1. What's the difference between the two branches of Bowen's reaction series? Fill in the blanks.

On the

branch, different minerals form through a sequence of chemical reactions. For example, the first mineral to form as ultramafic magma cools is . That mineral then reacts with the melt to make the next mineral, . In contrast, on the branch, the mineral is always but its composition varies.

2. How does Bowen's reaction series explain zoned plagioclase feldspar crystals? Drag the words.

sodium-rich1 of 2 draggables.
calcium-rich2 of 2 draggables.
Plagioclase that is
forms early on in the cooling process of a magma, but as the temperature drops, a more
variety forms around the existing crystals.

3. How does fractional crystallization change the composition of a magma chamber?

In a mafic magma chamber where the mineral

forms first, crystals will sink to the bottom of the magma chamber. The magma that's left behind will be more in composition. At the bottom of the chamber, if the crystals melt again, that magma will be more in composition.