Transcript RELATIVE DATING: WHICH CAME FIRST?

RELATIVE DATING: WHICH
CAME FIRST?
Brainstorm Questions
1.Why do think the Grand Canyon looks the
way it does?
2. Which layers of rock are the oldest?
WHAT IS RELATIVE
DATING?
• ANY METHOD OF
DETERMINING
WHETHER AN
EVENT OR
OBJECT IS OLDER
OR YOUNGER
THAN OTHER
EVENTS OR
OBJECTS.
WHAT ARE SOME
METHODS FOR RELATIVE
DATING?
• THE
PRINCIPLE/LAW
OF
SUPERPOSITION
• THE GEOLOGIC
COLUMN
THE PRINCIPLE/LAW OF
SUPERPOSITION
• A PRINCIPLE THAT
STATES THAT
YOUNGER ROCKS
LIE ABOVE OLDER
ROCKS IF THE
LAYERS HAVE
NOT BEEN
DISTURBED.
• ANALOGY??
THE GEOLOGIC COLUMN
• AN ARRANGEMENT
OF ROCK LAYERS IN
WHICH THE OLDEST
ROCKS ARE ON THE
BOTTOM.
• CONTAINS ALL THE
KNOWN FOSSIL AND
ROCK FORMATIONS
ON EARTH.
• THIS HELPS
SCIENTISTS
INTERPRETE ROCK
SEQUENCES.
EVENTS THAT DISTURB ROCK
LAYERS
• SOME FEATURES
CUT ACROSS
EXISTING ROCK
TO FORM NEW
ROCK.
• UNDERSTANDING
THESE FEATURES
HELPS
SCIENTISTS IN
RELATIVE DATING.
FAULT
• A FAULT IS A BREAK IN THE EARTH’S
CRUST ALONG WHICH BLOCKS OF THE
CRUST SLIDE RELATIVE TO ONE
ANOTHER.
INTRUSION
• AN INTRUSTION IS MOLTEN ROCK FROM
THE EARTH’S INTERIOR THAT SQUEEZES
INTO EXISTING ROCK AND COOLS.
FOLDING
• FOLDING OCCURS WHEN ROCK LAYERS
BEND AND BUCKLE FROM EARTH’S
INTERNAL FORCES.
TILTING
• TILTING OCCURS WHEN INTERNAL
FORCES IN THE EARTH SLANT.
UNCONFORMITIES
• A BREAK IN THE
GEOLOGIC
RECORD
CREATED WHEN
ROCK LAYERS
ARE ERODED OR
WHEN SEDIMENT
IS NOT
DEPOSITED FOR A
LONG PERIOD OF
TIME.
GaggleTube Video
Law of SuperpositionBozemanbiology
6:22