Chapter 8 Aeolian

Question 1

Where and why do most deserts form?

Answer 1

…

Question 2

How is sediment transported in eolian environments?

Answer 2

Fine sediments are transported by the wind

Question 3

What are the two major variables that control the types of dunes that form in an aeolian environment?

Answer 3

Sand supply and variability of prevailing wind directions

Question 4

Are cross laminations common in aeolian ripples?

Answer 4

Cross lamination is less common in aeolian ripples than their subaqueous counterparts

Question 5

A “frosted” grain is a distinguishing characteristic for sand in aeolian environments. What does this
mean? How does it happen?

Answer 5

The grains will have a dull, matt appearance under high magnification under an SEM. It occurs from impacts suffered during transport

Question 6

What is another facies that you might you find associated with an eolian deposit

Answer 6

fluvio-glacial facies
ephemeral lakes/rivers in deserts
poorly sorted fluvial and alluvial fan
beach deposits
glacial outwash

Question 7

What sized sand typically comprises an aeolian deposit?

Answer 7

fine to medium

Question 8

Why are aeolian deposits typically quartz arenites?

Answer 8

Quartz and chert are robust minerals, therefore are some of the last minerals to be broken down from transportation

Question 9

Are aeolian deposits compositionally mature or immature?

Answer 9

Mature

Question 10

Why are desert sands typically “yellow”?

Answer 10

Iron minerals acting as a fine mineral coating on the sand grains.
Iron hydroxide goethite is a common iron mineral