Igneous, sedimentary, metamorphic transformations — P-T phase diagram and cycling paths
Form from cooling magma/lava. Intrusive (plutonic): slow cooling → coarse crystals (granite, gabbro). Extrusive (volcanic): rapid cooling → fine/glassy (basalt, obsidian). ~90% of Earth's crust by volume.
Clastic: weathered particles compacted (sandstone, shale). Chemical: precipitated minerals (limestone, evaporites). Organic: from organisms (coal, chalk). Record Earth history; contain fossils. Cover ~75% of land surface.
Recrystallized under heat and pressure without melting. Contact metamorphism (heat-driven). Regional/burial metamorphism. Grade: slate→phyllite→schist→gneiss. Blueschist: high-P/low-T subduction. Eclogite: ultra-high pressure.