{"thcode":4,"term":{"code":"2.1.3","name":"Sandstone","parent":"2.1","scope":"A medium-grained clastic sedimentary rock composed of abundant sand-sized fragments, which may have a finer-grained matrix (silt or clay), and which is more or less indurated by a cementing material..."},"uf":[],"bt":[{"code":"2.1","name":"Clastic rock","parent":"2","scope":"A composed principally of broken fragments that are derived from preexisting rocks or minerals and that have been transported some distance from their place of origin."},{"code":"2","name":"Sedimentary rock","parent":"0","scope":"A rock resulting from the consolidation of loose sediment that has accumulated in layers..."},{"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":"2.1.3.1","name":"Arenite","parent":"2.1.3","scope":"A \"clean\" sandstone that is well-sorted, contains little or no matrix material, and has a relatively simple mineralogic composition; specif. a pure or nearly pure, chemically cemented sandstone containing less than 10% argillaceous matrix."},{"code":"2.1.3.2","name":"Arkose","parent":"2.1.3","scope":"A feldspar-rich sandstone, commonly coarse-grained and pink or reddish, that is typically composed of angular to subangular grains that may be either poorly or moderately well sorted... Quartz is usually the dominant mineral, with feldspars constituting at least 25%."},{"code":"2.1.3.3","name":"Wacke","parent":"2.1.3","scope":"A \"dirty\" sandstone that consists of a mixed variety of unsorted or poorly sorted mineral and rock fragments and of an abundant matrix of clay and fine silt; specif. an impure sandstone containing more than 10% argillaceous matrix."}],"rt":[]}