dead-ice
(not recommended) use stagnant ice.

dead-ice moraine
(not recommended) use disintegration moraine.

debris
any surficial accumulation of loose material detached from rock masses by chemical and mechanical means, as by decay and disintegration. it consists of rock clastic material of any size and sometimes organic matter. GG

debris avalanche [mass movement]
the process, associated sediments (debris avalanche deposit) or resultant landform characterized by a very rapid to extremely rapid type of flow dominated by the sudden downslope movement of incoherent, unsorted mixtures of soil and weathered bedrock which, although comparatively dry, behave much as a viscous fluid when moving. compare - debris flow, rock fragment flow, debris avalanche, earthflow, landslide. SW

debris fall [mass movement]
the process, associated sediments (debris fall deposit) or resultant landform characterized by a rapid type of fall involving the relatively free, downslope movement or collapse of detached, unconsolidated material which falls freely through the air (lacks an underlying slip face); sediments have substantial proportions of both fine earth and coarse fragments; common along undercut stream banks. compare - rock fall, soil fall, landslide. SW

debris flow [ mass movement]
the process, associated sediments (debris flow deposit) or resultant landform characterized by a very rapid type of flow dominated by a sudden downslope movement of a mass of rock, soil, and mud (more than 50% of the particles are > 2mm), and whether saturated or comparatively dry, behaves much as a viscous fluid when moving. compare - lahar, mudflow, landslide. SW

debris slide [ mass movement]
the process, associated sediments (debris slide deposit) or resultant landform characterized by a rapid type of slide, composed of comparatively dry and largely unconsolidated earthy material which slides or rolls downslope (does not exhibit backward rotation) and resulting in an irregular, hummocky deposit somewhat resembling a moraine. compare - rotational landslide, block glide, lateral spread, landslide. SW & GG

debris spread [mass movement]
the process, associated sediments (debris spread deposit) or resultant landforms characterized by a very rapid type of spread dominated by lateral movement in a soil and rock mass resulting from liquefaction or plastic flow of underlying materials that may be extruded out between intact units; sediments have substantial proportions of both fine earth and coarse fragments. compare - earth spread, rock spread, landslide. SW & DV

debris topple [mass movement]
the process, associated sediments (debris topple deposit) or resultant landform characterized by a localized, very rapid type of topple in which large blocks of soil and rock material literally fall over, rotating outward over a low pivot point; sediments have substantial proportions of both fine earth and coarse fragments. portions of the original material may remain intact, although reoriented, within the resulting debris pile. compare - earth topple, rock topple, landslide. SW

deflation
the sorting out, lifting and removal of loose, dry, fine-grained soil particles (clays, silts, and fine sands) by the turbulent eddy action of the wind; a form of wind erosion. GG & GSST

deflation basin
a topographic basin excavated and maintained by wind erosion which removes unconsolidated material and commonly leaves a rim of resistant material surrounding the depression. unlike a blowout, a deflation basin does not include adjacent deposits derived from the basin. compare - blowout. GG

degradation [geomorphology]
the wearing down or away, and the general lowering of the land surface by natural processes of weathering and erosion (e.g., the deepening by a stream of its channel) and may infer the process of transportation of sediment. compare - destructional. GG

Delmarva Bay
see Carolina Bay.

delta
a body of alluvium, nearly flat and fan-shaped, deposited at or near the mouth of a river or stream where it enters a body of relatively quiet water, usually a sea or lake. HP

delta plain
the level or nearly level surface composing the land-ward part of a large delta; strictly, a flood plain characterized by repeated channel bifurcation and divergence, multiple distributary channels, and interdistributary flood basins. GG

dendritic drainage pattern
a drainage pattern in which the streams branch randomly in all direction and at almost any angle, resembling in plan the branching habit of certain trees. GG

deposit
earth material of any type, either consolidated or unconsolidated, that has accumulated by natural processes. GG

deposition
the laying down of any material by any agent such as wind, water, ice or by other natural processes. HP

depression
any relatively sunken part of the Earth's surface; especially a low-lying area surrounded by higher ground. a closed depression has no natural outlet for surface drainage (e.g. a sinkhole). an open depression has a natural outlet for surface drainage. compare - closed depression, open depression. GG

desert pavement
a natural, residual concentration or layer of wind-polished, closely packed gravel, boulders, and other rock fragments, mantling a desert surface. it is formed where wind action and sheetwash have removed all smaller particles or where coarse fragments have migrated upward through sediments to the surface. it usually protects the underlying, finer-grained material from further deflation. The coarse fragments commonly are cemented by mineral matter. compare - erosion pavement, stone line. SW, GSST & GG

desert varnish
(not preferred) refer to rock varnish.

destructional [geomorphology]
(adjective) Said of a landform that owes its origin, form, position, or general character to the removal of material by erosion and weathering (degradation) processes resulting from the wearing-down or away of the land surface. compare - constructional. GG

detritus [geology]
a collective term for rock and mineral coarse fragments occurring in sediments, that are detached or removed by mechanical means (e.g. disintegration, abrasion) and derived from pre-existing rocks and moved from their place of origin. compare - clastic, epiclastic, pyroclastic. GG

diamict
(not preferred; refer to diamicton) a general term that includes both diamictite (coherent rock) and diamicton (unconsolidated sediments). GG

diamictite
a general term for any nonsorted or poorly sorted, noncalcareous, terrigenous sedimentary rock (e.g., pebbly mudstone) containing a wide range of particle sizes. compare - diamicton. GG

diamicton
a generic term for any nonlithified, nonsorted or poorly sorted sediment that contains a wide range of particle sizes, such as coarse fragments contained within a fine earth matrix (e.g. till) and used when the genetic context of the sediment is uncertain. compare - diamictite. SW & GG

diapir
a dome or anticlinal fold in which the overlying rocks or sediments have been ruptured by the squeezing-out of plastic core material. diapirs in sedimentary strata usually contain cores of salt or shale; igneous intrusions may also show diapiric structure. GG

diatomaceous earth
a geologic deposit of fine, grayish, siliceous material composed chiefly or wholly of the remains of diatoms. it may occur as a powder or a rigid material. also called diatomaceous materials. GSST

dike [intrusive rocks]
a tabular igneous intrusion that cuts across the bedding or foliation of the country rock. compare - sill. GG

dip
[soil survey] a geomorphic component (characteristic piece) of flat plains (e.g., lake plain, low coastal plain, low-relief till plain) consisting of a shallow and typically closed depression that tends to be an area of focused groundwater recharge but not a permanent water body and that lies slightly lower and is wetter than the adjacent talf, and favors the accumulation of fine sediments and organic materials. SW

dip
the maximum angle that a structural surface, e.g. a bedding or fault plane, makes with the horizontal, measured perpendicular to the strike of the structure and in the vertical plane. GG

dip slope
a slope of the land surface, roughly determined by and approximately conforming with the dip of underlying bedded rocks; (i.e. the long, gently inclined surface of a cuesta). compare - scarp slope. HP

discontinuity
[stratigraphy] any interruption in sedimentation, whatever its cause or length, usually a manifestation of nondeposition and accompanying erosion; an unconformity. GG

discontinuous permafrost
permafrost occurring in some areas beneath the exposed land surface throughout a geographic region where other areas are free of permafrost. compare - continuous permafrost, sporadic permafrost. NRC

disintegration moraine
a drift topography characterized by chaotic mounds and pits, generally randomly oriented, developed in supraglacial drift by collapse and flow as the underlying stagnant ice melted. slopes may be steep and unstable and there will be used and unused stream courses and lake depressions interspersed with the morainic ridges. characteristically, there are numerous abrupt, lateral and vertical changes between unconsolidated materials of differing lithology. SJ & SW

distal [sedimentology]
(adjective) Said of a sedimentary deposit consisting of fine clastics and deposited farthest from the source area. compare - proximal. GG

distributary [streams]
a) a divergent stream flowing away from the main stream and not returning to it, as in a delta or on a flood plain. it may be produced by stream deposition choking the original channel.
b) one of the channels of a braided stream; a channel carrying the water of a stream distributary. GG

ditch
an open and usually unpaved (unlined), channel or trench excavated to convey water for drainage (removal) or irrigation (addition) to or from a landscape; smaller than a canal; some ditches are modified natural waterways. GG

divide
a) the line of separation;
b) the summit area, or narrow tract of higher ground that constitutes the watershed boundary between two adjacent drainage basins; it divides the surface waters that flow naturally in one direction from those that flow in the opposite direction. compare - interfluve GG

doline
(not preferred; refer to synonym "sinkhole")

doline karst
(not preferred) refer to sinkhole karst.

dolomite [mineral]
a common rock-forming rhombohedral carbonate mineral: CaMg(CO3)2. GG

dolomite [rock]
a carbonate sedimentary rock consisting chiefly (more than 50 percent by weight or by areal percentages under the microscope) of the mineral dolomite. GG

dolostone
(not recommended - use dolomite) an obsolete term proposed for the sedimentary rock called dolomite, in order to avoid confusion with the mineral of the same name. compare - dolomite. GG

dome
a) [structural geology] an uplift or anticlinal structure, either circular or elliptical in outline, in which the rocks dip gently away in all directions. a dome may be small (e.g. a salt dome) or many kilometers in diameter.
b) [geomorphology] a smoothly rounded landform of rock mass such as a rock-capped mountain summit, that roughly resembles the dome of a building. (e.g. the rounded granite peaks of Yosemite, CA). GG

double-bedding mound
raised, linear mounds with subdued, convex slope cross-sections constructed by mounding and shaping spoil material dredged from adjacent drainage ditches and placed over natural soil. the mounds serve as preferred, better-drained bedding areas for managed timber plantations; common in the lower coastal plains of the Atlantic and Gulf coasts, USA. SW

drainage basin
a general term for a region or area bounded by a drainage divide and occupied by a drainage system. GG

drainage network
(not preferred) refer to drainage pattern.

drainage pattern
the configuration of arrangement in plan view of the natural stream courses in an area. it is related to local geologic and geomorphologic features and history. GG

drainageway
a) a general term for a course or channel along which water moves in draining an area. GG;
b) [soil survey] a term restricted to relatively small, roughly linear or arcuate depressions that move concentrated water at some time, and either lack a defined channel (e.g. head slope, swale) or have a small, defined channel (e.g. low order streams). SW

draw
a small, natural watercourse cut in unconsolidated materials, generally more open with a broader floor and more gently sloping sides than an arroyo, ravine or gulch, and whose present stream channel may appear inadequate to have cut the drainageway that it occupies. SW

drift [glacial geology]
a general term applied to all mineral material (clay, silt, sand, gravel, boulders) transported by a glacier and deposited directly by or from the ice, or by running water emanating from a glacier. drift includes unstratified material (till) that forms moraines, and stratified deposits that form outwash plains, eskers, kames, varves, and glaciofluvial sediments. the term is generally applied to Pleistocene glacial deposits in areas that no longer contain glaciers. GG

dropstone
an oversized stone (compared to the matrix sediments) in laminated sediment that depresses the underlying laminae and can be covered by "draped laminae". most dropstones originate through ice-rafting; another source is floating tree roots. compare - erratic, ice-rafting. GG

drumlin
a low, smooth, elongated oval hill, mound, or ridge of compact till that has a core of bedrock or drift. It usually has a blunt nose facing the direction from which the ice approached and a gentler slope tapering in the other direction. the longest axis is parallel to the general direction of glacier flow. drumlins are products of streamline (laminar) flow of glaciers, which molded the subglacial floor through a combination of erosion and deposition. compare - drumlinoid ridge. SW, HP, & GG

drumlin field
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). SW

drumlinoid ridge
a rock drumlin or drift deposit whose form approaches but does not fully attain that of a classic drumlin, even though it seemingly results from similar processes of moving ice. compare - drumlin, interdrumlin. SW & GG

dry wash
(not preferred - refer to wash). a dry, ephemeral stream channel, especially in semiarid regions which only moves water in response to intense, infrequent precipitation. compare - arroyo. SW

dump
an area of smooth or uneven accumulations or piles of waste rock, earthy material, or general refuse that without major reclamation are incapable of supporting plants. compare - sanitary landfill, fill. GSST

dune
a low mound, ridge, bank or hill of loose, windblown, subaerially deposited granular material (generally sand), either barren and capable of movement from place to place, or covered and stabilized with vegetation, but retaining its characteristic shape. (see barchan dune, parabolic dune, parna dune, shrub-coppice dune, seif dune, transverse dune). SW & GG

dune field
an assemblage of moving and/or stabilized dunes, together with sand plains, interdune areas, and the ponds, lakes, or swamps produced by the blocking of steams by the sand. see dune lake. SW

dune lake
a) a lake occupying a deflation basin as in a blowout on a dune.
b) a lake occupying a basin formed by the blocking of a stream by sand dunes migrating along a shore (e.g. Moses lake, WA). GG

dune slack
a damp depression or trough between dunes in a dune field or dune ridges on a shore, caused by intersecting the capillary fringe of the local water table; a moist type of interdune. compare - interdune, dune lake. SW & GG