<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="106" name="landform" parent="94" scope="a geomorphic feature recognized as distinct from the surrounding terrain."/><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="107" name="abyssal plain" parent="106" scope="large flat areas in the ocean basins."/><term thcode="61" code="108" name="atoll" parent="106" scope="ringlike island or islands surrounding a lagoon."/><term thcode="61" code="109" name="bank" parent="106" scope="used for either 1) the ground bordering a body of water or 2) an area of sea floor surrounded by deeper water."/><term thcode="61" code="110" name="basin" parent="106" scope="used for large topographic depressions, both subaerial and submarine; distinct from (but sometimes related to) sedimentary basins and structural basins."/><term thcode="61" code="111" name="bay" parent="106" scope="a recess in the shoreline, typically bounded by capes or headlands."/><term thcode="61" code="112" name="beach" parent="106" scope="a gently sloping shore, generally underlain by sand or gravel and subject to the action of waves and tides."/><term thcode="61" code="113" name="beach ridge" parent="106" scope="the ridge defining the landward limit of a current of former beach, often capped by dunes."/><term thcode="61" code="114" name="caldera" parent="106" scope="the crater formed by the collapse of a volcano."/><term thcode="61" code="115" name="canyon" parent="106" scope="a steeply walled valley formed by fluvial erosion."/><term thcode="61" code="116" name="cape" parent="106" scope="a prominent headland along the shore."/><term thcode="61" code="117" name="cave" parent="106" scope="a natural underground cavity or chamber."/><term thcode="61" code="118" name="cliff" parent="106" scope="a very steep, vertical, or overhanging slope."/><term thcode="61" code="119" name="coast" parent="106" scope="the distinctive terrain between the shore and inland areas; varies in width."/><term thcode="61" code="120" name="coastal barrier" parent="106" scope="relatively narrow, subaerial ridges parallel to the shore, formed by wind, waves, and longshore currents; includes both barrier islands (separated from mainland by a bay or lagoon) and spits (attached to the mainland)."/><term thcode="61" code="121" name="coastal plain" parent="106" scope="used for plains adjacent to a large body of water."/><term thcode="61" code="122" name="continental margin" parent="106" scope="the zone of transition between the continents and oceans, including the continental shelf, slope, and rise."/><term thcode="61" code="123" name="continental shelf" parent="106" scope="the gently sloping sea floor between the coast and the continental slope."/><term thcode="61" code="124" name="continental slope" parent="106" scope="the more steeply sloping sea floor seaward of the continental shelf."/><term thcode="61" code="125" name="cove" parent="106" scope="a recess in the shoreline smaller than a bay."/><term thcode="61" code="126" name="crater" parent="106" scope="used for both volcanic craters and impact craters."/><term thcode="61" code="127" name="creek" parent="106" scope="a stream that is smaller than a river."/><term thcode="61" code="128" name="deep sea fan" parent="106" scope="a fan composed of sediment deposited by turbidity currents."/><term thcode="61" code="129" name="delta" parent="106" scope="alluvial deposits at the mouth of a river."/><term thcode="61" code="130" name="dune" parent="106" scope="a mound or ridge of wind-blown sand."/><term thcode="61" code="131" name="escarpment" parent="106" scope="a steep slope separating two areas of flatter terrain."/><term thcode="61" code="132" name="estuary" parent="106" scope="the lower course of a river, subject to tides and mixing of fresh and salt water."/><term thcode="61" code="133" name="fjord" parent="106" scope="narrow, steep-sided ocean inlet representing a drowned glacial valley."/><term thcode="61" code="134" name="gulf" parent="106" scope="a recess in the shoreline larger than a bay."/><term thcode="61" code="135" name="harbor" parent="106" scope="a sheltered anchorage, natural or artificial."/><term thcode="61" code="136" name="hill" parent="106" scope="a topographic prominence smaller than a mountain."/><term thcode="61" code="137" name="inland sea" parent="106" scope="a shallow sea that is largely surrounded by land and has limited communication with the open ocean."/><term thcode="61" code="138" name="island" parent="106" scope="a relatively small landmass surrounded on all sides by water."/><term thcode="61" code="143" name="lagoon" parent="106" scope="a shallow body of water separated from the open ocean by barrier islands or coral reefs."/><term thcode="61" code="144" name="lake" parent="106" scope="a body of water surrounded by land and larger than a pond."/><term thcode="61" code="147" name="lava flow" parent="106" scope="used for either 1) streams of molten rock erupted from a volcanic vent or 2) the solidified products of such eruptions."/><term thcode="61" code="148" name="marsh" parent="106" scope="a wetland characterized by herbaceous plants."/><term thcode="61" code="149" name="mid-ocean ridge" parent="106" scope="ridge near the center of an ocean basin, where new oceanic crust is created by sea-floor spreading."/><term thcode="61" code="150" name="mountain" parent="106" scope="a topographic prominence larger than a hill."/><term thcode="61" code="152" name="mudbank" parent="106" scope="used for mudbanks along rivers or on the sea floor."/><term thcode="61" code="153" name="mudflat" parent="106" scope="used for tidal flats underlain by mud."/><term thcode="61" code="154" name="ocean" parent="106" scope="used for saltwater bodies larger than seas or lakes."/><term thcode="61" code="155" name="outcrop" parent="106" scope="a natural or artificial bedrock exposure."/><term thcode="61" code="156" name="peninsula" parent="106" scope="a narrow landmass surrounded by water on three sides but connected to the mainland."/><term thcode="61" code="157" name="plateau" parent="106" scope="an elevated, generally flat landform."/><term thcode="61" code="158" name="pond" parent="106" scope="a body of water surrounded by land and smaller than a lake."/><term thcode="61" code="159" name="reef" parent="106" scope="used for 1) shallow-water biotic reefs such as coral reefs, 2) biotic reefs preserved in the geologic record, and 3) rocky outcrops on the sea floor that create a hazard to navigation."/><term thcode="61" code="162" name="ridge" parent="106" scope="used generically for a narrow, prominent elevation in any physiographic setting."/><term thcode="61" code="163" name="ripple mark" parent="106" scope="a small, undulating bedform created by waves, currents, or wind."/><term thcode="61" code="164" name="river" parent="106" scope="a stream that is larger than a creek."/><term thcode="61" code="170" name="sand deposit" parent="106" scope="unconsolidated sand laid down by wind or water."/><term thcode="61" code="171" name="sand wave" parent="106" scope="a relatively large, undulating bedform created by currents."/><term thcode="61" code="172" name="sandbar" parent="106" scope="used for sandy ridges formed in rivers (by currents) and in nearshore marine environments (by wave action)."/><term thcode="61" code="175" name="sea stack" parent="106" scope="an exposed erosional remnant lying offshore."/><term thcode="61" code="173" name="seabed" parent="106" scope="the floor of a sea or ocean."/><term thcode="61" code="174" name="seamount" parent="106" scope="an undersea mountain, generally formed through volcanism."/><term thcode="61" code="176" name="shoal" parent="106" scope="a relatively shallow area in the bed of a sea, lake, or river."/><term thcode="61" code="177" name="shore" parent="106" scope="the boundary between an ocean, sea, or lake and the adjacent dry land."/><term thcode="61" code="178" name="sinkhole" parent="106" scope="a topographic depression created by collapse of the ground above a cave or cavern."/><term thcode="61" code="179" name="slough" parent="106" scope="generally used for a muddy channel or swampy depression near the coast."/><term thcode="61" code="180" name="sound" parent="106" scope="a relatively long ocean inlet separating an island from the mainland or connecting two larger bodies of water; wider than a strait."/><term thcode="61" code="181" name="strait" parent="106" scope="a relatively narrow waterway between two larger bodies of water."/><term thcode="61" code="182" name="stream" parent="106" scope="a body of flowing water, regardless of size."/><term thcode="61" code="183" name="submarine canyon" parent="106" scope="an underwater canyon crossing the continental shelf and slope."/><term thcode="61" code="184" name="swamp" parent="106" scope="a wetland characterized by woody plants."/><term thcode="61" code="185" name="terrace" parent="106" scope="bench-like landforms within river valleys or along the coast, often arranged in steps."/><term thcode="61" code="186" name="tidal flat" parent="106" scope="very gently sloping surface that is inundated at high tide."/><term thcode="61" code="187" name="tidal inlet" parent="106" scope="the narrow waterway between barrier islands that connects lagoon with open ocean."/><term thcode="61" code="188" name="trench" parent="106" scope="a narrow, steep-sided depression in subaerial or submarine topography."/><term thcode="61" code="189" name="trough" parent="106" scope="used for topographic depressions that are generally wider and more gently sloping than trenches."/><term thcode="61" code="190" name="valley" parent="106" scope="an elongate topographic low formed by fluvial erosion or tectonic action."/><term thcode="61" code="191" name="volcano" parent="106" scope="a crustal vent from which lava and other igneous products are erupted; term usually applied to a mountain created by repeated eruptions."/><term thcode="61" code="192" name="watershed" parent="106" scope="the land that contributes water and sediment to a stream; term may be used for drainage systems of any scale."/><term thcode="61" code="193" name="wetland" parent="106" scope="a low-lying area saturated with water."/></nt></descriptor>