chapter 7

Question 1

Why do geologists work in deserts?

Answer 1

protect the environment, assist people who live in these environments, study the origin of deserts

Question 2

what is desertification?

Answer 2

process by which fertile land becomes desert

Question 3

Why does desertification occur?

Answer 3

drought, deforestation, inappropriate agriculture

Question 4

What province is great sand dunes in?

Answer 4

southern rocky mountains geographical province.

Question 5

How many ranges are in the rocky mountains?

Answer 5

at least 100

Question 6

Where is great sand dunes located?

Answer 6

near the rio grande, river runs through the rio grande rift (failed divergent plate boundary?

Question 7

Four primary components of the great sand dunes system are the

Answer 7

mountain watershed, dune field, sand sheet, sabkha

Question 8

What are the creeks of great sand dunes?

Answer 8

sand, medano, and mosca

Question 9

Is a stream smaller than a river

Answer 9

yes

Question 10

river>stream>creek

Answer 10

yes

Question 11

Water can play a major role in creating desert landscapes. how?

Answer 11

dries up, leaves behind mud cracks. helps to drive the precipiation of minerals. water can carve sand, gravel

Question 12

does great sand dunes have the tallest sand dunes in north america?

Answer 12

yes

Question 13

sand dunes

Answer 13

low mound capable of movement that is created when strong winds pick up sand-sized grains from a valley floor and transport the grains by various methods

Question 14

wind

Answer 14

flow of gasses from regions of high pressure to low pressure because of uneven heating of earth by sun

Question 15

to create sand dunes what are the three requirements that must be met

Answer 15

wind (sufficient speed to carry), sand (specific grain sizes), trap (enough to trap sand)

Question 16

many different types of sand dunes exist. which are the ones that exist in great dunes?

Answer 16

barchan, transverse, reversing dune, star dune

Question 17

barchan

Answer 17

crescent-shaped dunes, always the products of limited sand supply and unidirectional winds

Question 18

transverse dunes

Answer 18

form in arid regions where there is abundant sands

Question 19

reversing dunes

Answer 19

occur when wind reverses direction, these appear to have a wall on top

Question 20

star dunes

Answer 20

form when the direction of the wind changes a lot. these dunes hvae three or more arms. can form in abundant or lower sand regions, grow vertically

Question 21

desertification causes

Answer 21

• climate
• population increase
  -over-exploitation of water resources
  -over-grazing, mining, forestry
• clearing of land without reforesting
• surface mining with reclamation
• rapid growth of large desert cities
• depletion of groundwater
• replacement of native plants with non-native
• soil salinization (salt) due to evaporation of irrigation water

Question 22

impacts of desertification

Answer 22

• expansion of deserts into formerly productive lands
• land degregation in arid, semi-arid and dry sub-humid areas results from various factors including climatic variations and human activities

Question 23

what underlie great sand dunes national park and are essential in recycling sand in the park and water sources in the region

Answer 23

artesian aquifer