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dynamic earth
test 1
97
Geology
Undergraduate 2
09/21/2010

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Term
Ion
Definition
charged atom
Term
Cation
Definition
+ charge
Term
anion
Definition
negative charge
Term
coordination number
Definition
number of anions that are its closest neighbors, i.e. how many anions are surrounding the cation.
Term
cations depends on size
Definition
In minerals where O is the only anion, the coordination numberof cations depends on their ...
Term
higher coordination numbers
Definition
Those with the larger ionic radii have...
Term
Oxygen and silicon
Definition
most abundant elements in the Earth's crust
Term
3 types of lithospheric plate boundaries
Definition
* divergent plate boundaries
* convergent plate boundaries
* translational plate boundaries (transform faults)
Term
lithosphere
Definition
The tectonic plates are made up of Earth’s crust and the upper part of the mantle layer underneath. Together the crust and upper mantle are called the
Term
30/70 km second
Definition
Today meteorites that reach Earth have velocities of approximately ...
Term
kinetic energy (kinetic energy = mass x velocity2)
Definition
Large meteorites therefore posses considerable...
Term
kinetic energy
Definition
compressing the atmosphere through which it travels (a small fraction), producing shock waves that compress rock, and breaking and moving rocks around craters (a large fraction). Ultimately, all motion (the shock wave and rocks) must cease, and the result is that ________ is converted to thermal energy
Term
heats up a bit
Definition
kinetic energy hits the earth and the motion is transferred to the atomic scale, and the planet _______
Term
uranium and thorium and potassium (about 0.01% of potassium is radioactive).
Definition
Some of the heat we measure in the Earth can be accounted for by the natural abundances of radioactive elements ______ and _______ and _______
Term
1 to 2 micro-calories per square cm per second
Definition
Heat (thermal energy) can be measured flowing out of the Earth at an average flux of ....
Term
geothermal gradient
Definition
The rate at which the temperature increases with depth in the Earth is the _____________
Term
An average sort of value might be 20 - 35 degrees per kilometer
Definition
geothermic gradient averages ....
Term
convection
Definition
heat is carried by matter which is flowing. Warmer and less dense matter rises, while cooler and more dense matter sinks.
Term
conduction
Definition
enhanced vibrational motion of atoms in materials is induced in neighboring atoms and this motion diffuses through the material (if you could actually see the atoms, a very crude analogy might be a crowd in a football stadium doing "the Wave")
Term
radiation
Definition
heat moves as electromagnetic radiation, such as heat transfered from the Sun to Earth
Term
convection
Definition
the primary means by which heat is lost from the Earth's deep interior.
Term
high pressure
Definition
the reason the earth is not molten at shallow depths is (even with high temperatures) ...
Term
high water pressure
Definition
The melting (crystallization) temperatures of minerals are reduced under...
Term
lower
Definition
"wet" rocks (those containg water) melt at __________ temperatures that do dry rock containing identicle mineral assemblages.
Term
volatiles
Definition
important factor in the melting and crystallization of magma is the presence of __________, especially water
Term
increases
Definition
the temperature required to melt minerals ________ with increasing pressure, so that minerals which are heated to temperatures sufficient to melt them at atmospheric pressure can remain solid under the high pressure in the Earth
Term
Cooling magmas crystallize assemblages of minerals referred to as
Definition
igneous rocks
Term
silicates
Definition
dominate minerals are ...
Term
slow cooling rates ... rapid
Definition
provides the time and high mobility of ions to grow large crystals; _____ cooling does not.
Term
slowly ... loosing heat
Definition
Magmas that crystallize at depth in the Earth cool ______, because of the difficulty with ________.
Term
faster and produce small crystals
Definition
Magmas in small bodies crystallizing very close to the surface or enclosed in cool rocks cool much ______ and produce small _______.
Term
any ... contain only microscopic
Definition
Magmas erupting onto the surface of the Earth might even cool so quickly, that they solidify before ___ crystals can form - producing a natural glass, or they might contain only _______ crystals.
Term
Plutonic
Definition
______ igneous rocks crystallize at depth and possess individual mineral crystals that can readily be seen with out the aid of magnification.
Term
Volcanic
Definition
_________ igneous rocks form at the Earth's surface and contain very small, usually microscopic, size crystals, and or glass.
Term
small crystals (volcanic)
Definition
basalt, andesite, rhyolite
Term
large crystals (plutonic)
Definition
gabbro, diorite, granite
Term
Mafic
Definition
________ mineral are relatively rich in Mg, and Fe, and relatively poor in silica and the alkali (K and Na) elements
Term
Felsic
Definition
______ minerals have relatively high silica and alkali contents and lower Mg and Fe.
Term
basalts and gabbros
Definition
two higher crystalization/melting temperature minerals and contain pyx, Ca-plag, ol, they are mafic igneous rocks
Term
granites and rhyolites
Definition
two felsic igneous rocks, made up of alkali-feld, bio, qtz, with lower crystallization/melting temperatures
Term
diorties & andesites
Definition
2 igneous rocks made up of intermed plag, amph, (pyx, bio) and are intermediate compositions
Term
fractional crystallization ; more
Definition
________ _________of a magma can result in a residual magma that is ______ felsic than the original magma.
Term
partial melting
Definition
______ ______ of rocks produce magmas that are more felsic than the rocks that are melted.
Term
batholith
Definition
enormous mass of intrusive igneous rock, usually are granitic in composition, have steeply inclined walls, have no visible floors, and commonly extend over areas of thousands of square miles, formed either as one large mass or many smaller masses at great depths in the earth's crust and are exposed at the surface only after considerable erosion of the overlying mountain mass
Term
dike
Definition
a body of rock that cuts across the layers of its surroundings, most made of magma some of sediments
Term
igneous dikes
Definition
molten basaltic magma rose through and cut across areas of basalt. _____ ______ are common in many bodies of plutonic or highly metamorphosed rock, where molten or fluid materials have invaded preexisting rock formations.
Term
Extrusive
Definition
____________ igneous rocks, or volcanics, form when magma makes its way to Earth's surface. The molten rock erupts or flows above the surface as lava, and then cools forming rock. The lava comes from the upper mantle layer, between 50 km and 150 km below the Earth's surface.
Term
intrusive / plutonic
Definition
Many kilometers below the Earth’s surface, magma flows into cracks or underground chambers. There, the magma sits, cooling very slowly over thousands to millions of years. As it cools, elements combine to form common silicate minerals, the building blocks of igneous rocks. These mineral crystals can grow quite large if space allows.
The mineral crystals within them are large enough to see without a microscope. There are many different types of _______ igneous rocks but granite is the most common type.
Term
O, Si, Al, Fe, Ca, Na, K, Mg
Definition
8 most abundant elements in earths crust
Term
clastic or detrital
Definition
sedimentary rocks. These are rocks composed primarily of fragments (i.e. clasts, or detritus) of pre-existing rocks.
Term
chemical / biochemical sedimentary rocks
Definition
Dissloved in waters of the oceans and lakes are chemical elements that have been acquired mainly as the result of chemical weathering.
Term
weathering
Definition
Physical processes break rocks into smaller and smaller fragments.include such things as falling rocks breaking pieces off of rocks they hit, abrasion of rocks by wind or water borne sand and rocks. Freezing of water in fractures of rocks can cause them to break. Rocks can also be broken by the growing roots of plants in cracks.
Term
transportation
Definition
Generally the debris from weathered and eroded rocks is moved down hill, under the influence of gravity. Water is the major agent of _______ Runoff from rain washes the loose laterial from hillslope. High energy streams can move large boulders, and even the slow moving streams have very fine material in suspension. The material moved by water (waves, glaciers) is referred to as sediment.
Term
deposition
Definition
when the agent of transportation no longer has sufficient energy to transport it's load. When streams reach the ocean, they likewise loose energy and ______ sediment as deltas.
Term
lithification
Definition
Under deep burial the elevated temperature and pressure in the presence of the water produces changes in the sediment. Some new minerals might grow. From the water cements such silica (SiO2), iron oxide (Fe2O3) and calcite (CaCO3), can be precipitated, cementing the sediment together to form sedimentary rock. Even with little compaction and at lower temperature, cements can be precipitated to __________ the sediment into rock.
Term
clasts
Definition
sizes of __________in sedimentary rocks reflects the energy of the transporting agent
Term
clasts
Definition
tend to become more rounded and less angular, the farther they are transported from their source.
Term
bedding
Definition
the stratification (layering) that is the most prominent structure in most sedimentary rocks. It represents the surfaces on which depositional events occur. Most commonly ______ planes are nearly horizontal when they form.
Term
cross bedding
Definition
these represent sloping depositional surfaces such as will form on the surfaces of dunes and delta fronts. Various types of cross beds form in a variety of environments.
Term
gradded bedding
Definition
a stratification in a bed of sedimentary rocks that in which the coarsest clasts occur at the bottom and clast size decrease toward the top of the bed. Each such graded bed represents a single and sudden depositional event. It is the result of different settling velocities for different size clasts (larger and heavier ones settle out first).
Term
ripple marks
Definition
small dune-like features that generally form in shallow waters. Their sizes are related to the velocities of the currents that form them, and their shapes are related to the current direction.
Term
mud cracks
Definition
these form when deposits of mud dry out. As it dries, it shrinks and polygonal dessication cracks form. The next layer of fine sediment will fill -n and cover the ____, thereby preserving them. They form in areas that experience frequent wetting by shallow water and drying.
Term
non-crystalline solid
Definition
_______ occurs when a liquid cools very quickly, the molecules do not have time to arrange themselves in the most favorable pattern (which will almost always be crystalline), and so they are locked into a disordered solid.
(Examples: glass, wax, plastic, etc.)
Term
viscosity
Definition
(a measure of a fluid's resistance to flowing) especially in magma is due to polymerization of silicon and oxygen in the magma.
Term
higher
Definition
higher silica = ______ viscosity
Term
higher
Definition
____ temp = lower viscosity
Term
Magma composition and gas content
Definition
control whether a volcano will erupt quietly like many Hawaian type basalt volcanoes do, or like the catastrophic silica rich eruption of Mt. St. Helens.
Term
basaltic
Definition
__________ lava- commonly flows over large distances.
Term
rhyolitic
Definition
_________ lava- has a very high viscosity and never travels far nor fast when extruded as a lava flow onto the surface of the Earth.
Term
highly viscous felsic
Definition
____ _____ ____ lava- commonly plugs up the shallow plumbing of volcanoes, preventing gases from escaping.
Term
ash
Definition
Volcanic _______ consists of rock, mineral, and volcanic glass fragments smaller than 2 mm (0.1 inch) in diameter, which is slightly larger than the size of a pinhead.
Term
tephra
Definition
term for fragments of volcanic rock and lava regardless of size that are blasted into the air by explosions or carried upward by hot gases in eruption columns or lava fountains.
Term
pyroclastic flow
Definition
is a ground-hugging avalanche of hot ash, pumice, rock fragments, and volcanic gas that rushes down the side of a volcano
Term
pumice
Definition
is a light, porous volcanic rock that forms during explosive eruptions.
Term
lahar
Definition
Indonesian word for a rapidly flowing mixture of rock debris and water that originates on the slopes of a volcano.
Term
lava flow
Definition
masses of molten rock that pour onto the Earth's surface during an effusive eruption.
Term
lava dome
Definition
are hemispherically shaped lava fountains that form when the upward pressure of magma from the conduit below is in approximate equilibrium with the mass of ponded lava through which it passes.
Term
pillow lava
Definition
are mounds of elongate lava ____ formed by repeated oozing and quenching of the hot basalt.
Term
AA ( ah ah )
Definition
is a Hawaiian term for lava flows that have a rough rubbly surface composed of broken lava blocks called clinkers.
Term
pahoehoe
Definition
basaltic lava that has a smooth, hummocky, or ropy surface.
Term
cinder cone
Definition
a steep, conical hill of volcanic fragments that accumulate around and downwind from a vent.
Term
sheild volcano
Definition
Volcanoes with broad, gentle slopes and built by the eruption of fluid basalt lava are called ______ volcano
Term
stratavolcano
Definition
steep, conical volcanoes built by the eruption of viscous lava flows, tephra, and pyroclastic flows, are called stratovolcanoes.
Term
caldera
Definition
a large, usually circular depression at the summit of a volcano formed when magma is withdrawn or erupted from a shallow underground magma reservoir.
Term
plinian eruption
Definition
are large explosive events that form enormous dark columns of tephra and gas high into the stratosphere
Term
olivines
Definition
independent tetrahedra / silicate mineral
Term
pyroxenes
Definition
single change / silicate mineral
Term
amphiboles
Definition
double chain silicate mineral
Term
biotite mica / muscovite mica
Definition
sheet silicates
Term
alkali feldspars / plagioclase feldspars
Definition
framework silicates
Term
foliation
Definition
As they are being deformed, a variety of textural fabrics that develope in metamorphic rocks produce the planar features
Term
gneiss
Definition
a compositional banding that is manifested by alternating bands of different minerals
Term
schist
Definition
a foliation resulting from the parallel alignment of flat minerals such as mica. The planes of this alignment are perpendicular to the principle compressional stress during the deformation
Term
blueschist metamorphism
Definition
occurs under conditions of low temperatures and a range of pressures. The high pressures required to produce some of the characteristic mineral assemblages found in ______ imply that the metamorphism occurs deep in the Earth where temperatures normally are also high
Term
regional metamorphism
Definition
We find metamorphic rocks exposed over regions of the Earth's surface, either in the cores of mountain belts or the roots of what were once mountain belts. Commonly, they show evidence of having been deformed and metamorphosed at great depth in the crust.
Term
contact metamorphism
Definition
Rocks can also be heated by intruding magmas, and the increase in their temperature can cause them to become metamorphosed. Because magmas often rise to very shallow levels in the crust (and of course often erupt), they carry their heat into low pressure environments. This heat is conducted into the rocks the magmas intrude
Term
obsidian
Definition
is a naturally occurring volcanic glass formed as an extrusive igneous rock. It is produced when felsic lava extruded from a volcano cools rapidly without crystal growth.
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