Geomorphology Quiz: 24 Questions with Answers

Correct answer: Explaining how a valley’s shape developed.

Geomorphology studies landforms and the processes that shape them. A valley’s form, sediment and history are central evidence, rather than simply its name or location.

Correct answer: Weathering.

Weathering breaks down or alters rock in place. When water, wind or ice carries the fragments away, transport and erosion are also involved.

Correct answer: Mechanical weathering.

Frost action can break rock physically without changing the mineral composition of each fragment. The question describes one mechanical weathering process, not every way ice can fracture rock.

Correct answer: The caprock slows erosion of the material beneath it.

Different rock layers resist weathering and erosion differently. A resistant upper layer can protect underlying material for a time, leaving a remnant as surrounding ground is removed.

Correct answer: Down-dropped basins beside fault-block mountains.

Extension can move crustal blocks vertically relative to one another along normal faults. Lowered basins and adjacent mountain blocks produce relief that erosion later modifies.

Correct answer: Soil creep.

Creep is very slow downslope movement of soil or rock. Tilted posts or bent fences may be clues, but measurements and the wider slope context are stronger evidence than one leaning object.

Correct answer: A rotational slide, or slump.

A slump rotates along a curved failure surface. A translational slide instead moves along a more nearly planar surface, while falls and flows involve different styles of movement.

Correct answer: It can reduce the soil’s resistance to shearing.

Water pressure within soil can reduce resistance to sliding. This is one reason heavy rainfall or snowmelt can trigger failure on a susceptible slope; rainfall does not make every slope fail.

Correct answer: Natural levees.

Natural levees build as overbank floods deposit sediment close to the river channel. They are depositional features, unlike terraces left above a river after downcutting.

Correct answer: Erosion on the outer bank and deposition on the inner bank.

The outer bend commonly develops an eroding cut bank, while the inner bend accumulates a point bar. This paired erosion and deposition helps a meander migrate.

Correct answer: An oxbow lake.

A cutoff gives the river a shorter route and can isolate the former bend as an oxbow lake. The abandoned loop may gradually fill with sediment.

Correct answer: A river terrace.

A terrace can preserve an abandoned floodplain after river incision. Its elevation records an earlier valley-floor position; terrace formation does not have just one universal cause.

Correct answer: A fall in the river’s base level or uplift of the land.

Base level is the lower limit toward which a river can cut. Lowering that level, or raising the land relative to it, can renew incision and deepen existing bends. The response also depends on flow, sediment and rock resistance.

Correct answer: River sediment accumulates faster than waves and currents remove it.

A delta grows as river sediment remains and builds up at the mouth. Waves and currents can remove or redistribute that material, so the balance between supply and removal matters.

Correct answer: Dissolution by slightly acidic water.

Water containing weak acids can dissolve calcium carbonate in limestone and enlarge cracks and openings. Karst is shaped by this chemical process, although other processes can modify it too.

Correct answer: Water travels through connected underground openings.

Dissolution can enlarge fractures into connected passages that carry water underground. A surface map alone may miss these connections; a particular stream-to-spring connection requires evidence such as tracing.

Correct answer: Deflation.

Deflation is the removal of loose surface material by wind. It differs from abrasion, in which particles carried by wind wear against a rock surface.

Correct answer: Loess.

Loess is a windblown, silt-rich deposit. It should not be confused with a sand dune or the unsorted mixture deposited directly by glacier ice.

Correct answer: Sand arriving over the crest cascades down it.

Wind moves sand toward and over the crest. When accumulated grains become unstable, they slide down the sheltered slip face, helping the dune advance and leaving inclined layers.

Correct answer: Net transport along the shore.

Oblique wave approach can drive longshore currents and sediment transport parallel to the coast. Direction and rate depend on the wave conditions and shoreline configuration.

Correct answer: Sand builds up west of the groin while erosion increases to the east.

Here the western beach is updrift and the eastern beach is downdrift. The groin retains sand on the western side, reducing the supply to the eastern beach and potentially increasing erosion there.

Correct answer: A wave-cut platform.

Wave erosion can cut a relatively flat rock surface at the foot of a retreating cliff. A wave-cut platform is an erosional feature, not a pile of beach sediment.

Correct answer: A broad U-shaped trough with steep sides.

A valley glacier can widen and deepen an earlier valley, producing a broad trough with steep sides. The characteristic U shape is a useful clue, but landscape history is checked with other evidence too.

Correct answer: Till first, outwash second.

Till is deposited directly by glacier ice and mixes particle sizes. Meltwater carries and sorts sediment into outwash deposits. The transporting agent, not merely proximity to a glacier, separates the two.