{"thcode":4,"term":{"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."},"uf":[],"bt":[{"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":[{"code":"5.5.7","name":"Amphibole schist","parent":"5.5","scope":"A schist whose essential constituent is amphibole with lesser amounts of feldspar, quartz, and\/or mica"},{"code":"5.5.2","name":"Blueschist","parent":"5.5","scope":"A schistose metamorphic rock with a blue color owing to the presence of sodic amphibole, glaucophane, or crossite, and commonly mottled bluish-gray lawsonite; characteristic of metamorphism in areas of unusually low thermal gradient, such as subduction zones"},{"code":"5.5.6","name":"Calc-silicate schist","parent":"5.5","scope":"A metamorphosed calcareous rock, commonly derived from argillaceous limestone or calcareous mudstone, containing calcium-bearing silicates such as diopside and wollastonite, with a schistose structure produced by parallelism of platy minerals"},{"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"},{"code":"5.5.3","name":"Mica schist","parent":"5.5","scope":"A schist whose essential constituents are mica and quartz, and whose schistosity is mainly due to the parallel arrangement of mica flakes."},{"code":"5.5.4","name":"Pelitic schist","parent":"5.5","scope":"A schistose metamorphic rock derived by metamorphism of an argillaceous or a fine-grained alluminous sediment."},{"code":"5.5.5","name":"Quartz-feldspar schist","parent":"5.5","scope":"A schist whose essential constituents are quartz and feldspar and having lesser amounts of mica and\/or hornblende"}],"rt":[]}