long period of time

Astronomy

the study of space, celestial bodies, and the behavior of the universe