Soil Science Chapter 2

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

True

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

True

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

True

Residual parent materials are best described as ___________.

materials formed by weathering of rocks and minerals in place.

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

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

False

Hydrolysis involves the splitting of water into its H+ and OH- components while hydration attaches intact water molecules to a compound.

True

Igneous rocks are formed when molten magma cools and solidifies.

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

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

False

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

False

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.

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

False

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

In most B horizons on of the dominant processes of soil formation has been eluviation.

False

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

False

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

False

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

Falsw

Which of the following statements is correct?

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

Which of the following statements is not correct?

Tropical forests protect the soil from excessive weathering

Which of the following statements is not correct?

Tropical forests protect the soil from excessive weathering.

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

True

Chemical weathering is accelerated by water, o2, and organic/inorganic acids moving down through the regolith.

True

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

True

The presence of rocks such as shale and sandstone indicate the existence of _____________.

ancient seas

The presence of rocks such as shale and sandstone indicate the existence of ______________.

ancient seas

Secondary minerals are most prominent in the __________fraction of soils.

clay

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

gibbsite

Which of the following is not a secondary mineral?

hornblende

Granite is an example of an ______________.

igneous rock

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

iron

The element most often invovled in oxidation reactions as minerals weather is _______.

iron

Igneous rocks can best be characterized as _______.

rocks formed when molten magma solidifies

Igneous rocks can best be characterized as _____________.

rocks formed when molten magma solidifies

Alluvial fans are usually characterized by ______ soils.

sandy and gravelly

Exfoliation is caused by changes in _______.

temperature

Exfoliation is caused by changes in ________.

temperature

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

true

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

true.

Igneous, sedimentary, and metamorphic are three _______.

types of rocks

Which of the following is not considered on the 5 major factors of soil formation?

valence state

"Biotite --> clay-->iron oxides" represents a _____________.

weathering sequence