Geomorphology Flashcards
Formed when weathering, together with mass collapse (and in arid areas with wind erosion), creates a tunnel through a slab of rock.
Rock Arch or Window
Where do most Arid areas are located?
Near Equator
A wind-eroded depression in the side of a cliff of a homogenous rock type.
Alcove and yardang windows
Low, triangular-shaped deposits built from the accumulation of sediments deposited at the mouth of a valley (i.e., from a mountainous or upland into a larger mainstream valley or lowland).
Alluvial Fan
The size of Alluvial fan depends on the following:
a. area of drainage basin
b. climate
c. lithologies in the source area
d. tectonic activity
e. space available for fan growth
A type of igneous rock that forms when magma rises into the earth’s crust, but does not erupt onto the surface. The magma cools beneath the earth’s surface, forming a rock structure that extends at least one hundred square kilometers across (40 square miles), and extends to an unknown depth.
Batholith
Generally concordant with the intruded strata with dike or funnel-shaped feeder bodies below the body.
Lopolith
An intrusion that has a surface exposure of less than 100 square kilometers and is smaller than a batholith. It has a discordant relationship with the surrounding rocks, meaning it cuts across the pre-existing rock layers.
Stock
Submarine, circular, steep-sided holes which occur in coral reefs. Blue holes are formed by the erosion of limestone bedrock over thousands of years.
Blue Hole (marine sinkhole)
A compound alluvial fan where neighboring alluvial fans converge into a single apron of deposits against a slope.
Bajada
Also called pan, flat, or dry lake, flat-bottom depression found in interior desert basins and adjacent to coasts within arid and semiarid regions, periodically covered by water that slowly filtrates into the ground water system or evaporates into the atmosphere, causing the deposition of salt, sand, and mud along the bottom and around the edges of the depression.
Playa
Their slopes are generally less than 0.2 metre per kilometre. When filled with only a few centimetres of water, many kilometres of surface may be inundated. It is the process of inundation that develops and maintains the near-perfect flatness so characteristic of these arid-region landforms.
A small steep-sided and flat-topped hill, built of flat lying soft rocks capped by a more resistant layer of sedimentary rock, lava flow or duricrust, surrounded by a plain.
Butte
A deeply incised, steep-sided river valley.
Canyon
Asymmetrical upland feature usually associated with gently dipping rocks and comprising a steep scarp slope (or escarpment) and a longer, gentler dip slope.
Cuesta
Also pericline; formed by tectonic warping, igneous intrusion, or diapir. The oldest rock layers are found at the core, with younger layers around them.
Dome
Convex upward, resembling an upside-down bowl. Can be caused by various geological processes, including compression, volcanic activity, or the intrusion of magma.
Formed by the downward warping or sinking of rock layers. Concave upward, similar to a bowl. The youngest rock layers are at the center, with older layers surrounding them.
Basin
Result of compression
A depositional landform produced by sedimentation at and around the mouth of a river.
Delta
These deltas occur where tidal forces are strong and significantly influence the distribution and reworking of the sediment. They often have features like tidal channels and mudflats, and the sediment can be extensively reworked by the tidal action.
Tide-dominated deltas
In these deltas, wave action is the primary force shaping the delta. Waves redistribute the sediment, sorting it and creating features like barrier islands and lagoons. The sediment is typically coarser, and the delta has a smoother, more regular shoreline.
Wave-dominated deltas
These deltas form when the river’s sediment load is high and the marine influence in terms of waves and tides is weak. As the river water slows down when it meets the sea, it deposits its sediment load, creating a delta that often has a characteristic ‘bird-foot’ pattern, with elongated projections into the sea.
River-dominated deltas
A large area of sand dunes.
Erg
A long winding ridge of stratified sand and gravel that are frequently several km long and are somewhat like railroad embankments. Probably former sites of sub-glacial streams and rivers.
Esker
A steep slope coinciding with the line of a fault.
Fault scarp
Associated with hogback ridges. Triangular-shaped remnants of the bed between V-shaped notches. Steeply sloping wedge shaped landscape features created by differential erosion.
Flatirons
Areas covered by large angular blocks (formed in situ), traditionally believed to have been created by freeze-thaw action.
Felsenmeer or blockfield
German ‘Sea of Rock’
Occurrence of triangular facets has been documented in mountainous areas in relation to base level changes and hydrographical network evolution; similarly shaped landforms are present even in recent tectonic uplift areas along faults.
Triangular facets
Major splits into limestone pavement, formed by widening, deepening, and eventual merging of solution features that develop along linear weakness in the rock.
Grikes (Bogaz)
Small closed depressions on horizontal and gently inclined rock surfaces; similar to solution pits in carbonate rocks
Gnamma (Weathering pit or Panhole)
A mountaintop that has been modified by the action of ice during glaciation and frost weathering; also pyramidal peak.
Glacial horn
A tall, thin spire of soft (sedimentary) rock topped by harder, more resistant stone that protects each column from erosion.
Hoodoo (demoiselle/earth pyramid/fairy chimney/tent rock)
Large, perennial, conical, ice-cored mounds that are common in some low-lying permafrost areas dominated by fine-grained sediments, with the ice forming from injected water.
Hydrolaccoliths (Pingo)
Large, freestanding, residual masses of rock. Most common and most well known in granitic rocks.
Inselberg (tor/monadnock)
A narrow piece of land connection two larger areas across an expanse of water that otherwise separates them.
Isthmus
Groups of residual, steep-sided conical-shaped hills produced by limestone solution.
Kegelkarst (cone karst or cockpit karst)
An umbrella term which covers an elaborately diverse group of small-scale solutional features and sculpturing found on limestone and dolomite surfaces exposed at the ground surface in caves.
Karren
Large spitzkarren
Pinnacle Karst
Permafrost mounds formed by ice segregation within mineral soils that occur within the zone of discontinuous permafrost.
Lithalsas (stone rings)
How are levees formed?
When a river floods friction with the floodplain leads to a rapid decrease in the velocity of the river and therefore its capacity to transport material. Larger material is deposited closest to the river bank. This often leads to large, raised mounds being formed.
An embankment, natural or man-made, that confines flow during high-water periods.
Levee
Occurs when a meandering river on alluvium eats down into the underlying bedrock.
Incised meander
A prominent limestone hill in an area of tower karst.
Mogote
An elongated cliff base hollow cut out by abrasion, usually where breaking waves are armed with rock fragments.
Abrasion Notch
A point of land, usually high and often with a sheer drop, that extends out into a body of water.
Ness (headland/promontory/cape)
A horse shoe shaped length of stream channel which is an almost closed meander loop.
Oxbow
Forms just under a boulder, from which the rate of surface lowering may be evaluated.
Pedestal
A large karst depression that may sometimes be flooded with water, and which has been formed either by solution, or cavern collapse or for structural reasons.
Polje
A sheet like surface of rock fragments that remains after wind and water have removed the fine particles. Covered with closely packed, interlocking angular or rounded rock fragments of pebble and cobble size.
Reg (desert pavement/gibber/hamada)
A long, narrow, often branching inlet formed by marine submergence of parts of a river valley that had previously been incised to a lower sea level
Ria
A collection of broken rock fragments at the base of a cliff or other steep rocky mass that has accumulated through periodic rockfall.
Scree
The product of movement and accumulation along the slope after the cracking of cliffs or steep rock walls, is a common landform in the mountain periglacial environment.
Talus
An isolated upstanding steep-sided rock pillar, column or pinnacle rising from the shore, a shore platform, or the sea floor close to a cliffed coast.
Stack or stump
A stack is an isolated column of rock that is formed when the base of an arch continually becomes wider through further erosion, until its roof becomes too heavy and collapses into the sea. The stack is undercut at the base until it collapses to form a stump. The stump usually forms a small rock island, low enough for a high tide to submerge.
Cavernous weathering hollows produced in vertical or near-vertical rock faces; singular tafone.
Tafoni in calcareous sandstone
A variety of limestone formed when carbonated minerals precipitate out of ambient temperature water.
Travertine or tufa
A depression or large hollow in limestone areas produced when several sinkholes or dolines coalesce
Uvala
Created when magma hardens within a vent on an active volcano. A distinctive upstanding landform produced when erosion removes the surrounding rock while the erosion-resistant plug remains.
Volcanic neck/pipe
Corrosion notches at the cliff foot sometimes have protruding visors above them and plinths below them.
Visor
Notch or abandoned former channel in resistant bedrock ridges that was formerly a water gap when there was insufficient stream power to complete the down cutting process. Also known as abandoned drainages, stream capture, or stream piracy.
Wind gap
A tributary stream that is prevented from joining the main river because of the levees which flank the latter.
Yazoo
A streamlined hill carved from bedrock or any consolidated or semi-consolidated material that resembles the hull of a boat. The process involves wind abrasion by dust and sand, as well as deflation, which is the removal of loose material by wind turbulence.
Yardang / Zeugen
Isolated rocks between joints that result from downward erosion of less resistant layers.
Rock fins
