Powerpoint for Earth and Life Science - Relative and Absolute Dating

1. Relative and Absolute Dating
Use words like “older” or “younger” instead of exact numbers
Prepared by: Engr. Ariel S. Motas
Engr. Andreana Amor M. Gulay

2. Relative Dating
• Tells us the sequence in which events occurred, not how long ago they occurred.
• Geologists used simple principles in order to get the relative ages.
Law of
Unconformomities
Law of Cross Cutting
Relationship
Law of Inclusions
Law of Original
Horizontality
Law of Faunal
Succession
Law of Superposition
LAWS OF
STRATIGRAP
HY

3. Arrange the rock layers from OLDEST to YOUNGEST
- Provide the correct answer and win a 50pesos load
H,O B, L, J,
A, F, M, D, G,
N, E, I, C, K

4. Absolute Dating
• Determining how old something is
• Using numbers (in millions of years, mya)
• Determines the specific age of a fossil
• Looks at chemical properties
• Numerical Dating
Scientists found a natural process that occurs at
constant rate and accumulates its record of radioactive
decay of elements in rocks.

5. Absolute Dating
• Radioactive elements
- decay because they are composed of unstable isotopes that
decompose spontaneously.
• Radioactive Decay
- spontaneous breakdown of an atomic nucleus resulting in the release
of energy and matter from the nucleus
- when an unstable radioactive element changes into a stable element
- proceeds at a constant, regardless of changes in conditions such as
temperature, pressure, or the chemical environment
• Half life
- time required for 1/2 of a
parent material to break down
to daughter material

6. Half life: The time required for 1/2 of a parent material to break down to
daughter material

7. Daughter isotopes accumulate in rocks. The longer the rocks exists, the
more daughter isotopes accumulate. The process of determining the
absolute ages of rocks and minerals by measuring the relative amounts of
parent and daughter isotopes is called radioactive dating

8. Here are the commonly used radioactive isotopes in radioactive dating