Vocab
Define law of superposition
When the newest layer is at the top and the oldest layer at the bottom unless disturbed.
In what geologic era are we currently living?
Cenozoic
Helps measure age of earth with strata
Relative age
How old is the earth
4.6 billion years old
Why did the evolution of life come before the rise in atmospheric pressure.
Plants produce oxygen. Life had to evolve in order to have plants producing greats amount of oxygen.
Mass extinction
When a whole species is wiped out from earth.
Dinosaurs ruled the earth during what era?
Mesozoic
Uses half-life of isotopes to get the exact age of a rock or mineral
Absolute age
The darkest portion of rock is at the (top/bottom) of the layers
Bottom
Known as the age of mammals
Cenozoic era
Principle of Original Horizontality
the layers of sediment are originally deposited horizontally under the action of gravity
Which time period lasted the longest?
Saying you are older than a baby is an example of
Relative age
What are characteristics index fossils have?
Recognizable, short life-span, and wide distribution
Fossils are found in what type of rock
Sedimentary
Index fossils are
Used to determine the age of strata they are in
Absolute dating is also known as
Radiometric and Radioactive dating
The study of rock layers that is part of geology is known as
Stratigraphy
Relative age is used best with what type(s) of rock
Sedimentary rock
What is cross-cutting relationships
Igneous rock is new and is cutting through other layers. It would be younger than the surrounding layers
A mass extinction happened at the beginning and the end of this era
Mesozoic
This type of dating has a "parent" and "daughter" isotope to determine age
Absolute age
If the same index fossils are found in different rock strata miles apart, what is true about these rock layers?
The strata are from the same relative time period
Absolute age is used best with what type(s) of rock
Igneous and Metamorphic