Term
|
Definition
One of many millions of small, rocky, and/or metallic objects that
orbit the Sun, consisting of fragments of once-larger
planetesimals, or chunks of protoplanetary material; most lie in the
region between Mars and Jupiter. |
|
|
Term
|
Definition
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. |
|
|
Term
|
Definition
| A layer of gases that surrounds a planet. |
|
|
Term
|
Definition
|
|
Term
|
Definition
A cataclysmic explosion that scientists suggest represents the
formation of the Universe; before this event, all matter and all
energy were packed into one volumeless point. |
|
|
Term
|
Definition
A ball of ice and dust, probably remaining from the formation of the
Solar System, that orbits the Sun. |
|
|
Term
|
Definition
| The dense, iron-rich center of the Earth |
|
|
Term
|
Definition
| The study of the overall structure of the Universe. |
|
|
Term
|
Definition
| The rock that makes up the outermost layer of the Earth. |
|
|
Term
|
Definition
In the context of planet formation, the process by which a planet
separates into a metallic core and a rocky mantle very early in its
history. |
|
|
Term
|
Definition
A vibration caused by the sudden breaking or frictional sliding of
rock in the Earth. |
|
|
Term
|
Definition
The global interconnecting web of physical and biological
phenomena involving the solid Earth, the hydrosphere, and the
atmosphere. |
|
|
Term
| expanding Universe theory |
|
Definition
The theory that the whole Universe must be expanding because
galaxies in every direction seem to be moving away from us. |
|
|
Term
|
Definition
| A fracture on which one body of rock slides past another. |
|
|
Term
|
Definition
| An immense system of hundreds of billions of stars. |
|
|
Term
|
Definition
The outer planets (Jupiter, Saturn, Uranus, Neptune) that are very
large and consist mostly of volatile elements. |
|
|
Term
|
Definition
| The rate of change in temperature with depth. |
|
|
Term
|
Definition
| A solid in which atoms are not arranged in an orderly pattern. |
|
|
Term
|
Definition
Water that resides under the surface of the Earth, mostly in pores
or cracks of rock or sediment. |
|
|
Term
|
Definition
The relatively rigid, non-flowable, outer 100- to 150-km-thick layer
of the Earth; constituting the crust and the top part of the mantle. |
|
|
Term
|
Definition
The deepest section of the mantle, stretching from 670 km down to
the core-mantle boundary. |
|
|
Term
|
Definition
| The region affected by the force emanating from a magnet. |
|
|
Term
|
Definition
The thick layer of rock below the Earthصs crust and above the
core. |
|
|
Term
|
Definition
|
|
Term
|
Definition
A solid composed almost entirely of atoms of metallic elements; it
is generally opaque, shiny, smooth, and malleable, and can
conduct electricity. |
|
|
Term
|
Definition
An object that has entered a planetصs atmosphere and is glowing
and evaporating as it streaks to the planetصs surface. |
|
|
Term
|
Definition
A piece of rock or metal alloy that fell from space and landed on
Earth. |
|
|
Term
|
Definition
A homogenous, 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 minerals are inorganic. |
|
|
Term
|
Definition
The seismic-velocity discontinuity that defines the boundary
between the Earthصs crust and mantle. |
|
|
Term
|
Definition
| A solid object of ice and/or rock and metal that orbits a planet. |
|
|
Term
|
Definition
| A cloud of gas or dust in space. |
|
|
Term
|
Definition
The concept that planets grow out of rings of gas, dust, and ice
surrounding a new-born star. |
|
|
Term
|
Definition
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. |
|
|
Term
|
Definition
A relatively large, spherical object that orbits a star and has
cleared its orbit of most debris. |
|
|
Term
|
Definition
| Tiny, solid pieces of rock and metal that collect in a planetary nebula and eventually accumulate to form a planet. |
|
|
Term
|
Definition
A body that grows by the accumulation of planetesimals but has
not yet become big enough to be called a planet |
|
|
Term
|
Definition
The flattened cloud of dust, gas, and ice that orbits a nascent star
prior to the formation of planets. |
|
|
Term
|
Definition
A dense body of gas that is collapsing inward because of
gravitational forces and that may eventually become a star. |
|
|
Term
|
Definition
The phenomenon in which a source of light moving away from you
very rapidly shifts to a lower frequency; that is, toward the red end
of the spectrum |
|
|
Term
|
Definition
A coherent, naturally occurring solid, consisting of an aggregate of
minerals or a mass of glass. |
|
|
Term
|
Definition
An accumulation of loose mineral grains, such as boulders,
pebbles, sand, silt, or mud, that are not cemented together. |
|
|
Term
|
Definition
The Sun and all the objects that orbit it (including planets, moons,
comets, and asteroids |
|
|
Term
|
Definition
A large sphere, composed dominantly of hydrogen and helium, in
which fusion reactions are producing energy. |
|
|
Term
|
Definition
Particles that have been ejected from a star and are shooting
through space. |
|
|
Term
|
Definition
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. |
|
|
Term
|
Definition
|
|
Term
|
Definition
The middle portion of the mantle, from 400 to 670 km deep, in
which there are several jumps in seismic velocity. |
|
|
Term
|
Definition
The sum of all matter and energy making up the hundreds of
billions of known galaxies |
|
|
Term
|
Definition
The uppermost section of the mantle, reaching down to a depth of
400 km |
|
|
Term
|
Definition
Space that contains very little matter in a given volume (e.g., a
region in which air has been removed) |
|
|
Term
|
Definition
A means of transmitting energy from one location to another;
waves can be vibrations that propagate through a material, or
undulations of electromagnetic fields that can propagate either
through a material or in a vacuum. |
|
|
Term
|
Definition
The horizontal difference between two adjacent wave troughs or
two adjacent crests. |
|
|
Term
|
Definition
| The movement of a plate relative to a fixed point in the mantle. |
|
|
Term
|
Definition
A broad, relatively fl at region of the ocean that lies at least 4.5
km below sea level. |
|
|
Term
|
Definition
| A continental margin that coincides with a plate boundary. |
|
|
Term
| apparent polarwander path |
|
Definition
A path on the globe along which a magnetic pole appears to
have wandered over time; in fact, the continents drift, while the
magnetic pole stays fairly fixed. |
|
|
Term
|
Definition
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. |
|
|
Term
|
Definition
The cloud of suspended minerals formed where hot water spews
out of a vent along a mid-ocean ridge; the dissolved sulfide
components of the hot water instantly precipitate when the water
mixes with seawater and cools. |
|
|
Term
|
Definition
The process of two buoyant pieces of lithosphere converging
and squashing together. |
|
|
Term
continental drift
hypothesis |
|
Definition
The idea that continents have moved and are still moving slowly
across the Earth's surface |
|
|
Term
|
Definition
A linear belt along which continental lithosphere stretches and
pulls apart. |
|
|
Term
|
Definition
A boundary at which two plates move toward each other so that
one plate sinks (subducts) beneath the other; only oceanic
lithosphere can subduct |
|
|
Term
|
Definition
A boundary at which two lithosphere plates move apart from
each other; they are marked by mid-ocean ridges. |
|
|
Term
|
Definition
A narrow band of vertical fractures in the ocean floor; fracture
zones lie roughly at right angles to a mid-ocean ridge, and the
actively slipping part of a fracture zone is a transform fault |
|
|
Term
global
positioning
system (GPS) |
|
Definition
A satellite system people can use to measure rates of movement
of the Earth's crust relative to one another, or simply to locate
their position on the Earth's surface. |
|
|
Term
|
Definition
A location at the base of the lithosphere, at the top of a mantle
plume, where temperatures can cause melting. |
|
|
Term
|
Definition
A chain of now-dead volcanoes transported off the hot spot by
the movement of a lithosphere plate. |
|
|
Term
|
Definition
The relatively rigid, nonflowable, outer 100- to 150-km-thick layer
of the Earth; constituting the crust and the top part of the mantle. |
|
|
Term
|
Definition
A portion of the outer, relatively rigid layer of the Earth; most
seismic activity happens at the boundaries of plates, while the
interior of a plate is relatively stable. |
|
|
Term
|
Definition
The difference between the expected strength of the Earth's
magnetic field at a certain location and the actual measured
strength of the field at that location. |
|
|
Term
|
Definition
The angle between the direction a compass needle points at a
given location and the direction of true north. |
|
|
Term
|
Definition
| A magnetic entity that has a north and south end. |
|
|
Term
|
Definition
The angle between a magnetic needle free to pivot on a
horizontal axis and a horizontal plane parallel to the Earth's
surface. |
|
|
Term
|
Definition
The north or south ends of a magnet; field lines point straight
down at the pole. |
|
|
Term
|
Definition
The change of the Earth's magnetic polarity; when a reversal
occurs, the field flips from normal to reversed polarity, or vice
versa. |
|
|
Term
magneticreversal
chronology |
|
Definition
| The history of magnetic reversals through geologic time. |
|
|
Term
|
Definition
| A column of very hot rock rising up through the mantle. |
|
|
Term
|
Definition
An unusually strong or unusually weak magnetic field, as
measured over the sea floor; in map view, they look like stripes
that are parallel to the mid-ocean ridge. |
|
|
Term
|
Definition
A 2-km-high submarine mountain belt that forms along a
divergent oceanic plate boundary. |
|
|
Term
|
Definition
| The record of ancient magnetism preserved in rock. |
|
|
Term
|
Definition
The supposed position of the Earth's magnetic pole in the past,
with respect to a particular continent. |
|
|
Term
|
Definition
A supercontinent that assembled at the end of the Paleozoic
Era. |
|
|
Term
|
Definition
A thick accumulation of sediment along a tectonically inactive
coast, formed over crust that stretched and thinned when the
margin first began. |
|
|
Term
|
Definition
One of about twenty distinct pieces of the relatively rigid
lithosphere. |
|
|
Term
|
Definition
| The border between two adjacent lithosphere plates. |
|
|
Term
|
Definition
| The movement of one lithosphere plate with respect to another. |
|
|
Term
|
Definition
The force that drives plates away from a mid-ocean ridge; it is
caused by the fact that the ridge is elevated relative to the
regions of oceanic plate away from the ridge. |
|
|
Term
|
Definition
The process by which continental lithosphere stretches and
breaks apart; rifting produces normal faults and, commonly,
volcanism. |
|
|
Term
|
Definition
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. |
|
|
Term
|
Definition
| An isolated submarine mountain. |
|
|
Term
|
Definition
The force that downgoing plates (or slabs) apply to oceanic
lithosphere at a convergent margin. |
|
|
Term
|
Definition
The process by which one oceanic plate bends and sinks down
into the asthenosphere beneath another plate. |
|
|
Term
|
Definition
A boundary at which one lithosphere plate slips laterally past
another. |
|
|
Term
|
Definition
A deep elongate trough bordering a volcanic arc; a trench
defines the trace of a convergent plate boundary. |
|
|
Term
|
Definition
| A point where three lithosphere plate boundaries intersect. |
|
|
Term
|
Definition
A curving chain of active volcanoes formed adjacent to a
convergent plate boundary. |
|
|
Term
|
Definition
A sloping band of seismicity defined by intermediate- and deepfocus earthquakes that occur in the downgoing slab of a
convergent plate boundary. |
|
|
Term
|
Definition
| Rocks containing calcite and/or dolomite. |
|
|
Term
|
Definition
1) The tendency of a mineral to break along preferred planes; (2) a
type of foliation in low-grade metamorphic rock. |
|
|
Term
|
Definition
Smoothly curving, clamshell-shaped surfaces along which materials
with no cleavage planes tend to break. |
|
|
Term
|
Definition
A single, continuous piece of a mineral bounded by flat surfaces that
formed naturally as the mineral grew. |
|
|
Term
|
Definition
| The flat surface of an euhedral mineral grain. |
|
|
Term
|
Definition
The general shape of a crystal or cluster of crystals that grew
unimpeded. |
|
|
Term
|
Definition
The orderly framework within which the atoms or ions of a mineral are
fixed. |
|
|
Term
|
Definition
| The internal arrangement of atoms or ions within a crystal. |
|
|
Term
|
Definition
| The flat surface of a cut gemstone; facets are produced by grinding. |
|
|
Term
|
Definition
A mineral or form of a mineral that is particularly beautiful and/or rare,
and thus has value. |
|
|
Term
|
Definition
A cavity in which euhedral crystals precipitate out of water solutions
passing through a rock. |
|
|
Term
|
Definition
In mineralogy, hardness refers to the resistance of a mineral to
scratching; a harder mineral can scratch a softer mineral. |
|
|
Term
|
Definition
| The way a mineral surface scatters light. |
|
|
Term
|
Definition
A homogenous, 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 minerals are inorganic. |
|
|
Term
|
Definition
|
|
Term
|
Definition
A list of ten minerals in a sequence of relative hardness, with which
other minerals can be compared. |
|
|
Term
|
Definition
Two minerals that have the same chemical composition but a different
crystal lattice structure. |
|
|
Term
|
Definition
Minerals composed of silicon-oxygen tetrahedra linked in various
arrangements; most contain other elements as well. |
|
|
Term
|
Definition
The basic building block of silicate minerals; it consists of one silicon
atom surrounded by four oxygen atoms |
|
|
Term
|
Definition
A number representing the density of a mineral, as specified by the
ratio between the weight of a volume of the mineral and the weight of
an equal volume of water. |
|
|
Term
|
Definition
The color of the powder produced by pulverizing a mineral on an
unglazed ceramic plate. |
|
|
Term
|
Definition
The condition in which the shape of one part of an object is a mirror
image of the other part. |
|
|
Term
|
Definition
The process of magma contamination in which blocks of wall rock
fall into a magma chamber and dissolve. |
|
|
Term
|
Definition
A vast composite, intrusive, igneous rock body up to several
hundred kilometers long and 100 km wide, formed by the intrusion of
numerous plutons in the same region. |
|
|
Term
|
Definition
The sequence in which different silicate minerals crystallize during
the progressive cooling of a melt. |
|
|
Term
|
Definition
A rock that solidifies from a melt and consists of interlocking
crystals. |
|
|
Term
|
Definition
A tabular (wall-shaped) intrusion of rock that cuts across the layering
of country rock. |
|
|
Term
|
Definition
Rock that forms by the freezing of lava above ground, after it flows or
explodes out (extrudes) onto the surface and comes into contact
with the atmosphere or ocean. |
|
|
Term
fractional
crystallization |
|
Definition
The process by which magma becomes progressively more silicic
as it cools, because early-formed crystals settle out. |
|
|
Term
|
Definition
Fragments of igneous material that have been stuck together to form
a coherent mass |
|
|
Term
|
Definition
| The change in temperature with depth in the Earth. |
|
|
Term
|
Definition
Igneous rock consisting entirely of glass, or of tiny crystals
surrounded by a glass matrix. |
|
|
Term
|
Definition
Rock that forms when hot molten rock (magma or lava) cools and
freezes solid. |
|
|
Term
|
Definition
| Rock formed by the freezing of magma underground. |
|
|
Term
|
Definition
| A shallow igneous intrusion that has a blister-like shape. |
|
|
Term
|
Definition
| Molten rock that has flowed out onto the Earthصs surface. |
|
|
Term
|
Definition
Sheets or mounds of lava that flow onto the ground surface or sea
floor in molten form and then solidify. |
|
|
Term
|
Definition
| Molten rock beneath the Earthصs surface. |
|
|
Term
|
Definition
| An igneous rock consisting of a solid mass of volcanic glass. |
|
|
Term
|
Definition
| The melting in a rock of the minerals with the lowest melting temperatures, while other minerals remain solid. |
|
|
Term
|
Definition
A coarse-grained igneous rock containing crystals of up to tens of
centimeters across and occurring in dike-shaped intrusions. |
|
|
Term
|
Definition
An irregular or blob-shaped intrusion; can range in size from tens of
meters across to tens of kilometers across. |
|
|
Term
|
Definition
A glassy igneous rock that forms from felsic frothy lava and contains
abundant (over 50%) pore space. |
|
|
Term
|
Definition
Rock made from fragments blown out of a volcano during an
explosion that were then packed or welded together. |
|
|
Term
|
Definition
| A glassy mafic igneous rock containing abundant air-filled holes. |
|
|
Term
|
Definition
A nearly horizontal table-top-shaped tabular intrusion that occurs
between the layers of country rock. |
|
|
Term
|
Definition
A process by which magma intrudes; blocks of wall rock break off
and then sink into the magma. |
|
|
Term
|
Definition
A pyroclastic igneous rock composed of volcanic ash and
fragmented pumice, formed when accumulations of the debris
cement together. |
|
|
Term
|
Definition
Open holes in igneous rock formed by the preservation of bubbles in
magma as the magma cools into solid rock. |
|
|
Term
|
Definition
Tiny glass shards formed when a fine spray of exploded lava freezes
instantly upon contact with the atmosphere. |
|
|
Term
|
Definition
A rock composed of angular chunks of volcanic debris that have
been cemented together. |
|
|
Term
|
Definition
(1) A vent from which melt from inside the Earth spews out onto the
planetصs surface; (2) a mountain formed by the accumulation of
extrusive volcanic rock. |
|
|
Term
|
Definition
A relict of wall rock surrounded by intrusive rock when the intrusive
rock freezes. |
|
|
Term
|
Definition
| A lava flow with a rubbly surface. |
|
|
Term
|
Definition
A volcano that has erupted within the past few centuries and will
likely erupt again. |
|
|
Term
|
Definition
| Ash that falls to the ground out of an ash cloud. |
|
|
Term
|
Definition
In the context of igneous materials, a block is a chunk of igneous
rock blasted out of a volcano. |
|
|
Term
|
Definition
A frozen blob of rock formed when magma ejected from a volcano
freezes in flight; bombs are typically streamlined. |
|
|
Term
|
Definition
A large circular depression with steep walls and a fairly flat floor,
formed after an eruption as the center of the volcano collapses into
the drained magma chamber below. |
|
|
Term
|
Definition
A subaerial volcano consisting of a cone-shaped pile of tephra
whose slope approaches the angle of repose for tephra. |
|
|
Term
|
Definition
A type of fracturing that yields roughly hexagonal columns of basalt;
columnar joints form when a dike, sill, or lava flow cools. |
|
|
Term
|
Definition
(1) A circular depression at the top of a volcanic mound; (2) a
depression formed by the impact of a meteorite. |
|
|
Term
|
Definition
A volcano that has not erupted for hundreds to thousands of years
but does have the potential to erupt again in the future. |
|
|
Term
|
Definition
| An eruption that yields mostly lava, not ash. |
|
|
Term
|
Definition
Violent volcanic eruption that produces clouds and avalanches of
pyroclastic debris. |
|
|
Term
|
Definition
A volcano that was active in the past but has now shut off entirely
and will not erupt in the future. |
|
|
Term
|
Definition
A line of damage formed in the crystal lattice of a mineral by the
impact of an atomic particle ejected during the decay of a
radioactive isotope. |
|
|
Term
|
Definition
Vast sheets of basalt that spread from a volcanic vent over an
extensive surface of land; they may form where a rift develops above
a continental hot spot, and where lava is particularly hot and has low
viscosity. |
|
|
Term
|
Definition
| Rock formed when deposits of pyroclactic flows solidify. |
|
|
Term
|
Definition
A thick slurry formed when volcanic ash and debris mix with water,
either in rivers or from rain or melting snow and ice on the flank of a
volcano. |
|
|
Term
|
Definition
| Marble-to-plum-sized fragments of pyroclastic debris |
|
|
Term
|
Definition
The empty space left when a lava tunnel drains; this happens when
the surface of a lava flow solidifies while the inner part of the flow
continues to stream downslope. |
|
|
Term
|
Definition
| A space below ground filled with magma. |
|
|
Term
|
Definition
| A lava flow with a surface texture of smooth, glassy, rope-like ridges |
|
|
Term
|
Definition
Fragmented material that sprayed out of a volcano and landed on
the ground or sea floor in solid form. |
|
|
Term
|
Definition
A fast-moving avalanche that occurs when hot volcanic ash and
debris mix with air and flow down the side of a volcano. |
|
|
Term
|
Definition
A subaerial volcano with a broad, gentle dome, formed either from
low-viscosity basaltic lava or from large pyroclastic sheets. |
|
|
Term
|
Definition
A large, cone-shaped subaerial volcano consisting of alternating
layers of lava and tephra. |
|
|
Term
|
Definition
| Unconsolidated accumulations of pyroclastic grains. |
|
|
Term
|
Definition
A pyroclastic igneous rock composed of volcanic ash and
fragmented pumice, formed when accumulations of the debris
cement together. |
|
|
Term
|
Definition
Open holes in igneous rock formed by the preservation of bubbles in
magma as the magma cools into solid rock |
|
|
Term
|
Definition
A mixture of water and clasts of volcanic material that moves down
the slope of a volcano. |
|
|
Term
|
Definition
A layer composed of fragments of igneous material (e.g., tephra,
ash, bombs) erupted from volcanoes. |
|
|
Term
|
Definition
1) A vent from which melt from inside the Earth spews out onto the
planet's surface; (2) a mountain formed by the accumulation of
extrusive volcanic rock. |
|
|
Term
|
Definition
A clastic sedimentary rock composed of sand-sized grains that
include quartz and feldspar. |
|
|
Term
|
Definition
| A distinct layer of sedimentary strata. |
|
|
Term
biochemical
sedimentary
rock |
|
Definition
Sedimentary rock formed from material (such as shells) produced
by living organisms. |
|
|
Term
|
Definition
Coarse sedimentary rock consisting of angular fragments; or rock
broken into angular fragments by faulting. |
|
|
Term
|
Definition
The phase of lithification in which cement, consisting of minerals
that precipitate from groundwater, partially or completely fills the
spaces between clasts and attaches each grain to its neighbor. |
|
|
Term
|
Definition
Sedimentary rock made up of minerals that precipitate directly from
water solution. |
|
|
Term
|
Definition
Sedimentary rock consisting of cemented-together detritus derived
from the weathering of preexisting rock. |
|
|
Term
|
Definition
| A fragment of detritus (e.g., a sand grain or a pebble). |
|
|
Term
|
Definition
Very coarse-grained sedimentary rock consisting of rounded
clasts. |
|
|
Term
|
Definition
A lamination inclined to the main bedding; it represents the slip
face of a layer deposited in a current. |
|
|
Term
|
Definition
The process by which sediment settles out of a transporting
medium. |
|
|
Term
|
Definition
Changes that happen to sediment or sedimentary rock during and
subsequent to lithification but at temperatures less than that of the
lowest grade metamorphism. |
|
|
Term
|
Definition
A type of carbonate sedimentary rock that contains significant
quantities of dolomite. |
|
|
Term
|
Definition
The grinding away and removal of Earth's surface materials by
moving water, air, or ice. |
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Term
|
Definition
A layer of clastic sediment or sedimentary rock in which clast size
progressively decreases from the base to the top of the bed;
graded beds form by deposition from a turbidity current. |
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Term
|
Definition
| Sedimentary rock composed of calcite. |
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Term
|
Definition
The transformation of loose sediment into solid rock through
compaction and cementation. |
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Term
|
Definition
Very fine-grained sedimentary rock that will not easily split into
sheets. |
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Term
|
Definition
Sedimentary rock (such as coal) formed from carbon-rich relicts of
organisms. |
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Term
|
Definition
The seaward migration of a shoreline caused by a lowering of sea
level. |
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Term
|
Definition
Wave-like ridges and troughs on the surface of a sedimentary layer
formed during deposition in a current. |
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Term
|
Definition
Coarse-grained sedimentary rock consisting almost entirely of
quartz. |
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Term
|
Definition
A depression, created as a consequence of subsidence, that fills
with sediment. |
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Term
|
Definition
Rock that forms either by the cementing together of fragments
broken off preexisting rock or by the precipitation of mineral
crystals out of water solutions at or near the Earthصs surface. |
|
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Term
|
Definition
A characteristic of sedimentary deposits that pertains to the
character of bedding and/or the surface features of a bed. |
|
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Term
|
Definition
| Very fine-grained sedimentary rock that breaks into thin sheets. |
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Term
|
Definition
Fine-grained sedimentary rock generally composed of very small
quartz grains. |
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Term
|
Definition
(1) The range of clast sizes in a collection of sediment; (2) the
degree to which sediment has been separated by flowing currents
into different-size fractions. |
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Term
|
Definition
| A succession of sedimentary beds. |
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Term
|
Definition
A recognizable layer of a specific sedimentary rock type or set of
rock types, deposited during a certain time interval, that can be
traced over a broad region. |
|
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Term
|
Definition
The vertical sinking of the Earthصs surface in a region, relative to a
reference plane. |
|
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Term
|
Definition
| The inland migration of shoreline resulting from a rise in sea level. |
|
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Term
|
Definition
A carbonate rock formed by precipitation of carbonate minerals
from water at springs or on the surface of caves. |
|
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Term
|
Definition
A submarine avalanche of sediment and water that speeds down a
submarine slope. |
|
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Term
|
Definition
Metamorphism due to the increase in temperature and
pressure in a rock when it has been buried to a depth of
several kilometers. |
|
|
Term
|
Definition
Metamorphism caused by heat conducted into country rock
from an igneous intrusion. |
|
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Term
|
Definition
A condition causing a material to experience a push or pull in
one direction of a greater magnitude than the push or pull in
another direction; in some cases, differential stress can result
in shearing. |
|
|
Term
|
Definition
Metamorphism that occurs as a consequence of shearing
alone, with no change in temperature or pressure. |
|
|
Term
Dynamothermal
metamorphism |
|
Definition
| Metamorphism that involves heat, pressure, and shearing. |
|
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Term
|
Definition
The process (involving uplift and erosion) that returns deeply
buried rocks to the surface. |
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|
Term
|
Definition
Layering formed as a consequence of the alignment of mineral
grains, or of compositional banding in a metamorphic rock. |
|
|
Term
|
Definition
A compositionally banded metamorphic rock typically
composed of alternating dark- and light-colored layers. |
|
|
Term
|
Definition
Rock that undergoes metamorphism simply because of a
change in temperature, without being subjected to differential
stress. |
|
|
Term
|
Definition
| The change that occurs in a rock due to interaction with hightemperature water solutions. |
|
|
Term
|
Definition
A metamorphic rock composed of calcite and transformed
from a protolith of limestone. |
|
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Term
|
Definition
Conglomerate that has undergone metamorphism, but in which
clasts are still recognizable; typically the clasts are stretched or
flattened. |
|
|
Term
|
Definition
The region around a pluton, stretching tens to hundreds of
meters out, in which heat transferred into the country rock and
metamorphosed the country rock. |
|
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Term
|
Definition
A set of metamorphic mineral assemblages indicative of
metamorphism under a specific range of pressures and
temperatures. |
|
|
Term
|
Definition
A fabric defined by parallel surfaces or layers that develop in a
rock as a result of metamorphism; schistocity and gneissic
layering are examples |
|
|
Term
|
Definition
An informal designation of the degree to which a rock has
undergone metamorphism; high-grade rocks have endured
higher temperatures than low-grade rocks. |
|
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Term
|
Definition
A mineral formed by solid-state transitions under metamorphic
conditions. |
|
|
Term
|
Definition
Rock that forms when preexisting rock changes into new rock
as a result of an increase in pressure and temperature and/or
shearing under elevated temperatures; metamorphism occurs
without the rock first becoming a melt or a sediment. |
|
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Term
|
Definition
The arrangement of grains (e.g., preferred orientation) formed
as a result of metamorphism. |
|
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Term
|
Definition
The region between two metamorphic isograds, typically
named after an index mineral found within the region. |
|
|
Term
|
Definition
The process by which one kind of rock transforms into a
different kind of rock. |
|
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Term
|
Definition
The process by which a rocks overall chemical composition
changes during metamorphism because of reactions with hot
water that bring in or remove elements. |
|
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Term
|
Definition
A fine-grained metamorphic rock with a foliation caused by the
preferred orientation of very fine-grained mica. |
|
|
Term
preferred mineral
orientation |
|
Definition
The metamorphic texture that exists where platy grains lie
parallel to one another and/or elongate grains align in the
same direction. |
|
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Term
|
Definition
| The original rock from which a metamorphic rock formed. |
|
|
Term
|
Definition
A metamorphic rock composed of quartz and transformed
from a protolith of quartz sandstone. |
|
|
Term
|
Definition
Metamorphism of a broad region, usually the result of deep
burial during an orogeny. |
|
|
Term
|
Definition
A medium- to coarse-grained metamorphic rock that
possesses schistosity. |
|
|
Term
|
Definition
| An older, interior region of a continent. |
|
|
Term
|
Definition
Solid-state changes in rock that result from the extreme
pressure accompanying a meteorite impact. |
|
|
Term
|
Definition
| Fine-grained, low-grade metamorphic rock, formed by the metamorphism of shale. |
|
|
Term
|
Definition
Metamorphism caused by heat conducted into country rock
from an igneous intrusion. |
|
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Term
|
Definition
| The series of smaller earthquakes that follow a major earthquake. |
|
|
Term
|
Definition
| Seismic waves that pass through the interior of the Earth. |
|
|
Term
|
Definition
Waves in which particles of material move back and forth parallel
to the direction in which the wave itself moves. |
|
|
Term
|
Definition
| The amount of movement or slip across a fault plane. |
|
|
Term
|
Definition
A vibration caused by the sudden breaking or frictional sliding of
rock in the Earth. |
|
|
Term
|
Definition
The concept that earthquakes occur when rock elastically bends
until it fractures; the fracturing generates earthquake energy and
decreases the elastic energy stored in the rock. |
|
|
Term
|
Definition
The point on the surface of the Earth directly above the focus of an
earthquake. |
|
|
Term
|
Definition
| A fracture on which one body of rock slides past another |
|
|
Term
|
Definition
A small step on the ground surface where one side of a fault has
moved vertically with respect to the other. |
|
|
Term
|
Definition
The series of smaller earthquakes that precede a major
earthquake. |
|
|
Term
|
Definition
The point below the Earth's surface where the energy is produced
during an earthquake. |
|
|
Term
|
Definition
| Earthquake that occurs away from plate boundaries. |
|
|
Term
|
Definition
The transformation of seemingly solid sediment into a liquid-like
slurry, in response to ground shaking. |
|
|
Term
|
Definition
Any numerical representation of the size of an earthquake as
determined by measuring the amplitude of ground motion |
|
|
Term
|
Definition
An earthquake characterization scale based on the amount of
damage that the earthquake causes. |
|
|
Term
|
Definition
A numerical representation of the size of an earthquake that takes
into account the area of the fault that slipped, the amount of slip,
and the strength of the rock that broke. |
|
|
Term
|
Definition
| The average time between successive geologic events. |
|
|
Term
|
Definition
A scale that defines earthquakes on the basis of the amplitude of
the largest ground motion recorded on a seismogram. |
|
|
Term
|
Definition
The relatively narrow strips of crust on Earth under which most
earthquakes occur. |
|
|
Term
|
Definition
|
|
Term
|
Definition
| Waves of energy emitted at the focus of an earthquake. |
|
|
Term
|
Definition
| The record of an earthquake produced by a seismograph. |
|
|
Term
|
Definition
An instrument that can record the ground motion from an
earthquake. |
|
|
Term
|
Definition
Seismic waves in which particles of material move back and forth
perpendicular to the direction in which the wave itself moves. |
|
|
Term
|
Definition
Stop-start movement along a fault plane caused by friction, which
prevents movement until stress builds up sufficiently. |
|
|
Term
|
Definition
| Seismic waves that travel along the Earth's surface. |
|
|
Term
|
Definition
A large wave along the sea surface triggered by an earthquake or
large submarine slump. |
|
|
Term
|
Definition
A sloping band of seismicity defined by intermediate- and deepfocus earthquakes that occur in the down-going slab of a
convergent plate boundary. |
|
|
Term
|
Definition
A fold with an arch-like shape in which the limbs dip away from the
hinge. |
|
|
Term
|
Definition
In the context of folds, this is the imaginary plane that contains the
hinge lines of successive layers in the fold; it is the surface that
divides a fold into its two separate limbs. |
|
|
Term
|
Definition
| A fold or depression shaped like a right-side-up bowl. |
|
|
Term
|
Definition
| The cracking and fracturing of a material subjected to stress. |
|
|
Term
|
Definition
| A push or squeezing felt by a body. |
|
|
Term
|
Definition
A long-lived block of durable continental crust commonly found in
the stable interior of a continent. |
|
|
Term
|
Definition
A change in the shape, position, or orientation of a material, by
bending, breaking, or flowing. |
|
|
Term
|
Definition
The angle at which a layer tilts, relative to horizontal; the angle is
measured in an imaginary vertical plane that trends perpendicular
to the strike. |
|
|
Term
|
Definition
| The amount of movement or slip across a fault plane. |
|
|
Term
|
Definition
| Folded or arched layers with the shape of an overturned bowl. |
|
|
Term
|
Definition
The bending and flowing of a material (without cracking and
breaking) subjected to stress. |
|
|
Term
|
Definition
| A fracture on which one body of rock slides past another. |
|
|
Term
|
Definition
A small step on the ground surface where one side of a fault has
moved vertically with respect to the other. |
|
|
Term
|
Definition
A bend or wrinkle of rock layers or foliation; folds form as a
consequence of ductile deformation. |
|
|
Term
|
Definition
Layering formed as a consequence of the alignment of mineral
grains, or of compositional banding in a metamorphic rock. |
|
|
Term
global
positioning
system
(GPS) |
|
Definition
A satellite system people can use to measure rates of movement of
the Earth's crust relative to one another, or simply to locate their
position on the Earth's surface |
|
|
Term
|
Definition
| The portion of a fold where curvature is greatest. |
|
|
Term
|
Definition
The condition that exists when the buoyancy force pushingithosphere up equals the gravitational force pulling lithosphere
down. |
|
|
Term
|
Definition
| Naturally formed cracks in rocks. |
|
|
Term
|
Definition
| The side of a fold, showing less curvature than at the hinge |
|
|
Term
|
Definition
A fold in the land surface whose shape resembles that of a carpet
draped over a stair step. |
|
|
Term
|
Definition
A fault in which the hanging-wall block moves down the slope of the
fault. |
|
|
Term
|
Definition
The process in which mountains begin to collapse under their own
weight and spread out laterally. |
|
|
Term
|
Definition
| A linear range of mountains. |
|
|
Term
|
Definition
| A mountain-building event. |
|
|
Term
|
Definition
Force per unit area, or the زpushس acting on a material in cases
where the push is the same in all directions. |
|
|
Term
|
Definition
| A steeply dipping fault on which the hanging-wall block slides up. |
|
|
Term
|
Definition
A stress that moves one part of a material sideways past another
part. |
|
|
Term
|
Definition
The change in shape of an object in response to deformation (i.e.,
as a result of the application of a stress). |
|
|
Term
|
Definition
The push, pull, or shear that a material feels when subjected to a
force; formally, the force applied per unit area over which the force
acts. |
|
|
Term
|
Definition
| The compass trend of an imaginary horizontal line on a plane. |
|
|
Term
|
Definition
A fault in which one block slides horizontally past another (and
therefore parallel to the strike line), so there is no relative vertical
motion. |
|
|
Term
|
Definition
| A trough-shaped fold whose limbs dip toward the hinge. |
|
|
Term
|
Definition
| A stress that pulls on a material and could lead to stretching. |
|
|
Term
|
Definition
A gently dipping reverse fault; the hanging-wall block moves up the
slope of the fault. |
|
|
Term
|
Definition
The upward vertical movement of the ground surface, as occurs
during mountain building. |
|
|
Term
|
Definition
A seam of minerals that forms when dissolved ions carried by water
solutions precipitate in cracks. |
|
|
Term
|
Definition
The remarkable diversification of life, indicated by the fossil
record, that occurred at the beginning of the Cambrian Period. |
|
|
Term
|
Definition
A radiometric dating process that can tell us the age of organic
material containing carbon originally extracted from the
atmosphere. |
|
|
Term
|
Definition
The boundary surface between two rock bodies (as between
two stratigraphic formations, between an igneous intrusion and
adjacent rock, between two igneous rock bodies, or between
rocks juxtaposed by a fault). |
|
|
Term
|
Definition
The process of defining the age relations between the strata at
one locality and the strata at another. |
|
|
Term
|
Definition
A means of determining the relative age of rock by looking at
which rock or structure cuts another; the feature that has been
cut is older. |
|
|
Term
|
Definition
| The decay product of radioactive decay. |
|
|
Term
|
Definition
| The largest subdivision of geologic time. |
|
|
Term
|
Definition
An interval of geologic time representing the largest subdivision
of a period. |
|
|
Term
|
Definition
An interval of geologic time representing the largest subdivision
of the Phanerozoic Eon. |
|
|
Term
|
Definition
The principle that the assemblage of fossil species in a given
sequence of sedimentary strata differs from that found in older
sequences or in younger sequences; a given species appears
at a certain level and then disappears (goes extinct) at a higher
level. |
|
|
Term
|
Definition
A composite stratigraphic chart that represents the entirety of
the Earth’s history. |
|
|
Term
|
Definition
A map showing the distribution of rock units and structures
across a region. |
|
|
Term
|
Definition
| The span of time since the formation of the Earth. |
|
|
Term
|
Definition
| A scale that describes the intervals of geologic time. |
|
|
Term
|
Definition
The time it takes for half of a group of a radioactive element’s
isotopes to decay. |
|
|
Term
|
Definition
Different versions of a given element that have the same atomic
number but different atomic weights. |
|
|
Term
|
Definition
The science of dating geologic events in years by measuring the
ratio of parent radioactive atoms to daughter product atoms. |
|
|
Term
|
Definition
The age of a rock or structure as specified in years; referred to
as زabsolute ageس in older literature. |
|
|
Term
|
Definition
The principle that sediments are deposited in nearly horizontal
layers. |
|
|
Term
|
Definition
| A radioactive isotope that undergoes decay. |
|
|
Term
|
Definition
An interval of geologic time representing a subdivision of a
geologic era. |
|
|
Term
|
Definition
The interval of geologic time between Earth’s formation about
4.57 Ga and the beginning of the Phanerozoic Eon 542 Ma. |
|
|
Term
|
Definition
The process by which a radioactive atom undergoes fission or
releases particles thereby transforming into a new element. |
|
|
Term
|
Definition
| The age of one geologic feature with respect to another. |
|
|
Term
|
Definition
A cross-section diagram of a sequence of strata summarizing
information about the sequence. |
|
|
Term
|
Definition
A recognizable layer of a specific sedimentary rock type or set
of rock types, deposited during a certain time interval, that can
be traced over a broad region. |
|
|
Term
|
Definition
The principle that younger layers of sediment are deposited on
older layers of sediment; thus, in a sequence of strata, the oldest
layer is at the base. |
|
|
Term
|
Definition
A boundary between two different rock sequences representing
an interval of time during which new strata were not deposited
and/or were eroded. |
|
|
Term
|
Definition
The principle that the same physical processes observed today
are responsible for the formation of ancient geologic features;
put concisely, زthe present is the key to the past.س |
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