Midterm Questions
Geology 1004 with Law at Virginia Polytechnic Institute and State University
About this deck
By: Jen Hoffman
Textbook:
Earth: Portrait of a Planet (Third Edition)
Created: 2010-12-10
Size: 105 flashcards
Views: 45
Textbook:
Earth: Portrait of a Planet (Third Edition)Created: 2010-12-10
Size: 105 flashcards
Views: 45
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The diameter of the earth is approximately... (how many km?)
12672 km
The thickness of the earth's crust varies from approximately... (how many km?)
7 to 70 km
The Principle of Uniformitarianism was proposed by...
James Hutton
The summit of Mount Everest is composed of... (what type of rock?)
Limestone laid down in a shallow tropical sea; either in Ordovician times (510-410 million years ago) or in Upper Carboniferous times (280-320 million years ago)
The atomic number of an element is equal to...
The total number of protons in an atom of that element
Isotopes of an element are atoms containing...
Different numbers of neutrons
Atomic bonding in which two adjacent atons 'share some of their outermost orbiting electrons is referred to as... (what type of bonding?)
Covalent bonding
Graphite and Diamond are polymorphs of carbon. Their different physical properties are due to the fact that... (focus on the types of bonds in each)
Diamond has covalent bonds while graphite has both covalent and Van der Waals bonds
The four most abundant elements in the earth's crust, listed in decreasing order of abundance are...
Oxygen, silicon, aluminum, iron
The earth's core is primarily made up of... (what element?)
Iron
The silica tetrahedron that forms the fundamental building block of all silicate minerals is composed of silicon and what other element?
Oxygen
Muscovite, a member of the mica group, crystallizes with the following structure...
Sheet
A felsic magma is chemically defined by having... (What percent SiO2?)
Greater than 65% SiO2
Felsic igneous rocks contain abundant ___ silicate minerals. (what structure?)
3D tetrahedral network
The grain size of an igneous rock is primarily controlled by...
Rate of cooling of the magma
Composite volcanoes are made up of alternating layers of lava and pyroclastic material of... (what composition of magma?)
Andesitic (intermediate) composition
If basalt with a melting temperature of 1200 degrees Celsius begins to melt at a depth of 40 km, then the geothermal gradient in that area is approximately...
30 degrees Celsius per km
Assume that water-saturated diorite will begin to melt at a temperature of 720 degrees Celsius under a wide range of pressures. If the geothermal gradient in a particular area was 24 degrees Celsius per km, what is the minimum depth at which granite would begin to melt?
30 km
Analysis of earthquakes on the Big Island of Hawaii indicates that mafic magma begins rising up beneath Kilauea at a depth of 28 km. If the average geothermal gradient for the Big Island is 50 degrees Celsius per km, and magma begins to form at a 28 km depth, the melting temperature of the rocks is
1400 degrees Celsius
T/F The viscosity of a lava increases as the silica content decreases.
False
If a body of magma became less felsic, its viscosity will... (increase, decrease, remain the same)
Decrease
T/F Gabbro has a higher melting temperature than granite
True
The presence of two distinctly different grain sizes in an igneous rock indicates... (what about the parent magma)
the parent magma cooled first slowly, then very quickly
One kind of discordant intrusive body is...
A dike
A coarse grained igneous rock with a composition intermediate between rhyolite and basalt is...
Diorite
If magma ascending beneath Mount Fuji in Japan became trapped deep beneath the earth's surface, the igneous rock formed from the cooling of this magma would most likely be...
Diorite
If magma ascending beneath the Big Island of Hawaii became trapped deep beneath the earth's surface, the igneous rock formed from the cooling of this magma would most likely be...
Gabbro
Within the Earth's crust, the densest igneous rocks are dominantly found in... (which crust, or an equal combination of the two?)
Oceanic crust
The volumes of the crust, mantle and core of the earth are...
Crust = 1.7 x 1010 km3
Mantle = 8.78 x 1011 km3
Core = 1.699 x 1011 km3
The percentage volumes of the earth occupied by the crust, mantle and core is approximately...
Crust = 2%
Mantle = 82%
Core = 16%
The breakdown of exposed rock into small fragments and dissolved ions is termed...
Weathering
In Hong Kong a series of quartz-cemented sandstones are cut by one granite dike and one gabbro dike. Of these three rock types, the rock type most susceptible to chemical weathering is probably...
Gabbro
Which of the following naturally occuring materials could provide the most weather resistant facing for buildings? (Halite, limestone, olivine basalt, granite)
Granite
Clay minerals like kaolinite, are a product of ___ weathering of ___ minerals and are a raw material for ___.
Chemical, silicate, pottery
Chemical weathering takes place most rapidly in environments that are... (Warm/Cool, Wet/Dry)
Warm and wet
When sediment grains of different sizes are carried by a stream, the sediment deposited first will be...
the coarsest (gravel)
What are the two most important processes that transform loose sediments into hard sedimentary rocks...
Compaction, cementation
Limestone consisting of blocks of coral-rich limestone cemented together by younger limestone deposits is most likely to have originally formed... (on which part of a beach/shore etc)
On the ocean side of a reef
Graded bedding in clastic sedimentary rocks is produced by...
Slowing down of water currents
In sedimentary rock sequences, the horizontal or lateral sequence indicates...
Change of environment from place to place at one time
In a marine transgression associated with rising sea levels... (What happens to the sediments from different depths?)
Deeper water sediments are deposited on top of shallower water sediments
Which of the following rock types is volumetrically the least abundant in the Earth's crust... (igneous, sedimentary, metamorphic, equally abundant)
Sedimentary
Which type of metamorphism affects the greatest volume of rock... (contact, regional, dynamic?)
Regional (dynamothermal) metamorphism
Metamorphism of material being carried down a subduction zone occurs under conditions involving... (what relationship of temperatures and pressures?)
Low temperatures and high pressures
Hornfells is a type of metamorphic texture most commonly associated with... (what type of metamorphism)
Contact metamorphism
An isograd is...
A line on a map connecting points of first occurence of a given mineral in metamorphic rocks
Which of the following metamorphic rocks cannot form from a shale? (schist, marble, hornfells, slate, migmatite)
Marble
The sillimanite isograd represents...
The high temperature end of a sequence of minerals whose low temperature end is chlorite
The oceans contain about what percent of the world's water?
97%
Which of the following sandstones will have the highest porosity? (Well-sorted/poorly-sorted, cemented/uncemented?)
Well sorted, uncemented sandstone
Porosity is a measure of a rock's...
water holding capacity
What is the difference between the saturated and the unsaturated zones of groundwater?
The pore spaces in the saturated zone are completely full of water, the pore spaces in the unsaturated zone are not completely full of water
In groundwater studies, the base of the unsaturated zone is called the...
Water table
If all other conditions are equal, ground water will move faster... (through loose/cemented, sand/clay)
through loose sand than through clay
Which of the following combinations make for the best groundwater reservoir? (high/low permeability and porosity)
High permeability and high porosity
The San Andreas fault of California is a large scale example of... (what type of fault?)
Dextral strike slip fault
A woman standing on a parquet floor weighs 140 lbs. The cross-sectional area of each of the heels on her high heel shoes measures .25". If she balances on one heel, the stress she would put on the parquet floor is...
560 pounds per square inch
A bar of sandstone is put under compression and shortened from an original length (lo) of 50 inches to a final length (l1) of 49.5 inches. The longitudinal strain (e) the bar of sandstone has undergone is...
-.01 or -1%
A woman is standing on a parquet floor. The cross-sectional area of each of the heels on her high heel shoes measures .25". If she balances on one heel, she places a stress of 480 lbs per square inch on the floor. The women therefore weighs...
120 pounds
T/F Dip is the intersection of a horizontal plane with the bedding plane
False
An erosional surface separating unaltered parallel sedimentary layers is referred to as a... (malconformity, disconformity, angular unconformity, nonconformity)
A disconformity
The erosional or depositional surface between an underlying igneous or metamorphic rock, and an overlying set of sedimentary rock strata is a... (malconformity, disconformity, angular unconformity, nonconformity)
A nonconformity
The erosional or depositional surface between an underlying igneous or metamorphic rock, and an overlying set of sedimentary rock strata is a... (malconformity, disconformity, angular unconformity, nonconformity)
A nonconformity
The contact between sedimentary rock and overlying gneiss and schists is probably a... (angular unconformity, nonconformity, disconformity, intrusive contact, reverse faulth, strike-slip fault)
Reverse fault
Each time an alpha particle is emitted from the nucleus of an atom, the atomic number of the parent atom... (goes up/down, by 1/2/4)
Goes down by two
Each time a beta particle is emitted from the nucleus of an atom, the atomic number of the atom... (goes up/down, by 1/2, doesn't change)
Goes up by one
If a radioactive parent isotope has a half life of one million years and a rock originally contained 1600 mg of this parent isotope, how much will remain after seven million years...
12.5 mg
Assume that the half life of a particular radioactive isotope is 10,000 years. Laboratory analysis shows that the ratio of parent to daughter product in a sample is 1:15. What is the age of the sample?
40,000 years
A single crystal of zircon dated by the U235 - Pb 206 method is 3200 million years old. The measured ratio of U235 - Pb206 in this mineral grain was 1:15. What is the half life of U235?
800 million years
Orthoclase feldspar grains are commonly dated by the K-Ar isotopic method. The Ar daughter product is present as a gaseous phase, and some of this Ar may have escaped from the mineral grains while above their blocking temperature for Ar diffusion. Would the estimated age be too young or too old?
Too young
At the present time, the oldest known rocks making up the earht's crust have been isotopically dated as...
Approximately 4400 million years old
All meteorites have been isotopically dated as...
4300 - 4600 million years old
According to the teory proposed by H.F. Read following the 1906 San Fransisco earthquake, the cause of many large earthquakes is...
The sudden release of elastic strain energy when stressed rocks slip along a fault
An earthquake focus is...
the point within the Earth from which seismic waves originate
Which seismic waves do not pass through liquids?
S waves
The parameter used to calculate the distance of a seismograph from an earthquake epicenter is...
Difference in arrival times of P and S waves
An earthquake with magnitude 8 on the richter scale releases how many times more energy than a richter 3 earthquake?
Approximately 30 million times more
In plate tectonics, what are the plates themselves composed of?
Lithosphere
The scale used to represent intensity of earthquake damage, in terms of the earthquake's effects on man-made structures, is referred to as the...
Modified Mercalli scale
Which part of the earth contains the asthenosphere?
the uppermost 8% of the mantle
The inward dipping zones of earthquake foci (shallow near trenches, deeper away from the trenches) that occur near the margins of certain tectonic plates are known as...
Benioff zones
The reason we have continents above sea level, as opposed to one single ocean covering the entire surface of the earth is due to a greater density of the...
Oceanic crust
The primary difference between lithospheric and asthenospheric mantle is...
Physical state: the lithosphere is completely solid while the asthenosphere is partially molten
If there is an earthquake at the north pole, what seismic waves could you record at the south pole?
P waves, but no S waves due to the S wave shadow zone
The main portion of the earth that is totally liquid is the...
Outer core
Which region of the earth consists primarily of solid iron?
Inner core
How deep are the abyssal plains of the ocean floor?
about 5000 meters deep
Continental coastlines that occur within the interior of a tectonic plate are called... (what kind of margin)
Passive margin
Mid ocean ridges are characterized by... (high/low heat flow; shallow/deep earthquake foci; basalt/andesitic/rhyolitic igneous rocks)
High heat flow, shallow earhtquake foci and basaltic (mafic) igneous rock
T/F Wegener offered the idea that "the existence of mid-ocean ridges and magnetic intensity strips" to support his theory of continental drift.
False
Plate tectonics theory took decades to be accepted because...
Wegener was not able to explain how and why continents might move
Pangea began to break up into a series of fragments which we now recognizes as the world's individual continents approximately...
200-180 million years ago
Panthalasa is...
the name of the ocean surrounding a super-continent that existed 200 million years ago
Magnetic Inclination may be defined as...
The angle between the line of magnetic force and the horizontal, measured in an imaginary vertical plane at any individual locality
During a period of normal magnetic polarity, magnetic lines of force travel in which direction?
the magnetic lines of force leave the earth near the magnetic south pole and re-enter the earth near the north pole
The last reversal of the earth's magnetic field occurred approximately...
650,000 years ago
The connection between stripes of alternating low and high magnetic intensity on the ocean floor and sea-floor spreading was firt proposed by...
Len Morley, Fred Vine and Drummond Matthews in two separate manuscripts in 1963
The oldest oceanic crust beneath the earth's present day oceans has been dated at...
Approximately 180 million years old
Where would you expect oceanic crust to be oldest beneath the Atlantic Ocean?
At the continental shelf off the coast of the eastern USA and Canada
In order to maintain a constant size planet through time, summed over the entire surface of Earth... (Rates of lithosphere production must be greater/less/equal to consumption at subduction zones)
Rates of lithospheric production and consumption must be equal
Plate velocities calculated from the distribution of magnetic stripes beneath the earht's oceans range between...
2.0 - 18 cm per year
This drill site was located at a distance of 100 km from the mid-atlantic ridge, measured perpindicular to the ridge. This information indicates that the average rate of motion of the oceanic crust away from the ridge over the last five million years is...
2.0 cm per year
If the average rate of motion of the Arabian Peninsula away from the spreading center beneath the Red Sea is 1.0 cm per year, how far away from the spreading center was this drill site located after 2 million years...
20 km
Basalts have been cored from the floor of the Pacific Ocean 1000 km to the NW of the East Pacific Rise. If the average rate of motion of the Pacific plate away from the East Pacific rise is 10 cm per year, how old are the basalts cored?
10 million years
About this deck
By: Jen Hoffman
Textbook: Earth: Portrait of a Planet (Third Edition)
Created: 2010-12-10
Size: 105 flashcards
Views: 45
Textbook:
Earth: Portrait of a Planet (Third Edition)Created: 2010-12-10
Size: 105 flashcards
Views: 45
About StudyBlue
STUDYBLUE makes things that make you better at school.
Things like online flashcards with photos and audio.
Things like personalized quizzes and friendly reminders about when (and what) to study next.
Think of it as a digital backpack™: access to all of your study materials online and on your phone.
STUDYBLUE exists to make studying efficient and effective for every student, for free. Join us.
“I have used this website for three exams, and I see a huge difference in my test results.”
Naj
Naj