Geology 101
Laboratory
Geological Map Problem
A geologic map is a primary means of communicating geologic information. Geologic
maps illustrate the types of rocks in an area and how they are related to each other in age
and in structural position. The rocks on the map are grouped into formations or units.
Faults and folds are also shown on geologic maps.
To better understand geologic maps, you and several other classmates will investigate the
history of a map area as a group. You will need to learn to identify the rocks of the map
area and understand how the rock units are related to each other in a relative time
sequence.
During the time scheduled for the final exam, you will have a quiz that will cover your
map area. The quiz will be taken individually rather than as a group. You may use notes
that are in your own handwriting on this quiz. You will submit the notes with your quiz
paper.
If you organize your studying into the following three parts, you will have more success
on the quiz:
Part I: The name and classification of each sample. (Some of the maps have a small box
of sediment included. You do not have to identify all of the rocks in the box, just describe
the sediment and explain how the sediment was deposited. )
Part II: The relative age sequence of the units. You will notice that the maps contain
areas bounded by major faults. A letter designates these fault-bounded areas. Determine
the relative age sequence of the events in each area noted by a letter. This history should
include all periods of erosion, faulting, folding, metamorphism, etc.) Part II is like an
outline for part III. (Remember, the map is a top view, not a side view!)
Part III: The geological history of the area represented on the map. Include the
depositional environment for each unit, if known, and folding and/or faulting events.
Again, if the map has major faults that separate the map into fault-bounded areas, discuss
the history of each area separately, then note when the faulting occurred to bring the
various rocks into the same area.
I expect the each member of the group will do all three parts. The benefit of having
a group is to help you understand the map history.
There will be fourth part on the quiz. This part is not related to the map that you and you
group will investigate.
Part IV: A different (simpler) map will be on the quiz. You will be given the rock types
on this additional map and I will ask you questions about the history of this different map
area. The questions will be similar to part II above, but will be for this additional map
only.
If you have questions about what you or your group is to do, please let me know.
Geology 101
Geological Map 1
9
7
12
2
6
5
8
11
7
4
N
10
3
9
6
5
12
8
4
7
3
6
5
4
3
2
Area A
40
1
17
15
Area B
15
18
14
15
14
16
13
14
15
16
19
Additional Data:
Rock type Age
Rock type Age
9
Cretaceous
15
1.7 billion years old
10
Oligocene
16
1.7 billion years old
11
Pliocene
17
Triassic
13
600 million years old
18
800 million years old
The contacts between rock types 5 and 6 and 6 and 7 show slight metamorphism. Faults with “barbs” are
thrust faults. The barb points to the upper plate. See your text for further explanation.
Geology 101
Geological Map 2
6
Area B
1
Area A
4
17
N
2
3
16
4
15
5
14
13
6
30
7
8
8
18
15
7
14
6
13
5
9
10
11
Area C
12
Additional data:
Rock type
2
3
4
5
Age
1.7 billion
1.7 billion
800 million
Pennsylvanian
Rock type
8
10
12
13
17
Age
Triassic
Pliocene
Mississippian
Devonian
Permian
Geology 101
Geological Map 3
12
18
30
8
8
18
9
12
11
8
river
12
10
10
13
11
Area D
6
15
5
Area B
Area A
Area D
7
Area C
10
12
N
14
15
11
2
5
13
45
5
4
16
12
3
2
1
20
2
17
13
Additional Data:
Rock
Age
type
1
Pennsylvanian
2
4000 years
5
Cambrian
7
Devonian
8
Precambrian
The river is in the bottom of a canyon.
Rock type
Age
10
13
14
15
17
Oligocene
Miocene
Triassic
Triassic
Cretaceous
Geology 101
Geological Map 4
2
Area C
1
4
3
8
5
Area A
8
9
6
Lake
1
10
7
1
11
1
12
12
13
14
15
13
30
16
14
N
15
40
Area B
16
17
17
Additional data:
Rock type
Age
1
ages vary within period of 2000-5000
years age
2
1.4 billion
3
1.4 billion
5
2800 years
6
4000 years
7
4200 years
Rock type
9
11
12
13
17
Age
800 million
800 million
1.7 billion
Pennsylvanian
Cretaceous
Geology 101
Geological Map 5
15
ocean
18
Fault X
Area B
Fault Z
13
16
13
7
6
14
14
5
14
5
14
8
17
30
6
4
9
3
20
2
10
Area C
10
1
11
Area A
2
3
12
4
5
6
6
6
5
30
7
Additional Data:
Rock type
Age
Rock type
Age
Rock type
Age
1
600 million
8
Paleocene
14
400 million
4
Pennsylvanian
11
Jurassic
16
Oligocene
7
Triassic
12
Jurassic
Faults with “barbs “ are thrust faults. The barb points to the upper plate of the thrust fault. See your text for
a further description.
Geology 101
Geological Map 6
Dinwoody and Park City Fms.
Area A
3
2
2
1
3
4
5
6
4
1
60
13
40
14
13
7
13
17
13
14
13
Area B
10
15
12
N
14
11
10
13
14
9
8
30
16
30
Additional Data:
Rock types
Age
Rock types
Age
1
Precambrian
15
200 million
5
Cambrian
16
Eocene
6
Pennsylvanian
17
Quaternary
11
Cretaceous
The contacts between rock types 8 and 9 and 9 and 10 show slight thermal metamorphism. Faults with the
“barbs” are thrust faults. The barb points to the upper plate. See your text for a further description.
Geology 101
Geological Map 7
10
11
Fault B
10
2
10
10
3
Fault A
9
9
9
4
9
8
8
7
4
4
5
4
4
3
5
6
5
N
2
4
1
20
Additional Data:
Rock type
1
3
4
5
6
9
10
Age
Miocene
Eocene
Devonian
Permian
Jurassic
1.2 billion
1.2 billion
4
Sediment Sample locations for Map 7
At the locations shown by letters below, sediment samples were taken by drilling into the
ground. The data for these drill cores are on two separate sheets.
H
11
J
rivers
F
G
I
E
7
D
C
B
A
Sediment Samples for Map 7 (dates before present in parentheses)
B
A
Lahar (2400)
Andesitic ash (1100)
Andesitic ash (6000)
Andesitic ash (2400)
Fine dacitic ash (4000)
Andesitic ash (6000)
Andesitic ash (6600)
Coarse andesitic ash (6600)
Lahar (8400)
Pyroclastic flow (8400)
Fine dacitic ash (10300)
C
D
Lahar (100)
Pyroclastic flow (1100)
Coarse andesitic ash (2400)
Coarse andesitic ash (2400)
Lahar (4000)
Dacitic ash (4000)
Andesitic ash (6600)
Fine andesitic ash (8400)
Lahar (6600)
Lahar (10300)
F
G
E
Andesitic ash (2400)
Coarse andesitic ash (2400)
Pyroclastic flow (4000)
Dacitic ash (4000)
Andesitic ash (6600)
Andesitic ash (8400)
Pyroclastic flow (6600)
Pyroclastic flow (10300)
Dacitic ash (10300)
Coarse dacitic ash (12500)
H
G
Andesitic ash (1100
Andesitic ash ( 1100)
Lahar (2400)
Lahar (2400)
Dacitic ash (4000)
Dacitic ash (4000)
Pyroclastic flow (6600)
Andesitic ash (6600)
Lahar (8400)
Dacitic ash (10300)
Lahar (8400)
Dacitic ash (10300)
Coarse dacitic ash (12500)
Coarse dacitic ash (12500)
I
Andesitic ash (100)
Andesitic ash (1100)
J
Andesitic ash (100)
Andesitic ash (1100)
Dacitic ash (4000)
Andesitic ash (2400)
Dacitic ash (4000)
Coarse andesitic ash (6600)
Andesitic ash (6600)
Andesitic ash (8400)
Dacitic ash (10300)
Coarse andesitic ash (8400)
Dacitic ash (10300)
Dacitic ash (12500)
Dacitic ash (12500)