unit 13

Part F - Features of Alluvial FansPart complete A fan in Death Valley, California is shown in the photos below. Use the information you learned from the video to fill in the sentence blanks.

1. The cross-fan profile is concave *down.* 2. The *inactive* portion of the fan is outlined in yellow. 3. A(n) *decrease* in water velocity causes sediment to be deposited on the fan. 4. The *active* portion of the fan is outlined in blue.

Which of the placemarked locations in the Arid Streams folder would be the best example of an exotic stream?

A

Which of the placemarks in the Alluvial Fan folder is the best example of an alluvial fan?

A

Which of the placemarks in the Dune Types folder best represents a star dune?

A

Based on the evidence in the Lake Faguibine, Mali folder, what has been the change in the east-west extent of Lake Faguibine from 1978 to 2006?

A decrease of 50 km.

Part D - Grain Size Changes on a Fan In the photo below, choose the photo showing the most likely grain size that you would find at the apex, middle, and toe of an alluvial fan. Drag the appropriate photos to their respective targets. All photos will be used.

A. big rocks B. medium rocks C. fine rocks

Part C - A Bird's-Eye View of Death Valley, California Three Google Earth images from the northern part of Death Valley are shown below. Each photo shows highlighted features associated with alluvial fans or surrounding landforms. Drag the appropriate labels or photos to their respective targets.

A. distributary channels B. fan apex C. basin center dune field D. toe of a fan E. long fan profile

Which of the placemarked locations in the Arid Streams folder would be considered an ephemeral stream?

B

Which of the following placemarks in the Basin-and-Range folder best represents basin-and-range topography?

C

Which of the placemarks in the Dune Types folder best represents a barchan dune?

D

Which of the following placemarks in the Badlands folder does not show badlands topography?

E

Which of the following statements is best supported by the evidence seen at the Irrigation placemark?

Humans have established areas of agricultural production in the heart of the eastern Sahara Desert.

After the collapse of the Ottoman Empire, what new nation-state was carved out of the region known as Mesopotamia?

In 1923, Iraq was the new nation-state carved out of Mesopotamia.

What was the major negative consequence of the boundary line drawn between Iraq and Saudi Arabia?

Once the boundary line was defined and mapped between Iraq and Saudi Arabia, the animal economy collapsed.

Two men determined the border between Iraq and Saudi Arabia: Sir Percy Cox and Ibn Saud, the king of Saudi Arabia. Unfortunately, these two men disagreed over how this border would be defined and mapped. How did Sir Percy Cox and Ibn Saud differ in opinion over how this new border would be defined?

Sir Percy Cox wanted to draw boundary lines straight through the desert but Ibn Saud wanted to keep the boundaries fluid and open.

Which of the following statements is best supported by the evidence seen at the Landscape Change placemark?

The area has been fenced and vegetation has started to recover.

Part E False

The second photo shows the cross-profile of the fan outlined in yellow. The basin center and the alluvial fan are both made up of fine-grained sediments.

Part E True

The second photo shows the long profile of the fan. The toe of the fan can be seen in both photos.

Up to 40 percent of the developing world's national borders were defined and mapped by these two countries.

Up to 40 percent of the developing world's national borders were mapped and defined by the United Kingdom and France.

The area outlined in orange is a(n) __________, which is an apron of sediment formed by neighboring __________.

bajada; alluvial fans

The landscape seen in the Namib Desert image is best described by which of the following desert types?

erg

Which of the following is a characteristic of many desert landscapes that best explains the presence of the feature seen in at the Okavango placemark?

interior drainage

Which of the following arid land features is best represented by placemark C in the Unique Arid Landforms folder?

mesa

Which of the following prevailing wind directions is most likely responsible for the dunes seen at the Prevailing Wind Direction placemark?

northwest

Which of the following arid land features is best represented by placemark E in the Unique Arid Landforms folder?

plateau

How do pieces of rock move under the influence of wind?

rolling, sliding, bouncing, suspension

What property of a piece of material will most directly determine how it is carried by wind?

size

Alluvial fans occur where a _____ exits the _____ and enters the _____.

stream; mountains; basin

Based on the evidence in the Las Vegas folder, what is the best characterization for the change in size of the Las Vegas metropolitan area between 1973 and 2006?

substantial increase

What is dust?

the particles carried in suspension by wind