<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-C054" name="Tectonic Setting" parent="GC-C005"/><bt><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-030" name="Abyssal Plain" parent="GC-C054" scope="Tectonic Setting: A flat region of the deep ocean floor (with a slope less than 1:1,000) that was formed by the deposition of pelagic and gravity-current sediments, which obscure the pre-existing topography. ..."/><term thcode="62" code="GC-031" name="Convergent Active Continental Margin" parent="GC-C054" scope="Tectonic Setting: Intense areas of active magmatism, where the oceanic lithosphere is subducted beneath the continental lithosphere. ..."/><term thcode="62" code="GC-032" name="Divergent Active Continental Margin" parent="GC-C054" scope="Tectonic Setting: Areas where tensional tectonic forces result in the crustal rocks being stretched and?ultimately?split apart or rifted. These areas are marked by subsidence and a continental rise."/><term thcode="62" code="GC-033" name="Fracture Zone" parent="GC-C054" scope="Tectonic Setting: An elongate zone of unusually irregular topography (on the deep seafloor) that often separates basins and regions of different depths; fracture zones commonly follow (and extend beyond) offsets of the mid-ocean ridge."/><term thcode="62" code="GC-035" name="Mid-Ocean Ridge" parent="GC-C054" scope="Tectonic Setting: An extremely large, global spreading center. ..."/><term thcode="62" code="GC-036" name="Passive Continental Margin" parent="GC-C054" scope="Tectonic Setting: The transition between oceanic and continental crust that is not an active plate margin. ..."/><term thcode="62" code="GC-034" name="Spreading Center" parent="GC-C054" scope="Tectonic Setting: Spreading centers are areas where tectonic plates are moving apart, allowing new oceanic crust to reach the surface of the sea floor."/><term thcode="62" code="GC-038" name="Tectonic Trench" parent="GC-C054" scope="Tectonic Setting: A narrow, elongate depression of the deep seafloor associated with a subduction zone. ..."/><term thcode="62" code="GC-037" name="Transform Continental Margin" parent="GC-C054" scope="Tectonic Setting: A feature defined by the transform fault that develops during continental rifting. ..."/></nt></descriptor>