Mastering Geology: Chapter 19 Deserts and Wind

What is the natural angle of repose for sand?

34 degrees

What is a playa commonly occupied by?

an ephemeral lake

What type of rocks would you expect to find in a playa lake depositional environment?

evaporites and claystone

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

rolling, sliding, bouncing, suspension

Steppe

A desert has a drier climate than a ___________________

evaporation

A high rate of ______________ is often characteristic of a climate with high temperatures and low humidity

soil, humid

Thick__________ is not found in deserts because there are fewer plants than in more ____________ climates

What is an ephemeral stream?

an intermittent stream that carries water only in response to specific episodes of rainfall

What is dust?

the particles carried in suspension by wind

What is the most important erosional agent in deserts?

water

semiarid

Also known as steppe, _____________ climates are a type of dry climate that contain more water than arid climates

- Many deserts are found in subtropical and middle latitudes. Although low levels of precipitation and sparse vegetation are present in both regions, different factors characterize and influence the creation of subtropical and middle latitude deserts. - Subtropical deserts form in areas of high pressure that stretch worldwide because of global atmospheric circulation patterns. - At these latitudes (~30° N, S), dry air persistently descends from above. - These deserts have clear skies, sunshine, and very dry conditions. - Middle latitude deserts form in the interiors of continents, far from the ocean or other sources of moisture. - At these locations, low levels of precipitation are the main factor. - Characterized by less consistently clear skies. Not all deserts are the same. Refer to the map below, and sort the desert features by the type of desert in which they are most common.

Subtropical desert: - Form due to persistent high atmospheric pressure. - Location is due to global atmospheric patterns. Middle latitude desert: - Characterized primarily by minimal precipitation. - Located far from major moisture sources like oceans. Uncommon desert features: - Precipitation never occurs. - Plants do not grow.

How is loess related to glaciers

When glaciers retreat, their meltwater contains loess, which can be picked up by winds and distributed elsewhere.

Which of the following accurately describes the Basin and Range region of the western United States?

a region with alternating mountains and basins that have been produced by normal faulting

A(n) _______ is a cone-shaped deposit of sediment that is deposited when a stream exits the mouth of a canyon.

alluvial fan

How does the rate of rock weathering in dry climates compare with the rate in humid regions?

dry climates have much lower rates of chemical weathering and mechanical weathering than humid climates

Why is it impossible to define the boundary between humid climates and dry climates by a single precipitation amount?

dryness is not only related to annual precipitation totals, but is also a function of evaporation

Which one of the following is an evaporite mineral?

gypsum

An isolated, heavily eroded hill or mountain that rises abruptly from a plain is a(n) _______.

inselberg

Other than the landforms you learned about in the video, what is another landform present in the Basin and Range Province?

sand dunes

What does salivating mean?

sand grans are lifted by the wind, leap a short distance, and then fall back to the ground

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

size

What factor limits the depths of blowouts?

the local water table

What is interior drainage?

Interior drainage is when an arid region exhibits a discontinuous pattern of intermittent streams that do not flow out of the desert to the ocean.

What are two hypotheses that are used to explain the formation of desert pavement?

Pavement develops on a surface that initially consists of coarse particles. Fine, windblown grains sift and settle downward between the larger surface stones. Wind removes sand and silt from poorly sorted surface deposits until all of the fine particles are gone, leaving only pebbles that are too large to be moved by the wind.