Subject: Effect on melting temperature of mantle upon addition of water

Hi

Was wondering if someone can explain the processes involved when water is added 
the mantle above a subducting plate. The resulting magma is less dense and 
therefore rises to the surface, but also the water reduces the rocks melting 
point. How does that work? What equations could I use to help me figure it out 
how the temperatures pressures and volumes tie in together, if any?

Thanks to anyone for their help!

Nuala 

Re: Effect on melting temperature of mantle upon addition of water