<descriptor thcode="62"><thesaurus thcode="62" name="Coastal and Marine Ecological Classification Standard" scope="Categories of ecosystems for coastal, estuarine, and marine environments." creator="FGDC" rights="public domain" date="2017-05-10" codetype="alpha" prefix="cmecs" uri="https://www2.usgs.gov/science/CMECS" tblname="cmecs" root_code="root" contact="pschweitzer"><category><term thcode="25" code="16" name="hierarchical" parent="11" scope="Substantive broader-narrower relationships exist among the terms."/><term thcode="25" code="16" name="hierarchical" parent="11" scope="Substantive broader-narrower relationships exist among the terms."/></category><altlabel><altlabel>CMECS</altlabel><altlabel>CMECS</altlabel><altlabel>Coastal and Marine Ecological Classification Standard (CMECS)</altlabel><altlabel>Coastal and Marine Ecological Classification Standard (CMECS)</altlabel></altlabel></thesaurus><term thcode="62" code="GC-011" name="Geologic" parent="GC-C052" scope="Geoform Origin: Geologic geoforms are formed by the abiotic processes of uplift, erosion, volcanism, deposition, fluid seepage, and material movement. ..."/><bt><term thcode="62" code="GC-C052" name="Geoform (levels 1 and 2 subcomponents)" parent="GC-C005"/><term thcode="62" code="GC-C005" name="Geoform" parent="root"/><term thcode="62" code="root" name="CMECS" scope="Coastal and Marine Ecological Classification Standard: Category terms encompassing waters from the head of tide or inland incursion of ocean salinity to the splash zone of the coasts to the deepest portions of the oceans and the deep waters of the Great Lakes."/></bt><nt><term thcode="62" code="GC-012" name="Apron" parent="GC-011" scope="Geoform: An extensive, subaqueous, blanket-like deposit of alluvial, unconsolidated material that is derived from an identifiable source and deposited at the base of a mountain or seamount."/><term thcode="62" code="GC-013" name="Bank" parent="GC-011" scope="Geoform: An elevated area above the surrounding seafloor that rises near the surface. ..."/><term thcode="62" code="GC-014" name="Bar" parent="GC-011" scope="Geoform: A relatively shallow place (in a stream, lake, sea, or other body of water) that is typically a submerged ridge, or bank consisting of (or covered) by sand or other unconsolidated material?but may also be composed of rock or other material (modified from Jackson 1997)."/><term thcode="62" code="GC-015" name="Basin" parent="GC-011" scope="Geoform: General term for an area of the seafloor or land surface that lies below the surrounding bottom or terrain elevation. They are normally areas of low relief."/><term thcode="62" code="GC-016" name="Beach" parent="GC-011" scope="Geoform: A gently sloping zone formed by unconsolidated material at the shoreline, typically with a concave profile. ..."/><term thcode="62" code="GC-017" name="Beach Berm" parent="GC-011" scope="Geoform: The natural bench or platform lying below the main beach slope and above the foreshore."/><term thcode="62" code="GC-018" name="Boulder Field" parent="GC-011" scope="Geoform: An area dominated by large, boulder-sized (256 millimeters - 4,096 millimeters) stones or pieces of rock. ..."/><term thcode="62" code="GC-019" name="Cave" parent="GC-011" scope="Geoform: A natural passage extending beneath the earth's surface."/><term thcode="62" code="GC-065" name="Channel" parent="GC-011" scope="Geoform: A general term for a linear or sinuous depression on an otherwise more flat area (for example, a valley- or groove-like feature through which water flows). This is a very broad term that is often used in connection with other terms to provide more meaning."/><term thcode="62" code="GC-070" name="Cone" parent="GC-011" scope="Geoform: (a) A type of submarine, fan-shaped deposit?especially a deep-sea fan associated with a major active delta (such as deltas of the Mississippi, Nile, and Ganges Rivers). ..."/><term thcode="62" code="GC-071" name="Cove" parent="GC-011" scope="Geoform: A small, narrow, sheltered bay or recess in an estuary; often found inside a larger embayment (modified from Jackson 1997)."/><term thcode="62" code="GC-074" name="Delta" parent="GC-011" scope="Geoform: The low, nearly flat, alluvial tract of land at (or near) the mouth of a river. ..."/><term thcode="62" code="GC-080" name="Delta Plain" parent="GC-011" scope="Geoform: The level (or nearly level) surface that makes up the landward part of a large delta; strictly, a flood plain characterized by repeated channel bifurcation and divergence, multiple distributary channels, and interdistributary flood basins."/><term thcode="62" code="GC-081" name="Depression" parent="GC-011" scope="Geoform: General term for any relatively sunken part of the earth's surface?especially a low-lying area surrounded by higher ground. Depressions often have no natural outlet for surface drainage (such as an interior basin or a karstic sinkhole) (Jackson 1997)."/><term thcode="62" code="GC-083" name="Diapir" parent="GC-011" scope="Geoform: A dome or anticlinal fold in which the overlying rocks or sediments have been ruptured when the plastic core material was squeezed out. ..."/><term thcode="62" code="GC-085" name="Dike" parent="GC-011" scope="Geoform: A tabular, igneous intrusion that cuts across the bedding or foliation of the country rock. Dikes are often more resistant to erosion than the surrounding country rock, and dikes can form long ridges."/><term thcode="62" code="GC-583" name="Drumlin" parent="GC-011" scope="Geoform: Drumlins are products of the streamline (laminar) flow of glaciers, which molded the subglacial floor through a combination of erosion and deposition. ..."/><term thcode="62" code="GC-086" name="Drumlin Field" parent="GC-011" scope="Geoform: Groups or clusters of closely spaced drumlins or drumlinoid ridges, distributed more or less en echelon, and commonly separated by small, marshy tracts or depressions (interdrumlins)."/><term thcode="62" code="GC-088" name="Dune" parent="GC-011" scope="Geoform: An active accumulation of sand (formed by wind action) with some elevation; dunes occur on a beach or further inland."/><term thcode="62" code="GC-087" name="Dune Field" parent="GC-011" scope="Geoform: An assemblage of moving and/or stabilized dunes; sand plains; interdune areas; and the ponds, lakes, or swamps produced by the blocking of waterways by migrating dunes (U.S. Department of Agriculture 2008)."/><term thcode="62" code="GC-089" name="Fan" parent="GC-011" scope="Geoform: A low, outspread gently to steeply sloping mass of loose material, which is shaped like an open fan or a segment of a cone. ..."/><term thcode="62" code="GC-094" name="Flat" parent="GC-011" scope="Geoform: A general term for a level (or nearly level) surface or area of land marked by little or no relief; flats are often composed of unconsolidated sediments (such as mud or sand). ..."/><term thcode="62" code="GC-102" name="Fluvio-Marine Deposit" parent="GC-011" scope="Geoform: Stratified materials (clay, silt, sand, or gravel) formed by both marine and fluvial processes, resulting from non-tidal sea-level fluctuations, subsidence, and/or stream migration (e.g., materials originally deposited in a nearshore environment and subsequently reworked by fluvial processes as the sea level fell)."/><term thcode="62" code="GC-103" name="Fracture" parent="GC-011" scope="Geoform: A crack or split formed in a rock or bedrock as a result of local erosion or rock stress; they are not due to tectonic actions (which form larger faults and fracture zones)."/><term thcode="62" code="GC-104" name="Hole/Pit" parent="GC-011" scope="Geoform: A generally more steep- sided indentation or depression that is lower than the surrounding surface formed through a variety of processes."/><term thcode="62" code="GC-108" name="Hydrothermal Vent" parent="GC-011" scope="Geoform: Structures on the seafloor through which materials related to volcanic activity are extruded. These often form tall, chimney-like structures and can support diverse chemosynthetic biota and associated communities."/><term thcode="62" code="GC-107" name="Hydrothermal Vent Field" parent="GC-011" scope="Geoform: An area where several hydrothermal vents, either active or inactive, are present."/><term thcode="62" code="GC-109" name="Inlet" parent="GC-011" scope="Geoform: Inlets are narrow constrictions through which water flows. The term is commonly used to describe gaps between barrier islands that allow tidal exchange with the adjacent?more enclosed?bays, lagoons, or marshes."/><term thcode="62" code="GC-112" name="Island" parent="GC-011" scope="Geoform: An area of land completely surrounded by water?or an elevated area of land surrounded by swamp or marsh, which is isolated at high water or during floods."/><term thcode="62" code="GC-114" name="Karren" parent="GC-011" scope="Geoform: Repeating, surficial solution channels, grooves, or other forms that are etched onto massive, bare limestone surfaces; types range in depth from a few millimeters up to one meter, and they are separated by ridges May also refer to the total complex (all varieties) of surficial solution forms found on compact, pure limestone (U.S. ..."/><term thcode="62" code="GC-115" name="Knob" parent="GC-011" scope="Geoform: A rounded protuberance, usually prominent or isolated with steep sides; also including peaks or other projections from seamounts, or a groups of boulders, or other protruding areas of resistant rocks"/><term thcode="62" code="GC-116" name="Lagoon" parent="GC-011" scope="Geoform: Lagoons tend to be shallow, highly enclosed, with reduced exchange with the ocean, often experiencing high evaporation, and quiescent in terms of wind, current, and wave energy. ..."/><term thcode="62" code="GC-117" name="Lava Field/Plain" parent="GC-011" scope="Geoform: A relatively well-defined area that is covered by lava flows. ..."/><term thcode="62" code="GC-118" name="Ledge" parent="GC-011" scope="Geoform: Bedding planes that are exposed (either on the surface or at depth) often form ledges that have a high habitat value and support colonizing plants and animals. ..."/><term thcode="62" code="GC-119" name="Marine Lake" parent="GC-011" scope="Geoform: An inland body of permanently standing brackish or saline water whose water level is commonly influenced by ocean tides through subterranean cavities connecting to nearby lagoons. ..."/><term thcode="62" code="GC-120" name="Marsh Platform" parent="GC-011" scope="Geoform: The flat, often thick, accumulation of peat that supports emergent marsh vegetation. It is commonly dissected by tidal creeks, and it is occasionally buried and re-exposed through the action of beach erosion and new inlet development."/><term thcode="62" code="GC-121" name="Megaripples" parent="GC-011" scope="Geoform: Large, sand waves or ripple-like features having wavelengths greater than 1 meter or a ripple height greater than 10 centimeters; Megaripples are formed in a subaqueous environment, and they are also known as subaqueous dunes. ..."/><term thcode="62" code="GC-122" name="Moraine" parent="GC-011" scope="Geoform: A mound, ridge, or other distinct accumulation of unsorted, unstratified, glacial drift (predominantly till) that is deposited chiefly by direct action of glacier ice."/><term thcode="62" code="GC-130" name="Mound/Hummock" parent="GC-011" scope="Geoform: A low, rounded, natural hill of unspecified origin, which is generally less than 3 meters high and composed of earthy material."/><term thcode="62" code="GC-132" name="Mud Volcano" parent="GC-011" scope="Geoform: An accumulation (usually conical in shape) of mud and rock formed by volcanic gases; may also refer to a similar accumulation formed by escaping petroliferous gases (Bates and Jackson 1984) (see Figure 6.3)."/><term thcode="62" code="GC-133" name="Natural Levee" parent="GC-011" scope="Geoform: An embankment of sediment, bordering one or both sides of a submarine canyon, fan valley, deep-sea channel, river, or other feature. ..."/><term thcode="62" code="GC-135" name="Overhang (Cliff)" parent="GC-011" scope="Geoform: A rock mass jutting out from a slope, especially the upper part or edge of an eroded cliff projecting out over the lower, undercut part (as above a wave-cut notch). Generally these are characterized as having a slope greater than 90 degrees."/><term thcode="62" code="GC-136" name="Panne" parent="GC-011" scope="Geoform: Shallow depressions or flats, often occurring in and adjacent to marshes in the high intertidal that zone that receive saltwater inflow on an infrequent basis. They often are unvegetated and can have encrustations of salt left by evaporation."/><term thcode="62" code="GC-137" name="Pavement Area" parent="GC-011" scope="Geoform: Flat (or gently sloping), low-relief, solid, carbonate rock with little or no fine-scale rugosity. ..."/><term thcode="62" code="GC-138" name="Platform" parent="GC-011" scope="Geoform: Any level or nearly level surface, ranging in size from a terrace or bench to a plateau defined by slopes around its edges."/><term thcode="62" code="GC-141" name="Pockmark" parent="GC-011" scope="Geoform: Small craters in the seabed caused by fluids (gas and liquids) erupting and streaming through the sediments. Some pockmarks discovered off Nova Scotia have been up to 150 meters in diameter and 10 meters deep."/><term thcode="62" code="GC-140" name="Pockmark Field" parent="GC-011" scope="Geoform: An area of the seafloor dominated by many pockmarks."/><term thcode="62" code="GC-142" name="Ridge" parent="GC-011" scope="Geoform: A long, narrow elevation, usually sharp crested with steep sides. Larger ridges can form an extended upland between valleys."/><term thcode="62" code="GC-145" name="Ripples" parent="GC-011" scope="Geoform: Small, linear structures that form as a result of water movement over unconsolidated sediments. ..."/><term thcode="62" code="GC-146" name="Rock Outcrop" parent="GC-011" scope="Geoform: An area where bedrock is exposed at the earth's surface."/><term thcode="62" code="GC-148" name="Rubble Field" parent="GC-011" scope="Geoform: A loose mass of angular rock fragments. These can occur both on land and underwater."/><term thcode="62" code="GC-149" name="Runnel/Rill" parent="GC-011" scope="Geoform: A small, transient channel carrying the water of a wave after it breaks on a beach. They can also be formed by tidal ebb or runoff (following moderate rains or ice/snow melts). Larger runnels can have steep sides."/><term thcode="62" code="GC-155" name="Scar" parent="GC-011" scope="Geoform: A scar can be either a gouge or deformation of the bottom, or an area where the surface of the substrate, vegetation, or other colonizing organisms have been removed by abrasion or impact. These may be temporary or permanent features."/><term thcode="62" code="GC-151" name="Scarp/Wall" parent="GC-011" scope="Geoform: A relatively straight, cliff-like face or slope of considerable linear extent, which breaks up the general continuity of the land by separating surfaces lying at different levels (as along the margin of a plateau or mesa). ..."/><term thcode="62" code="GC-158" name="Seamount" parent="GC-011" scope="Geoform: An elevation of the seafloor, which is 1,000 meters or higher. Seamounts may be discrete, arranged in a linear or random grouping, or connected at their bases and aligned along a ridge or rise."/><term thcode="62" code="GC-162" name="Sediment Sheet" parent="GC-011" scope="Geoform: A thin, widespread, sedimentary deposit, formed by a transgressive sea advancing for a considerable distance over a stable shelf area; may also be called a blanket deposit (Bates and Jackson 1984)."/><term thcode="62" code="GC-150" name="Sediment Wave Field" parent="GC-011" scope="Geoform: An area of wave-like bedforms in sand or other unconsolidated material which are formed by the action of tides, currents, or waves. ..."/><term thcode="62" code="GC-163" name="Shelf Valley" parent="GC-011" scope="Geoform: A valley crossing the continental shelf, often forming an extension of an existing terrestrial river and terminating in a canyon as the valley reaches the shelf break. ..."/><term thcode="62" code="GC-164" name="Shoal" parent="GC-011" scope="Geoform: A relatively shallow area in a body of water that rises very close to, or reaches, the surface. ..."/><term thcode="62" code="GC-167" name="Shore" parent="GC-011" scope="Geoform: The intersection of a specified plane of water with the beach that migrates with changes of the tide or of the water level."/><term thcode="62" code="GC-166" name="Shore Complex" parent="GC-011" scope="Geoform: Generally a narrow, elongate area that parallels a coastline?commonly cutting across diverse inland landforms. ..."/><term thcode="62" code="GC-170" name="Slope" parent="GC-011" scope="Geoform: An inclined area of ground or substrate with a change in depth or elevation between its upper and lower limits. ..."/><term thcode="62" code="GC-173" name="Spit" parent="GC-011" scope="Geoform: (a) A small point, low tongue, or narrow embankment of land, which commonly consists of sand or gravel deposited by longshore transport. ..."/><term thcode="62" code="GC-174" name="Stack" parent="GC-011" scope="Geoform: A rocky subaerial landform consisting of a steep (and often vertical) column or columns of rock in the sea near a coast which have been isolated from the mainland by wave erosion."/><term thcode="62" code="GC-175" name="Submarine Slide Deposit" parent="GC-011" scope="Geoform: This form includes a wide variety of mass-movement landforms and processes involving the down slope transport (under gravitational influence) of soil and rock material en masse. ..."/><term thcode="62" code="GC-176" name="Swale/Slack" parent="GC-011" scope="Geoform: A long, narrow, generally shallow trough-like depression between two beach ridges and aligned roughly parallel to the coastline. These typically will be found in the intertidal or supratidal zones."/><term thcode="62" code="GC-177" name="Terrace" parent="GC-011" scope="Geoform: Any long, narrow, relatively level or gently inclined surface, generally less broad than a plain, but broader than a ledge and bounded along one edge by a steeper descending slope and along the other by a steeper ascending slope. ..."/><term thcode="62" code="GC-181" name="Tidepool" parent="GC-011" scope="Geoform: A pool of salt water left by an ebbing tide that generally persists until the next flood tide. These normally occur in rock substrates and support diverse animal and plant communities (see Figure 6.4)."/><term thcode="62" code="GC-182" name="Till Surface" parent="GC-011" scope="Geoform: An area of substrate (predominantly unsorted and unstratified drift) that is generally unconsolidated, because it was deposited directly by a glacier without subsequent reworking by melt water. ..."/><term thcode="62" code="GC-183" name="Tombolo" parent="GC-011" scope="Geoform: A sand or gravel bar or barrier that connects an island with the mainland (or with another island)."/></nt></descriptor>