Short answers, pulled from the story.
The Scottish naturalist James Hutton wrote that some rock beds of the Scottish Highlands had originally been sedimentary rock but had been transformed by great heat. This observation marked a pivotal moment in geological history when the concept of metamorphism began to take shape.
James Hall found that sealing chalk into a makeshift pressure vessel constructed from a cannon barrel and heating it produced a material strongly resembling marble rather than the usual quicklime produced by heating chalk in open air. His experiment confirmed that pressure was important in metamorphism.
Hot fluids circulating through pore space dissolve existing minerals and precipitate new ones while dissolved substances are transported out of the rock by the fluids. Complex high-temperature reactions occur between minerals without them melting due to rapid diffusion of atoms at elevated temperatures.
At atmospheric pressure, the mineral kyanite transforms to andalusite at a temperature of about 500 degrees Celsius. Andalusite transforms to sillimanite when the temperature reaches about 600 degrees Celsius.
A magnitude 7.2 earthquake destabilized a mountain slope composed of schistose bedrock which poses challenges for civil engineering because of pronounced planes of weakness. The event caused a massive landslide killing twenty-six people camping in the area.