"Metamorphic rocks provide a record of the processes that occurred inside earth as the rock was subjected to changing physical and chemical conditions. This gives the geologist literally "inside information" on what occurs within the earth during such processes as the formation of new mountain ranges, the collision of continents, the subduction of oceanic plates, and the circulation of sea water into hot oceanic crust. Metamorphic rocks are like probes that have gone down into the earth and come back, bringing an record of the conditions they encountered on their journey in the depths of the earth. "
"But she also identified epidote. This news perked me up a little. Epidote is a pale green mineral found only in metamorphic rocks. If you compare rocks to music, sedimentary rocks are like major keys, metamorphic rocks are like minor keys. They have more mystery."
A nice discussion of sand in the linked blog...
"Metamorphic rocks are like a granola bar that has been stepped on. The layers are squished but they are compressed into an organized pattern."
"For any readers who might not know, sedimentary rocks come from sand/mud/etc being deposited and then squished a whole lot over millenia to turn them into rock. Different from igneous rocks, like granite, that come from the rock melting of volcanic activity and metamorphic rock that are normal rocks that have been squished and pressurized even more due to plates colliding. Metamorphic rocks are like the superhero versions of sedimentary and igneous rocks. Super hard and durable slate (for roofs and sidewalks) is the metamorphic version of mudstones, statue-making marble the metamorphic version of soft, sedimentary limestone."
METAMIA is a free database of analogy and metaphor. Anyone can contribute or search. The subject matter can be anything. Science is popular, but poetry is encouraged. The goal is to integrate our fluid muses with the stark literalism of a relational database. Metamia is like a girdle for your muses, a cognitive girdle.