GLY 101 Exam 2

Which rock type is most likely to contain fossils

Sedimentary

Which rock type makes up the majority of earths outermost solid surface

Sedimentary

What is diagenesis

the changes that convert sediments to sedimentary rocks after deposition

Which of these processes describes eroding of existent rocks and ions to produce sediments?

Weathering

Which minerals are the main constituents in most sedimentary rocks

quartz and clay minerals

which of the following rocks composed of silt- and clay- sized particles displays fissility

shale

Which environment would be likely to produce a black shale

swamp

_______ describes the range in particle sizes in a detrital sedimentary rock

sorting

Which of the following methods of transportation will result in the nest degree of sorting

Wind

Which of the following methods of transportation will result in the least sorted deposit

streams

which of the following best describes the texture of a conglomerate

rounded fragments; poorly sorted

Which is the the most abundant chemical sedimentary rock

limestone

______ processes, such as evaporation or precipitation, can precipitate chemical sediments

inorganic

The famous Permian _____ reefs in the Guadalupe mountains national park are a rich source of organic material.

Limestone

_____ are tiny "seed" particles created when small sediments or shell fragments are rolled waves in water supersaturated with calcium carbonate

ooids

Which of the following best describes interbedded gypsum and halite

evaporitic sedimentary rocks

A soft, porous rock made up almost entirley of the hard parts of microscopic marine organisms is _______

chalk

Which of the following locations will see the deposition of sylvite and gypsum

evaporating sea basins

The mineral _____ is composed of calcium carbonate with magnesium incorporated in its chemical structure

dolostone

Which of these forms of coals is a metamorphic rock?

Anthracite

Compaction will be the most significant lithification process for which of the following rocks

shale

The primary basis for classifying detrital rocks is _____, whereas the primary basis for classifying chemical rocks is _______

Particle size; mineral composition

Medium grains are those that are between _____ mm in size

1/16 to 2

A _____ describes the observation of successive changes in a laterally continuous sedimentary layer that are visible and are interpreted as a result of many depositional processes taking place over a large area.

facies

Which of the following represents the single most common characteristic structures in sedimentary rocks?

Strata

A ______ marks the end of one episode of sedimentation and the beginning of another

bedding plane

______ is a variety of sandstone that is associated with submarine landslides called turbidity currents.

graywacke

Which of these aquatic organisms can form chemical sediments

corals

What sediment particle size(s) makes up shale

silt and clay

What information can evaporites provide about the past environment of deposition

The paleoenvironment was wet

______ is the process by which a rock changes form or mineral content as a result of environmental changes such as heat and pressure

metamorphism

What is the definition of a parent rock

The rock that was altered by metamorphism

Which of the following is the parent rock of quartzite

sandstone

Which low grade metamorphic rock displays thin, parallel layers and contains very fine grains of mica

slate

Which of the following lists of metamorphic rocks places the rocks in order from lowest metamorphic grade to highest

slate, phyllite, schist, gneiss

Which of the following rocks is produced by high-grade metamorphism

gneiss

______ is the process by which new mineral grains larger than the original mineral grains form as a result of metamorphic heat

recrystallization

Generally speaking, how does the chemical composition of most metamorphic rocks compare to that of the parent rock

nearly same

What kind of force creates foliation in metamorphic rocks

compression

What are foliations

roughly parallel layers of mineral crystals aligned perpendicular to the direction of pressure

Which of the following is not an example of foliation

recrystallization of spherical minerals to create crystalline metamorphic rock, with no alignments of minerals

Metamorphic rocks can sometimes contain unusually large grains surrounded by a fine-grained matrix of other minerals. These large crystals are called _______

porphyroblasts

A coarse-grained, banded metamorphic rock in which elongated minerals predominate is called ________

gneiss

Which of the following is not an environment of metamorphism

slow cooling of magma

Which of the following scenarios best describes the formation of hornfels

shales and mudstone are baked during contact metamorphism

Which style of metamorphism will be generated by a magma pluton

contact

______ is a widespread type of metamorphism typically associated with mountain building

regional metamorphism

______ are materials that are good indicators of the metamorphic environment in which they formed and can be used to distinguish between various zones of metamorphism

index minerals

What is a metamorphic facies

an assemblage of minerals that form in very similar metamorphic environments

A(n) ______ facies is associated with a high-pressure, low-temperature environment

blueschist

What is the most important factor driving metamorphism

heat

Why will metamorphic rocks found in a containing metamorphism aureole be non-foliated

Because the main agent of metamorphism is heat, which will result in intergrown crystals

_______ metamorphism is responsible for the emplacement of metallic ore veins

hydrothermal

_______ metamorphism will occur where two blocks of rock are grinding against each other

fault zone

Why is quartz a bad mineral to use to determine a metamorphic environment

because silicate minerals do not metamorphose

What kind of temperature and pressure conditions will exist in a burial metamorphism environment

high temperature high pressure

What is the average increase in temperature along the geothermal metamorphism environment

25°C per km

What are the two main categories of metamorphic texture

foliated and nonfoliated

Most metamorphic rocks near the earths surface are derived from three common sedimentary rocks. Which three

shale, quartz sandstone, and limestone

Which list below contains three rocks that are produced by contact metamorphism

quartzite, marble, and hornfels

A(n) _____ is a type of unconformity with parallel beds above and below the erosional surface

Disconformity

Which of the following is an example of a numerical date

A meteorite impacted the earth 65 million years ago

Which of the following is an example of a relative date

The Silurian period came before the Devonian period

What scientific development made accurate numerical dating possible

discovery of radioactivity

What is the definition of an inclusion

a fragment of one rock unit enclosed in another rock unit

When rocks are ______ several adjacent layers were deposited without interruption

conformable

What is a fossil

evidence of past life that can include skeletal as well as trace material

A black, organic residue of an ancient fern would be an example of which type of fossilization

Carbonization

Which of the following is an example of a trace fossil

gastroliths

When a shell is buried in sediment and subsequently dissolved, a cavity called a _______ is left behind. When this cavity is filled with sediments, a ______ is created.

Mold; cast

A worm burrow is an example of which type of fossilization

Trace fossil

What is stratigraphic correlation

Matching up rocks of similar age in different regions

The principle of _______ states that organisms succeed one another in a definite, determinable order that can be used to recognize a specific time period

fossil succession

When correlating rock between widely separated areas or between continents, what features(s) do geologists rely on the most to link distant rock units of similar age

fossils

What is an index fossil

An organism that was geographically widespread but limited to a short span of geologic time

What is a fossil assemblage

A group of fossils used to establish the age of a rock unit

If 235U has 95 protons, how many neutrons does it have

143

_______ is a technique where the decay rate of radioactive isotopes is measured and used to determine the age of a geologic material

Radiometric dating

What is the definition of half-life

The time it takes for half of the parent isotope to decay to the daughter

Which particle of an atom will determine the atomic number of an element

proton

You are trying to determine the age of a lava flow using an isotope with a half-life of 1.5 million years. If the sample has gone through four half-lives, what is the age of the rock

6 million years

What materials are best dated with carbon-14

organic materials

What is the effective maximum range for carbon- 14 dating

70,000 years

A deposit of volcanic tuff contains the isotope potassium- 40 which is slowly decaying into argon-40. How might the apparent age of the sample be affected if the volcanic tuff is heated and remains heated for a long period of time

Younger than actual age

What does "zoic" in the eras of the geologic time scale refer to

life

which two conditions are the most important in order for an organism to become fossilized

rapid burial and possession of hard parts

A neutron is a combination of a(n) _______ and a(n) _______

electron; proton

The white granite of the Idaho batholith near Boise, Idaho, contains dark gray xenoliths of metamorphic material. Which is older and how do you know

Xenoliths; the principle of inclusions

Which of the following would make the best index fossil: Olenellus (522-510 million), Flexicalymene (490-418 million) or Phacops (418-360 million)

Olenellus

What is the ultimate source of naturally occurring carbon- 14

Cosmic ray collisions and neutron capture involving nitrogen

______ refers to the changes in shape or position of a rock body in response to differential stress

deformation

Which of the following is the best description for structural geology

study of rock deformation in response to tectonic forces

How does compressional force change a rock body

Shorten and thicken rock

How does tensional force change a rock body

Stretch and thin the rock

Which tectonic boundary is associated with compressional stress

convergent

A rubber band being stretched in preparation to fire across the room is an example of what kind of deformation

elastic deformation

Unbending a paper clip wire is an example of what kind of deformation

Ductile deformation

If you were to place a circular mark on a rock surface and then subject it to shear stress, what shape would the circle then become

oval

Which of the following rocks would be more likely to experience brittle deformation rather than ductile deformation when subjected to stresses that exceed their strength

Sandstone

A chocolate bar will behave similarly to a rock. If you try to bend a chocolate bar at room temperature it will ______ exhibiting ______ behavior

Snap; brittle

What is a fault

A fracture in a rock along which motion has occurred

Folds form in ______ temperature _____ pressure environments

High; high

faults form in _______ temperature ______ pressure environments

low; high

A ______ is a circular fold where the youngest layers are in the middle and the oldest layers are on the outside

Basin

You are accuracy-checking a geologic map of a structural dome with the inner layers dating back to the Paleogene and its outer layers dating back to the Permian. You immediately know this map is wrong. What is your evidence

Domes have the oldest layers in the middle, not the youngest

What is the outcrop pattern of a plunging syncline

The layers will open up in the direction of plunge

A(n) _______ fold has limbs that are tilted beyond the vertical to the point that the axial plane is horizontal, giving it the appearance of lying on its side

overturned

Which tectonic boundary would have many normal faults associated with it

Divergent

A _____ fault is created when the hanging wall moves down relative to the footwall

Normal

What is the difference between a reverse fault and a thrust fault

A thrust fault has a fault angle less than 45 degrees whereas the angle of a reverse fault is greater

Which of the following scenarios would best indicate that a thrust fault is present at a location

Cambrian aged rocks have been shoved on top of Jurassic-aged rocks

Faults that exhibit both dip-slip and strike-slip movement are called _____ faults

oblique-slip

Mountain ranges such as the Appalachians and the Himalayas are examples of mountains that formed as a result of _____ faulting.

thrust

A ______ fault has a vertical fault plane and shows movement parallel to the orientation of the fault

strike-slip

What are slickensides

polished and striated surfaces made on fault blocks

Which of the following are examples of fault block mountains

rocky mountains

________ is the compass direction of the line produced by the intersection of an inclined rock layer with a horizontal plane

Strike

_______ is the angle of inclination of the surface of a rock unit measured from a horizontal plane

dip

Which of the following best describes the age relationship of the layers in a syncline

Oldest on the inside of the fold, youngest on the outside

Movements along normal faults can produce alternating upthrown and down-dropped fault blocks. What are the names associated with these blocks, respectively

horsts and grabens

What is the term for stored up energy released by earthquakes

Seismic

What is an epicenter

The location on earths surface directly above the point of slippage

What is the definition of the focus

The exact location on the fault where slippage occurs

Which of the following researchers coined the term elastic rebound after the 1906 San Francisco earthquake

H. F. Reid

The elastic rebound associated with earthquakes is an example of ______ behavior

Elastic

______ are smaller earthquakes of lesser magnitude, but nonetheless sometimes dangerous, that follow a major earthquake

Aftershocks

Which tectonic boundary is associated with megathrust

Convergent

Which tectonic boundary is responsible for the most powerful and destructive earthquakes recorded

Convergent

What is the term used to describe slow, gradual displacement along a fault without the accumulation of significant strain

Fault creep

_______ is a measurement of displacement on the fault surface

Fault slip

The San Andreas fault is a ______ fault

Strike-slip

_______ are records of seismic waves

seismograms

_____ are instruments that sense earthquake waves and transmit them to recording device

Seismometers

The suspended weight in a seismograph allows it to remain ______, which allows it to give a wave reading after the earth moves

motionless

Which seismic waves are released first during an earthquake

P waves

What is the minimum number of points needed to pinpoint the epicenter location of an earthquake, using the radius of a circle of possible points, as obtained from the lag time in arrival between a P wave and an S wave

3

When going from a 5 to a 6 on the Richter scale, what is the increase in amplitude of seismic waves

32 times

What information is needed to determine the distance from the focus of an earthquake to the seismic receiving station

The time interval between the P and S waves

Generally speaking, which seismic waves will have the greatest amplitude on seismogram

Surface waves

Which of the following best describes a seismic gap

faults that have not been active for several million years

The _______ is a newer scale that measures the total energy released during an earthquake by determining the average amount of slip on the fault, the area of the fault surface that slipped, and the strength of the faulted rock

Moment magnitude scale

The modified Mercalli scale is ______

still used today by the US Geological survey to gather data from those who felt an earthquake

Which of the following would be the most unstable during an earthquake

Unconsolidated sediments

Propagation of fault slip occurs at a rate of about ______ per second

2 to 4 km

Which plate boundary type along the circum-pacific belt is responsible for the majority of that belt's earthquakes

convergent

During an earthquake, energy waves radiate outward in all directions through the interior from the _____ whereas energy waves radiate outward in all directions along the surface from the ______

Focus; epicenter

The ground shaking produced by large earthquakes is not only _____, but takes a ______ time than shaking produced by slippage along small fault segments

stronger; longer

What are the two categories of seismic waves

Body waves and surface waves

Earthquake A is classified as a 3 on the Richter scale. Earthquake B is classified as a 6. Approximately how many times more energy has earthquake B released than earthquake A

1,000 times

What is the highest level on the Mercalli intensity scale

XII