Fascinating
Fossils
A Unison
Reading by
Alfredo, Luis,
Jesus, Gian,
and Marcos
[The group stops at the end of the first paragraph]
Alfredo: Everyone understand this paragraph?
Jesus: Yes, you?
Alfredo: The dinosaur dies and is in the rock. Then the
people find the rock.
Luis: Miss, he said it all!
Jesus: The fossil people can know how the life changed.
Luis: I understand that the dinosaurs died million years
ago and we can find them all over the world.
Jesus: The bones.
Gian: The animals, plants die, the life on Earth changed
through time.
Alfredo: And at the museum we can see the fossils.
Relative Dating
There are rules to relative dating. Here are the
ones you need to know:
1) Law of Original Horizontality
2) Law of Superposition
3) Law of Cross-cutting Relationship
4) Law of Included Fragments
5) Unconformities
Laws of Original Horizontality and
Superposition
1) Layers are
deposited
horizontally
2) The oldest layer is
on the bottom, the
youngest layer is on
the top
Law of Superposition: The Pizza Rule
Law of Superposition
Law of Cross-Cutting Relationships
A fault or intrusion
that goes through a
rock layer is
younger than that
rock layer
Law of Cross-Cutting Relationships:
The Twinkie Rule
Law of Cross-Cutting Relationships
Law of Included Fragments
• A rock layer with
pieces of another
rock layer inside it is
younger than the
pieces
• Pieces of a rock layer
inside another rock
layer are older than
the rock layer they
are inside
Law of Included Fragments: The
Chocolate Chip Cookie Rule
Unconformities
An unconformity
can represent:
– lost time
– A tilting or
folding event