Soil Formation
T or F: A soil developed in residual parent materials will likely have properties related to the properties of the rock below the C horizon
True
T or F: Animals, insects and worms affect soil formation primarily by mixing the soil, which increases the porespace where air and water move
True
T or F: Chemical weathering is accelerated by water, oxygen, and organic and inorganic acids moving down through the regolith
True
T or F: Climate influences not only the rate of weathering but the type of native vegetation dominant in an area
True
T or F: Eluviation of clay, iron, and other materials is the principal process responsible for the formation of an E horizon
True
T or F: Hydrolysis involves the splitting of water into its H+ and OH- components while hydration attaches intact water molecules to a compound
True
T or F: Igneous rocks are formed when molten magma cools and solidifies
True
T or F: Marine sediments are typical parent materials in coastal plain areas
True
T or F: Minerals containing iron are generally more resistant to chemical breakdown than minerals that contain Calcium Carbonate
True
T or F: Organic deposits are common in areas where water ponds for extended periods of time
True
T or F: Residual parent materials have formed in place and have not been transported from one area to another
True
T or F: Residual parent materials have generally been subjected to weathering for a longer period of time than have lacustrine or alluvial parent materials
True
T or F: Sapric and fibric are terms used to describe peat parent materials
True
T or F: Secondary minerals are recrystallized products of the chemical breakdown an/or alteration of primary minerals
True
T or F: The A horizons are more apt to be cultivated than the E horizons
True
T or F: The O horizons of a soil are dominantly organic horizons occurring above mineral horizons
True
In which horizon has the process of illuviation most likely occurred?
B horizon
Silicate clay accumulation is most common in the
B horizon
Mica + H2O --> K(+) + OH(-) + acid clay is an example of
Chemical weathering
Secondary minerals are most prominent in the _______ fraction of soils
Clay
Five major factors influencing soil formation
Climate, Bioorganisms, topography, parent material, time
Mixed angular gravel, rock, and soil found at the foot of a slope is typically of what type of parent material?
Colluvial
T or F: A soil developed in transported parent materials will likely have properties related to the properties of the rock below the C horizon
False
T or F: Alluvial parent materials are those that have been laid down in former lake bottoms
False
T or F: Even if all the glaciers present today in the world were to melt, the melt water would have no measurable effect on the level of the world's oceans
False
T or F: Glacial till can be recognized by the distinct layering of different kinds of particles
False
T or F: Glacial till is laid down by melt waters gushing out from the front of glaciers
False
T or F: In most B horizons one of the dominant processes of soil formation has been eluviation
False
T or F: Iron and aluminum oxides are major components of igneous rocks
False
T or F: Sandstones are good examples of metamorphic rocks
False
T or F: Soils developed in the wind-blown parent materials such as loess are generally of little agricultural value
False
T or F: The C horizons are generally more completely weathered than the other horizons
False
T or F: The parent materials for most coastal plain soils are residual in nature
False
T or F: The topmost horizon in most humid region forest soils is the A horizon
False
T or F: Weathering of rocks usually is most intense in the center of a rock fragment, and gradually decreases toward the outside
False
Which mineral is most resistant to weathering under humid temperate conditions?
Gibbsite
Which of the following is not a secondary mineral? Gibbsite, calcite, hornblende, silicate clay
Hornblende
Granite is what type of rock?
Igneous
What are the three types of rocks?
Igneous, Sedimentary, Metamorphic
The element most often involved in oxidation reactions as minerals weather is ___
Iron
Residual parent materials are:
Materials formed by weathering of rocks and minerals in place
Do tropical forests protect the soils from weathering?
NO
Organic matter accumulation is most pronounced in the
O horizon
The transformation of gneiss into smaller mica, quartz, and feldspar pieces is an example of
Physical Weathering
Have Lacustrine parent materials been subjected to weathering for shorter or longer periods of time than residual parent materials near by?
Shorter
What causes exfoliation?
Temperature
"Biotite --> clay --> iron oxide" represents a
Weathering sequence
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 presence of rocks such as shale and sandstone indicate the existence of
ancient seas
Glacial till is a term used to describe parent materials that
contain a heterogeneous mixture of mineral debris dropped by receding glaciers
Igneous rocks can best be characterized as
rocks formed when molten magma solidifies
Mechanical weathering processes result in
the disintegration of rcoks due to differential expansion of minerals
