Unit 3: Geologic time-Fossils

Preservation requires ____ and ____

Hard parts

Rapid burial

What are the different types of preservation?

Petrified-Cavities or pores are filled with precipitated mineral matter

Mold-Shell or other structure is buried then dissolved by underground water

Cast-Hollow space of a mold is filled with mineral matter

Carbonization-Organic matter becomes a thin residue of carbon

Impression-Replica of the fossils surface preserved in fine grained sediment

Preserved in amber

True or False:

Fossils succeed one another in a definite and determineable order

True

Index fossils ____, ____, ____, and ____

Widespread geographically

Existed for a short ranged of geologic time

Function as point of time reference in strata assemblages

Help pinpoint the point in time a fossil was in a mineral

Match the following:

Eons ___ 100 millions

Eras ___ billions

Periods ___ 10 millions

Eons-Billions

Eras-100 millions

Periods-10 millions

Scientists accept that the earth is ____ years old

4.6 billion