<descriptor thcode="61"><thesaurus thcode="61" name="Marine Realms Information Bank (MRIB) keywords" scope="Theme keywords from the former Marine Realms Information Bank, focusing on characteristics of coasts and oceans, processes acting on them, and human concerns about them." creator="U.S. Geological Survey" rights="Public domain" date="2016-09-07" codetype="number" prefix="mrib" tblname="mrib" nonpref="mribnp" relterm="mribrt" root_code="1" contact="aallwardt"><category><term thcode="25" code="27" name="types" parent="26" scope="Terms are types of things rather than named instances"/><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="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="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="27" name="types" parent="26" scope="Terms are types of things rather than named instances"/><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="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="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"/></category><altlabel><altlabel>MRIB keywords</altlabel><altlabel>MRIB keywords</altlabel><altlabel>Marine Realms Information Bank keywords</altlabel><altlabel>Marine Realms Information Bank keywords</altlabel></altlabel></thesaurus><term thcode="61" code="194" name="geological features" parent="94" scope="features associated with a particular geologic phenomenon, origin, or interpretation."/><bt><term thcode="61" code="94" name="feature type" parent="1"/><term thcode="61" code="1" name="Marine Realms Information Bank (MRIB) keyword categories"/></bt><nt><term thcode="61" code="195" name="accretionary wedge" parent="194" scope="deformed and metamorphosed sedimentary rocks that were scraped off the subducting plate and accreted to the overriding plate at a convergent plate boundary."/><term thcode="61" code="196" name="anticline" parent="194" scope="an upward fold with older strata in the core."/><term thcode="61" code="197" name="diapir" parent="194" scope="a subsurface structure in which buoyant, ductile earth materials pierce the overlying, more brittle earth materials."/><term thcode="61" code="199" name="earthquake zone" parent="194" scope="an area of recurrent seismic activity."/><term thcode="61" code="200" name="fault" parent="194" scope="a rock fracture with displacement."/><term thcode="61" code="201" name="formation" parent="194" scope="a rock unit sufficiently distinct to be mapped and correlated over a wide area."/><term thcode="61" code="202" name="fossil" parent="194" scope="the remains or traces of organisms preserved in rocks."/><term thcode="61" code="203" name="fracture" parent="194" scope="a mechanical break in rock, with or without displacement."/><term thcode="61" code="204" name="glacial till" parent="194" scope="poorly sorted rock debris deposited by a glacier."/><term thcode="61" code="206" name="hotspot" parent="194" scope="a persistent igneous source in the mantle, often expressed at the surface as a string of volcanoes formed sequentially as a lithospheric plate moves over the stationary hotspot."/><term thcode="61" code="207" name="intrusion" parent="194" scope="a subsurface igneous body that invades older rock."/><term thcode="61" code="208" name="joint" parent="194" scope="a rock fracture without displacement; often found in parallel sets."/><term thcode="61" code="209" name="karst" parent="194" scope="terrain underlain by soluble bedrock such as limestone or marble and characterized by caves, caverns, sinkholes, and disappearing streams."/><term thcode="61" code="210" name="landslide" parent="194" scope="used for slope failures including slumps, rockfalls, earth flows, and debris flows (&quot;mudslides&quot;), among others."/><term thcode="61" code="211" name="magma chamber" parent="194" scope="a reservoir of molten rock within the crust."/><term thcode="61" code="212" name="oil and gas seep" parent="194" scope="site where hydrocarbons escape to the surface under low pressure, following rock fractures or permeable strata."/><term thcode="61" code="213" name="ophiolite" parent="194" scope="uplifted and exposed oceanic crust and upper mantle."/><term thcode="61" code="214" name="outwash plain" parent="194" scope="a gently sloping surface underlain by sediment deposited by glacial meltwater."/><term thcode="61" code="215" name="petroleum deposit" parent="194" scope="subsurface accumulations of oil and oil sands."/><term thcode="61" code="216" name="plate" parent="194" scope="a large, rigid slab of crust and upper mantle, which moves slowly over the ductile asthenosphere."/><term thcode="61" code="217" name="plate boundary" parent="194" scope="used for three types of boundaries between lithospheric plates: divergent boundaries, where lithosphere is created; convergent boundaries, where lithosphere is destroyed; and transform boundaries, where lithospheric plates slide past one another."/><term thcode="61" code="218" name="rift" parent="194" scope="a deep crustal fissure."/><term thcode="61" code="219" name="rift zone" parent="194" scope="a zone of fissures associated with 1) crustal extension or 2) strike-slip faulting."/><term thcode="61" code="220" name="sediment" parent="194" scope="unconsolidated weathering products that have been eroded, transported, and deposited in another location."/><term thcode="61" code="221" name="soil" parent="194" scope="a mixture of weathering products and organic material that can support plant life."/><term thcode="61" code="223" name="spreading center" parent="194" scope="a divergent plate boundary, where new lithosphere is created; typically expressed at the surface as a mid-ocean ridge."/><term thcode="61" code="224" name="subduction zone" parent="194" scope="a convergent plate boundary, where one lithospheric plate dives beneath another and is consumed in the asthenosphere; typically expressed at the surface as a deep-sea trench."/><term thcode="61" code="225" name="syncline" parent="194" scope="a downward fold with younger strata in the core."/><term thcode="61" code="226" name="unconformity" parent="194" scope="a surface of erosion or nondeposition between strata, representing a significant gap in the geologic record."/></nt></descriptor>