{"thcode":2,"term":{"code":1198,"name":"unconformities","parent":452,"scope":"The contact between older rocks and younger sedimentary rocks where erosion had removed some of the older rocks before the younger rocks were deposited."},"uf":[],"bt":[{"code":452,"name":"geologic contacts","parent":1103,"scope":"Junctions of two different rock formations varying by type or age of rock, including faults, unconformities, and bedding planes."},{"code":1103,"name":"stratigraphic sections","parent":287,"scope":"Vertical arrangement in layers of rock units whose sequence is used to study the geological history of the strata."},{"code":287,"name":"earth characteristics","parent":1174,"scope":"The measurable, definable properties and features of the earth."},{"code":1174,"name":"topics","parent":1,"scope":"Themes, subjects, and concerns for which USGS information resources are relevant."},{"code":1,"name":"Categories","parent":null,"scope":"Thematic terms for categorizing information resources.  This thesaurus is intended to support finding and understanding scientific information."}],"nt":[],"rt":[{"code":1104,"name":"stratigraphy","parent":464,"scope":"Branch of geology concerned with the study of the formation, composition, ordering in time, and arrangement in space of stratified rocks."}]}