Michigan Geologic Time Line List
Michigan Rocks: www.educ.msu.edu/michiganrocks
Student No. Event
Age
Name
1.
Modern Humans
.01 (10,000
years)
2.
Ice Age Begins; Glaciers
2 million years
cover all of Michigan; Great ago
Lakes carved out by
Glaciers
3.
First Humans
4.5 million
years ago
4.
First Horses
40 million years
ago
5.
Last Dinosaurs
65 million years
ago
6.
First Flowering Plants
100 million
years ago
7.
First Birds
150 million
years ago
8.
Redbeds (reddish
145 million
sandstones and shales)
years ago
deposited at the end of the
Michigan Basin
9.
First Mammals
215 million
years ago
10. First Conifer Trees
230 million
years ago
11. First Dinosaurs
240 million
years ago
12. Last Trilobites
250 million
years ago
13. Swampland in Lower
290 million
Peninsula and eastern
years ago
Upper Peninsula, Michigan
Basin. Peat deposits. Also
oil and gas deposits
14. First Reptiles
300 million
years ago
15. Gypsum and Limestone
320 million
deposited in shallow seas in years ago
Lower Peninsula and
eastern Upper Peninsula –
Michigan Basin
16. First Sharks
350 million
years ago
Geologic Time
Division
Holocene
Pleistocene
Pliocene
Eocene
Cretaceous/Tertiary
Boundary
Cretaceous
Jurassic
Jurassic
Triassic
Triassic
Triassic
Permian/Triassic
Boundary
Pennsylvanian
Pennsylvanian
Mississippian
Devonian
Student No. Event
Name
17.
18.
Hexagonaria coral deposits
(becomes MI state fossil aka
Petosky Stone) in Michigan
Basin
First Amphibians
19.
First Insects
20.
First Land Plants
21.
Salt deposited in shallow seas
in southern Michigan in
Michigan Basin
First Fish
22.
23.
24.
Sandstones of the Pictures
Rocks National Lakeshore
deposited in shallow seas;
Beginning of the Michigan Basin
First Trilobites
25.
First abundant fossils
26.
Mountains as big as the Rocky
Mountains in western Upper
Peninsula
Oldest known fossil (algae) in
iron deposits probably similar
to black smokers in oceans
today
Volcanoes, basalt flows, pillow
lavas (lavas erupted in ocean
water)
Metamorphic rocks of the
Canadian Shield, oldest rocks in
Michigan, exposed in Western
UP
Earth Formed
27.
28.
29.
30.
Age
360 million years
ago
370
ago
400
ago
420
ago
430
ago
Geologic
Time
Division
Devonian
million years
Devonian
million years
Devonian
million years
Ordovician
million years
Ordovician
480 million years
ago
500 million years
ago
Ordovician
550 million years
ago
600 million years
ago
1.0 billion years
ago
Cambrian
2.1 billion years
ago
Archean
2.8 billion years
ago
Archean
3.5 billion years
ago
Archean
4.6 billion years
ago
Hadean
Cambrian
Precambrian
Proterozoic