geological time scale
DESCRIPTION
A very short (and largely photographic) presentation on the Geological Time-ScaleTRANSCRIPT
The
Geological
Time
Scale (GTS)
Bedashree Choudhury14109MWS
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 Earth scientists.
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]
Mining
Bottom-most layer = oldest; topmost layer = newest ← Principle of Uniformitarianism (geology)
Fossils, artifacts, ecofacts, biofacts; evidence in the different layers
Segments of rock (strata) in
chronostratigraphy
Time spans in geochronology
Notes to geochronological
units
Eonothem Eon Half a billion years or more
Erathem Era Several hundred million years
System Period Few hundred million years
Series Epoch Tens of millions of years
Stage Age Millions of years
Units
Age of the Earth : 4.54 ± 0.05 billion years
Comparatively...
Major extinction events ( The “Big Five”)
en.wikipedia.org