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An incomplete list of thoughts ...
We introduced metamorphic rocks via the seemingly simple question of "when did plate tectonics start?"
To address this we finally hit upon the idea that the metamorphic rock blueschist could help us with that. We saw from an article I linked to that our hypothesis is not likely to be true. You should be able to articulate via text and/or annotated sketches:
What the hypothesis is about blueschist that might help us understand when plate tectonics started, and
What the article I gave you says about this hypothesis - i.e. why it is unlikely to be true.
How is it that metamorphic rocks get exposed at the surface when they form so deep in the subsurface? We saw a model in the materials I gave you (webpage, slide sets) that shows how this can work. Related to this is the concept of shields.
How do the presence of specific recrystallized minerals show us the extent of previous mountain ranges? We looked at in class an example from the New England area, there is a similar example in your reading.
Indicator minerals are also a way to name metamorphic rocks (with funny names like amphibolite, etc.). These names function as shorthand for collections of minerals that recrystallize in metamorphic rocks (kind of like how "diorite" or "granite" indicate a collection of minerals in an igneous rock).
Do not worry about the names per se, but in your reading recognize that this is a way in which metamorphic rocks can be named more precisely, and differs from the textural names we learned in the Discussion Meeting activity (i.e. slate, schist, gneiss, etc.).
What are the main examples of each class? What are the protoliths for each?