GEOL 1010 - INTRODUCTION TO GEOLOGY
FINALIZED MIDTERM III STUDY GUIDE – FALL 2011
Utah Valley University
READ THIS FIRST: this outline is not meant to be fully comprehensive. This is the finalized version of the midterm three study
guide; it was prepared on 11/29. This guide covers the major topics to be discussed in class, but it does not completely
cover everything involved with every topic, so use this as a guide to your notes, and to what to look at in the text. Because
lectures leading up to this exam were given by two instructors, it is particularly important that you carefully review
this study guide for this exam.
WHAT THE EXAM WILL COVER: The exam will focus on the sedimentary rocks (including depositional environments),
metamorphism and metamorphic rocks, and earthquakes. You will be responsible for the corresponding chapters from
your textbook (Ch. 6, Ch. 7, Ch. 8). For insurance, submit questions from chapters 6, 7 and 8 (Ch. 6: 1-3, 5, 7-11, Ch. 7:
1-7, 10, 11, Ch. 8: 1-3, 5, 6, 8-12), plus the study guide questions included with this document.
WHEN THE EXAM WILL TAKE PLACE: The exam will take place Friday 12/2. On campus students (section 151) must take the
exam in the CTC; distance site students may take the exam during regular class time on Friday 12/2 or in the CTC. It will
be available in the CTC all day and there will not be a lecture. You must take the exam on Friday unless you’ve made
other prior arrangements with Prof. Bunds.
INSURANCE: Insurance will comprise the study questions included with this document and the following questions from the
text: Ch. 6: 1-3, 5, 7-11, Ch. 7: 1-7, 10, 11, Ch. 8: 1-3, 5, 6, 8-12. Insurance is due by 1 pm Friday 12/2 in the College of
Science main office or to your facilitator before you take the exam (distance site students). Make yourself a photocopy of
your insurance work and be sure to follow the directions to ensure you get full credit.
HANDOUTS: There are handouts on oil and metamorphic rocks available on the class website on Canvas and on Prof. Bunds’
website: http://research.uvu.edu/EarthSci/bunds
DIFFERENCES BETWEEN THIS AND PRELIMINARY VERSIONS: A significant amount of information on earthquake has been
added to the outline, and a few questions on earthquakes have been added.
SUMMARY OF MATERIAL COVERED IN CLASS
a. Sedimentary rocks:
i. Detrital (know the various types of detrital rocks)
ii. Bio-chemical (know the various types of bio-chemical rocks, such as coal, chert, limestone, evaporites)
b. Transportation.
i. Detrital sediments (bits of rock fragments, like pieces of sand) are transported by streams, wind, glaciers and
waves. Weathering continues during transportation, and detritus is rounded (amount of rounding of detritus can
indicate the transportation distance). Wind and streams have a bed load, suspended load and a dissolved load.
ii. Dissolved rock is transported primarily by water, although CO2 (a constituent of calcite in limestone and
important to global warming) is transported by wind.
c. Sedimentation/Deposition. Need to talk separately about detrital and chemical sediments.
i. Detrital material
1) comes in several sizes - gravel, sand, silt, clay (see book).
2) When detrital material (ground up rock) is deposited, it forms layers of sediment (its not rock yet!).
3) fine material is deposited in low energy environments (e.g. quite water like out in the ocean or in a bay,
coarse material (sand, or especially gravel) gets deposited in energetic water (fast river or creek, right on a
beach). Think about the jug I brought in. Important thing here is the grain size of sediment or a
sedimentary rock tells you a LOT about where it was deposited (the depositional environment).
4) Sorting also results from the deposition environment; beach sands tend to be very well sorted because they
are subjected for a long time to a particular amount of water ‘energy’ (energy is sort of like turbulence).
5) Sorting and rounding together are the important detrital sedimentary textures
6) Detrital structures - geometric features in the rock. They tell you about how the rock formed: cross
bedding, ripples, mudcracks, etc. see book, notes.
ii. Chemical material mostly forms calcite (CaCO3), dolomite (CaMg(CO3)2, gypsum, and good ol’ salt (NaCl).
When water - especially water that was ‘salty’ to begin with, like seawater - evaporates, it leaves a bunch of
biochemical sediments (mostly gypsum and salt) behind.
iii. Also must consider organic or biochemical sediments, such as accumulations of calcite shells which form
coquina, leaves and other vegetation which make peat (can become coal with proper heating and compaction),
or silica (SiO2) shells which can form chert.
iv. Depositional Environments –
1) examples are alluvial fans, lakes, rivers, oceans (beach, near shore, reef/offshore, deep sea), glacial, sand
dunes, evaporite basins (where a lake or sea evaporates, like the salt flats)
2) Determining the environment that sediment was deposited in is like detective work; depositional
environments are generally identifiable by sedimentary structures and features in a sedimentary rock..
a) features include chemical vs detrital sediment, grain size + sorting + rounding (for detrital).
GEOL 1010, Introduction to Geology, Professor Bunds, Utah Valley University
b) structures include mudcracks, ripples and cross-beds.
c) An example: the very fine grained, very will sorted sandstones with very thick (3 to maybe 20+
meters) cross-beds (and a few dinosaur footprints) in southern Utah are mostly ancient sanddunes.
d. Lithification - transformation of sediment into rock by compaction and cementation. Fundamental driving force here
is the burial of the sediment under more and more layers of sediment. For example, there are maybe 4km of
sediments in the Salt Lake Valley, so the sediments at the bottom are under a lot of pressure (think how heavy a 2.5
mile tall pile of dirt must be!!), and they are a bit warm, maybe 80oC.
i. Compaction - sediment typically is 15 to 90% pore space ( voids in the rock, usually filled with water or air).
When the sediment gets buried under layers of more sed., the weight compacts the sediment, usually to where it
has 5 to 15% pore space. Remember that there is a lot of weight on a rock that is buried a mile or two deep in
the Earth.
ii. Cementation - basically the sediment grains get glued together. The cement minerals commonly are calcite, silica
or clay. The glue is either material from the sed. grains that gets dissolved off the sharp tip of a sed. grain and
precipitates next to the sharp tip, or its material that is carried by water flowing through the rock (say water
getting squeezed out of sediments buried even deeper).
e. Sedimentary rock resources
i. Coal, oil, natural gas, sand & gravel, gypsum, uranium (Moab), etc.
ii. Coal comes from plant material (peat), whereas oil primarily is derived from plankton in marine sediments. Oil
migrates from a source rock into a trap (‘reservoir’). Each must be cooked to the correct respective temperature
to become valuable coal or oil.
iii. see the handout on sedimentary rock resources
Metamorphic Rock - Igneous or sedimentary rock modified by heat and pressure. A metamorphic rock has NOT melted.
Temperature in the crust increases about 20 or 25oC with each kilometer of depth; pressure increases by about 250 bars
(one bar equals one atmosphere of pressure, which is about 15 psi or about one half the air pressure in a car tire). At 20
km depth, it is pretty hot and a rock feels a lot of pressure, which leads to chemical changes, like cooking something in an
oven.
2. Heat (temperature) and pressure in the Earth’s crust cause rocks to be metamorphosed. In the Earth’s crust, temperature
increases about 25oC per kilometer depth (equal to about 75oF per mile). Pressure increases greatly with depth.
Metamorphism happens within the crust (i.e., not deeper).
3. Heat and pressure modify rocks through 3 mechanisms - recrystallization (grow bigger crystals; this happens when marble
forms from limestone), neomorphism (make new minerals out of the pre-existing ones), metasomatism (composition of
the rock changes, usually because gnarly water moves through and dissolves then removes or precipitates material; new
minerals form). Many economically important ore deposits result from metasomatism. After a sediment is
metamorphosed, it will have almost no pore space (voids), and the crystals in it will all nicely interlock with each other (as
opposed to the random pile you get at the bottom of the jug of sediment I brought in). At least to some extent, all three of
these mechanisms operate when a rock gets metamorphosed. However, one or two commonly dominate.
4. Metamorphic Grade. Grade describes how much heat and pressure a metamorphic rock experienced (and no doubt
enjoyed). Low grade means not too much heat and press., high grade means a lot. Low grade is about 200 to 300oC; high
grade is 500 and above, medium is in between. The same pre-existing rock can end up as a slate, phyllite, schist or even
gneiss (listed from low to high grade) depending upon on how much heat and pressure it undergoes (with more heat, a
slate becomes a phyllite; with yet more heat a phyllite becomes a schist). Know this sequence of rocks, in order of
increasing grade. Note that these are foliated rocks typical of regional metamorphism (see below).
5. 4 Metamorphic rocks have textures that tell you about how they formed. Textures are so important that met. rocks are often
named on the basis of their textures. Note that these textures are different from the types of textures that are found in
sedimentary rocks.
a. Foliation - planar layering that you can see. 2 types
i. Schistose - platy minerals - like biotite and muscovite - are lined-up parallel to each other, so the rock tends to
break in sheets like slate, and may look layered from the side. This layering is perpendicular to the direction
of maximum squeezing (flattening) that the rock enjoyed during metamorphism. The minerals become aligned
because the squeezing rotates the platy minerals into that position, and because the minerals can more easily
grow (recrystallization) in the directions of the least squeezing. Slates, phyllites and schists all have this type of
texture.
ii. Gneissic foliation - compositional layering, usually dark and light bands. Often enough the banding has been
folded, like a throw rug after your dog is done chasing your cat around your house.
b. Textural rock names
i. schistose foliation => slate, phyllite, schist (see page table 6.2)
ii. gneissose foliation => gneiss
iii. granular metamorphic rocks (no foliation) => marble (from limestone) and quartzite (from quartz-rich sandstone)
are common.
GEOL 1010, Introduction to Geology, Professor Bunds, Utah Valley University
c. Metamorphic rocks can also contain a lineation, which is formed by the parallel alignment of elongate or pencil shaped mineral grains. A lineation indicates the direction in which a metamorphic rock was stretched.
6. Metamorphic environments. Regional, contact and hydrothermal metamorphism.
7. Regional metamorphism occurs where a large (say state-sized, at least a little east-coast state) volume of rock gets buried
deeply enough to get metamorphosed, then makes its way back to the surface for us to look at and get fired up about. This
typically happens as a result of subduction and/or mountain building and leads to the formation of foliated rocks like
slates, schists, gneisses etc. Regional metamorphism usually lasts a long time, since it takes time for rocks to get buried
deeply then pushed back to the surface; consequently, large crystals may grow if the rock gets hot enough.
a. Regional metamorphism at subduction zones can be relatively low temperature but high pressure (low T/P), high
temperature but low pressure (high T/P), or high-Temperature and high-pressure. In fact, belts of the first two
types of regional metamorphism almost always form alongside each other at subduction zones. Rocks that get pushed
downwards (subducted) with the subducting oceanic plate enjoy low T/P metamorphism because they go deep into the
Earth (say 20km = 12 miles, or more) but stay relatively cool because the subducting plate is cool from being at the
surface of the Earth. (Eventually the subducting plate gets heated by the surrounding crust/mantle, but that takes
millions of years). Under and along the volcanoes over the subduction zone, relatively high-T, low-P regional
metamorphism happens. This is caused by the hot magma that moves up into the crust over the 10’s of millions of
years that the subduction and causes volcanism and plutonism. Both the low T/P and high T/P rocks commonly are
exposed at the surface by erosion, and they form two belts. The belts are called PAIRED METAMORPHIC BELTS and
they record the presence of a subduction zone in the past. A nice example of such a pair exists in California; the pair
tells us there was a subduction zone there for a long time. Very deep under mountains rocks undergo very high-grade
metamorphism that is both high-Temperature and high-pressure. Know these three types of regional
metamorphism and be able to place them on an illustration of a convergent plate boundary. See your handout for
illustrations.
b. Contact metamorphism occurs around intrusive igneous bodies, where the hot magma cooks the surrounding preexisting rock. This results in rather high-temperature, low pressure, quick metamorphism. This cooking along a
pluton is a relatively local effect that usually is confined to within to hundreds of yards of an individual pluton. The
resulting rocks usually are fine grained and non-foliated because contact metamorphic event doesn’t provide enough
time for crystals to grow large and the pressure is relatively small and doesn’t cause a foliation to develop.
Hydrothermal Metamorphism: Hot fluids often circulate around cooling plutons and cause metasomatism to occur.
Metasomatism caused by reactions between hot fluids and rock is also called hydrothermal metamorphism. It is the
origin of many economic ore deposits, such as the Bingham copper mine, and ore deposits in. Wasatch - Alta, Park
City, Mineral Fork, etc. They form when hot, often acidic fluids carry economically important elements and dissolved
minerals, undergo chemical reactions in rocks and leave the valuable metals as ore minerals or as native elements.
They typically are associated with plutons, which supply the heat that warms and mobilizes fluid. The plutons in the
Wasatch mountains (e.g., the Alta Stock) have well – developed zones of contact metamorphism around them.
c. Gold deposits. Lode deposits are vein-like accumulations of valuable material,usually a metal like gold or silver.
Lode – type gold deposits occur where hydrothermal fluids that carried dissolved gold underwent a chemical reaction
and precipitated the gold in the vein. The ‘Mother Lode’ is/was a huge gold lode deposit in California that was mined
after the gold rush. Placer deposits consist of gold (or other metals) in river sediments (usually gravels). They form
when gold – from a lode deposit – is eroded and washed down a river, then the gold collects in sediment left by the
gold. When people ‘pan for gold,’ they are trying to get gold from placer deposits. People work placer deposits in
Tibble Fork (near American Fork, Utah County) today. The last major gold rush in the lower 48 (U.S.) was to
Deadwood, South Dakota, in 1876.
EARTHQUAKES.
Definition.
Most are caused by brittle slip on faults. Approximate maximum depth at which this happens.
Faults
1. Hanging wall vs footwall. In a tunnel dug along an inclined (non-vertical) fault, you stand on the footwall,
hang your lantern on the hanging wall.
2. Normal fault – hanging wall down. The Wasatch fault is an active normal fault. From in response to
horizontal extension or stretching of the Earth’s crust, and are most common at divergent plate boundaries.
Generally produce earthquakes magnitude 7.5 and smaller.
3. Thrust or Reverse faults – hanging wall up; most slope or dip shallowly and are called thrust faults. Form
in response to horizontal shortening or compression of the Earth’s crust and are most common at convergent
plate boundaries. The area of contact between a subducting plate and overriding plate at a subduction zone is
a thrust fault; sometimes its referred to as a “megathrust.” Can produce earthquakes up to magnitude 9.5.
4. Strike slip faults – are right-lateral or left-lateral. The San Andreas is _____ - lateral. Most common at
transform plate boundaries. Generally produces earthquakes magnitude 8 and smaller.
Elastic Rebound theory – know it; be able to explain it.
GEOL 1010, Introduction to Geology, Professor Bunds, Utah Valley University
Wave types: P, S, surface (Rayliegh and Love). Movement of particles in disturbed medium, speed, the order they
arrive a distant site, which is most damaging.
Epicenter and Hypocenter (or focus). The hypocenter (focus) of an earthquake is the location underground where
the sliding on a fault that produced the earthquake initiated. For smaller earthquakes (up to perhaps
magnitude 5) it can be thought of as the location underground where the earthquake happened (i.e., where the
sliding occurred on a fault). However, for larger earthquakes (especially magnitude 8 or 9), 100’s of
kilometers of fault undergo sliding, and the sliding doesn’t happen simultaneously at every location on the
fault. Rather, the sliding initiates at a spot then spreads across and along the fault over time, much as a crack
propagates across a car windshield.
The epicenter is the spot on the ground surface directly above the hypocenter.
The locations of the hypocenter and epicenter are determined from P and S-wave arrival times at at least
three seismometers. Be able to do this.
Magnitude, shaking intensity and energy of earthquakes
How Richter magnitude is determined
What a seismometer is, basics of how one works
Distinguish intensity from magnitude. Magnitude is an intrinsic property of an earthquake; no matter where
its measured the same magnitude should be found. Intensity refers to the intensity of shaking at a particular
place; the shaking at a place depends primarily upon an earthquake’s magnitude, distance from the shaking
site, and the ground type at the site. The two parameters are measure using different scales (see below)
Magnitude: there are several measures of magnitude; the most common are Local Magnitude (very similar
to Richter magnitude) and moment magnitude. Both are logarithmic, and with each increment increase in
magnitude waves are tenfold larger and the EQ lasts ~ 3x longer, so a 7 releases over 30 times more
energy than a 6 (same for a 5 compared to a 4, etc.). Local magnitude is determined from the amplitude
of the earthquake waves after adjusting for distance between the seismometer and hypocenter. Moment
magnitude is defined as the area of fault that underwent slip multiplied by the amount of multiplied by
the strength of rocks cut by the fault. Moment magnitude is the better measure, especially for
earthquakes greater than magnitude 7.5.
Magnitude of an earthquake depends largely on the area of fault that undergoes sliding and amount of slip –
bigger fault with more slip means bigger EQ (for example, fault length ~ 40 km = M7. M8 on 400 km
fault. Consequently, it is possible to infer magnitude from amount of slip in past earthquakes: 1 – 2
yards => M7 to M7.5; 5 to 10 yards => M8.
Modified Mercalli Intensity Scale is used to measure shaking intensity at a site – know general idea and its
utility (can be applied to pre-seismometer earthquakes, describes shaking at a spot, damage).
Energy: The amount of energy released in an earthquake increases approximately 33 times for every
increase in magnitude of one. For example, a magnitude 4 earthquake releases 33 times more energy
than a magnitude 3, and a magnitude 5 releases 33x33=1100 times more energy than a 3.
Earthquake Hazards
Shaking: Controls on Shaking Intensity
destructive shaking produced mainly from surface waves, well-measured by peak ground
acceleration and peak ground velocity
depends on magnitude, distance from the EQ and rock type, and the design and construction of
structures.
liquefaction, and its importance to us
Building design and construction is key to their resistance to EQ Damage. Wood frame houses are
pretty good, unreinforced masonry pretty bad (including brick chimneys). There are many
layer-cake multi-story structures in the world that tend to ‘pancake’ in earthquakes; many of
these in California have been retrofitted and reinforced for earthquake safety.
Ground rupture: In large earthquakes (generally magnitude 6.5 or 7 and larger) the ground surface is
ruptured and offset by sliding on the fault. The offset of the ground surface can disrupt or destroy
structures such as building, dams and roadways.
Tsunamis – Large waves. Caused by actual movement of land surface in earthquake or by landslides
triggered by earthquake. Can wash thousands of feet vertically onto land. Large, damaging, oscillating
waves called seiches can be created in lakes.
Landslides also are a significant hazard from earthquakes.
Fire: Fire is a major potential hazard following earthquakes because broken gas lines or other damage can
lead to fires in urban areas, and damage to infrastructure such as roadways and water lines can limit
people’s ability to fight them.
Forecasting earthquake hazards
GEOL 1010, Introduction to Geology, Professor Bunds, Utah Valley University
We cannot predict earthquakes, strictly speaking. A prediction would be to accurately state when, where and
how large a future earthquake will be. Instead, we forecast the probability (chance) of a large earthquake
occurring in a future time period, along with the likely magnitude of the earthquake.
paleoseismology - when EQ’s happened in the past ; much information is taken from trenching studies. In
Utah, there have been no large EQ’s in historic time, so we depend on trenching studies for information on
past EQ’s on the Wasatch fault. In a trenching study, the location of a fault is identified, usually by the
presence of a scarp, and a trench is dug across the fault. Geologists examine the walls of the trench for soil
and sediment layers broken by fault slip during past earthquakes. The size of the earthquakes can be
estimated from the amount of slip, and the age of the earthquake can be estimated by radiocarbon dating of
the soil layers.
Then, the average of times between past EQ’s is calculated; it is called the recurrence interval or repeat time
Next, using the repeat time and the amount of time since the last EQ on the fault, geologists forecast the
likelihood of the next EQ occurring within a future time period, often the next 30 or 50 years
How big a future large earthquake may be is estimated from the amount of slip in past earthquakes, as well as
from the length of fault expected to rupture. For example, slip of 1 – 2 yards on a fault 40 km in length
will produce approximately a M7 EQ, whereas; 5 to 10 yards of slip on a fault 200 to 400 km in length will
produce an M8.
Geologists also use distance from the
expected epicenter & rock type to
predict shaking intensity at a location.
EARTHQUAKE HAZARDS IN UTAH
Steep mountains are an indication of active faulting
Geologists look for fault scarps along the
mountain front, and elsewhere. Scarps
indicate recent (past 1000’s of years)
earthquake activity. We looked at a scarp
from the Wasatch fault on a field trip to
Rock Canyon. Examples from the mouth of
Little Cottonwood Canyon (top), and
California are shown on the right.
Trenches are dug through fault scarps to identify
ancient, buried soil layers broken by past
earthquakes.
By dating the broken soil layers, we have
identified when large earthquakes have
struck in the past 7000 years or so along the
Wasatch fault.
Using this information, we can forecast the
likelihood of a large earthquake occurring
in a future period of time (say the next 25
or 50 years). This is like forecasting the
likelihood of a large snow storm in Orem
based on how often very large storms have
struck Orem in the past, and how large the
storms have been.
Several important points:
A large earthquake may (hopefully) result
from a fault breaking and sliding
along only one segment of the fault’s
entire length. For example, UVU is
on the Provo segment (Payson to Pt.
of the Mtn.) of the Wasatch fault.
SLC is on the Salt Lake Segment (Pt
of the Mtn.
to about the State Capitol). The segments of the Wasatch fault are about 40 km long. The amount of
movement that has occurred in past earthquakes on the Wasatch fault, as determined from trenching
studies, varies from about 1 to 3 meters. Based on the length of the segments of the Wasatch fault and the
amount of slip in past earthquakes, it is estimated that a large earthquake on the Wasatch fault would be
GEOL 1010, Introduction to Geology, Professor Bunds, Utah Valley University
magnitude 7 to 7.5. An earthquake on more than one segment at once could be M7.8 or even larger, but
this is unlikely to happen.
Large earthquakes strike somewhere along the Wasatch front about every 350 years. A large earthquake strikes
on any given segment of the Wasatch fault about every 1200 to 2600 years. The Salt Lake segment last
had an earthquake about 1200 years ago, and has had earthquakes about every 1200 years, so it is due. The
Provo segment last had a large earthquake about 650 years ago so it is not ‘due.’ However, there are no
guarantees based on our current understanding of earthquakes.
Threats posed by earthquakes
ground shaking, liquefaction, landslides, fire and even disease
And don’t forget:
Most Earthquakes happen at plate boundaries
Largest are at convergent
Medium at transform
Smallest at divergent (normal faults)
Study Questions
Being able to answer these questions is a great path to success on the midterm.
If you want to turn these in for insurance, please be sure to answer them on separate sheets of paper and staple everything
together! Be sure to answer these and the book questions in complete sentences, using sketches where appropriate or
useful. Note that if you score below C- on the exam you can receive points equivalent to a C- by doing these questions AND
the suggested problems from the back of the appropriate chapter AND turning them all in before the end of the testing
period. The suggested chapter problems are listed on the course syllabus.
1.
Which happens first - erosion or weathering?
2.
What are the two main effects of chemical weathering?
3.
What types of minerals are common products of chemical weathering?
4.
What common rock type is particularly susceptible to being dissolved by water?
5.
Why is water such a powerful solvent?
6.
Is quartz susceptible to chemical weathering?
7.
Name 4 main causes of mechanical weathering, and give the name of the material produced by mechanical weathering.
8.
List the different types of detritus in order from smallest grain size to largest.
9.
What are the two main types of sedimentary rock? How do they relate to the types of weathering?
10. How are detrital (or clastic) sedimentary rocks classified (i.e., named)?
11. Name 5 common types of bio-chemical sedimentary rocks. For each, explain how they form, and what type of
environment they form in.
12. What is meant by a 'high energy' depositional environment?
13. Give an example of a type of sedimentary rock that is deposited in a high energy environment.
14. There is a great deal of limestone in the Wasatch Mountains near Orem. Much of it is approximately 300 to 340 million
years old. What was the geography of Utah like at that time (desert, ocean, lakes, etc.)? Be as specific as you can.
15. As you walk along a sedimentary bed (one layer of rock formed at the same time by the same process), you notice that the
large sand grains get more and more angular. Are you getting closer or further from where the sand grains were eroded?
16. Above the sedimentary bed of sandstone mentioned above (which clearly formed near an ocean beach, since it contains
marine clam fossils) you find a pair of thick layers of salt (NaCl) and gypsum (CaSO4*H20). What do those rocks tell you
probably happened in the past (how did the salt and gypsum layers probably form?).
17. Above the salt and gypsum, you find a layer of rock that contains boulders as well as sand and even flour-sized grains.
The boulders are moderately well rounded. In what sort of environment was the layer formed?
18. The Entrada Sandstone (a thick layer/horizon of sandstone) in Arches National Park was deposited as sanddunes. One of
the reasons we know this is that it contains very large cross-beds. Sketch crossbedding (like we did in class), and explain
how it can be created by sand dunes. An additional sketch will aid your explanation. How does the shape of crossbedding relate to the law of superposition and identifying younger and older layers of sedimentary rock in nature?
19. Describe what an alluvial fan is, and how one can be recognized by its shape and location (as seen from a distance) and by
the sediment it consists of.
20. List 2 depositional environments (other than the ones described above), and list some sedimentary rock features that would
be indicative of deposition in each of the environments.
GEOL 1010, Introduction to Geology, Professor Bunds, Utah Valley University
21. Describe what must have happened to the sand in the Entrada to transform it from sand in sand dunes (i.e., sediment) into
sandstone?
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Briefly describe what a sedimentary basin is, and give an example of one.
Describe the origin and formation of coal.
List three other resources that humans get from sedimentary rock (i.e., other than coal and oil).
What are the basic factors that cause metamorphism? (Rocks are tough, why do they ever change?).
What are the three types of change that can occur in rocks during metamorphism? Explain each.
Explain how the results of neomorphism are very useful for determining how hot a rock was during metamorphism.
Which one of the three types of change can form rocks rich in gold, silver and copper (among other elements)?
What type of change is most important in creating marble?
What is the parent rock (protolith) of marble?
What two factors are the main controls on what type of metamorphic rock is produced by metamorphism?
What type of mineral is particularly susceptible to neomorphism, and how is this type of mineral often formed in the first
place? [we talked about this in class at least twice!]
About how hot are the rocks 10 km below where you are sitting right now? Show your work.
What are the two main types of metamorphic foliations, and how do they differ?
Draw a sketch of a schist that was squeezed and flattened (as much as a canned ham under a steam roller) horizontally
(i.e., it was much wider in the horizontal direction than it is now, as you draw it). Be sure to draw the texture of the rock
correctly in relation to the direction that the rock was squeezed and flattened.
What causes the minerals to become aligned in a schist?
Which is higher grade - a schist or a slate? List the series of regional metamorphic rocks that we discussed in class.
What aspect of metamorphic rock best indicates the temperature (and pressure) at which it was metamorphosed? [hint,
look at your answers above!].
What are the two main types or settings in which metamorphic rocks are formed?
Describe paired metamorphic belts.
Where do paired metamorphic belts form? Use a sketch as part of your answer.
Name a place where paired metamorphic belts can be found (we talked about a location in class).
Many precious metal deposits are associated with metamorphic rocks. Using a sketch and words, explain the type of
metamorphism that can form precious metal deposits, and how the deposits are formed.
What is hydrothermal metamorphism.
Draw a left-lateral strike-slip fault offsetting a road, and label it with motion arrows.
At what type of plate boundary are strike – slip faults common? Why? Give an example of a well-known strike-slip fault.
Draw and label a normal fault.
A t what type of plate boundary are normal faults common? Why? Give an example of a well-known normal fault.
Draw and label a reverse fault.
At what type of plate boundary are reverse faults most common?
A t what type of plate boundary are normal faults common? Why? Give an example of a well-known normal fault.
Explain the 3 types of waves produced by earthquakes.
Which type(s) of earthquake waves are most damaging?
Explain, using words and a sketch, what the epicenter and hypocenter of an earthquake are.
How does the concept of a hypocenter differ for very large earthquakes in comparison to small ones?
Explain how the energy of the slow movement of lithospheric plates is stored and released suddenly to produce
earthquakes. Use a series of 3 or 4 sketches in your answer.
What kind of plate boundary produces the largest earthquakes?
What is the largest magnitude earthquake likely to occur at a transform plate boundary?
What is the largest magnitude earthquake likely to occur at a divergent plate boundary?
How is the Richter magnitude of an earthquake determined?
How is the moment magnitude of an earthquake defined?
How much bigger are the waves from a magnitude 6 (M6) earthquake than a magnitude 5 (M5)?
How much longer does the M6 (magnitude 6) last than the M5 (magnitude 5)?
So how much more energy is released in an M6 than the M5?
How about an M8 compared to an M5?
How is the distance to the epicenter of an earthquake determined from a seismogram?
GEOL 1010, Introduction to Geology, Professor Bunds, Utah Valley University
67. If the P-waves from an earthquake arrive at your house 3.5 minutes before the S-waves, about how far away did the
earthquake occur? (use the figure in your textbook to solve this problem – be able to work with the figure and answer this
type of question.)
68. When the ‘big one’ strikes Utah, what magnitude will it probably be? On what basis is the estimate of the magnitude of a
big one on the Wasatch fault made?
69. What are the four crucial factors that combine to control how much damage occurs to a building as a result of an
earthquake?
70. What is liquifaction, what characteristics of the ground make it likely to happen, and where are these characteristics
prevalent in Utah Valley and/or the Salt Lake Valley?
71. In the past, how often on average has a large earthquake occurred along the Wasatch front?
72. In the past, how often on average has a large earthquake occurred at any one location along the Wasatch fault?
73. Name five major types of hazard from earthquakes.
74. Is there a danger from earthquake-induced waves in Utah?
GEOL 1010, Introduction to Geology, Professor Bunds, Utah Valley University