{"thcode":4,"term":{"code":"2.1.3.3.1","name":"Graywacke","parent":"2.1.3.3","scope":"...a dark gray, firmly indurated, coarse-grained sandstone that consists of poorly sorted angular to subangular grains of quartz and feldspar, with a variety of dark rock and mineral fragments embedded in a compact clayey matrix having the general composition of slate and containing an abundance of very fine-grained illite, sericite, and chloritic minerals."},"uf":[],"bt":[{"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."},{"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..."},{"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":[],"rt":[]}