This week begins our discussion of the magmatic evolution of mid ocean ridge basalt. The considerations introduced here are of course applicable also to other tectonic settings. We will define some new terms, then examine the results of last time (mantle melting) in comparison with melts actually produced at ridges. Then we will critically evaluate whether the simplified system of last time is adequate to describe basalt evolution (of course not!) and choose another (pseudo-) ternary system (Fo-Di-An).
In the laboratory we will use the program MELTS running on Unix workstations to model the liquid line of descent of a hypothetical olivine picrite.
Topics:
(Probably next week)