Geologic history test review

What is the name of the longest period of time before the eras
precambrian

What is the earth's history

1. earth forms

2. first life

3. formation of oxygen atmosphere

4. fossil fuel formation

5. Pangea extinction

6. dinosaur extinction

7. first man

8. pleistocene ice age

What separates the 3 main eras
mass extinction

what is the main form of the Paleozoic era
Amphibians

what is the main form of the Mesozoic era
reptiles

what is the main form of the Cenozoic era
mammal

What is relative dating
tells which rock layer is older

what is absolute dating
tells the actual age of the rock

How is igneous formed
magma cools and hardens

How is sedimentary formed
rocks weather erode and get deposited

How are metamorphic formed
by adding heat and pressure

what law tells you what is older if there are layers of sedimentary rocks
law of superposition

what is a fault
a break or crack in earth's crust along with rocks swifting their position

what is a fold
a bend in the rock

what is tilting
when the layers become angled instead of flat

What law tells you what is older between a fault or intrusion and the rest of the rocks
the law of crosscutting

What does it mean when an element is radioactive and what does it turn into during radioactive decay?
it is unstable and would like to decay and become stable and turns into a stable daughter isotope

what is half life
time it takes for half of the unstable isotope to become a stable isotope

What type of isotopes do you compare to age rocks
the amount of parent and daughter isotopes

what do we use to Carbon 14 to date
things that are up to 70k years old

which type of rock is used for radiometric dating
igneous

in which type of rocks would you find most fossils
sedimentary

what makes a good fossil index

1. organism lived for a short period of time

2. organism lived over a large geographic area