Midterm review Geo 2120 Spring 2018 EXAM
with Questions and Answers/Plus a Rationale
Updated 2026 A+/Instant Download PDF
EXAM COVERAGE
1. Geomorphic Processes and Earth Surface Dynamics
2. Plate Tectonics and Crustal Deformation
3. Fluvial Systems and Channel Morphology
4. Glacial Processes and Periglacial Landscapes
5. Weathering, Soil Development, and Mass Wasting
6. Coastal Geomorphology and Processes
7. Aeolian Systems and Desert Landscapes
8. Karst Topography and Groundwater Geomorphology
1. A researcher is investigating the rate of chemical weathering in a temperate rainforest versus an
arid desert. If both locations have similar parent material, why would the rainforest demonstrate
significantly higher rates of hydrolysis and oxidation?
A. The higher altitude of the rainforest increases atmospheric pressure and particle velocity.
B. The synergistic effect of increased temperature and consistent moisture accelerates
chemical reaction kinetics.
C. The arid desert experiences higher mechanical weathering, which precludes chemical
weathering processes.
, D. Rainforest vegetation produces alkaline secretions that neutralize the acidic weathering
products.
Answer: B
CORRECT ANSWER : B
Rationale: Chemical weathering processes like hydrolysis and oxidation are temperature and
moisture-dependent; high rainfall provides the solvent for reactions, and higher temperatures
increase reaction rates (Arrhenius equation). Option A is incorrect because higher altitude
usually decreases temperature. Option C is incorrect as chemical weathering occurs in deserts,
albeit slowly. Option D is incorrect because vegetation typically produces organic acids that
enhance, rather than neutralize, weathering.
2. During an analysis of a river channel, you observe a transition from a straight, high-gradient
reach to a meandering reach in a low-gradient valley. What geomorphic adjustment is occurring?
A. The stream is increasing its competency by decreasing its load.
B. The stream is increasing its sinuosity to dissipate excess energy as the gradient
decreases.
C. The stream is undergoing headward erosion to capture an adjacent drainage basin.
D. The stream is shifting from a suspension-load dominant system to a bed-load dominant
system.
Answer: B
CORRECT ANSWER : B
Rationale: As gradient decreases, the stream must adjust to maintain equilibrium; increasing
sinuosity increases the channel length and decreases the slope, allowing the stream to dissipate
energy. Option A is incorrect because competency is related to velocity, not just load. Option C
refers to stream piracy, which is unrelated to gradient adjustment. Option D is incorrect because
meandering streams are typically associated with higher suspended loads.
3. A landscape features a series of jagged, arête-like ridges, cirques, and U-shaped valleys. Which
set of processes best explains this morphology?
A. Predominantly fluvial erosion by high-velocity mountain streams.
B. Glacial plucking and abrasion during periods of maximum glacial advance.
C. Eolian deflation processes in an exposed high-altitude environment.
, D. Mass wasting of weak, unlithified sedimentary rock.
Answer: B
CORRECT ANSWER : B
Rationale: These landforms are characteristic of glacial landscapes; cirques are formed by
plucking at the head of a glacier, and U-shaped valleys are carved by ice abrasion. Options A,
C, and D describe fluvial, wind, or mass wasting landforms that do not produce this specific
assemblage of features.
4. You are analyzing a landslide event. If the safety factor ($SF$) drops from 1.2 to 0.8, what does
this signify?
A. The slope has achieved a state of equilibrium and is becoming more stable.
B. The driving forces now exceed the resisting forces, leading to slope failure.
C. The pore water pressure has decreased significantly, strengthening the material.
D. The angle of repose has increased due to increased vegetation root cohesion.
Answer: B
CORRECT ANSWER : B
Rationale: The safety factor is defined as the ratio of resisting forces to driving forces. An $SF <
1$ indicates that driving forces (gravity, pore pressure) exceed resisting forces (shear strength),
causing failure. Option A is incorrect as $SF < 1$ is unstable. Option C is incorrect because
high pore water pressure decreases shear strength. Option D is incorrect as vegetation increases
stability.
5. A soil profile shows a distinct B-horizon enriched with illuviated clays and iron oxides. Which
pedogenic process is primarily responsible?
A. Podzolization in an alkaline environment.
B. Translocation (eluviation and illuviation) within the soil profile.
C. Calcification via rapid evaporation and capillary action.
D. Laterization resulting from extreme mechanical fragmentation.
Answer: B
CORRECT ANSWER : B
, Rationale: The B-horizon is the zone of accumulation (illuviation) where materials like clay and
iron oxides are deposited after being leached (eluviated) from the A-horizon. Option A is
incorrect because podzolization is associated with acidic environments. Option C refers to
carbonate accumulation. Option D is incorrect because laterization involves the leaching of
silica, not just mechanical weathering.
6. Which observation in a karst landscape would indicate that the surface is currently undergoing
active sinkhole development?
A. A lack of surface streams in the region.
B. A sudden collapse of the ground exposing an underlying cavernous void.
C. The presence of mature, stable hummocks in the valley.
D. Extensive surface deposits of loess or wind-blown dust.
Answer: B
CORRECT ANSWER : B
Rationale: Sinkhole development involves the removal of soluble bedrock, leading to the collapse
of the overlying mantle into an underground void. Option A describes regional drainage but isn't
specific to active collapse. Option C refers to residual limestone hills (towers), and Option D is
unrelated to karst dissolution.
7. Why do arid landscapes often exhibit high rates of wind erosion (deflation) despite the presence
of protective desert pavement?
A. Desert pavement increases surface roughness and traps wind.
B. High-velocity gusts can bypass the pavement to erode fine-grained sediments beneath.
C. The pavement is constantly being chemically dissolved by rain, leaving no protection.
D. Arid landscapes are not affected by wind erosion; they are dominated by fluvial processes.
Answer: B
CORRECT ANSWER : B
Rationale: While desert pavement (lag deposits) protects the surface, deflationary wind can
penetrate or erode the material beneath the stones, especially if the surface is disturbed. Option
A is incorrect because pavement decreases roughness. Option C is incorrect because chemical
weathering is negligible. Option D is incorrect as both fluvial and eolian processes are
significant.
with Questions and Answers/Plus a Rationale
Updated 2026 A+/Instant Download PDF
EXAM COVERAGE
1. Geomorphic Processes and Earth Surface Dynamics
2. Plate Tectonics and Crustal Deformation
3. Fluvial Systems and Channel Morphology
4. Glacial Processes and Periglacial Landscapes
5. Weathering, Soil Development, and Mass Wasting
6. Coastal Geomorphology and Processes
7. Aeolian Systems and Desert Landscapes
8. Karst Topography and Groundwater Geomorphology
1. A researcher is investigating the rate of chemical weathering in a temperate rainforest versus an
arid desert. If both locations have similar parent material, why would the rainforest demonstrate
significantly higher rates of hydrolysis and oxidation?
A. The higher altitude of the rainforest increases atmospheric pressure and particle velocity.
B. The synergistic effect of increased temperature and consistent moisture accelerates
chemical reaction kinetics.
C. The arid desert experiences higher mechanical weathering, which precludes chemical
weathering processes.
, D. Rainforest vegetation produces alkaline secretions that neutralize the acidic weathering
products.
Answer: B
CORRECT ANSWER : B
Rationale: Chemical weathering processes like hydrolysis and oxidation are temperature and
moisture-dependent; high rainfall provides the solvent for reactions, and higher temperatures
increase reaction rates (Arrhenius equation). Option A is incorrect because higher altitude
usually decreases temperature. Option C is incorrect as chemical weathering occurs in deserts,
albeit slowly. Option D is incorrect because vegetation typically produces organic acids that
enhance, rather than neutralize, weathering.
2. During an analysis of a river channel, you observe a transition from a straight, high-gradient
reach to a meandering reach in a low-gradient valley. What geomorphic adjustment is occurring?
A. The stream is increasing its competency by decreasing its load.
B. The stream is increasing its sinuosity to dissipate excess energy as the gradient
decreases.
C. The stream is undergoing headward erosion to capture an adjacent drainage basin.
D. The stream is shifting from a suspension-load dominant system to a bed-load dominant
system.
Answer: B
CORRECT ANSWER : B
Rationale: As gradient decreases, the stream must adjust to maintain equilibrium; increasing
sinuosity increases the channel length and decreases the slope, allowing the stream to dissipate
energy. Option A is incorrect because competency is related to velocity, not just load. Option C
refers to stream piracy, which is unrelated to gradient adjustment. Option D is incorrect because
meandering streams are typically associated with higher suspended loads.
3. A landscape features a series of jagged, arête-like ridges, cirques, and U-shaped valleys. Which
set of processes best explains this morphology?
A. Predominantly fluvial erosion by high-velocity mountain streams.
B. Glacial plucking and abrasion during periods of maximum glacial advance.
C. Eolian deflation processes in an exposed high-altitude environment.
, D. Mass wasting of weak, unlithified sedimentary rock.
Answer: B
CORRECT ANSWER : B
Rationale: These landforms are characteristic of glacial landscapes; cirques are formed by
plucking at the head of a glacier, and U-shaped valleys are carved by ice abrasion. Options A,
C, and D describe fluvial, wind, or mass wasting landforms that do not produce this specific
assemblage of features.
4. You are analyzing a landslide event. If the safety factor ($SF$) drops from 1.2 to 0.8, what does
this signify?
A. The slope has achieved a state of equilibrium and is becoming more stable.
B. The driving forces now exceed the resisting forces, leading to slope failure.
C. The pore water pressure has decreased significantly, strengthening the material.
D. The angle of repose has increased due to increased vegetation root cohesion.
Answer: B
CORRECT ANSWER : B
Rationale: The safety factor is defined as the ratio of resisting forces to driving forces. An $SF <
1$ indicates that driving forces (gravity, pore pressure) exceed resisting forces (shear strength),
causing failure. Option A is incorrect as $SF < 1$ is unstable. Option C is incorrect because
high pore water pressure decreases shear strength. Option D is incorrect as vegetation increases
stability.
5. A soil profile shows a distinct B-horizon enriched with illuviated clays and iron oxides. Which
pedogenic process is primarily responsible?
A. Podzolization in an alkaline environment.
B. Translocation (eluviation and illuviation) within the soil profile.
C. Calcification via rapid evaporation and capillary action.
D. Laterization resulting from extreme mechanical fragmentation.
Answer: B
CORRECT ANSWER : B
, Rationale: The B-horizon is the zone of accumulation (illuviation) where materials like clay and
iron oxides are deposited after being leached (eluviated) from the A-horizon. Option A is
incorrect because podzolization is associated with acidic environments. Option C refers to
carbonate accumulation. Option D is incorrect because laterization involves the leaching of
silica, not just mechanical weathering.
6. Which observation in a karst landscape would indicate that the surface is currently undergoing
active sinkhole development?
A. A lack of surface streams in the region.
B. A sudden collapse of the ground exposing an underlying cavernous void.
C. The presence of mature, stable hummocks in the valley.
D. Extensive surface deposits of loess or wind-blown dust.
Answer: B
CORRECT ANSWER : B
Rationale: Sinkhole development involves the removal of soluble bedrock, leading to the collapse
of the overlying mantle into an underground void. Option A describes regional drainage but isn't
specific to active collapse. Option C refers to residual limestone hills (towers), and Option D is
unrelated to karst dissolution.
7. Why do arid landscapes often exhibit high rates of wind erosion (deflation) despite the presence
of protective desert pavement?
A. Desert pavement increases surface roughness and traps wind.
B. High-velocity gusts can bypass the pavement to erode fine-grained sediments beneath.
C. The pavement is constantly being chemically dissolved by rain, leaving no protection.
D. Arid landscapes are not affected by wind erosion; they are dominated by fluvial processes.
Answer: B
CORRECT ANSWER : B
Rationale: While desert pavement (lag deposits) protects the surface, deflationary wind can
penetrate or erode the material beneath the stones, especially if the surface is disturbed. Option
A is incorrect because pavement decreases roughness. Option C is incorrect because chemical
weathering is negligible. Option D is incorrect as both fluvial and eolian processes are
significant.
