<descriptor thcode="3"><thesaurus thcode="3" name="Alexandria Digital Library Feature Type Thesaurus" scope="Types of named geographic features.  Applicable also to many unnamed features but reflects the level of detail traditionally shown on maps, so some feature types specified in scientific studies may not be well represented here.  Not highly specific." creator="Alexandria Digital Library Project, University of California at Santa Barbara" rights="Copyright (c) 1999-2004 by the Regents of the University of California. All rights reserved.\r\n\r\nRedistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:\r\n\r\n   1. Redistributions of source code or dataset must retain the above copyright notice, this list of conditions and the following disclaimer.\r\n   2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.\r\n   3. Neither the name of the University of California, Santa Barbara nor the names of its contributors may be used to endorse or promote products derived from this software or dataset without specific prior written permission.\r\n\r\nTHIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS &quot;AS IS&quot; AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS AND CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE OR DATASET, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.\r\n\r\n[This statement is derived from the BSD license template, http://www.opensource.org/licenses/bsd-license.php]" edition="2.0" date="2002-07-03" codetype="number" prefix="feature" uri="http://www.usgs.gov/science/ADLFeatureType" tblname="feature" nonpref="featnp" relterm="featrt" root_code="1" contact="pschweitzer"><category><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="16" name="hierarchical" parent="11" scope="Substantive broader-narrower relationships exist among the terms."/><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="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="16" name="hierarchical" parent="11" scope="Substantive broader-narrower relationships exist among the terms."/><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."/></category><altlabel><altlabel>ADLFTT</altlabel><altlabel>ADLFTT</altlabel><altlabel>ADLFeatureType</altlabel><altlabel>ADLFeatureType</altlabel></altlabel></thesaurus><term thcode="3" code="1010" name="seafloor features" parent="816"/><uf><usefor name="arrugados"/><usefor name="banks (seafloor)"/><usefor name="benches (seafloor)"/><usefor name="holes (seafloor)"/><usefor name="moats (seafloor)"/><usefor name="ocean floor features"/><usefor name="ramps (seafloor)"/><usefor name="rises (seafloor)"/><usefor name="seachannels (seafloor)"/><usefor name="shelf valleys (seafloor)"/><usefor name="subsea features"/><usefor name="tongues (seafloor)"/><usefor name="underwater features"/></uf><bt><term thcode="3" code="816" name="physiographic features" parent="1"/><term thcode="3" code="1" name="Categories"/></bt><nt><term thcode="3" code="2" name="abyssal features" parent="1010" scope="Features on the ocean floor at a depth of 3500 - 6000 meters. [Adapted from Glossary of Geology, 4th ed.]"/><term thcode="3" code="249" name="continental margins" parent="1010" scope="Ocean floor between the shoreline and the abyssal ocean floor. [Glossary of Geology, 4th ed.]"/><term thcode="3" code="421" name="fracture zones" parent="1010" scope="Elongated zones of unusually irregular topography on the deep-sea floor that often separate regions of different depths [Glossary of Geology, 4th ed.]"/><term thcode="3" code="527" name="hydrothermal vents" parent="1010" scope="Cracks along a rift or ridge in the deep ocean floor that spews out water heated to high temperature by the magma under the Earth's crust. [Columbia Electronic Encyc., 1999]"/><term thcode="3" code="756" name="ocean trenches" parent="1010" scope="Narrow, elongate depressions of the deep-sea floor associated with a subduction zone. They are oriented parallel to volcanic arcs and commonly to the edge of the continent, between the continental margin and the abyssal hills. [Glossary of Geology, 4th ed.]"/><term thcode="3" code="1011" name="seamounts" parent="1010" scope="Elevations of the sea floor, 1000 m or higher, either flat-topped (guyots) or peaked (seapeaks). [Glossary of Geology, 4th ed.]"/><term thcode="3" code="1106" name="submarine canyons" parent="1010" scope="Steep-sided, V-profile valley often heading in the continental shelf running down the continental slope, having tributaries and resembling unglaciated, river-cut land canyons. [Glossary of Geology, 4th ed.]"/></nt><rt><term thcode="3" code="921" name="reefs" parent="816" scope="Chains of rocks or coral at or near the surface of water. [USGS Circ 1048]"/><term thcode="3" code="952" name="ridges" parent="710" scope="Elevations with a narrow, elongated crest which can be part of a hill or mountain. [USGS Feature Class Definitions &lt;http://geonames.usgs.gov/domestic/feature_class.htm&gt;]"/><term thcode="3" code="1197" name="valleys" parent="816" scope="Low-lying land bordered by higher ground; especially elongate, relatively large gently sloping depressions of the Earth's surface, commonly situated between two mountains or between ranges of hills or mountains, and often containing a stream with an outlet. [Glossary of Geology, 4th ed.]"/></rt></descriptor>