Transcript GeologicTimehowmuchmillion

Why is time important for
science?
4.6 Billion years
The Geologic Time Scale is a broad
division of
time that chunks the Earth’s
history five
ways, based upon specific
characteristics in the geologic record.
It utilizes geologic and biologic events.
It was first proposed in 1913 by British
geologist Arthur Holmes.
Two or more geological eras form
an Eon, which is the largest division
of geologic time, lasting many
hundreds of millions of years.
Broad time spans based upon the
characteristics of life
(Biologic Events)
Two or more geological periods comprise an era,
which is hundreds of millions of years in duration.
Shorter time spans based upon major
disturbances of the Earth’s crust
(Geologic Events)
The period is the basic unit of geological
time in which a single
type of rock system is
formed, lasting tens of
millions of years.
Short time spans which are
subdivisions of the periods
An epoch is a division of a geologic
period;
it is a small
division of geologic time, lasting
several million years
An age is a unit of geological time
which is distinguished by some
feature (like an Ice Age). An age
is shorter than epoch, usually
lasting from a few million years to
about a hundred
million years.
The Geologic
Time
Scale is
arranged
chronologically,
with the oldest
events at the
bottom and
the most
recent events
at the top.
The Geologic Time Scale combines
two types of time:
Relative Time
Time based upon the relationships of (igneous)
rocks or approximate orders of events
Absolute Time
Time based upon units stated with numbers
Geologic Time Line
The age of the earth is estimated at 4.6 billion
years. That span of time is difficult to
imagine. The following examples may help:
How Big is a Billion?
One sheet has 4000 asterisks.
500 sheets would have 2 million asterisks
How many sheets for a
billion asterisks?
It would take 250,000 pages or
500 bundles to show one billion
asterisks!
You would need a
stack of paper over
83 feet tall!!!
Other Billion examples:
• Save a billion $- you save $100 a
day for 27,397.26 years
• Count to a billion- 3 seconds per
number would take you 95.1 years
• Walk a billion steps- each step at 2
feet per step will take you 15.278
times around the equator.