Name: ___________________________________
Section #: __________
GEOLOGIC DATING: How do we know the age of rocks, fossils, and
other geologic events?
Introduction: Using the model and diagram provided by your instructor,
hypothesize the order of events that had to occur to form the colored
sand diagram.
Event #
Description
Reasoning
Correct
answer
1
2
3
4
5
Model Analysis
1. Think about it: What direction did all of the layers go?
1
Name: ___________________________________
Section #: __________
Law of original horizontality: Sedimentary layers of rock are deposited in a
__________________ direction. The exception to this rule is if layers are
deposited on a ___________________. (Greater than 30o.)
 When layers are folded, which will be younger, the layer or the fold?
2. Think about it: How did you figure out which layer came first or last?
 Would this reasoning always hold true, or would there be a
situation(s) where it may not be true?
Law of Superposition: The layer on top of another layer is
__________________ than the layer below. Some situations where this
would not occur are when layers are flipped over, faulted, or folded.
3. Think about it: Did all of the layers reach the edge? ____ Yes or ____ No
Lateral Continuity: Layers will continue until they reach an ___________ or
______________ as the materials that formed them ran out.
4. Think about it: Which came first, the layers or the sticks? How do you
know?
Law of Cross Cutting Relationships: Anything _____________ across
something else is __________________.
2
Name: ___________________________________
Section #: __________
Example: Using the diagram below, identify the order of events to form
this section of rock.
J=
Erosion
surface
F
D
A
I=
Erosion
surface
H=
E
B
G
C
Erosion
surface
Youngest
Place the events in the
correct order with the
oldest event on bottom
and the youngest event
on top.
Oldest
3
Name: ___________________________________
Section #: __________
Analysis: Try this one on your own!
2
Place the events
in the correct
order with the
oldest event on
bottom and the
youngest event
on top.
Youngest
1
10
6
7
5
3
9
8
4
Oldest
Key: 1 = Sedimentary Rock, 2 = surface erosion of cliff top, 3 = folding, 4 = fault,
5 = sedimentary rock, 6 = folding, 7 = igneous rock, 8 = igneous rock, 9 =
metamorphic rock, 10 = erosional surface
4
Name: ___________________________________
O
Section #: __________
P
J
A
Key:
P = tilt
of
layers
D, J, K,
M, & N
Place the events in the correct order with the oldest event on bottom and the youngest event
on top.
Event
Reasoning
5
Name: ___________________________________
L=
Tilt of
layers
E&X
C=
bend
of
layers
A, B,
H,
and R
Section #: __________
X
K
O
Place the events in the correct order with the oldest event on bottom and the youngest event on top.
Event
Reasoning
_______________ ___________________________________
_______________ ___________________________________
_______________ ___________________________________
_______________ ___________________________________
_______________ ___________________________________
_______________ ___________________________________
_______________ ___________________________________
_______________ ___________________________________
_______________ ___________________________________
_______________ ___________________________________
_______________ ___________________________________
_______________ ___________________________________
_______________ ___________________________________
_______________ ___________________________________
_______________ ___________________________________
_______________ ___________________________________
6
Name: ___________________________________
Section #: __________
_______________ ___________________________________
7