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Difficulty: Very hardLandform Development by Wind Action and Glaciation

In an arid environment, wind deflation selectively removes loose, fine-grained sediments until a continuous armor of polished, coarse pebbles covers the desert floor. In contrast, in areas where wind abrasion attacks alternating horizontal strata of hard and soft rocks near the surface, deep parallel furrows are gouged out, leaving standing ridges of resistant rock. Which pair of aeolian features describes these respective erosion landforms?

  1. Desert pavement and yardangsAnswer
  2. B
    Oxbow lakes and deltas
  3. C
    Scree slopes and talus cones
  4. D
    River terraces and natural levees

Answer

The combination of desert pavement and yardangs correctly identifies the described aeolian erosional features.
Desert pavement is formed when wind deflation carries away fine sand and silt, leaving a concentrated layer of heavy pebbles on the desert surface. Yardangs are elongated, steep-sided ridges carved out by wind abrasion operating on alternating belts of hard and soft rocks aligned parallel to the prevailing wind direction.

Step-by-Step Solution

1
Identify the first process and landform described in the stem.
The selective removal of fine particles by wind deflation leaving coarse pebbles creates a desert pavement (also known as reg or hamada lag deposit).
Wind deflation removes sand and dust, concentrating larger pebbles into an armoring surface layer.
2
Identify the second process and landform described in the stem.
Differential wind abrasion carving out soft rock strata to leave prominent parallel ridges forms yardangs.
Abrasion by wind-blown sand carves out linear furrows in soft rock, leaving ridges aligned parallel to the prevailing wind direction.
3
Compare candidate options to eliminate features formed by other geomorphic agents.
Options featuring oxbow lakes, river terraces, or scree slopes belong to fluvial action or mass wasting, leaving desert pavement and yardangs as the only valid aeolian landforms.
Ensures precise attribution to wind action rather than running water or mass movement under gravity.

Key Concept

Aeolian Erosional Landforms and Mechanics
Estimated Time:1m 30s
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Topics

Landform Development by Wind Action and Glaciation

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