Chapter 21: Problem 7

Explain how the following features form: (a) desert varnish, (b) desert pavement, (c) ventifacts, and (d) yardangs. (C)

Short Answer

Expert verified

Desert varnish forms on rocks in arid environments due to bacteria oxidizing manganese and iron, which are then deposited as oxides on the rock surface. Desert pavement is created by the removal of fine-grained materials by wind and water, resulting in closely packed rocks that prevent further erosion. Ventifacts are rocks shaped by wind-blown sand and dust particles through abrasion, causing smoothed or grooved surfaces. Yardangs are elongated landforms created by wind erosion through differential erosion, leaving behind resistant rocks and resulting in boat-like shapes.

Step by step solution

(a) Forming Desert Varnish)

Desert varnish is a thin, dark coating that forms on rocks in arid environments. It consists of clay minerals, iron, manganese, and other elements. The formation process is not fully understood, but it is believed to be caused by bacteria present on the rock surfaces. These bacteria obtain energy by oxidizing manganese and iron, which are then deposited as oxides on the rock surface, leading to the formation of a dark coating over time.

(b) Forming Desert Pavement)

Desert pavement is a natural surface layer in deserts, consisting of closely packed, interlocking rock and pebble fragments. The formation process involves the removal of fine-grained materials (usually sand or dust) from the surface by wind and water. The remaining angular rocks and pebbles become interlocked and form a protective layer known as desert pavement. This layer of closely packed rocks prevents further soil erosion and maintains the desert landscape.

(c) Forming Ventifacts)

Ventifacts are rocks that have been eroded and shaped by wind-blown sand and dust, resulting in smooth, polished, or grooved surfaces. The formation process occurs when wind-driven sand and dust particles collide with exposed rocks, causing the gradual removal of softer and weaker rock material. This process, called abrasion, creates the distinct shapes and smoothed surfaces observed on ventifacts.

(d) Forming Yardangs)

Yardangs are elongated landforms created by wind erosion, typically found in deserts. They form through a process called differential erosion, which involves the selective removal of weaker rocks and sediments by wind, leaving behind the more resistant ones. Over time, yardangs are sculpted and streamlined as the wind continues to erode them, eventually resulting in their unique boat-like shapes. These landforms are generally aligned parallel to the prevailing wind direction that causes their formation.

Unlock Step-by-Step Solutions & Ace Your Exams!

Full Textbook Solutions
Get detailed explanations and key concepts
Unlimited Al creation
Al flashcards, explanations, exams and more...
Ads-free access
To over 500 millions flashcards
Money-back guarantee
We refund you if you fail your exam.

Start your free trial

Over 30 million students worldwide already upgrade their learning with Vaia!

Recommended explanations on Geography Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Explain how the following features form: (a) desert varnish, (b) desert pavement, (c) ventifacts, and (d) yardangs. (C)

Short Answer

Step by step solution

(a) Forming Desert Varnish)

(b) Forming Desert Pavement)

(c) Forming Ventifacts)

(d) Forming Yardangs)

One App. One Place for Learning.

Most popular questions from this chapter

Recommended explanations on Geography Textbooks

Global Resource Management

Diverse Places

Water Cycle

Energy Security

River Landscapes

Globalisation

Study anywhere. Anytime. Across all devices.