What is one way scientists can determine the relative age of rock layers?
By looking at similar rock type, fossils, or position of rock.
100
All the members of a species die.
Extinct
200
How is a trace fossil made?
The organism produces something that is preserved.
200
Draw a layer that is cracked.
Must have a line showing a crack
200
How can we tell from looking at rock layers when an organism went extinct?
We no longer see it in newer layers of sedimentary rock.
200
How can the law of superposition be used to determine the relative age of rock?
The oldest layer will be the farthest down. They get younger as they get higher. The highest layer will be the youngest.
200
Magma is injected into rock and cools to become solid
Intrusion
300
How is a mold fossil made?
The organism is covered, decays, and leaves an empty space where it was.
300
Draw a layer that is folded.
Must be bent or U shaped
300
Where are the layers of sedimentary rock in comparison to the soil?
Sedimentary rock is under soil.
300
How can fossils be used to determine the relative ages of rock layers?
Similar fossil types show similar ages between rock. If it has the same fossils it must be from the same general time.
300
A break or crack in the Earth’s crust where rocks can move
Fault
400
How is a cast fossil made?
The organism is covered, decays, and leaves an empty space where it was. THEN sediment fills the space leaving a rock copy.
400
Draw a layer that is injected.
Must have another layer crossing through it
400
What would happen if more sediment layers were deposited on old layers? Would they mix?
They would pile up on top of them, they wold not mix.
400
How can similar rock types be used to determine the relative ages of rock layers?
Similar types of rocks will be from the same layer, and therefore around the same age.
400
A missing layer of rock. It forms when rock is eroded or not deposited.
Unconformity
500
How are fossil fuels made?
Extreme heat and pressure change the remains of dead organisms into materials like oil, gas, and coal.
500
Draw a layer that is missing.
must have a layer that is present then that vanishes. The layer above it and below it must touch where it is not present.
500
Do you think all sediment would be deposited at the same speed? Why or why not?
All sediment would not be deposited at the same speed. Heavier sediment like gravel will be deposited more quickly. Lighter sediment like soil will be deposited slowly.
500
What are three ways scientists can determine the relative age of rock layers?
By looking at similar rock type, fossils, or position of rock.
500
Older rocks in lowest layers, newest rocks in highest layers