3.13.R - Lesson Review: Relative Age Dating of Rock Layers / Rock Correlations Flashcards
If rock layers have not been disturbed, the oldest rock layers should be at the bottom. This is called the __________ _____ ___________.
Principle of Cross-Cutting
Principle of Inclusions
Principle of Superposition
Principle of Subposition
Principle of Superposition
An unconformity in the rock layers can be an area ___________.
that was laid down first
that was eroded
that was intruded upon
that was eroded
Rock is always laid down __________.
vertically
in an igneous intrusion
horizontally
horizontally
The Law of Original Horizontality states that rock layers are going to be deposited __________.
in mounds
diagonally
in layers
in layers
Match the following:
Older layers are laid down first with younger layers on top
Law of Original Horizontality
Igneous intrusions and faults are younger than the rock layer they are in
Unconformity
Rock layers that have been laid down horizontally, tilted, eroded, and submerged
Contact metamorphism
An igneous rock layer laid down on the surface of the Earth
Nonconformity
Rock that is found inside other rocks are older than the rocks that contain them
Uplifting
Igneous intrusions have caused sedimentary rocks to change to metamorphic rocks
Extrusive igneous layer
A sedimentary rock layer overlies a non-sedimentary rock layer with the erosion in between
Law of Intrusions
In undisturbed rock layers, sedimentary rocks are generally laid down in horizontal layers
Law of Cross-Cutting Relationships
A gap in the geological record due to erosion
Angular unconformity
Rock layers that have been pushed up
Law of Superposition
Older layers are laid down first with younger layers on top
Law of Superposition
Law of Original Horizontality
In undisturbed rock layers, sedimentary rocks are generally laid down in horizontal layers
Igneous intrusions and faults are younger than the rock layer they are in
Law of Cross-Cutting Relationships
Unconformity
A gap in the geological record due to erosion
Rock layers that have been laid down horizontally, tilted, eroded, and submerged
Angular unconformity
Contact metamorphism
Igneous intrusions have caused sedimentary rocks to change to metamorphic rocks
An igneous rock layer laid down on the surface of the Earth
Extrusive igneous layer
Nonconformity
A sedimentary rock layer overlies a non-sedimentary rock layer with the erosion in between
Rock that is found inside other rocks are older than the rocks that contain them
Law of Intrusions
Uplifting
Rock layers that have been pushed up
What is the order of undisturbed rock layers?
The youngest rocks are on the top; the oldest are on the bottom.
The oldest are on the top; the youngest are on the bottom.
Rock layers may be faulted, so the oldest will be the fault, and the youngest will be the bottom.
The youngest rocks are on the top; the oldest are on the bottom.
Index fossils help geologists __________. (Select all that apply)
to determine the order in one outcrop and how it matches another outcrop
to devise the order layers in an area were laid down
to see where the volcanic ash is
to compare outcrops
to determine the order in one outcrop and how it matches another outcrop
to devise the order layers in an area were laid down
to compare outcrops
All of the following are examples of outcrops except ___________.
roadcuts
dirt piles from road construction
riverbanks
dirt piles from road construction
If a geologist “walks the outcrop” he ____________________.
walks along the actual outcrop matching the layers from one spot to the next
walks along the top of the outcrop to see where the next outcrop begins
layers several maps and looks for index fossils
walks along the actual outcrop matching the layers from one spot to the next
What is an outcrop?
The opposite of an incrop
An exposed layer of bedrock
An outside crop
An exposed layer of bedrock
What practical application might geologists have in using index fossils and geologic maps?
They can find natural resources, such as oil and coal, in similar rock layers as elsewhere.
They might be able to find where to put a building.
They might be able to find underground rivers.
They can find natural resources, such as oil and coal, in similar rock layers as elsewhere.
Fill in the following blanks.
The Grand Staircase in the desert of the Southwest United States includes the Grand Canyon. The
[ Select ]
__________ of the Grand Canyon is the
[ Select ]
__________ of Zion National Park. The
[ Select ]
__________ of Zion is the
[ Select ]
__________ of Bryce National Park.
top
bottom
top
bottom
Explain the difference between an unconformity and a disconformity. Please answer with 3 to 5 sentences using your best grammar.
There are many differences between unconformity and disconformity. One primary way they are different is how disconformity is when a sedimentary rock lies on top of an eroded sedimentary rock. Unconformity is when most or sometimes all of the rock layers are eroded, and it can even show the rocks breaking at two separate times. Therefore, the difference is that disconformity affects one rock layer while unconformity affects both rock layers.
