Igneous Rocks Test Review

1. There is an area in Idaho called Craters of the Moon, where most of the ground is covered with basalt, a black igneous rock with no visible crystals. Which statement best describes how the rocks likely formed in this area?

• The rocks cooled slowly below ground, and tiny crystals formed.
• The rocks were under tremendous heat and pressure, so no crystals formed.
• The rocks cooled quickly above ground forming crystals too small to see.
• Basalt rocks do not form crystals, no matter how they cooled.

2. A student shared an igneous rock he bought that has beautiful fish and plant fossils in it. Another student gently pointed out that he may want to try to get his money back. How did the student know the rock was fake?

• Fish and plants don't fossilize in the same rocks.
• It is impossible for fossils to form in igneous rocks.
• It is not legal to sell real fossils.
• Igneous rocks don't form underwater.

3. This layer drives the movement of tectonic plates.

• asthenosphere
• lithosphere

4. The upper mantle is found in this layer.

• asthenosphere
• lithosphere

5. Convection Currents happen in this layer.

• asthenosphere
• lithosphere

6. Tectonic plates are in this layer.

• asthenosphere
• lithosphere

7. Which question is the best one to ask in order to learn how an igneous rock is formed?

• What color is the rock?
• What size are the crystals in the rock?
• What is the rock made of?
• How heavy is the rock?

8. Volcanoes and earthquakes are often found near plate boundaries.

• True
• False

9. The continents are made of tectonic plates, but the seafloor is not.

• True
• False

10. Different tectonic plates have different densities.

• True
• False