1. Fossils

2. Vocabulary Fossil Molds and Casts Films Mineral replacement Amber
Brachiopod
Trilobite
Dinosaur
Index Fossil

3. Fossils Fossils are cool little pictures to our past.
To be a fossil it must:
Once been alive
Now Dead
Buried in sediment
No longer of interest to bacteria.

4. Methods of fossilization
Fossils form many ways.
Things die and then weathering, Erosion and deposition take over.
Ways to make a fossil:
Molds and Casts
Films
Mineral replacement
Amber

5. Molds & Casts
Organisms buried in sediment decay away leaving a cavity or mold. If the space is filled with sediment, a cast is made.
A mold preserves a negative imprint of the surface, while a cast preserves the external form of the organism.

6. Films
Imprints of leaves and seed cones are so perfectly preserved that minute details are visible through modern microscopes.

7. Mineral Replacement
Sometimes a shell can be filled with minerals and then dissolve away.
Ground water carrying dissolved minerals infiltrates the microscopic pores and cavities in bone, wood or shell.

8. Amber Amber is tree sap that drips from conifers (Pines.)
This sap drips unto insects below it trapping the insect in the sap.
The sap eventually turns rock hard and the insect remains are forever preserved in the amber.

9. Types of fossils you need to know.
Brachiopods – aka old clams
Trilobite – looks like an old cockroach
Dinosaurs – Big lizards
Plants
Snails – Look like today’s snails

10. Page 8/9 In ESRT

11. Index Fossils Index Fossil Humans (so far): Dinosaurs:
A fossil of an animal that lived all over the world and didn’t live that long.
Humans (so far):
Time lived________ worldwide? Yes / No
Dinosaurs:

12. Types of index fossils
Bottom of ESRT 8/9 all good index fossils.

13. Tracks We can see today fossil footprints.
Even in NYS there are places where Dinos roamed.
If you look at the tracks you can
see what it was doing.

14. How do we use Index fossils
Relative dating
Correlations