SSC 200 Quiz 2

Sandstones are good examples of metamorphic rocks.

False

Animals, insects and worms affect soil formation primarily by mixing the soil, which increases the porespace where air and water move.

True

Alluvial parent materials are those that have been laid down in former lake bottoms.

False

Residual parent materials have generally been subjected to weathering for a longer period of time than have lacustrine or alluvial parent materials.

True

Sapric and fibric are terms used to describe peat parent materials.

True

Secondary minerals are recrystallized products of the chemical breakdown and/or alteration of primary minerals.

True

The A horizons are more apt to be cultivated than the E horizons.

True

The O horizons of a soil are dominantly organic horizons occurring above mineral horizons.

True

Which mineral is most resistant to weathering under humid temperate conditions?

gibbsite

Residual parent materials have formed in place and have not been transported from one area to another.

True

Igneous, sedimentary, and metamorphic are three ________.

types of rocks

In which of the following horizons has the process of illuviation most likely occurred?

B horizon

Silicate clay accumulation is most common in the ________.

B horizon

A soil developed in transported parent materials will likely have properties related to the properties of the rock below the C horizon.

False

Glacial till can be recognized by the distinct layering of different kinds of particles.

False

Glacial till is laid down by melt waters gushing out from the front of glaciers.

False

Soils developed in wind-blown parent materials such as loess are generally of little agricultural value.

False

The C horizons are generally more completely weathered than the other horizons.

False

The parent materials for most coastal plain soils are residual in nature.

False

Weathering of rocks usually is most intense in the center of a rock fragment, and gradually decreases toward the outside.

False

The topmost horizon in most humid region forest soils is the A horizon.

False (In most humid forests the top layer is the O horizon)

Which of the following statements is correct? a. Nutrient cycling in forested areas contributes little to soil formation. b. Lacustrine parent materials have been subject to weathering for shorter periods of time than residual parent materials nearby. c. Soils on hillsides tend to be deeper than those on level lands. d. Calcium carbonate accumulation is more prominent in humid than in arid regions. e. Limestone parent materials enhance the process of acidification.

Lacustrine parent materials have been subject to weathering for shorter periods of time than residual parent materials nearby.

Organic matter accumulation is most pronounced in the ________.

O horizon

Which of the following statements is not correct? a. Grasslands are found in semi-arid and sub-humid areas. b. Coniferous forests are found mostly in cool humid areas. c. Where dense forests are found, soil profiles have prominent O horizons. d. The type of native vegetation is controlled primarily by climate. e. Tropical forests protect the soil from excessive weathering.

Tropical forests protect the soil from excessive weathering.

A soil developed in residual parent materials will likely have properties related to the properties of the rock below the C horizon.

True

Chemical weathering is accelerated by water, oxygen, and organic and inorganic acids moving down through the regolith.

True

Climate influences not only the rate of weathering but the type of native vegetation dominant in an area.

True

Eluviation of clay, iron, and other materials is the principal process responsible for the formation of an E horizon.

True

Igneous rocks are formed when molten magma cools and solidifies.

True

Marine sediments are typical parent materials in coastal plain areas.

True

Minerals containing iron are generally more resistant to chemical breakdown than minerals that contain CaCO3.

True

Organic deposits are common in areas where water ponds for extended periods of time.

True

If you wanted to find a soil where physical weathering dominated over chemical breakdown you would be most apt to find it in ________.

a desert region of Arizona

The reaction: mica + H2O → K+ + OH- + acid clay is an example of ________.

chemical weathering

Secondary minerals are most prominent in the ________ fraction of soils.

clay

The mixed angular gravel, rock, and soil found at the foot of a slope is typical of what type of parent material?

colluvial

Glacial till is a term used to describe parent materials that ________.

contain a heterogeneous mixture of mineral debris dropped by receding glaciers.

Granite is an example of a(n) ________.

igneous rock

The element most often involved in oxidation reactions as minerals weather is ________.

iron

Residual parent materials are best described as ________.

materials formed by weathering of rocks and minerals in place.

The transformation of gneiss into smaller mica, quartz, and feldspar pieces is an example of ________.

physical weathering

Igneous rocks can best be characterized as ________.

rocks formed when molten magma solidifies

Exfoliation is caused by changes in ________.

temperature

Mechanical weathering processes result in ________.

the disintegration of rocks due to differential expansion of minerals

Which of the following is not considered one of the five major factors influencing soil formation?

valence state

"Biotite --> clay --> iron oxide" represents a ________.

weathering sequence