Chapter 2: Mantle Melting and Plate tectonics
What causes rock to melt?
- Change in composition - Decrease in pressure - increase in temperature
Why is decompression melting common at mid-ocean ridges but not at subduction zones?
Tectonic plates are moving apart at mid-ocean ridges, resulting in a lowering of pressure beneath the ridge. Tectonic plates are moving together at subduction zones, resulting in an increase of pressure under new mountains.
Why is water a necessary component of the melting process in subduction zones?
The addition of water lowers the melting temperature of rock.
Part complete Where does the water involved in melting at subduction zones come from?
Water contained within minerals in the subducting plate is released during metamorphism.
Which two processes commonly generate magma?
decompression melting and wet melting (the addition of volatiles)
What is peridotite?
the rock making up the mantle
