What types of features are found at a convergent boundary?
Volcanoes, Volcano Island Arc, Folded Mountains, Ocean Trench
Explain how a divergent boundary makes new crust.
Magma rises and is pushed out and sideways. The seafloor spreads and new crust is formed.
Rocks formed over long periods of time retain record of pole reversals. How is this possible?
Magnetic minerals in the molten rock become aligned to the magnetic field. When the rock solidifies, minerals lock in the magnetic field like many tiny compasses.
Describe how a mid-ocean ridge would look if you could see the magnetic reversals in the crust.
There would be alternating bands of rock showing the magnetic reversals over time. Both sides of the mid-ocean ridge would look exactly alike.
How can you tell the difference between new and old mountains?
New mountains are steep and jagged. Old mountains are shorted and more rounded, smooth
What is a geothermometer?
A geothermometer is a metamorphic rock that can only form at a minimum temperature and pressure.
How is a Dome Mountain formed?
1. Magma bulges under the ground and forces the crust up. 2. The magna never breaks the surface. 3. The magma hardens into rock. 4. The layers on top of the hardened magma erode away exposing the Dome Mountain.
What does a Folded mountain look like?
What does a Fault-Block mountain look like?
What does a Dome mountain look like?
What is a subduction zone?
A subduction zone is a place where one plate is sliding under another, or subducting. It happens at a convergent boundary.
Where are you likely to find Mafic minerals?
Mafic minerals are found in ocean crust.
Where are you likely to find Felsic minerals?
Felsic minerals are found in continental crust.
What is a mid-ocean ridge?
A mid-ocean ridge is a place where the ocean plates are diverging, creating more crust.
What is a rift valley?
A rift valley is a place where the continental plates are diverging, creating more crust.
What is an ocean trench?
An ocean trench is a place where two ocean plates or an ocean plate and a continental plate are converging. It is the place of the subduction zone (See "What is a subduction zone?)