GEOL 1001 FINAL (LSU, ACHIMM).

Geologist

Geologist

A scientist who specializes in studying the Earth

Geology (geoscience)

The study of the Earth, including our planet’s composition, behavior, and history

Lithosphere

The relatively rigid, nonflowable, outer 100-150 km-thick layer of the Earth, constituting the crust and the top part of the mantle

Asthenosphere

The layer of the mantle that lies between 100-150 km and 350 km deep; the asthenosphere is relatively soft and can flow when acted on by force

Plate

One of about 20 distinct pieces of the relatively rigid lithosphere

Theory of plate tectonics

the theory that the outer layer of the Earth (the lithosphere) consists of separate plates that move with respect to one another

earth system

The interacting assembly of physical and biological reservoirs and phenomena involving the solid Earth, the hydrosphere, the atmosphere, and the biosphere

Internal process

A process in the Earth System, such as plate motion, mountain building, or volcanism, ultimately caused by the Earth’s internal heat

External process

A geomorphologic process—such as downslope movement, erosion, or deposition—that is the consequence of gravity or of the interaction between solid Earth and its fluid envelope (air and water); energy for these processes comes from gravity and sunlight

Gravity

the attractive force that one mass exerts on another; the magnitude depends on the size of the objects and the distance between them

Geologic time

The span of time since the formation of the Earth

geologic time scale

A scale that describes the intervals of the geologic time

Science

The systematic study of natural phenomena via observation, computation, experiment, and modeling

Scientific method

A sequence of steps for systematically analyzing scientific problems in a way that leads to verifiable results

Hypothesis

An idea that has the potential to explain a phenomenon; a hypothesis must be rigorously tested if it is to eventually become a theory

Shatter cones

Small, cone-shaped fractures formed by the shock of a meteorite impact

Theory

A scientific idea supported by an abundance of evidence that has passed many tests and failed none

Scientific law

A concise statement that completely describes a natural relationship or phenomenon; it does not, however, explain the phenomenon

Cosmology

The study of the overall structure of the Universe

Geocentric model

An Ancient Greek idea suggesting that the Earth sat motionless in the center of the Universe while stars and other planets and the Sun orbited around it

Heliocentric model

An idea proposed by Greek philosophers around 250 BCE suggesting that all heavenly objects including the Earth orbited the Sun

Element

A material consisting entirely of one kind of atom; elements cannot be subdivided or changed by chemical reactions

atom

The smallest piece of an element that has the properties of the element; it consists of a nucleus surrounded by an electron cloud

Atomic number

The number of protons in the nucleus of an atom

atomic mass

The amount of matter in an atom; roughly, the sum of the number of protons plus the number of neutrons in the nucleus

Molecule

The smallest piece of a compound that has the properties of the compound; consists of 2 or more atoms attached by chemical bonds

Gas

Matter that consists of atoms or molecules that are not attached to each other; fills the container that contains it

Liquid

Matter that can flow to conform to the shape of the container that holds it

Solid

A material that can maintain its shape indefinitely

Energy

The capacity to do work

Universe

All of the space and all of the matter and energy within it

star

An object in the Universe in which fusion reactions occur, producing vast amounts of energy

Galaxy

An immense system of hundreds of billions of stars

Solar system

Our Sun and the materials that orbit it (including planets, moons, asteroids, Kuiper Belt objects, and Oort Cloud objects)

Planet

an object that orbits a star, is roughly spherical, and has cleated its neighborhood of other objects

Ecliptic

the plane defined by a planet’s orbit

Terrestrial planets

Planets that are of comparable size and character to the Earth and consist of a metallic core surrounded by a rock mantle

Giant planets

The four outer, or Jovian, planers of our Solar System, which are significantly larger than the rest of the planets and consist largely of gas and/or ice

Moon

A sizable solid body locked in orbit around a planet

Asteroid

One of the fragments of solid material, left over from a planet formation or produced by collision of planetesimals, that resides between the orbits of Mars and Jupiter

Comet

A ball of ice and dust, probably remaining from the formation of the Solar System, that orbits the Sun

Expanding Universe Theory

The theory that the whole Universe must be expanding because galaxies in every direction seem to be moving away from us

Big bang theory

A theory suggested by scientists in which a cataclysmic explosion represents the formation of the Universe; before this event, all matter and all energy were packed into one volume-less point

Nuclear fusion

The process by which the nuclei of atoms fuse together, thereby creating new, larger atoms

Big bang Nucleosynthesis

The formation of new atomic nuclei (mostly hydrogen and helium) during the Big Bang

Nebula

A cloud of gas or dust in space

Vacuum

Space that contains very little matter in a given volume (e.g. a region in which air has been removed)

Thermal energy

The total kinetic energy in a material due to the vibration and movement of atoms in the material

Heat

Thermal energy resulting from the movement of molecules

Temperature

A measure of the hotness or coldness of a material

Accretion disk

A pancake-shaped accumulation of matter that forms as a nebula and then transforms into a star and its associated planets; the bulbous central zone of the accretion disk become the star

Protostar

A dense body of gas that is collapsing inward because of gravitational forces and that may eventually become a star

Supernova

A short-lived, very bright object in space that results from the cataclysmic explosion marking the death of a very large star; the explosion ejects large quantities of matter into space to form new nebulae

Stellar Nucleosynthesis

The production of new, larger atoms by fusion reactions in stars; the process generates more massive elements that were not produced by the Big Bang

stellar wind

The stream of atoms emitted from a star into space

Nebular theory of planet formation

The concept that planets grow out of rings of gas, dust, and ice, surrounding a newborn star

Protoplanetary disk

The plate-shaped region of gas and dust, surrounding the newborn Sun, from which the planets formed

volatiles (volatile materials)

Elements or compounds such as H2O and CO2 that evaporate at relatively low temperatures and can exist in gaseous forms at the Earth’s surface

Refractory materials

Substances that have a relatively high melting point and tend to exist in solid form

Planetesimal

Tiny, solid pieces of rock and metal that collect in a planetary nebula and eventually accumulate to form a planet

Protoplanet

A body that has green by the accumulation of planetesimals but has not yet become a planet

Differentiation (of a planet)

A process early in a planet’s history during which dense iron alloy melted and sank downward to form the core, leaving less dense mantle behind

Magnetic filed

The region affected by the force emanating from a magnet

Dipole

A magnetic field with a north and south pole, like that of a bar magnet

Magnetosphere

The region protected from the electrically charged particles of the solar winds by the Earth’s magnetic field

Earth system

the interacting assembly of physical and biological reservoirs and phenomena involving the solid earth, the hydrosphere, the atmosphere, and the biosphere

Groundwater

Water that resides under the surface of the earth, mostly in pores or cracks of rock or sediment

Hydrosphere

The earth’s water, including surface water (lakes, rivers, and oceans), groundwater, and liquid water in the atmosphere

Cryosphere

The realm of the earth system that consists of frozen water (ice); it includes glaciers, sea ice, and permafrost

Geosphere

In the context of the earth system, the solid part of the earth from the surface to the center

Topography

Variations in elevation

Bathymetry

Variations in depth

Earth materials

a general term for the great variety of substances that make up this planet

Organic chemical

A carbon-containing compound that occurs in living organisms, or that resembles such compounds; it consists of carbon atoms bonded to hydrogen atoms along with varying amounts of oxygen, nitrogen, and other chemicals

Mineral

A naturally occurring solid inorganic substance with a definable chemical composition and an internal structure characterized by an orderly arrangement of atoms, ions, or molecules in a lattice; most are inorganic

Crystal

A single, continuous piece of a mineral bounded by flat surfaces that formed naturally as the mineral grew

Glass

A solid in which atoms are not arranged in an orderly pattern

Melt

Molten (liquid) rock

Rock

A coherent, naturally occurring solid, consisting of an aggregate of minerals or a mass of glass

Grain

A fragment of a mineral crystals or of a rock

Sediment

An accumulation of loose mineral grains, such as boulders, pebbles, sand, silt, or mud, that are not cemented together

Metal

a solid composed almost entirely of atoms of metallic elements; it is generally opaque, shiny, smooth, malleable, and can conduct electricity

Silicate rock

rock composed of silicate minerals

Biosphere

The region of the earth and atmosphere inhabited by life; this region stretches from a few km below the earth’s surface to a few km above

meteor

A streak of bright, glowing, gas created as a meteoroid vaporizes in the atmosphere due to friction

meteorite

A piece of rock or metal alloy that fell from space and landed on the earth

Crust

The rock that makes up the outermost layer of the earth

Moho

The seismic-velocity discontinuity that defines the boundary between the earths crust and mantle

Mantle

The thick layer of rock below the earths crust and above the core

Core

The dense, iron-rich center of the earth

Continental drift

The hypothesis that continents have moved and are still moving slowly across the Earth’s surface

Mid-ocean ridge

A 2 km high submarine mountain belt that forms along a divergent oceanic plate boundary

Trench

A deep, elongated trough bordering a volcanic arc; a trench defines the trace of a convergent plate boundary

Volcanic arc

A curving chain of active volcanoes formed adjacent to a convergent plate boundary

Fracture zone

A narrow band of vertical fractures in the ocean floor; lie roughly at right angles to a mid-ocean ridge, and the actively slipping part is a transform fault

Seamount

An isolated submarine mountain

Seismic belts

The relatively narrow strips of crust on the earth at which most earthquakes occur

Seafloor spreading

the gradual widening of an ocean basin as new oceanic crust forms at a mid-ocean ridge axis and then moves away from the axis

Paleomagnetism

The record of ancient magnetism preserved in rock

Magnetic declination

The angle between the direction a compass needle points at a given location and the direction of true north