What is it?
a system of chronological measurement that relates stratigraphy to
time, to describe the timing and relationships between events that
have occurred throughout Earth's history.
Who uses it?
Geologists, paleontologists, archaeologists, anthropologists, and other
Why do we need to know about it?
History Important events Exploration
Record Calendar Evolution
Dating General knowledge Links; Chains
How does one construct a geological time scale?
By studying rock layers [Stratigraphy]
Bottom-most layer = oldest; topmost layer = newest ← Principle of
Fossils, artifacts, ecofacts, biofacts; evidence in the different layers
Segments of rock
Time spans in
Eonothem Eon Half a billion years or
Erathem Era Several hundred
System Period Few hundred million
Series Epoch Tens of millions of
Stage Age Millions of years