{"thcode":4,"term":{"code":"2.2.1","name":"Limestone","parent":"2.2","scope":"A sedimentary rock consisting chiefly (more than 50% by weight or by areal percentages under the microscope) of calcium carbonate, primarily in the form of the mineral calcite..."},"uf":[],"bt":[{"code":"2.2","name":"Carbonate rock","parent":"2","scope":"A sedimentary rock composed of more than 50% by weight carbonate minerals."},{"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":[]}