<descriptor thcode="2"><thesaurus thcode="2" name="USGS Thesaurus" scope="Topics and methods of scientific study carried out by USGS, with product types, scientific disciplines, geologic time, and types of institutional structure and activities.  Broad and shallow, used to help people find scientific information." creator="U.S. Geological Survey" rights="Public domain" edition="2.0" date="2020-01-09" codetype="number" prefix="topic" uri="https://www2.usgs.gov/science/USGSThesaurus" tblname="term" nonpref="nonpref" relterm="relterm" root_code="1" contact="pschweitzer"><category><term thcode="25" code="29" name="distinct labels" parent="26" scope="Preferred labels (descriptor texts) are distinct within the thesaurus. A concept can be specified either by its unique identifier (code) or by the text of its descriptor."/><term thcode="25" code="16" name="hierarchical" parent="11" scope="Substantive broader-narrower relationships exist among the terms."/><term thcode="25" code="13" name="transitive" parent="12" scope="Narrower terms have an &quot;is a&quot; relationship with their broader terms, and generally can be described as part-of, type-of, or instance-of the broader term."/><term thcode="25" code="21" name="disciplines" parent="2" scope="Broad categories of human inquiry or activity, such as scientific disciplines."/><term thcode="25" code="20" name="methods" parent="2" scope="Actions taken to obtain or analyze information"/><term thcode="25" code="19" name="organizational functions" parent="2" scope="Things that organizations do, typically including various types of programs, projects, and services."/><term thcode="25" code="7" name="temporal" parent="2" scope="Terms indicate periods of time, such as chronostratigraphic units, named historical periods or intervals surrounding known historical events, or seasons."/><term thcode="25" code="5" name="theme" parent="2" scope="Terms indicate domains of human concern, such as scientific discipline, societal problems, or characteristics of earth, space, oceans, and living things."/><term thcode="25" code="29" name="distinct labels" parent="26" scope="Preferred labels (descriptor texts) are distinct within the thesaurus. A concept can be specified either by its unique identifier (code) or by the text of its descriptor."/><term thcode="25" code="16" name="hierarchical" parent="11" scope="Substantive broader-narrower relationships exist among the terms."/><term thcode="25" code="13" name="transitive" parent="12" scope="Narrower terms have an &quot;is a&quot; relationship with their broader terms, and generally can be described as part-of, type-of, or instance-of the broader term."/><term thcode="25" code="21" name="disciplines" parent="2" scope="Broad categories of human inquiry or activity, such as scientific disciplines."/><term thcode="25" code="20" name="methods" parent="2" scope="Actions taken to obtain or analyze information"/><term thcode="25" code="19" name="organizational functions" parent="2" scope="Things that organizations do, typically including various types of programs, projects, and services."/><term thcode="25" code="7" name="temporal" parent="2" scope="Terms indicate periods of time, such as chronostratigraphic units, named historical periods or intervals surrounding known historical events, or seasons."/><term thcode="25" code="5" name="theme" parent="2" scope="Terms indicate domains of human concern, such as scientific discipline, societal problems, or characteristics of earth, space, oceans, and living things."/></category><altlabel><altlabel>USGSThesaurus</altlabel><altlabel>USGSThesaurus</altlabel></altlabel></thesaurus><term thcode="2" code="1199" name="unconsolidated deposits" parent="1005" scope="Loosely bound sediments such as sand, gravel, and silt which tend to accumulate in low areas or valleys."/><uf><usefor name="alluvium"/><usefor name="eolian sediments"/><usefor name="loess"/><usefor name="sediment geochemistry"><usewith><term thcode="2" code="153" name="chemical analysis" parent="619" scope="Chemical techniques used to identify the composition of substances."/></usewith></usefor><usefor name="sediments"/><usefor name="surficial deposits"/></uf><bt><term thcode="2" code="1005" name="rocks and deposits" parent="287" scope="Solid masses that make up the earth's crust as well as accumulations of materials. Use for major rock types and unconsolidated deposits. For deposits of economic value, see related terms."/><term thcode="2" code="287" name="earth characteristics" parent="1174" scope="The measurable, definable properties and features of the earth."/><term thcode="2" code="1174" name="topics" parent="1" scope="Themes, subjects, and concerns for which USGS information resources are relevant."/><term thcode="2" code="1" name="Categories" scope="Thematic terms for categorizing information resources.  This thesaurus is intended to support finding and understanding scientific information."/></bt><nt><term thcode="2" code="164" name="clay deposits" parent="1199" scope="Fine-grained sedimentary soil deposits, containing hydrated silicas of aluminum, that are plastic and sticky when wet and harden when heated."/><term thcode="2" code="500" name="gravel deposits" parent="1199" scope="Alluvial accumulations of small unconsolidated rock fragments, such as pebbles and cobbles, used in construction as fill, ground cover, or aggregate for concrete."/><term thcode="2" code="1998" name="mine waste" parent="1199" scope="Earth materials removed during mining and concentrated in piles or beds, typically near the site of extraction.  Tailings are mine waste that has been processed to remove valuable components; unprocessed mine waste includes overburden removed to reach commodity materials such as ore or coal."/><term thcode="2" code="1011" name="sand deposits" parent="1199" scope="Deposits of loose particles of rock or mineral (sediment) that range in size from 0.0625-2.0 millimeters in diameter."/><term thcode="2" code="2044" name="soil horizons" parent="1199" scope="Layers in soil defined by physical, chemical, biological, or mineralogical properties which vary with depth."/><term thcode="2" code="2271" name="solid industrial waste material" parent="1199" scope="Waste solid materials produced by industrial processing of earth materials, not simply material extracted in the search for ores."/></nt></descriptor>