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237 terms

GeoPhysical Science

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astronomy
study of the universe
anticyclone
a high-pressure center characterized by a clockwise flow of air in the Northern Hemisphere
aphelion
the place in the orbit of a planet where the planet is farthest from the sun
apogee
the point where the moon is farthest from the Earth
apparent magnitude
the brightness of a star when viewed from Earth
aquifer
rock or soil throuugh which groundwater moves easily
astronomical unit (AU)
average distance from Earth to the sun
atmosphere
the gaseous portion of a planet; the planet's envelope of air;
aqueduct
a pipe or channel through which water flows from a higher elevation to a lower elevation
aurora
a bright display of ever changing light caused by solar radiation interacting with the upper atmosphere in the region of the poles
barometer
instrument that measures atmospheric pressure
big bang theory
the theory that proposes that the universe originated as a single mass, which subsequently exploded
binary star
one of two stars revolving around a common center of mass under their mutual gravitational attraction
biosphere
all life on Earth; the parts of the solid Earth, hydrosphere and atmosphere that living organisms can be found
black hole
massive star that has collapsed to such a small volume that its gravity prevents the escape of everything, including light
caldera
a large depression typically caused by collapse or ejection of the summit area of a volcano
cementation
solidification of sediments by the deposition of dissolved minerals in the tiny spaces between the sedimentary particles
chromosphere
the first layer of the solar atmosphere found directly aove the photosphere
cinder cone
a small volcano built primarily of pyroclastic material ejected from a singl vent
cleavage
tendency of a mineral to break along planes of weak bonding
cold front
a front along which a cold air mass thrusts beneath a warmer air mass
comet
a small body made of rocky and metallic pieces held together by frozen gases
compaction
process by which sediments are squeezed together by the weight of overlying materials driven out by water
condensation
the change of state from a gas to a liquid
conduction
the transfer of heat through matter by molecular activity; Energy is transferred through collisions from one molecule to another
conservation
the careful use of resources
constellation
an apparent group of stars originally named for mythical characters
contact metamorphism
changes in rock caused by the heat from a nearby magma body
continental drift
a hypothesis that originally proposed that the continents had once been joined to form a single supercontinent; the supercontinent broke into several pieces, which drifted to their present day positions
continuous spectrum
an uninterrupted band of light emitted by an incandescent solid, liquid or gas under pressure
convection
the transfer of heat by the movement of a mass or substance; it can take place only in fluids
convergent boundary
a boundary in which two plates move together
core
the innermost layer of Earth, located beneath the mantle
Coriolis Effect
the apparet deflective force of Earth's rotation on all free-moving objects, including the atmosphere and oceans; Deflection is to the right in the Northern Hemisphere and to the left in the Southern Hemisphere
Corona
the outer weak layer of the solar atmosphere
crater
the depression at the summit of a volcano or that which is produced by a meteorite impact
cross-cutting relationships, principle of
principle of relative dating; a rock or fault is younger than any rock or fault through which it cuts
crust
the thin, outer layer of Earth
crystal form
the external appearance of a mineral as determined by its internal arrangement of atoms
cyclone
a low-pressure center characterized by a counter-clockwise flow of air in the Northern Hemisphere
deformation
general term for the processes of folding, faulting, shearing, compression, or extension of rocks as the result of various natural forces
density
mass per unit volume of a substance, usually expressed as grams per cubic centimeter
deposition
the process by which an agent of erosion loses energy and drops the sediment it is carrying;
divergent boundary
a region where the rigid plates are moving apart, typified by the oceanic ridges
Doppler effect
the apparent change in frequency of electromagnetic or sound waves caused by the relative motions of the source and the observer
earthquake
the vibration of Earth produced by the rapid release of energy
Doppler effect
the apparent change in frequency of electromagnetic or sound waves caused by the relative motions of the source and the observer
elastic rebound hypothesis
the explanation stating that when rocks are deformed, they break, releasing the stored energy that results in the vibrations of an earthquake
contour lines
lines on a topographic map that indicates an elevation
contour interval
on a topographic map, tells the distance in elevation between adjacent contour lines
Earth Science
the name for all the sciences that collectively seek to understand Earth; it includes geology, oceanography, meteorology,
electromagnetic spectrum
the arrangement of electromagnetic radiation according to wavelength
ellipse
an oval
El Nino
the name given to the periodic warming of the ocean that occurs in the central and eastern Pacific
emission spectrum
a series of bright lines of particular wavelengths produced by a hot gas under low pressure
epicenter
the location on Earth's surface directly above the focus, or origin, of an earthquake
erosion
the incorporation and transportation of material by a mobile agent, such as water, wind, or ice
evaporation
the process of converting a liquid to a gas
extrusive igneous rock
igneous rock that has formed on Earth's surface
fault
a fracture in Earth along which movement has occurred
fault-block mountain
a mountain formed when large blocks of crust are tilted, uplifted or dropped between large normal faults
flood
occurs when the discharge of a stream becomes so great that it exceeds the carrying capacity of its channel and overflows its banks
focus
the point within Earth where an earthquake originates
folded mountain
a mountain created primarily by compressional stresses, which create folds in the rock layers
foliated metamorphic rock
a metamorphic rock with a texture that gives the rock a layered appearance
foreshock
a small earthquake that often proceeds a major earthquake
fossil
the remains or traces of an organism preserved from the geologic past
fossil fuel
general term for any hydrocarbon that may be used as a fuel, including coal, oil, and natural gas
fracture
any break or rupture in rock along which no appreciable movement has taken place
front
the boundary between two adjoining air masses having contrasting characteristics
frost wedging
the mechanical breakup of rock caused by the expansion of freezing water in cracks and crevices
galaxy
a group of stars, dust, and gases held together by gravity
galaxy cluster
a system of galaxies containing from several to thousands of member galaxies
geocentric
describes the concept of an Earth-centered universe
geology
the science that examines the Earth, its form and composition, and the changes it has undergone and is undergoing
geosphere
layer of Earth under both the atmosphere and the oceans; composed of the core, mantle and crust
geothermal energy
energy that can be extracted from Earth's internal heat, for example, natural steam used for power generation
geothermal field
an area of land where magma lies relatively close to the surface and heats the groundwater
geothermal gradient
the gradual increase in temperature with depth in the crust
global warming
the increase in average temperatures of Earth and the atmosphere due in part to increase carbon dioxide levels
gradient
the slope of a stream over a certain distance
granitic composition
a compositional group of igneous rocks that indicate a rock is composed almost entirely of light-colored silicates, mainly quartz and feldspar
greenhouse effect
the heating of Earth's surface and atmosphere from solar radiation being absorbed and emitted by the atmosphere, mainly by water vapor and carbon dioxide
groundwater
water underground in the zone of saturation
hardness
the resistance a mineral offers to scratching
heliocentric
describes the view that the sun is at the center of the solar system
heat
thermal energy transferred from one object to another
hot spot
a concentration of heat in the mantle capable of producing magma, which rises to Earth's surface; The Pacific Plate moves over a hot spot, producing the Hawaiian Islands
H-R Diagram
a plot of stars according to their absolute magnitudes and temperatures
Hubble's Law
a law that states that the galaxies are retreating from the Milky Way at a speed that is proportional to their distance
humidity
a general term referring to water vapor in the air but not to liquid droplets of fog, cloud, or rain
humid subtropical climate
a climate generally located on the eastern side of a continent and characterized by hot, sultry summers and cool winters
hurricane
a tropical cyclonic storm having winds in excess of 119km per hour
hydrogenous sediment
seafloor sediment consisting of minerals that crystallize from seawater
hydrosphere
the water portion of Earth; one of the traditional subdivisions of Earth's physical environment
hydrothermal solution
the hot, watery solution that escapes from a mass of magma during the later stages of crystallization; such solutions may alter the surrounding rock
hypothesis
a tentative explanation that is tested to determine if it is valid
igneous rock
a rock formed by the crystallization of molten magma
infiltration
the movement of surface water into rock or soil through cracks or pore spaces
inner core
the solid innermost layer of Earth
intertidal zone
the area where land and sea meet and overlap; the zone between high and low tides
intraplate volcanism
igneous activity that occurs within a tectonic plate away from plate boundaries
intrusive igneous rock
igneous rock formed below Earth's surface
jet stream
swift, high altitude winds
Jovian planet
the Jupiter like planets; Jupiter, Saturn, Uranus, and Neptune. These planets have relatively low densities and are huge gas giants
Koppen Classification System
a system for classifying climates based on mean monthly and annual values of temperature and precipitation
laccolith
a massive igneous body intruded between preexisting strata
latitude
the distance north or south of the equator, measured in degrees
lava
magma that reaches Earth's surface
light-year
the distance light travels in a year, about 9.5 trillion km
liquefaction
a phenomenon, sometimes associated with earthquakes, in which soils and other unconsolidated materials saturated with water are turned into a liquid that is not able to support buildings
lithosphere
the rigid outer layer of earth, including the crust and upper mantle
longitude
the distance east or west of the prime meridian, measured in degrees
lunar eclipse
an eclipse of the moon; occurs when the moon passes through Earth's shadow
lunar regolith
a thin. gray layer on the surface of the moon, consisting of loosely compacted, fragmented material believed to have formed by repeated impacts of meteorites
luster
the appearance or quality of light reflected from the surface of a mineral
magma
a body of molten rock found at depth, including any dissolved gases and crystals
main-sequence star
a star that falls into the main sequence category on the H-R diagram; this category contains the majority of stars and runs diagonally from the upper left to the lower right on the H-R diagram
mantle
layer of Earth located below the crust
mass movement
the downslope movement of rock, regolith and soil under the direct influence of gravity
mechanical weathering
the physical disintegration of rock, resulting in smaller fragments
mesosphere
the layer of the atmosphere immediately above the stratosphere and characterized by decreasing temperatures with height
metamorphic rock
rock formed by the alteration of pre-existing rock deep within the Earth (but still in the solid state) by heat, pressure, and/or chemically active fluids
metamorphism
the changes in mineral composition and texture of a rock subjected to high temperature and pressure within Earth
meteor
the luminous phenomenon observed when a meteoroid enters Earth's atmosphere and burns up, popularly called a shooting star
meteorite
any portion of a meteoroid that reaches Earth's surface
mineral
a naturally occurring, inorganic crystalline material with a unique chemical composition
Mohs Scale
a series of 10 minerals used as a standard in determining hardness
moment magnitude
a more precise measure of earthquake magnitude than the Richter scale, which is derived from the amount of displacement that occurs along a fault zone and estimates the energy released by an earthquake
monsoon
seasonal reversal of wind direction associated with large continents, especially Asia;
mudflow
quickly moving downhill flow of soil and rock fragments containing a large amount of water
natural hazard
an event that results from Earth processes that can cause damage and endanger human life
nebula
a cloud of gas and/or dust in space
neutron star
a star of extremely high density composed entirely of neutrons
nonfoliated metamorphic rock
metamorphic rock that does not exhibit a banded or layered appearance
nonrenewable resource
resource that takes millions of years to form
normal fault
a fault in which the rock above the fault plane has moved down relative to the rock below
normal polarity
a magnetic field that is the same as that which exists at present
nova
a star that explosively increases in brightness
nuclear fusion
the way in which the sun produces energy;
ocean current
mass of ocean water that flows from one place to another
oceanic ridge
a continuous elevated zone on the floor of all the major ocean basins and varying in width from 1000-4000km; the rifts at the crests represent divergent plate boundaries
oceanography
the scientific study of the oceans and oceanic phenomena
ore
a material from which a useful mineral or minerals can be mined for profit
original horizontality, principle of
a principle of relative dating; Layers of sediments are generally deposited in a horizontal or nearly horizontal position.
orogenesis
the processes that collectively result in the formation of mountains
ozone
a molecule of oxygen containing three oxygen atoms
P wave
earthquake wave that pushes and pulls rocks in the direction of the wave; also known as a compression wave
paleomagnetism
the study of changes in Earth's magnetic field, as shown by patterns of magnetism in rocks that have formed over time
Pangaea
the proposed supercontinent that 200 million years ago began to break apart and form the present landmasses
perigee
the point at which the moon is closest to the Earth
perihelion
the point in the orbit of a planet where it is closest to the sun
phases of the moon
the progression of changes in the moon's appearance during the month
photon
a small packet of light energy
photosphere
the region of the sun that radiates energy into space; visible surface of the sun
photosynthesis
the process by which plants, algae, and certain prokaryotes use light energy to convert water and carbon dioxide into energy rich glucose molecules
planetesimal
small, irregularly shaped body formed by colliding matter
plate
one of numerous rigid section of the lithosphere that moves as a unit over the material of the asthenosphere
plate tectonics
the theory that proposes that Earth's outer shell consists of individual plates that interact in various ways and thereby produce earthquakes, volcanoes, mountains and the crust itself.
pluton
an intrusive igneous structure that results from the cooling and hardening of magma beneath the surface of Earth
polar easterlies
in the global pattern of prevailing winds, winds that blow from the polar high toward the polar low;
polar front
a stormy frontal zone separating cold air masses of polar origin from warm air masses of tropical origin
polar zone
the region between 66.5 degrees north and south latitudes and the poles; the sun's rays strike at a very small angle in the polar zone
porosity
the volume of open spaces in rock or soil
precession
a slow motion of Earth's axis that traces out a cone over a period of 26,000 years
precipitation
any form of water that falls from a cloud
pressure gradient
the amount of pressure change occurring over a given distance
prevailing wind
a wind that consistently blows from one direction more than from another
prominence
a concentration of gases above the solar surface that appears as a bright archlike structure
protostar
a collapsing cloud of dust and gas destined to become a star; a developing star not yet hot enough to engage in nuclear fusion
pulsar
a variable radio source of small size that emits radio pulses in very regular periods
pyroclastic material
the volcanic rock ejected during an eruption, including, ash, bombs, and blocks
radiation
the transfer of energy (heat) through space by electromagnetic waves
radioactivity
the spontaneous decay of certain unstable atomic nuclei
radio telescope
a telescope designed to make observations in radio wavelengths
ray
any of a system of bright elongated streaks, sometimes associated with a crater on the moon
red giant
a large, cool star of high luminosity; a star occupying the upper right portion of the H-R diagram
reflecting telescope
a telescope that concentrates light from distant objects by using a concave mirror
reflection
the process whereby light bounces back from an object at the same angle at which it encounters a surface and with the same intensity
refracting telescope
a telescope that uses a lens to bend and concentrate the light from distant objects
regional metamorphism
metamorphism associated with large-scale mountain-building processes
regolith
the layer of rock and mineral fragments that nearly everywhere covers Earth's surface
relative dating
process by which rocks are placed in their proper sequence or order; Only the chronological order of events is determined, not the absolute age in years
renewable resource
a resource that is virtually inexhaustible or that can be replenished over relatively short time spans
reservoir rocks
porous rocks in which oil collects and becomes trapped
retrograde motion
the apparent westward motion of the planets with respect to the stars
reverse fault
a fault in which the material above the fault plane moves up in relation to the material below
reverse polarity
a magnetic field opposite to that which exists at present
revolution
the motion of one body about another, as Earth about the sun
ridge-push
a mechanism that may contribute to plate motion; it involves the oceanic lithosphere sliding down the oceanic ridge under the pull of gravity
rift valley
deep faulted structure found along the axes of divergent plate boundaries; can develop on seafloor or on land
rille
long channel associated with lunar maria
rock
a consolidated mixture of minerals
rock cycle
a model that illustrates the origin of the three basic rock types and the interrelatedness of Earth materials and processes
rotation
the spinning of a body, such as Earth, about its axis
runoff
water the flows over the land surface rather than seeping into the ground
S wave
a seismic wave that shakes particles perpendicular to the direction the wave is traveling
salinity
the proportion of dissolved salts to pure water, usually expressed in parts per thousand
scattering
the redirecting (in all directions) of light by small particles and gas molecules in the atmosphere; the result is more light rays with weaker intensity
seafloor spreading
the process by which plate tectonics produces new oceanic lithosphere at ocean ridges
sediment
loose particles created by the weathering and erosion of rock, by chemical precipitation from solution in water, or from the secretions of organisms and transported by water, wind, or glaciers
sedimentary rock
rock formed from the weathered products of preexisting rocks that have been transported, deposited, compacted and cemented
seismic gap
an area along a fault where there has not been any earthquake activity for a long period of time
seismic shaking
a measure of how much ground movement occurs during and earthquake
seismogram
the record made by a seismograph
seismograph
an instrument that records earthquake waves
shield
a large, relatively flat expanse of ancient metamorphic rock within the stable continental interior
shield volcano
a broad, gently sloping volcano built from fluid basaltic lava
silicate
any one of numerous minerals that have the oxygen and silicon tetrahedron as their basic structure
sinkhole
a depression produced in a region where soluble rock has been removed by groundwater
slab-pull
a mechanism that contributes to plate motion in which cool, dense oceanic crust sinks into the mantle and "pulls" the trailing lithosphere along
soil
a combination of mineral and organic matter, water, and air; that portion of the regolith that supports plant life
solar eclipse
an eclipse of the sun; a solar eclipse occurs when the moon moves in a line directly between Earth and the sun, casting a shadow on earth
solar flare
a sudden and tremendous eruption in the solar chromosphere
solar wind
streams of protons and electrons ejected at high speed from the solar corona
source rocks
rocks in which oil forms
spectroscopy
the study of the properties of light that depend on wavelength
stratosphere
the layer of the atmosphere immediately above the troposphere, characterized by increasing temperatures with height, due to the concentration of ozone
streak
the color of a mineral in powdered form
stress
the force per unit area acting on a solid
strike-slip fault
a fault along which the movement is horizontal and parallel to the trend of the fault
stalacite
an icicle-like structure that hangs from the ceiling of a cavern
stalagmite
a columnlike form that grows upward from the floor of the cavern
subarctic climate
climate found north of the humid continental climate and south of the polar climate; characterized by bitterly cold winters and short cool summers
subduction zone
a destructive plate margin where oceanic crust is being pushed down into the mantle beneath a second plate
sublimation
the conversion of a solid directly to a gas without passing through the liquid state
sunspot
a dark spot on the sun, which is cool by contrast to the surrounding photosphere
supergiant
a very large, very bright red giant star
supernova
an exploding star that increases in brightness many 1000s of times
superposition, law of
a law that states that in any undeformed sequence of sedimentary rocks, each bed is older than the layers above and younger than the layers below
surface current
movement of water that flows horizontally in the upper part of the ocean's surface
surface wave
a seismic wave that travels along the surface of the Earth
system
any size group of interacting parts that form a complex whole
temperate zone
region located between 23.5 degrees and 66.5 degrees north and south of the equator
temperature
a measure of the average kinetic energy of individual atoms or molecules in a substance
temperature inversion
a layer of limited depth in the atmosphere of limited depth where the temperature increases rather than decreases with height
terrane
a crustal block bounded by faults, whose geologic history is distinct from the histories of adjoining crustal blocks