Chapter 13-2 Flashcards
What is one way to describe hot, solid mantle rock?
It is stiff putty and does not move for millions of years.
Under what conditions do mantle rocks melt?
- Mantle rock melts when it is carried toward the surface at mid-ocean ridges.
- As the mantle rock rises, the pressure drops and the rock melts, becomes a liquid.
- Both decreased pressure and the addition of water lower the melting temperature of mantle rock so that is melts
Why is the mantle so hot?
- Interior of Earth is so hot because Earth is still cooling from when is formed so long ago.
- As materials came together to form Earth, collisions from outside of Earth’s atmosphere and was impacted and forms heat.
- Heat inside Earth is caused by the decay of radioactive elements.
What is crystallization?
the process by which crystals form and grow in size.
When does crystallization begin?
When atoms in a liquid begin to collect on the surface of a solid particle called the “seed crystal.”
What happens when liquids take a long time to crystallize and what happens when liquids are slow when they crystsallize?
- long time to crystallize –> Large crytals form.
2. slow to crystallize –> Small crystals form
How is an igneous rock related to how fast the magma or lava cools?
The size of crystals.
What determines how fast melted rock will cool?
The surface area of a cooling liquid.
How are basalt and gabbro similair rocks?
They are rocks that are both formed from magma or lava.
What is basalt?
a dark-colored igneoua rock with fine crystals. Formed from lava that is not silica-rich. This rock forms oceanic crust.
What is granite?
an igneous rock with large, visible crytals. Formed from silica-rich magma. This rock forms continental crust.
What is an extrusive rock?
an igneous rock that cools outside of Earth’s crust.
What are granite and obsidian made from?
silica-rich magma
What is an intrusive rock?
an igneous rock that cools inside Earth’s crust.
What are the differences between granite and obsidian?
Granite cools very slowly, so it has very large crystals. Obsidian cools very quickly, so it has very small crystals.
