Earth's Interior
Name Earth's four major layers.
Crust, mantle, outer core, and inner core.
What are tectonic plates?
Large pieces of Earth's lithosphere that move over the softer material beneath them.
What is a fossil?
Preserved remains, impressions, or traces of an ancient organism.
What process breaks rock into smaller pieces?
Weathering.
Approximately what percentage of Earth's surface is covered by ocean water?
71%.
Which layer of Earth is liquid?
The outer core.
What happens at a divergent plate boundary?
Two plates move apart and new crust can form between them.
According to the Law of Superposition, where are the oldest layers usually found in undisturbed sedimentary rock?
At the bottom.
What is the difference between erosion and deposition?
Erosion transports sediment; deposition occurs when sediment is dropped or settles.
What primarily drives surface ocean currents?
Wind
Why is Earth's inner core solid even though it is extremely hot?
The enormous pressure keeps the material solid.
What type of plate boundary occurs when two plates move toward each other?
A convergent boundary.
A fossil is found several layers below another fossil. Assuming the layers have not been disturbed, which fossil is older?
The fossil in the lower layer.
A river enters the ocean, slows down, and drops the sediment it was carrying. What process is occurring?
Deposition.
As you travel deeper into the ocean, what happens to light and water pressure?
Light decreases and pressure increases.
What process in the mantle helps drive the movement of tectonic plates?
Convection currents.
How does seafloor spreading provide evidence that tectonic plates move?
New oceanic crust forms at mid-ocean ridges and moves outward, showing that the seafloor is moving.
Scientists find the same index fossil in rock layers hundreds of kilometers apart. What can they infer?
The rock layers are approximately the same age.
What agent of erosion commonly creates U-shaped valleys?
Glaciers.
What causes most deep-ocean currents?
Density differences caused mainly by differences in temperature and salinity.
The inner and outer core have similar compositions. Why is the inner core solid while the outer core is liquid?
Pressure is much greater in the inner core, keeping it solid despite the extreme temperature.
An oceanic plate collides with a continental plate. What happens to the oceanic plate, and name two features or events that can result.
The denser oceanic plate subducts beneath the continental plate. Possible results include trenches, volcanoes, mountains, and earthquakes.
An igneous intrusion cuts through three sedimentary rock layers. Another sedimentary layer lies undisturbed above the intrusion. Which formed last?
The sedimentary layer above the intrusion.
Waves wear sediment away from a cliff. The sediment is transported along the coast and eventually becomes part of a beach. Identify the three processes occurring in order.
Weathering/erosion → transportation → deposition.
Cold, salty water forms near the poles. Explain what happens to this water and how it contributes to global ocean circulation.
It becomes denser and sinks, helping drive deep-ocean currents that connect with surface currents as part of global ocean circulation.