Weathering and erosion are the fundamental exogenic processes that sculpt the Earth’s surface, breaking down rocks and transporting debris across landscapes. Weathering acts in situ—mechanically disintegrating or chemically decomposing rocks via frost action, oxidation, and carbonation without horizontal movement. Once weakened, these materials are picked up and transported by external geomorphic agents such as rivers, glaciers, wind, waves, and gravity through mass wasting. Mastering these dynamics is vital for earth sciences, geomorphology, and competitive examinations.
1. What is the primary difference between weathering and erosion?
Correct Answer: a) Weathering breaks down rocks in place, while erosion transports the broken fragments.
Explanation:
Weathering is the in-situ disintegration or decomposition of rocks, whereas erosion involves the physical removal and transport of those materials by agents like water, wind, or ice.
2. Which of the following is an example of mechanical (physical) weathering?
Correct Answer: b) Frost wedging in rock crevices
Explanation:
Frost wedging is a physical process where water freezes and expands within rock cracks, physically breaking the rock apart without changing its chemical composition.
3. What process involves the peeling away of outer rock layers due to the unloading of overlying pressure?
Correct Answer: a) Exfoliation (sheeting)
Explanation:
Exfoliation occurs when deep-seated intrusive rocks are uplifted and exposed, leading to a drop in pressure that causes the rock to expand and fracture in concentric sheets.
4. Which chemical weathering process is primarily responsible for turning iron-bearing minerals into rust?
Correct Answer: b) Oxidation
Explanation:
Oxidation occurs when oxygen reacts with iron-bearing minerals, forming iron oxides (rust) and weakening the rock structure.
5. What happens during the chemical weathering process known as hydrolysis?
Correct Answer: b) Hydrogen ions in water replace other ions in silicate minerals, forming clay
Explanation:
In hydrolysis, hydrogen ions from water react with silicate minerals (like feldspar) to break down their crystal structure and create clay minerals.
6. Which rock type is most susceptible to chemical weathering via dissolution and carbonation?
Correct Answer: c) Limestone
Explanation:
Limestone consists mainly of calcite (calcium carbonate), which readily dissolves in acidic waters formed when carbon dioxide mixes with rain.
7. How does biological weathering contribute to rock breakdown?
Correct Answer: c) Through both physical root penetration and organic acids secreted by lichens and mosses
Explanation:
Biological weathering combines mechanical action (plant roots splitting rocks) and chemical action (chelating organic acids from lichens dissolving minerals).
8. What climatic conditions generally produce the fastest rates of chemical weathering?
Correct Answer: b) Hot and wet
Explanation:
High temperatures accelerate chemical reaction rates, and abundant water provides the necessary medium for chemical weathering processes like hydrolysis and dissolution.
9. What is differential weathering?
Correct Answer: b) The varying rates of weathering across different rock types or mineral compositions within a single rock body
Explanation:
Differential weathering occurs when softer or less resistant rocks weather and erode faster than harder, more resistant rocks, forming distinct landscape features.
10. What is the primary driving force behind all mass wasting events?
Correct Answer: b) Gravity
Explanation:
Gravity is the sole driving force pulling regolith, soil, and rock downslope during mass wasting events.
11. Which mass wasting process is characterized by the extremely slow, gradual downslope movement of soil and regolith?
Correct Answer: c) Creep
Explanation:
Soil creep is a very slow, continuous downslope movement driven by freeze-thaw or wet-dry cycles, often evidenced by tilted fence posts and trees.
12. What type of mass wasting involves the rapid sliding of a coherent block of material down a curved surface?
Correct Answer: b) Slump
Explanation:
A slump is a form of mass wasting where a mass of rock or unconsolidated material slides downward along a concave, curved slip plane.
13. Which rapid mass wasting event is saturated with water and flows quickly down a valley like a wet slurry of concrete?
Correct Answer: b) Debris flow (mudflow)
Explanation:
Debris flows and mudflows are water-saturated masses of soil and rock that move rapidly down channels, possessing high destructive power.
14. What is solifluction?
Correct Answer: b) The slow downslope flow of water-saturated soil over impermeable permafrost
Explanation:
Solifluction occurs in cold, high-latitude or high-altitude environments where melted surface soil flows slowly over frozen subsoil (permafrost).
15. What term describes the accumulation of loose, angular rock fragments at the base of a steep cliff?
Correct Answer: b) Talus (or scree)
Explanation:
Talus consists of angular rock debris that accumulates at the foot of cliffs due to repeated rockfalls and weathering.
16. What is the primary agent of erosion across the majority of Earth's land surface?
Correct Answer: c) Running water (streams and rivers)
Explanation:
Running water is the single most dominant agent of erosion and sediment transport on Earth's terrestrial surface.
17. How do streams transport dissolved minerals such as calcium and sodium?
Correct Answer: c) By solution
Explanation:
Ions dissolved from minerals are carried invisibly within the water column as part of the stream's dissolved load (solution).
18. What stream transport process involves fine particles like silt and clay being kept afloat by water turbulence?
Correct Answer: b) Suspension
Explanation:
Suspended load consists of lightweight particles (like silt and clay) held aloft by the turbulent flow of water without touching the streambed.
19. The bouncing or skipping of sand-sized particles along a streambed is called:
Correct Answer: a) Saltation
Explanation:
Saltation describes bedload particles that move downstream in a series of short leaps or bounces along the channel floor.
20. What is stream capacity?
Correct Answer: b) The total maximum load of solid material a stream can transport
Explanation:
Stream capacity measures the total quantity of sediment a stream can carry, which depends largely on its discharge.
21. What is stream competence?
Correct Answer: a) The maximum particle size (diameter) a stream can transport
Explanation:
Competence refers to the maximum size of clasts a stream is capable of moving, which increases dramatically with flow velocity.
22. What type of drainage pattern resembles the branching roots or limbs of a tree?
Correct Answer: b) Dendritic
Explanation:
A dendritic pattern develops on rocks of uniform resistance, forming a tree-like branching tributary system.
23. Which drainage pattern features parallel main streams with short tributaries cutting through alternating hard and soft rocks at right angles?
Correct Answer: c) Trellis
Explanation:
Trellis drainage patterns typically develop in folded mountain regions with parallel ridges and valleys.
24. What landform is created when a river enters a standing body of water and deposits its sediment load?
Correct Answer: b) Delta
Explanation:
Deltas form where rivers lose velocity upon entering a lake, sea, or ocean, dropping sediment in characteristic distributary patterns.
25. An abandoned, curved loop of a meandering river is known as:
Correct Answer: a) An oxbow lake
Explanation:
When river meanders become extreme, high water can cut straight across the neck, abandoning the loop to form a crescent-shaped oxbow lake.
26. What is the steep slope on the outer edge of a river meander where erosion occurs called?
Correct Answer: b) Cut bank
Explanation:
Water flows faster on the outside of a bend, causing erosion that creates a steep cut bank.
27. What depositional feature forms on the inside bend of a river meander where water velocity is slower?
Correct Answer: b) Point bar
Explanation:
Slower water on the inner bend drops sediment, accumulating into a depositional feature called a point bar.
28. What is a valley glacier?
Correct Answer: b) A river of ice confined within a mountain valley
Explanation:
Valley (alpine) glaciers occupy former or active stream valleys in mountainous terrain, flowing slowly downhill under gravity.
29. What shape do glacier-eroded valleys typically exhibit?
Correct Answer: b) U-shape
Explanation:
Glaciers widen, deepen, and straighten V-shaped river valleys into broad, steep-sided U-shaped glacial troughs.
30. What is the primary mechanism by which glaciers erode underlying bedrock through the freezing of water in fractures?
Correct Answer: a) Plucking (quarrying)
Explanation:
Glacial plucking occurs when meltwater penetrates bedrock cracks, freezes, and shatters rock fragments that are then lifted and carried away by the moving ice.
31. How does glacial abrasion alter bedrock?
Correct Answer: b) It scours, polishes, and scratches bedrock using rock fragments embedded in the base of the ice
Explanation:
Glacial abrasion acts like sandpaper, scratching (striations) and polishing bedrock as debris-laden ice moves over it.
32. What is a cirque?
Correct Answer: a) An amphitheater-shaped basin carved into a mountain headwall by a glacier
Explanation:
Cirques are bowl-shaped depressions found at the head of glacial valleys where alpine glaciers originate and accumulate snow.
33. What is a sharp, knife-edge ridge formed between two adjacent glaciated valleys called?
Correct Answer: b) Arete
Explanation:
An arête is a narrow, jagged ridge of rock separating two adjacent cirques or glacial troughs.
34. What pyramidal peak is formed by the headward erosion of multiple surrounding glacial cirques?
Correct Answer: b) Horn (e.g., the Matterhorn)
Explanation:
A glacial horn is a steep, pyramidal mountain peak created when three or more cirques erode backward into a mountain.
35. What term describes unsorted, unstratified glacial sediment deposited directly by melting ice?
Correct Answer: b) Till
Explanation:
Glacial till is a heterogeneous mix of particle sizes ranging from fine clay to massive boulders dropped directly by melting ice without sorting.
36. What ridge of till marks the furthest advance or maximum extent of a glacier?
Correct Answer: a) Terminal moraine
Explanation:
A terminal moraine forms a ridge across the valley floor at the terminus, marking the maximum reach of the glacier.
37. What is an esker?
Correct Answer: a) A steep-sided winding ridge of sand and gravel deposited by streams flowing in tunnels beneath melting ice
Explanation:
Eskers are sinuous ridges formed by meltwater streams running through sub-glacial tunnels.
38. What is a kettle lake?
Correct Answer: b) A depression formed when a buried block of stagnant glacial ice melts, filling with water
Explanation:
Kettles form when ice blocks break off a retreating glacier, get buried in outwash, and subsequently melt, leaving a pitted depression that fills with water.
39. In which environments are wind (eolian) erosion and deposition most active and effective?
Correct Answer: b) Arid deserts and semi-arid coastlines with sparse vegetation
Explanation:
Wind is most effective as an erosional and depositional agent in dry regions where loose sediment is abundant and protective vegetation cover is minimal.
40. What wind erosion process involves the sweeping away of loose, fine-grained particles from the land surface?
Correct Answer: b) Deflation
Explanation:
Deflation is the lowering of the land surface due to the wind lifting and removing loose sand, silt, and clay.
41. How does wind abrasion shape landscape features like desert rock pillars (yardangs or ventifacts)?
Correct Answer: b) By sandblasting rock surfaces with wind-driven sand grains
Explanation:
Wind abrasion acts as a natural sandblaster, polishing and sculpting rocks close to the ground using airborne mineral grains.
42. What type of sand dune forms as a crescent shape with horns pointing downwind in areas with limited sand and unidirectional winds?
Correct Answer: b) Barchan dune
Explanation:
Barchans are solitary crescent-shaped dunes that migrate across flat surfaces with limited sand supply, with tips pointing downwind.
43. What are transverse dunes?
Correct Answer: a) Long ridges of sand oriented perpendicular to the prevailing wind direction, occurring where sand supply is abundant
Explanation:
Transverse dunes form extensive wave-like ridges oriented at right angles to strong, steady winds in areas with heavy sand supply.
44. What is loess?
Correct Answer: b) Wind-blown silt blankets that form exceptionally fertile agricultural soils
Explanation:
Loess is fine silt transported and deposited by wind, forming massive blanket deposits found across parts of China, Europe, and the U.S. Midwest.
45. What is the primary driving force behind ocean waves that shape coastlines?
Correct Answer: b) Friction from winds blowing across the water surface
Explanation:
Surface waves are generated by energy transferred from wind blowing across the open ocean.
46. What happens when waves approach a coastline at an angle?
Correct Answer: b) They create longshore currents that move sediment parallel to the shoreline
Explanation:
Oblique wave approach generates a swash and backwash cycle that drives longshore currents, moving sand along the coast (longshore drift).
47. What coastal depositional feature is a narrow ridge of sand connected to land at one end and extending into a bay?
Correct Answer: b) Spit
Explanation:
A spit is a ridge of sand extending from the shore into the mouth of a bay, often hooked at the end due to changing wave refraction.
48. What is a tombolo?
Correct Answer: a) A sand ridge that connects an offshore island to the mainland
Explanation:
A tombolo is a depositional landform where sand builds up to link an offshore island to the adjacent mainland.
49. What isolated vertical pillar of rock stands in the ocean after a sea arch collapses?
Correct Answer: a) Sea stack
Explanation:
Continued wave erosion on headlands cuts sea caves and arches; when an arch roof collapses, an isolated sea stack remains.
50. What is a wave-cut platform?
Correct Answer: b) A gently sloping rocky bench left behind at sea level as a coastal cliff retreats due to wave erosion
Explanation:
As waves batter and erode coastal cliffs, they cut a notch that causes the cliff to collapse, leaving behind a wave-cut platform at sea level.
51. Which weathering process involves the expansion of water freezing in cracks?
Correct Answer: a) Frost wedging
Explanation:
Water expands by about 9% when it freezes, exerting immense pressure that wedges rock cracks open.
52. What type of chemical weathering turns feldspar minerals into clay?
Correct Answer: a) Hydrolysis
Explanation:
Hydrolysis reactions between water and silicate minerals like feldspar yield stable clay minerals and dissolved ions.
53. Which of the following processes is a form of mass wasting?
Correct Answer: a) Soil creep
Explanation:
Soil creep is the slow, gravity-driven downslope movement of regolith.
54. What term refers to the bouncing of sand grains along a riverbed or desert floor?
Correct Answer: a) Saltation
Explanation:
Saltation describes sediment bouncing along the bed in short leaps.
55. What is the primary factor controlling the velocity and erosive power of a river?
Correct Answer: a) Channel gradient (slope)
Explanation:
The steepness of the channel slope (gradient) directly influences water velocity and its capacity to erode and transport sediment.
56. What landform is formed when sediment is dropped by a stream entering a dry mountain valley floor?
Correct Answer: a) Alluvial fan
Explanation:
Alluvial fans form when steep mountain streams emerge onto flatter lowland areas, losing velocity and dropping sediment in a fan shape.
57. What is a hanging valley?
Correct Answer: a) A tributary glacial valley whose floor is at a higher elevation than the main glacial trough, often creating waterfalls
Explanation:
Because main glaciers erode deeper than tributary glaciers, when the ice melts, the tributary valleys are left hanging high above the main valley floor.
58. Which glacial feature is an elongated, teardrop-shaped hill formed of till pointing in the direction of ice flow?
Correct Answer: a) Drumlin
Explanation:
Drumlins are streamlined, asymmetrical hills composed of till, molded beneath moving glacial ice sheets.
59. What is a ventifact?
Correct Answer: a) A wind-abraded rock with flat, polished facets
Explanation:
Ventifacts are stones shaped, etched, and faceted by wind-driven sand abrasion in arid environments.
60. What is longshore drift?
Correct Answer: a) The movement of sediment parallel to the coast by wave action and longshore currents
Explanation:
Longshore drift transports beach sand along the shoreline as waves break at an angle and backwash pulls straight down.
61. Which of the following describes karst topography?
Correct Answer: a) Landscapes shaped by the dissolution of soluble rocks like limestone, featuring sinkholes and caves
Explanation:
Karst topography develops through chemical weathering (dissolution) of soluble rocks such as limestone, dolomite, or gypsum.
62. What is physical weathering?
Correct Answer: a) The breakdown of rocks into smaller pieces without changing their chemical composition
Explanation:
Physical (mechanical) weathering disintegrates rocks into smaller fragments without altering their underlying minerals.
63. Which of the following is a chemical weathering reaction involving carbon dioxide dissolved in water?
Correct Answer: a) Carbonation
Explanation:
Carbonation is the reaction of carbonic acid (formed when CO2 dissolves in water) with minerals, notably calcite in limestone.
64. What is talus?
Correct Answer: a) An accumulation of rock debris at the base of a cliff
Explanation:
Talus slopes form from rockfalls accumulating at steep cliff bases.
65. What term describes the rolling or sliding of large, heavy particles along a streambed?
Correct Answer: a) Traction
Explanation:
Traction involves heavy bedload particles rolling, sliding, or dragging along the bottom of a channel.
66. What is a floodplain?
Correct Answer: a) A flat area bordering a river channel built of sediment deposited during periodic floods
Explanation:
Floodplains are broad, flat valley floors adjacent to rivers that are routinely inundated during high-water events.
67. What glacial depositional feature is an irregular ridge or mound of till dropped directly by melting ice?
Correct Answer: a) Moraine
Explanation:
Moraines are landforms composed of unsorted glacial till deposited by melting glaciers.
68. What type of sand dune forms long parallel ridges aligned with the prevailing wind direction where sand supply is moderate?
Correct Answer: a) Longitudinal (seif) dune
Explanation:
Longitudinal dunes form as long, linear ridges parallel to the dominant wind direction.
69. What is a barrier island?
Correct Answer: a) A long, narrow offshore sand ridge parallel to the mainland coast that protects lagoons and bays
Explanation:
Barrier islands are long, sandy depositional islands lying parallel to the coast, shielding the mainland from direct wave attack.
70. Which weathering process is driven by daily temperature fluctuations causing minerals to expand and contract at different rates?
Correct Answer: a) Thermal expansion
Explanation:
Thermal expansion occurs when intense heating and cooling cycles cause mineral crystals to expand and contract unequally, fracturing the rock.
71. What is exfoliation dome?
Correct Answer: a) A large, dome-shaped rock formation created when overlying layers peel off due to pressure release
Explanation:
Exfoliation domes (like Stone Mountain or Half Dome) form as thick sheets of rock fracture and slide off due to unloading.
72. Which mass wasting event involves the sudden free-fall of detached rock fragments from a steep cliff?
Correct Answer: a) Rockfall
Explanation:
Rockfalls occur when rocks detach and plummet freely down steep slopes or cliffs.
73. What term describes the maximum load of sediment a stream can carry?
Correct Answer: a) Capacity
Explanation:
Stream capacity is the total mass of sediment a stream can transport.
74. What is stream piracy (capture)?
Correct Answer: a) The diversion of the headwaters of one stream into another stream with more aggressive headward erosion
Explanation:
Stream capture occurs when an energetic stream erodes through a watershed divide and diverts the flow of an adjacent stream.
75. What are glacial striations?
Correct Answer: a) Scratches and grooves gouged into bedrock by rocks embedded in the base of a moving glacier
Explanation:
Striations are parallel scratches etched into bedrock surfaces, recording the direction of glacial movement.
76. What is a parabolic dune?
Correct Answer: a) A U-shaped dune with horns pointing upwind, typically anchored by vegetation in semi-arid coastal areas
Explanation:
Parabolic dunes have a U-shape where vegetation anchors the outer arms, causing the central portion to migrate forward downwind.
77. What coastal structure is built perpendicular to the shoreline to trap sand moving via longshore drift?
Correct Answer: a) Groin
Explanation:
Groins are barrier structures built out into the water perpendicular to the beach to trap sand carried by longshore drift.
78. Which of the following describes spheroidal weathering?
Correct Answer: a) The chemical weathering of jointed rock blocks into rounded, sphere-like shapes
Explanation:
Spheroidal weathering occurs when chemical weathering attacks the sharp corners and edges of jointed rocks faster than their flat faces, turning them rounded.
79. What is soil creep driven by?
Correct Answer: a) The expansion and contraction of soil particles from freeze-thaw or wetting-drying cycles
Explanation:
Creep occurs when soil expands outward perpendicular to the slope and settles straight down under gravity upon shrinking.
80. What is the primary difference between a debris slide and a debris flow?
Correct Answer: a) A slide moves as a coherent or semi-coherent block along a slip plane, whereas a flow moves as a fluid slurry of water and sediment
Explanation:
Slides maintain structural integrity along a planar failure surface, whereas flows behave internally like viscous fluids.
81. What is a drainage basin (watershed)?
Correct Answer: a) The entire land area drained by a main river and all its tributaries
Explanation:
A drainage basin represents the total catchment area contributing surface water runoff to a specific river system.
82. What is a braided stream?
Correct Answer: a) A stream with a complex network of interweaving channels separated by bars of sand and gravel, typical of glacial outwash plains
Explanation:
Braided streams occur when rivers carry a heavy bedload of coarse sediment in environments with fluctuating water discharge.
83. What is an erratic?
Correct Answer: a) An oversized boulder transported and deposited by a glacier, different from the local bedrock geology
Explanation:
Glacial erratics are boulders carried long distances by ice sheets and deposited in areas with completely different underlying geology.
84. What is a star dune?
Correct Answer: a) A pyramidal sand mound with multiple ridges radiating outward, formed in areas with multidirectional winds
Explanation:
Star dunes grow tall in areas where winds blow from multiple directions throughout the year.
85. What coastal engineering structure is built parallel to the shore in the water to protect a harbor or beach from wave energy?
Correct Answer: a) Breakwater
Explanation:
Breakwaters are constructed offshore, parallel to the coast, to absorb wave energy and create calm waters behind them.
86. What is biological weathering?
Correct Answer: a) The breakdown of rocks by living organisms through physical and chemical mechanisms
Explanation:
Biological weathering encompasses all rock disintegration and decomposition driven by plant roots, lichens, burrowing animals, and microbes.
87. Which of the following rocks is most resistant to both chemical and physical weathering at Earth's surface?
Correct Answer: a) Quartzite
Explanation:
Quartzite is composed of fused quartz grains, making it extremely hard and chemically inert compared to soluble limestone or marble and soft shale.
88. What is a mudflow (debris flow)?
Correct Answer: a) A fast-moving slurry of water-saturated soil, rock, and mud rushing down a slope or channel
Explanation:
Mudflows are rapid mass-wasting events triggered by heavy rainfall or volcanic melting, behaving like fluid mud.
89. What is the base level of a stream?
Correct Answer: a) The lowest elevation to which a stream can erode its channel, typically sea level
Explanation:
Base level is the lowest limit of stream erosion, with ultimate base level being sea level.
90. What is a fjord?
Correct Answer: a) A U-shaped glacial trough that has been flooded by rising sea levels
Explanation:
Fjords are deep, narrow coastal arms of the sea occupying glacially carved U-shaped valleys flooded after post-glacial sea level rise.
91. What is salt weathering (haloclasty)?
Correct Answer: a) The physical disintegration of rocks caused by the growth of salt crystals in pore spaces and cracks
Explanation:
Salt weathering occurs in arid or coastal regions when saline groundwater enters rock pores, evaporates, and growing salt crystals exert expansive pressure.
92. What is a rockslide?
Correct Answer: a) A rapid mass-wasting event where rocks slide down a pre-existing planar fault or bedding plane
Explanation:
Rockslides involve rapid movement of rock masses sliding intact down inclined planar surfaces such as bedding planes or fractures.
93. What is stream gradient?
Correct Answer: a) The slope or steepness of a stream channel, measured as drop in elevation over a given horizontal distance
Explanation:
Stream gradient defines the steepness of descent from source to mouth, controlling flow energy.
94. What is a terminal moraine?
Correct Answer: a) A ridge of till marking the maximum farthest advance of a glacier
Explanation:
Terminal moraines map the outermost limit reached by advancing glacial ice.
95. What is deflation in eolian geomorphology?
Correct Answer: a) The lifting and removal of loose, fine-grained particles by wind
Explanation:
Deflation is wind erosion that sweeps away loose dust and sand, sometimes leaving behind a desert pavement of heavier pebbles.
96. What is a sea arch?
Correct Answer: a) An arch-shaped rock formation created when waves erode completely through a coastal headland
Explanation:
Sea arches form when waves cut caves from opposite sides of a narrow headland until they meet, creating an arch.
97. What is thermal expansion weathering?
Correct Answer: a) The fracturing of rocks caused by repeated heating and cooling cycles
Explanation:
Thermal expansion causes cyclic stress and fracturing in rocks exposed to extreme temperature swings between day and night.
98. What is a slump?
Correct Answer: a) A mass-wasting movement where regolith slips downslope along a concave, curved fracture plane
Explanation:
Slumps involve rotational movement of earth materials along curved slip surfaces, often leaving a crescent-shaped scarp at the top.
99. What is a meandering stream?
Correct Answer: a) A single, highly sinuous river channel characterized by sweeping loops and bends
Explanation:
Meandering streams develop broad, looping curves as water erodes cut banks and deposits point bars on low-gradient flat terrain.
100. What is a recessional moraine?
Correct Answer: a) A ridge of till deposited behind the terminal moraine as a glacier temporarily pauses during retreat
Explanation:
Recessional moraines mark intermittent halting stages during the overall retreat of a glacier.
