{"thcode":4,"term":{"code":"5.5.1","name":"Greenschist","parent":"5.5","scope":"A schistose metamorphic rock whose green color is due to the presence of chlorite, epidote, or actinolite; a common product of low-grade regional metamorphism of pelitic or basic igneous rocks"},"uf":[],"bt":[{"code":"5.5","name":"Schist","parent":"5","scope":"A strongly foliated crystalline rock, formed by dynamic metamorphism, that can be readily split into thin flakes or slabs due to the well developed parallelism of more than 50% of the minerals present, particularly those of the lamellar or elongate prismatic habit, e.g. mica and hornblende."},{"code":"5","name":"Metamorphic rock","parent":"0","scope":"A rock derived from pre-existing rocks by mineralogical, chemical, and\/or structural changes, essentially in the solid state, in response to marked changes in temperature, pressure, shearing stress, and chemical environment, generally at depth in the earth's crust."},{"code":"0","name":"Earth material","parent":null,"scope":"Geologic map unit classification (Bruce R. Johnson) version 6.2: A hierarchical classification of earth materials for digital geologic maps."}],"nt":[],"rt":[]}