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Geology 101 Midterm
ROCKS FOR JOCKS!
81
Geology
Undergraduate 1
02/06/2012

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Cards

Term
Which volcanic gas was not added to the earths atmosphere during early differentiation of the planet.
Definition
O2 (the 2 is a subscript)
Term
Why does the Yellowstone hotspot volcanism produce more explosive volcanic eruptions than the Hawaiian hotspot volcanism?
Definition
Upwelling basaltic magma partially melts the overlying continental crust producing viscous rhyolitic lava
Term
How can we best ecplain the fact that the inner and outer cores are both composed of metallic iron (Fe) and nickel (Ni) yet the outer core is liquid and the inner core is solid
Definition
the melting temperature for Fe-Ni is lower than the geothermal gradient temperature in the outer core
Term
The ___________ mineral group is a major economic source of iron
Definition
Oxide
Term
Meteorites that strike the earth are predominantly composed of
Definition
iron-nickel and silicate minerals
Term
Why are S-waves completely absorbed as they enter the "low velocity zone" (asthenosphere)
Definition
Non of the above are correct as S-waves are not completely absorbed by the asthenosphere
Term
During differentiation of the earth, heat was generated from
Definition
All of the above
-kinetic energy of impacting planetesimals
-compressional heating during condensation of planetesimals
-radioactive heating
Term
How do geologists explain the uplift in the colorado plateau and the rifting of nevada and utah?
Definition
a spreading ridge was subducted under california and is now upwelling beneath the basin and range
Term
Transform plate boundaries are typically associated with
Definition
divergent margins where the rate of spreading is different along segments of the spreading ridge
Term
Which of the following plate motions would not likely occur in the future
Definition
The isthmus of panama will close and the gulf stream current will be diverted northward to europe.
Term
As magma crystallizes into igneous rock the residual melt is typically
Definition
more felsic AND lower density than the rock
Term
The silicate mineral amphibole has 50 percent of its silicate tetrahedra possessing 3-shared oxygen atoms and 1 unshared and 50 percent of its silicate tetrahedra possessing 2 shared oxygen atoms and 2 unshared oxygen atoms. What is the ratio of Si:O in the tetrahedral structure of this mineral
Definition
2 different ratios of 2.5 and 3 so answer is 2.75
Term
Match the Lava type with the appropriate geographic/tectoni setting where it likely formed

-Yellowstone Calderas
-Ural Mts.
-Mt. Rainier, Cascades

-basalt
-Granite
-andesite
peridotite
-rhyolite
Definition
Yellowstone- rhyolite

Ural- Granite

Mt. Rainier- andesite
Term
The lava composition of Mt. St. Helens is ___________ and it tends to be more ____________ than lavas erupted from Rainier.
Definition
Dacite, Silica rich
Term
What kind of tectonic setting is represented by the Appalachian mountains in the eastern united states
Definition
Ancient collision margin (continent-continent)
Term
Following differentiation the earth became compositionally zoned according to
Definition
density of constituent matter
Term
The cause of volcanism observed in the Cascades in most similar to that of
Definition
Japan
Term
What scientific observations of the solar system indicate that the sun and planets formed from a rotating disk shaped nebular dust cloud
Definition
-The planets all revolve in a counter clockwise direction around the sun

-Most of the planets and their moons rotate on their axis in a counter clockwise direction

-The planetary orbits are aligned along the suns equatorial plane
Term
What mineral group is vital to proper cell function in human beings
Definition
halide
Term
Why is the S-wave shadow zone larger than the p wave shadow zone
Definition
S-waves are completely absorbed by the liquid outer core
Term
Divergent margins typically originate under continents because
Definition
the insulating property of thick continental lithosphere retains more heat than ocean lithosphere
Term
Magnetic minerals that crystallize in a lava flow erupted near the equator today will
Definition
-be oriented perpendicular to the surface of the lava flow

-will have normal polarity and point toward magnetic north
Term
What evidence have geophysicist used to indicate that the core is metallic and has a liquid component?
Definition
-The presence of the earths magnetic field

-seismic wave studies, specifically the s-wave shadow zone
Term
How are minerals produced on earth
Definition
-can crystallize directly from a magmatic melt

-can precipitate from aqueous solutions
Term
What are the mechanisms that likely drive subduction of the ocean lithosphere
Definition
ridge push

plate sliding

slab pull
Term
Why does Ca-rich plagioclase develop cleavage planes yet it is a framework silicate mineral with all of its oxygen atoms shared between tetrahedra
Definition
This mineral may have an Al atom in its tetrahedra, which requires additional ionic bonds with Ca atoms
Term
In the geologic techniques lab you calculated the stream length of a section of the wenatchee river ________
Definition
using a string and the topographic maps bar scale
Term
Im the plate tectonics lab we observed that oceanic crust compromising the Juan de Fuca plate was being created at the spreading ridge at a rate ________ the rate of its subduction beneath the North American plate
Definition
less than
Term
In the minerals lab the main diagnostic criteria for identifying biotite mica was
Definition
its cleavage into dark flexible sheets
Term
What is Terry's favorite tree
Definition
Bristlecone pine
Term
Match the magma/lava type with the appropriate geographic/tectonic setting where it likely formed

-Columbia Plateau, Washington
-Ural Mts.
-Mt. Pinatubo

-Basalt
-granite
-andesite
-peridotite
-rhyolite
Definition
Columbia Plateau- basalt

Ural Mts.- Granite

Mt. Pinatubo- andesite
Term
Arrange the compositional zones of the earth according to their respective density (lightest to densest)
Definition
Continental crust, ocean crust, mantle, outer core, inner core
Term
The cause of volcanism observed in the cascades is similar to that of __________
Definition
The phillipines
Term
Australia has unique faunal (animal) assemblages compared to the other continents because _________
Definition
it has been tectonically isolated from other continents for a very long period of time
Term
The olympic and coast mountains are composed of
Definition
marine sedimentary rock scraped off from the ocean floor during subduction
Term
The spreading ridge, which represents the plate boundary between the Juan de Fuca and Pacific Plates will eventually be subducted under the north american plate
Definition
the convergence rate along the subduction zone is greater than the rate of production of new ocean crust
Term
Divergent margins typically originate under continents because
Definition
the insulating property of thick continental lithosphere retains more heat than ocean lithosphere
Term
What are the two most common elements comprising the ocean crust?
Definition
Silicon (Si) and Oxygen (o)
Term
Which of the following answers is not correct regarding metallic bonds and properties of metals
Definition
strength does not depend upon the atomic radius and type of crystal lattice (structure)
Term
The __________ mineral group is a major component of marine limestone
Definition
Carbonate
Term
Why do seismic waves decelerate as they enter the low velocity zone
Definition
The "low velocity" zone is at the pressure melting temperature for the earths mantle
Term
In a recent NASA mission to the moon a rocket smashed into the surface near the south pole kicking up lunar debris. How was water measured
Definition
Spectrometry measuring the light emitted/absorbed by debris
Term
What type of fault motion resulted in the Jan 12th 2010 earthquake in Haiti
Definition
left lateral strike ship motion
Term
Rank chemical bonds forming minerals from strongest to weakest
Definition
Covalent, ionic, vander waal
Term
Phenocrysts crystallize _________ and at a _________ temperature than the minerals within ground mass in porphyritic rocks
Definition
first, higher
Term
As magma crystallizes into igneous rock the residual melt _________
Definition
Will become more felsic than the rock

will become more viscous than original source magma
Term
When two continental plates converge
Definition
-Andesitic volcanism will erupt at the surface

-a collision mountain belt will form
Term
The phenocrysts in porphyritic basalt would crystallize ________ and have a __________ melting temperature than the matrix minerals
Definition
first, higher
Term
What type of volcanic eruption caused the destruction of St. Pierre on the Caribbean Island of Martinique
Definition
Basaltic pahoehoe flows
Term
What type of volcanic rock would contain welded lithic fragments
Definition
Volcanic Breccia
Term
Why does quartz develop cleavage planes yet it has all its oxygen atoms shared between tetrahedra
Definition
This mineral does not cleave
Term
The Silicon Oxygen ratio in the amphibole crystal structure is_______
Definition
1:3
Term
Valencies within the silicate tetrahedra of the amphibole structure are satisfied___________
Definition
-by covalent bonds between adjacent oxygen atoms

-by ionic bonds with available cations
Term
Roof pendant refers to _________
Definition
remnant country rock "draped" over intrusive rock
Term
Why do large Jovian planets have molecular hydrogen in their atmospheres but the smaller terrestrial planets do not?
Definition
The jovian planets are further from the sun and the hydrogen gas can condense and be held by gravity
Term
The fishing community of Heimey, Iceland was nearly inundated by _________ lava flows, but was saved _______
Definition
andesite; using fire hoses to solidify the lava flows and divert them to the sea
Term
Transform plate boundaries are typically associated with _________
Definition
divergent margins where the rate of spreading is different along segments of the spreading ridge
Term
The cause of volcanism observed in the Hawaiian islands is similar to that of _________
Definition
Yellowstone park
Term
A shield volcano has a lower slope angle than a strato (composite) volcano because _________
Definition
its basaltic lava flows have lower viscosities than the andesitic flows of strato volcanoes
Term
What are the two most common elements comprising rocks of the outer core
Definition
Iron Nickel
Term
Basaltic magma can form
Definition
All the above
-at sea floor spreading zones
-at continental rift zones
-above hotspots
-back arc spreading basins
Term
How can mantle rocks be brought to the surface of the earth, such as in the Cascades or Fidalgo Island
Definition
they are squeezed to the surface along suture zones where collisions occur
Term
Which of the following is not true regarding the 1980 Mt. St. Helens eruption
Definition
the volcano is presently rebuilding its lava dome
Term
Most carbonate rocks are produced
Definition
within a subduction zone setting
Term
As magma crystallizes into igneous rock the residual melt__________
Definition
will become more felsic (silica rich)

-will yield more explosive eruptions
Term
Strato Volcanoes are largely composed of
Definition
interlayered lava and pyroclastic flows
Term
Valencies within the silicate tetrahedra of the olivine struacture are satisfied
Definition
by ionic and metallic bonds with available iron and magnesium atoms
Term
Van der waal bonds are form...
Definition
When electrons are preferentially aligned to one side of an atome resulting in weak negative charge
Term
Metallic bonds form
Definition
when electrons are loosely held and move between atoms
Term
Yellowstone caldera volcanic rocks are composed of rock rich in
Definition
rhyolite
Term
Pahoehoe Basalts
Definition
Are ropey textured flows that form as the viscosity decreases during degassing
Term
When two continental plates converge
Definition
a collision mountain belt will form
Term
The most widely accepted explanation for the earth's magnetic field
Definition
movement of electrons in the molten iron of its outer core
Term
What kind of margin exists today along the western margin of central California
Definition
transform margin
Term
What type of volcanic rock would preserve gas bubbles during cooling
Definition
scoria
Term
Granitic composition magma will not typically rise to the surface because
Definition
its melting temperature increases with decreasing pressure and it will solidify at depth
Term
Where is basaltic magma not typically found
Definition
continental collision boundary
Term
Why does the topographic expression of the Hawaiian islands become progressively lower from the big island to the island lying northwest?
Definition
The ocean lithosphere is lighter over the hotspos and it floats higher
Term
What are the two most common elements comprising rocks of the crust and mantle
Definition
Silicon and Oxygen
Term
Andesitic composition magma can form
Definition
-ocean/ocean convergent boundaries

-ocean/continent convergent boundaries
Term
P-Waves _____________ as they travel through the asthenosphere
Definition
Decelerate
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