CEEES/SC 10111-20111
Planet Earth
Geologic
Time Laboratory
Click here for a copy of the Lab Manual
Chapter
Colour
versions of the figures
for the lab questions.
Absolute Time – uses
radioactive
decay by measuring parent & daughter isotopes.
Relative Time – uses cross
cutting
relationships or index fossils to tell which rock sequence/structure is
older.
Examples of sequences/structures
in the field.
Example – Figure 13.2
Testing Hypotheses.
Basic Principles
Principle
of Original Horizontality
Principle of Superposition
Principle of Original Lateral Continuity
Principle of Cross Cutting Relationships
Principle of Inclusions
Principle
of Fossil Succession: Fossil organisms succeed one
another
in time in a definite and recognizable order. Each distinct organism
existed
for a specific time interval.
Principle of Fossil Assemblages:
Characteristic groups of fossils (fossil assemblages) define unique
geologic
ages. Fossils also good for correlating isolated outcrops
either
regionally or across continents.
Unconformities
Geologic Time Scale
Eons: largest
subdivisions;
Eras: subdivisions
of Eons
Periods:
subdivisions of Eras
Epochs:
subdivisions of Periods