GEOLOGY

Geosphere

any of the almost spherical concentric regions of matter that make up the earth and its atmosphere, as the lithosphere and hydrosphere.

Crust

outermost layer of the Earth

Lithosphere

region made of solid rocks; includes the crust and upper solid mantle

Asthenosphere

region made of semi-solid rocks; portion 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 2900km inro the center ; mostly molten rocks

Outer core

molten elements and mostly iron and nickel

Inner core

solid light elements like iron and nickel ; highest temperature and highest pressure

Tectonic plates

rigid pieces of the Earth’s crust and upper mantle

Plate tectonics

scientific theory that describes the large scale motion of the tectonic plates

Continental drift theory

Alfred Wegner theorizes that the Earth had a single continent through most of geologic time

Pangea

single super continent

Panthalassa

vast ocean surrounding it

Sea floor spreading

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

Divergent boundary

plate boundary where plates move away from each other, forming ridges

Convergent boundary

plate boundary where plates move towards each other, forming mountain ranges and volcanoes

Transform boundary

plate boundary where plates move along or slide past each other

Earthquake

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

Focus/hypocenter

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 under the focus

Body waves

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

Primary waves

compressional; fast and can travel through all medium — particles move in the direction of the wave

Surface waves

shear; slower and can only travel through solid rocks — particles move perpendicular to the direction of the wave

Richter scale

numerical scale for expressing the magnitude (actual energy released by the earthquake)

Mercalli scale

measures the intensity in different locations from the epicenter - subjective

Volcano

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

Cinder cones

built from particles and blobs of congealed lava ejected from a single vent

Composite volcanoes

steep-sided, symmetrical cones of large dimensions build of alternating layers of lava material

Shield volcanoes

built almost entirely of fluid lava flows

Igneous

formed from solidified magma/lava

Intrusive

crystallize's below the Earth’s surface; cools slowly, so larger crystals are formed

Extrusive

erupt onto the surface; cools quickly forming amorphous glass

Sedimentary

rock residues that accumulate over time and hardens, where fossils are also found

Metamorphic

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

Strata

term to call layers of rock

Stratigraphy

method of reading the order or sequence of the rock layers

Weathering

process of breakdown of rocks

Erosion

movement of sedimentary rocks

Deposition

settling of rocks to form a new layer

Composition

sediments are compressed

Cementation

bonding of sediments

Minerals

naturally occurring inorganic solids

Properties of minerals

composition, hardness, color, streak, density, crystalline structure, cleavage, luster

Angle of repose

the steepest angle at which a granular material can be piled without collapsing

Oceanic water

covers 70% of the Earth

Saturated zone

ground region where water is always present

Water table

ground region where water level changes depending on the environment

Unsaturated zone

ground region where water passes but does not accumulate

Evaporation

heat from the sun vaporize water

Condensation

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

Precipitation

moisture accumulating in the air becomes too heavy and fall back to the Earth

Atmosphere

encloses the earth in gases — 78% of nitrogen, 21% of oxygen, and other gases

Troposphere

layer where weather conditions occur (-20km)

Stratosphere

layer where the ozone later is situated (20km-50km)

Mesosphere

layer with low temperature and strong winds; can slow down meteors (50km-85 km)

Thermosphere

very hot layer due to the Sun’s radiation; gases are not uniformly mixed (85km-690km)

Exosphere

Thin outer layer made of light gases (650km-10 000km)

Ionosphere

layer where ionized particles exist

Magnetosphere

region where the Earth’s magnetic field exist