| eolian deposit [soil survey] | Sand, silt or clay-sized clastic material transported and deposited primarily by wind, commonly in the form of a dune or a sheet of sand or loess. conventionally, primary volcanic deposits (e.g. t... |
| erosion pavement | A surficial lag concentration or layer of gravel and other rock fragments that remains on the soil surface after sheet or rill erosion or wind has removed the finer soil particles and that tends t... |
| erosion remnant | A topographic feature that remains or is left standing above the general land surface after erosion has reduced the surrounding area; e.g., a monadnock, a butte, or a stack. gg |
| erosion surface | A land surface shaped by the action of erosion, especially by running water. gg |
| estuarine deposit | Fine-grained sediments (very fine sand, silt and clay) of marine and fluvial origin commonly containing decomposed organic matter, laid down in the brackish waters of an estuary; characteristicall... |
| estuarine subaqueous soils | Soils that form in sediment found in shallow-subtidal environments in protected estuarine coves, bays, inlets, and lagoons. excluded from the definition of these soils are any areas “permanently c... |
| everglades - (colloquial | Southern usa) a large expanse of marshy land, covered mostly by grasses, e.g. the florida everglades. gg |
| exhumed | (adjective) formerly buried landforms, geomorphic surfaces, or paleosols that have been reexposed by erosion of the covering mantle. compare - relict, buried, ground soil. hp |
| extramorainic | (not preferred) refer to extramorainal part 629 - glossary 629-29 (430-vi-nssh, 2008) |
| faceted spur | The inverted v-shaped end of a ridge that has been truncated or steeply beveled by steam erosion (e.g. meander scar or bluff), glacial truncation, or fault scarp displacement. compare - spur. sw |
| facies [stratigraphy] | A distinctive group of characteristics that distinguish one group from another within a stratigraphic unit; the sum of all primary lithologic and paleontological characteristics of sediments or se... |
| fall [mass movement] | (a) a category of mass movement processes, associated sediments (fall deposit), or resultant landforms (e.g., rock fall, debris fall, soil fall) characterized by very rapid movement of a mass of r... |
| falling dune | An accumulation of sand that is formed as sand is blown off a mesa top or over a cliff face or steep slope, forming a solid wall, sloping at the angle of repose of dry sand, or a fan extending dow... |
| fan [geomorphology] | (a) a gently sloping, fan-shaped mass of detritus forming a section of a low-angle cone commonly at a place where there is a notable decrease in gradient; specifically an alluvial fan (not |
| fan apron | A sheet-like mantle of relatively young alluvium and soils covering part of an older fan piedmont (and occasionally alluvial fan) surface, commonly thicker and further down slope (e.g., mid-fan or... |
| fan collar | A landform comprised of a thin, short, relatively young mantle of alluvium along the very upper margin (near the proximal end or apex) of a major alluvial fan. the young mantle somewhere buries an... |
| fan piedmont | The most extensive landform on piedmont slopes, formed by (a) the lateral, downslope, coalescence of mountain-front alluvial fans into one generally smooth slope with or without the transverse und... |
| fan remnant | A general term for landforms that are the remaining parts of older fan-landforms, such as alluvial fans, fan aprons, inset fans, and fan skirts, that either have been dissected (erosional fan-remn... |
| fan skirt | The zone of smooth, laterally-coalescing, small alluvial fans that issue from gullies cut into the fan piedmont of a basin or that are coalescing extensions of the inset fans of the fan piedmont, ... |
| fanhead trench | A linear depression formed by a drainageway that is incised considerably below the surface of an alluvial fan. gg part 629 - glossary 629-30 (430-vi-nssh, 2008) |
| fault block | A displaced crustal unit, formed during block faulting, that is bounded by faults, either completely or in part, and behaves as a coherent unit during tectonic activity. sw & gg |
| fault line | The trace of a fault plane on the ground surface or on a reference plane. compare - fault-line scarp. gg |
| fault zone | - A fault that is expressed as a zone of numerous small fractures or of breccia or fault gouge. a fault zone may be as wide as hundreds of meters. compare - fault, fault-scarp. gg
- A f...
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| fault-block mountains | Mountains that formed primarily by block faulting, and commonly exhibit asymmetrical rotation and vertical displacement from a horizontal plane by large, coherent fault-block units hinged along fa... |
| fault-line scarp | (a) a steep slope or cliff formed by differential erosion along a fault line, as by the more rapid erosion of soft rock on the side of a fault as compared to that of more resistant rock on the oth... |
| felsic rock | A general term for igneous rock containing abundant, light-colored minerals (granite, etc); also applied to those minerals (quartz, feldspars, feldspathoids, muscovite) as a group. compare - mafic... |
| filled marshland | A subaerial soil area composed of fill materials (construction debris, dredged or pumped sandy or shell-rich sediments, etc.) deposited and smoothed to provide building sites and associated uses (... |
| finger ridge | One in a group of small, tertiary spur ridges that form crudely palmate extensions of erosional remnants along the flanks or nose of larger ridges. compare - ballena, rib. sw |
| first bottom | (not recommended; colloquial: midwest usa) refer to flood-plain step. an obsolete, informal term loosely applied to the lowest flood-plain steps that experience regular flooding. however, the freq... |
| fissure vent | An opening in earth’s surface of a volcanic conduit in the form of a crack or fissure rather than a localized crater; a roughly linear crack or area along which lava, generally mafic and of low vi... |
| flood-plain landforms | A variety of constructional and erosional features produced by stream channel migration and flooding, e.g., backswamp, braided stream, flood-plain splay, meander, meander belt, meander scroll, oxb... |
| flood-plain playa | A landform consisting of very low gradient, broad, barren, axial-stream channel segments in an intermontane basin. it floods broadly and shallowly and is veneered with barren fine-textured sedimen... |
| flood-plain splay | A fan-shaped deposit or other outspread deposit formed where an overloaded stream breaks through a levee (natural or artificial) and deposits its material (often coarse-grained) on the flood plain... |
| flood-plain step | An essentially flat, terrace-like alluvial surface within a valley that is frequently covered by flood water from the present stream (e.g., below the 100 year flood level); any approximately horiz... |
| flood-tidal delta | A largely subaqueous (sometimes intertidal), crudely fan-shaped deposit of sand-sized sediment formed on the landward side of a tidal inlet (modified from boothroyd et al., 1985; davis, 1994; ritt... |
| flood-tidal delta flat | The relatively flat, dominant component of the flood-tidal delta. at extreme low tide this landform may be exposed for a relatively short period (modified from boothroyd et al., 1985). sss |
| flood-tidal delta slope | An extension of the flood-tidal delta that slopes toward deeper water in a lagoon or estuary, composed of flood channels, inactive lobes (areas of the flood-tidal delta that are not actively accum... |
| floor [geomorphology] | (a) a general term for the nearly level, lower part of a basin or valley; (not preferred) refer to basin floor, valley floor, (b) the bed of any body of water; e.g., the nearly level surface benea... |
| flow [mass movement] | A category of mass movement processes, associated sediments (flow deposit) and landforms characterized by slow to very rapid downslope movement of unconsolidated material which, whether saturated ... |
| flute [glacial] | A lineation or streamlined furrow or ridge parallel to the direction of ice movement, formed in newly deposited till or older drift. they range in height from a few centimeters to 25 m, and in len... |
| fluve | (refer to drainageway) a roughly linear or elongated depression (topographic low) of any size, along which water flows, at some time. compare - interfluve. ffp & sw. |
| fluviokarst | A karst landscape dominated by both 1) karst features (deranged and subsurface drainage, blind valleys, swallow holes, large springs, closed depressions, and caves), generally limited to low-lying... |
| fluviomarine bottom | The nearly level or slightly undulating, relatively low-energy, depositional environment with relatively deep water (1.0 to >2.5 m) directly adjacent to an incoming stream and composed of interfin... |
| fluviomarine deposit | 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 (i.e. materials ... |
| fluviomarine terrace | A constructional coastal strip, sloping gently seaward and/or down valley, veneered or completely composed of fluviomarine deposits (typically silt, sand, fine gravel). compare - terrace, stream t... |
| fold [structural geology] | A curve or bend of a planar structure such as rock strata, bedding planes, foliation, or cleavage. gg |
| foothills | A steeply sloping upland composed of hills with relief of 30 up to 300 meters and fringes a mountain range or high-plateau escarpment. compare - hill, mountain, plateau. sw & hp |
| footslope | The hillslope profile position that forms the concave surface at the base of a hillslope. it is a transition zone between upslope sites of erosion and transport (shoulder, backslope) and downslope... |
| formation [stratigraphy] | The basic lithostratigraphic unit in the local classification of rocks. a body of rock (commonly a sedimentary stratum or strata, but also igneous and metamorphic rocks) generally characterized by... |
| fosse [glacial geology] | A long, narrow depression or trough-like hollow between the edge of a retreating glacier and the wall of its valley, or between the front of a moraine and its outwash plain. gg |
| free face | The part of a hillside or mountainside consisting of an outcrop of bare rock (scarp or cliff) that sheds colluvium to slopes below and commonly stands more steeply than the angle of repose of the ... |
| free face [geomorphology] | A geomorphic component of hills and mountains consisting of an outcrop of bare rock that sheds rock fragments and other sediments to, and commonly stands more steeply than the angle of repose of, ... |
| freshwater marl | A soft, grayish to white, earthy or powdery, usually impure calcium carbonate precipitated on the bottoms of present-day freshwater lakes and ponds largely through the chemical action of algal mat... |
| fringe-tidal marsh | Narrow salt marsh adjacent to a relatively higher energy environment. sss |
| frost boil | A small mound of fresh soil material formed by frost action. a type of nonsorted circle commonly found in fine-grained sediment underlain by permafrost, or formed in areas affected by seasonal fro... |
| frost shattering | The mechanical disintegration, splitting, or breakup of a rock or soil caused by the pressure exerted by freezing water in cracks or pores, or along bedding planes. sometimes referred to as congel... |
| geology] (not preferred | Refer to sandy outwash plain) a small outwash plain composed chiefly of sand deposited by meltwater streams flowing from a glacier. gg |
| geomorphic component | - Flat plains: - a group of fundamental, three dimensional pieces or areas of flat plains. in descending elevational order, the geomorphic components of a simple, flat plain (e.g. lake plain, lo...
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| geomorphic surface | A mappable area of the earth`s surface that has a common history; the area is of similar age and is formed by a set of processes during an episode of landscape evolution. a geomorphic surface can ... |
| geyser basin | A valley that contains numerous springs, geysers, and steam fissures fed by the same groundwater flow. gg |
| geyser cone | A low hill or mound built up of siliceous sinter around the orifice of a geyser. gg |
| giant ripple | A ripple that is more than 30 m in length; e.g., the jokulhlaup derived giant ripples in camas prairie, mt.; it usually exhibits superimposed megaripples. compare - ripple mark. gg |
| glacial drainage channel | A channel formed by an ice-marginal, englacial, or subglacial stream during glaciation. gg |
| glacial groove | A deep, wide, usually straight furrow cut in bedrock by the abrasive action of a rock fragment embedded in the bottom of a moving glacier; it is larger and deeper than a glacial striation, ranging... |
| glacial-marine sedimentation | The accumulation of glacially eroded, terrestrially derived sediment in the marine environment. sediment may be introduced by fluvial transport, by ice rafting, as an ice-contact deposit, or by eo... |
| glacial-valley floor | The comparatively flat bottom of a mountain valley predominantly mantled by till but which can grade from glacial scour (scoured rock-outcrop) near it’s head to a thick mantle of till, and ultimat... |
| glacial-valley wall | The comparatively steep, glacially scoured, concave sides of a u-shaped, mountain valley mantled by colluvium with little or no till; (not preferred: colloquial - western usa) sometimes called a t... |
| glacier outburst flood | A sudden, often annual, release of meltwater from a glacier or glacier-damned lake sometimes resulting in a catastrophic flood, formed by melting of a drainage channel or buoyant lifting of ice by... |
| glaciofluvial deposit | Material moved by glaciers and subsequently sorted and deposited by streams flowing from the melting ice. the deposits are stratified and may occur in the form of outwash plains, valley trains, de... |
| glaciolacustrine deposit | Material ranging from fine clay to sand derived from glaciers and deposited in glacial lakes by water originating mainly from the melting of glacial ice. many are bedded or laminated with varves o... |
| glaciomarine deposit | Glacially eroded, terrestrially derived sediments (clay, silt, sand, and gravel) that accumulated on the ocean floor. sediments may be accumulated as an ice-contact deposit, by fluvial transport, ... |
| glade - (colloquial | Ozark uplands, usa) (a) a largely treeless, open, grassy area (e.g., oak savanna) on high, broad interfluves and hillsides, commonly with shallow soils. compare - park. sw (b) (not preferred) refe... |
| glauconite pellets | Silt to sand-sized, nodular aggregates with a characteristic greenish color, dominantly composed of the clay mineral glauconite; formed in near-shore marine sediments and subsequently exposed by a... |
| gravel pit | A depression, ditch or pit excavated to furnish gravel for roads or other construction purposes; a type of borrow pit. sw |
| greensands | A) an unconsolidated, near-shore marine sediment containing substantial amounts of dark greenish glauconite pellets, often mingled with clay or sand (quartz may form the dominant constituent); pro... |
| ground moraine | (a) commonly an extensive, low relief area of till, having an uneven or undulating surface, and commonly bounded on the distal end by a recessional or end moraine; (b) a layer of poorly sorted roc... |
| ground soil | Any soil at the present-day land surface and actively undergoing pedogenesis, regardless of its history (i.e., relict, exhumed). compare - buried soil. sw & rr grus - the fragmental products of in... |
