THE GEOLOGIC TIME SCALE
The scale of geologic time is vast, currently
estimated at nearly 4.
6 billion years.
During
that time, life evolved into the familiar forms we
see today.
These materials are provided to
assist in understanding time relationships...
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THE GEOLOGIC TIME SCALE
The scale of geologic time is vast, currently
estimated at nearly 4.
6 billion years.
During
that time, life evolved into the familiar forms we
see today.
These materials are provided to
assist in understanding time relationships and
how life on Earth changed through time.
The dates shown were compiled from
several available sources.
Table 1 shows some
important events in Earth history, presented in
the order in which they occurred.
The data are
also shown on the scale of a calendar year.
When geologic time is compressed to the scale
of a calendar year, 1 second equals about 146
years.
At this scale, World War II began about
0.
4 second before midnight on December 31;
because of rounding, this is shown as midnight
of the new year.
On the back of this sheet is a chart showing
the geologic eras, systems, and series; the
oldest is at the bottom.
On the chart, each dot,
number, or letter represents 1 million years.
The dots get “older” as you read down the
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