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23 Cards in this Set

  • Front
  • Back
A trace of remain of a once living thing from long ago.
Original Remains
A fossil that is the actual body or body parts of an organism.
Ice Core
A tubular sample that shows the layers of ice and snow that have built up over the years.
Relative Age
The age of an event or object in relation to other events or objects.
Index Fossil
A fossil of an organism that was common, lived in many areas, and existed only during a certain span of time.
Absolute Age
The actual age in years of an event or object.
Half - life
The length of time it takes for half of the atoms in a sample of a radio-active element to change from an unstable from into another form.
A theory stating that processes shaping Earth today, such as erosion and deposition, also shaped Earth in the past, and these processes cause large changes over time.
Geologic Time Scale
The summary of Earth's history, divided into intervals of time defined by major events of changes on Earth.
What things can we learn from fossils?
How big they were
What they ate
What kind of skin they had
How much it weighed
Where they lived
What are the different types of fossils?
Petrified wood
Carbon Films
Original remains
How do fossils form?
A protective layer of sediment covers the organism and hardens into rock.

The soft parts decay and the hard parts are replaced by minerals.

The process where hard parts are replaced by minerals is called permineralization. This is how you get petrified wood.

Later erosion reveals the organism.
What is the difference between relative age and absolute age?
Relative age is a comparison. From sedimentary.

Absolute is the exact age.
From Igneous
What things help us determine relative age?
Undisturbed layers of sedimentary rock. Index fossils
What things help us determine absolute age?
Half - life of unstable sample you find in igneous rock.
What are the different division s of the geologic time scale and how do they fit with eachother?
What Era, Period, and Epoch do we live in?
Cenozoic, Quaternary, Holocene
What period are dinosaurs from?
Triassic, Jurassic, Cretacouse
What determines the length of time or the changes for the different parts of the GTS?
Big events, new form of life, mass extinction, eruption, climate change.
What are the 4 eons?
Hadean, Archean, Protozoic, Phanerozoic.
What are the 3 eras?
Paleozoic, Mesozoic, Cenozoic
What is Precambrian time?
A time after the dinosaurs were extinct by a massive meteor in which no life existed except animals.
How old is a sample of rock with 25% uranium 235?