This Powerpoint Presentation tells about the Relative Geologic Time that had happened in the Earth.

1. RELATIVE GEOLOGIC
TIME

2. Geologists use a
combination of
common sense and a
few simple principles
to determine the
order in which rocks
formed and changed
over time.

3. Principle of Original
Horizontality
• The principle that most
sediment is deposited as
nearby horizontal beds,
and therefore most
sedimentary rocks
started out with nearly
horizontal layering.

4. Principle of
Superposition
• The principle that in any
undisturbed layers of
sediment or sedimentary
rock, the age becomes
progressively younger from
bottom to top, younger layers
always accumulates on top
of older layers.

6. Principle of Crosscutting
Relationships
• The principle states that a
rock or feature must first
exist before anything can
happen to it; thus, if an
intrusion of rock cuts across
an existing rock, the dike
(intrusion) is younger.

8. Theory of Evolution
• It states that life-forms
have changed throughout
geologic time
• Species emerge, persist
for awhile; and then
become extinct

9. Principle of Faunal
Succession
• The principle states that
species succeeded one
another through time in a
definite order, so that
sedimentary rocks of the
same age contain identical
fossils and rocks of different
ages contain different fossils.