Geology Reference
In-Depth Information
Figure 7-16:
The
foliation of miner-
als by direct pres-
sure.
However, not all metamorphic rocks are foliated. Rocks that are metamorphosed by con-
tact with heated magma or indirect pressure still experience changes in the organization
of the mineral grains, but the minerals do not create sheets or layers. New minerals cre-
ated by this process are called
metamorphic minerals.
Other minerals respond to meta-
morphism by growing larger (marble is an example).
I describe examples of metamorphic rocks with all these different textures in the next
section.
Categorizing metamorphic rocks