Begin Slideshow. 1  If you've got a Trader Joe's in your neighborhood, chances are it's your go-to supermarket. It's cheap, convenient, and the snacks are unbeatable. 2  When I sent out an office poll about people's favorite items, I quickly found I wasn't the only one who can't get enough of what that grocery store offers.
Addendum: Differentiation of magma (fractional crystallization) also plays a big role in creating felsic magmas from mafic magmas. Also, granite can form at convergent boundaries that involve continental crust only (e.g., Indian and Asian plates).
Convergent margins. A subduction zone is formed at a convergent plate boundary when one or both of the tectonic plates is composed of oceanic crust. The denser plate, made of oceanic crust, is subducted underneath the less dense plate, which can be either continental or oceanic crust.