Stalactites grow downward from cave ceilings, while stalagmites build upward from the floor.
Incorrect! Try again.
39An area of exposed limestone has deep grooves separated by sharp ridges because acidic water follows joints. What landform is this?
karst processes and landforms
Medium
A.A Marine terrace
B.A Limestone pavement
C.A Barchan field
D.A Floodplain levee
Correct Answer: A Limestone pavement
Explanation:
Limestone pavement consists of exposed rock blocks called clints separated by dissolution grooves called grikes.
Incorrect! Try again.
40A broad, flat karst depression temporarily floods during wet seasons and contains thick alluvial sediment. Which feature is most likely?
karst processes and landforms
Medium
A.A Deflation hollow
B.A Polje
C.A Coastal spit
D.A Cave arch
Correct Answer: A Polje
Explanation:
A polje is a large, flat-floored karst depression that may contain seasonal lakes, streams, and alluvial deposits.
Incorrect! Try again.
41A sand surface experiences a steady increase in wind speed. Which sequence best describes the usual order of sediment responses as the threshold for each mode is exceeded?
The largest grains first move by creep, intermediate grains begin saltating, and the finest particles can enter suspension as wind competence increases.
Incorrect! Try again.
42A barchan dune field receives a sudden and sustained increase in sand supply while wind direction remains constant. Which morphological change is most likely?
aeolian processes and landforms
Hard
A.Dune horns extend directly upwind
B.Dunes develop transverse ridges and merge
C.The field changes immediately into parabolic dunes
D.Barchans become smaller and more isolated
Correct Answer: Dunes develop transverse ridges and merge
Explanation:
Barchans form under limited sand supply. Increasing the supply allows dunes to grow, coalesce, and evolve toward transverse or more continuous dune forms.
Incorrect! Try again.
43A dune migrates downwind even though its windward slope is gentle and its lee slope is near the angle of repose. Which explanation best accounts for the migration?
aeolian processes and landforms
Hard
A.Avalanching occurs on the windward slope
B.Groundwater flow pushes grains downwind
C.Deflation lowers the crest on the lee side
D.Saltation deposits sediment on the lee slope
Correct Answer: Saltation deposits sediment on the lee slope
Explanation:
Wind transports grains up the windward face, and avalanching on the steep lee face advances the dune in the downwind direction.
Incorrect! Try again.
44Two nearby surfaces receive identical winds. Surface A is gravel-covered, whereas Surface B is composed of fine, loose sand. Which contrast is most likely?
aeolian processes and landforms
Hard
A.A generates suspension while B prevents sediment motion
B.A undergoes deflation while B undergoes abrasion
C.A suppresses deflation while B supplies saltating grains
D.A forms dunes while B forms desert pavement
Correct Answer: A suppresses deflation while B supplies saltating grains
Explanation:
A gravel armor protects the surface from further deflation, whereas loose sand can be entrained and transported by saltation.
Incorrect! Try again.
45A ventifact has one highly polished, faceted face and a rough, unmodified opposite face. What is the strongest inference?
aeolian processes and landforms
Hard
A.Wind abrasion came from a persistent direction
B.The stone rolled repeatedly in a river channel
C.Glacial plucking exposed the polished face
D.Chemical weathering acted equally on both faces
Correct Answer: Wind abrasion came from a persistent direction
Explanation:
Faceting and polishing occur where wind-driven sand repeatedly strikes an exposed surface, allowing the dominant wind direction to be inferred.
Incorrect! Try again.
46A loess blanket is thickest immediately downwind of a former braided outwash plain and becomes thinner with distance. Which interpretation is most defensible?
aeolian processes and landforms
Hard
A.The thickest loess marks the direction of groundwater flow
B.The loess formed from marine clay deposited during flooding
C.The outwash plain blocked winds and caused local accumulation
D.The outwash plain supplied silt during exposed, windy phases
Correct Answer: The outwash plain supplied silt during exposed, windy phases
Explanation:
Outwash plains provide abundant glacial silt, which can be deflated during dry periods and deposited downwind as loess.
Incorrect! Try again.
47A longitudinal dune lies between two nearly persistent wind directions that are oblique and approximately opposite. Which process most plausibly controls its alignment?
aeolian processes and landforms
Hard
A.A single seasonal wind builds a crescentic dune
B.Sediment moves mainly along the dune axis
C.Vegetation fixes the dune before wind transport begins
D.Sediment moves only perpendicular to the dune axis
Correct Answer: Sediment moves mainly along the dune axis
Explanation:
Bidirectional oblique winds can produce a resultant transport direction parallel to the dune crest, favoring longitudinal dune development.
Incorrect! Try again.
48A beach has a strong oblique wave approach and a groyne is built across the shore. Which pattern is most likely shortly after construction?
coastal processes and landforms
Hard
A.Accretion occurs updrift and erosion downdrift
B.Accretion occurs downdrift and erosion updrift
C.Erosion occurs equally on both sides of the groyne
D.Longshore transport stops throughout the entire coast
Correct Answer: Accretion occurs updrift and erosion downdrift
Explanation:
The groyne traps sediment moving alongshore, producing updrift deposition and reducing sediment supply to the downdrift beach.
Incorrect! Try again.
49A wave approaches a gently sloping shore and begins to refract. Which consequence is most likely near a protruding headland?
coastal processes and landforms
Hard
A.Longshore transport reverses permanently
B.Wave energy converges and erosion intensifies
C.Wave energy diverges and deposition dominates
D.Wave height becomes zero at the headland
Correct Answer: Wave energy converges and erosion intensifies
Explanation:
Wave orthogonals converge around headlands, concentrating wave energy and promoting hydraulic action, abrasion, and cliff retreat.
Incorrect! Try again.
50A sea cliff retreats along a coast where resistant rock alternates with weaker rock, and a wave-cut platform develops. Which outcome is most likely over time?
coastal processes and landforms
Hard
A.The coastline becomes straighter as resistant sections retreat faster
B.Wave refraction eliminates all differential erosion
C.The coastline becomes straighter as weaker sections retreat faster
D.Weak rock forms headlands while resistant rock forms bays
Correct Answer: The coastline becomes straighter as weaker sections retreat faster
Explanation:
Differential erosion initially creates bays in weak rock and headlands in resistant rock; continued retreat and wave refraction tend to reduce irregularity.
Incorrect! Try again.
51A barrier island migrates landward while maintaining its approximate form despite a rising relative sea level. Which mechanism best explains this behavior?
coastal processes and landforms
Hard
A.Longshore drift transports all sediment seaward
B.Storm overwash transfers sand toward the back-barrier zone
C.Tidal currents prevent any vertical island adjustment
D.Offshore sediment is permanently removed
Correct Answer: Storm overwash transfers sand toward the back-barrier zone
Explanation:
During overwash, storm waves move barrier sediment landward, allowing the island to roll over and maintain elevation relative to rising water.
Incorrect! Try again.
52A ria coast contains drowned river valleys, whereas a fjord coast contains drowned glacial troughs. Which additional distinction is most reliable?
coastal processes and landforms
Hard
A.Rias are always sediment-free; fjords are always delta-filled
B.Rias form only in deserts; fjords form only in tropical climates
C.Rias have U-shaped valleys; fjords have V-shaped valleys
D.Rias are commonly shallow and branching; fjords are deep and steep-sided
Correct Answer: Rias are commonly shallow and branching; fjords are deep and steep-sided
Explanation:
Rias inherit branching fluvial valleys, while fjords inherit overdeepened, steep-sided glacial troughs, often with submerged thresholds.
Incorrect! Try again.
53A wave-dominated delta receives abundant sediment, but a nearby storm-dominated coast has a relatively small delta despite similar river discharge. Which explanation is most plausible?
coastal processes and landforms
Hard
A.Storm waves redistribute sediment alongshore and offshore
B.Storms eliminate all fluvial sediment before it reaches the sea
C.Wave-dominated deltas cannot experience longshore transport
D.River discharge has no influence on delta size
Correct Answer: Storm waves redistribute sediment alongshore and offshore
Explanation:
High wave energy can rework and disperse fluvial sediment, preventing it from accumulating into a large protruding delta.
Incorrect! Try again.
54A beach profile changes from a wide, gently sloping summer form to a narrower, steeper form after repeated storms. Which sediment redistribution best explains the change?
coastal processes and landforms
Hard
A.Sediment moves offshore into bars during storm conditions
B.Sediment becomes permanently trapped in beach vegetation
C.Sediment dissolves because wave energy increases
D.Sediment moves onshore into berms during storm conditions
Correct Answer: Sediment moves offshore into bars during storm conditions
Explanation:
Storm waves commonly move beach sediment offshore, forming bars and producing a narrower, lower beach profile.
Incorrect! Try again.
55Why does limestone dissolution commonly accelerate where soil is thick and biologically active?
karst processes and landforms
Hard
A.Soil organisms increase oxygen pressure in groundwater
B.Organic matter directly melts limestone at the surface
C.Thick soil prevents water from contacting carbonate minerals
D.Respiration raises soil carbon dioxide and forms carbonic acid
Correct Answer: Respiration raises soil carbon dioxide and forms carbonic acid
Explanation:
Carbon dioxide from soil respiration dissolves in infiltrating water, producing weak carbonic acid that enhances carbonate dissolution.
Incorrect! Try again.
56A karst region contains a dry valley, a disappearing stream, and a resurgence several kilometers away. Which interpretation best integrates these features?
B.Surface drainage has been captured by a subterranean conduit
C.The resurgence marks a permanently sealed aquifer
D.The valley formed entirely through wind deflation
Correct Answer: Surface drainage has been captured by a subterranean conduit
Explanation:
Swallow holes can divert surface streams underground, producing dry valleys and re-emergence at springs or resurgences.
Incorrect! Try again.
57A cave passage contains scalloped walls whose asymmetry indicates the direction of former groundwater flow. Which process most directly produced the scallops?
karst processes and landforms
Hard
A.Glacial abrasion by basal debris
B.Differential dissolution by turbulent groundwater
C.Collapse caused solely by roof loading
D.Wind abrasion by airborne sand
Correct Answer: Differential dissolution by turbulent groundwater
Explanation:
Flowing water dissolves cave walls unevenly, and scallop geometry can preserve evidence of groundwater-flow direction.
Incorrect! Try again.
58A limestone cave contains stalactites, stalagmites, and a dry passage above the modern water table. What environmental change most likely allowed these deposits to form?
karst processes and landforms
Hard
A.The passage became permanently flooded as the water table rose
C.The passage became vadose as the water table fell
D.Sea level rose and increased marine abrasion underground
Correct Answer: The passage became vadose as the water table fell
Explanation:
Speleothems commonly form in air-filled passages where infiltrating water degasses carbon dioxide and precipitates calcium carbonate.
Incorrect! Try again.
59A closed depression in a humid limestone terrain repeatedly floods after intense rainfall but drains through a narrow opening. Which landform and process are most likely involved?
karst processes and landforms
Hard
A.A drumlin with meltwater spillway drainage
B.A deflation hollow with wind-driven drainage
C.A polje with periodic overflow and conduit drainage
D.A marine lagoon with tidal exchange
Correct Answer: A polje with periodic overflow and conduit drainage
Explanation:
Poljes are large closed karst depressions that may flood when conduit capacity is exceeded and drain through ponors or underground channels.
Incorrect! Try again.
60Two wells in the same karst aquifer are separated by a short distance, yet a contaminant appears in one well within hours and in the other only after weeks. Which explanation is most plausible?
karst processes and landforms
Hard
A.The contaminant can move only through unfractured limestone
B.The delayed well must lie outside the same groundwater basin
C.Karst aquifers transmit contaminants at a uniform rate
D.The aquifer contains conduits mixed with slower diffuse-flow zones
Correct Answer: The aquifer contains conduits mixed with slower diffuse-flow zones
Explanation:
Karst aquifers combine rapid conduit flow with slower fracture and matrix storage, producing highly variable travel times over short distances.
Incorrect! Try again.
Did this save you a night before the exam?
LPU Notes is free, and it stays free. Ads cover part of the server bill.
The rest comes out of a student's own pocket: the domain, the storage,
and keeping the site up through the weeks everyone needs it at once.
The payment button didn't load. An ad blocker or a filtered network is the usual reason.
to try again.
Nothing here is ever locked, and nothing unlocks. Chip in only if it was worth it.
What it pays for →