Chapter 7 Weathering and Soil Flashcards
Process in which sediment is laid down in new locations.
Deposition
The process that breaks down rock through chemical changes.
Chemical Weathering
The process by which wind, water, glaciers, or gravity transports soil and sediment from one location to another.
Erosion
Type of weathering caused by reducing pressure on a rock surface, allowing slabs of outer rock to break off in layers.
Exfoliation
Rich, dark organic material formed by decay of matter, essential to soil’s fertility.
Humus
Process that splits rock when water seeps into cracks, then freezes and expands.
Ice Wedging
A chemical change in which a substance combines with oxygen, as when iron oxidizes, forming rust.
Oxidation
Weathering in which solid rock is fragmented by mechanical processes that do not change its chemical composition.
Physical Weathering (mechanical)
The part of the earth’s surface consisting of humus and disintegrated rock.
Soil
A layer in a soil profile.
Soil Horizon
All the vertical layers or horizons that make up a soil in a particular place.
Soil Profile
The chemical and physical processes that break down rock at Earth’s surface.
Weathering
Rainfall that is made sufficiently when carbon dioxide combines with water. This is chemical weathering.
Acid Rain
A crack in the ground made by a narrow or thin piece of ice that expands the ground when it freezes. This is mechanical weathering.
Ice Wedging
When a substance combines with oxygen, and oxides and forms rust. This is chemical change.
Oxidation
A type of weathering caused by reducing pressure on a rocks surface and makes the outer rock break off in layers. This is mechanical weathering.
Exfoliation
When Rock is split by roots of plants. This is mechanical weathering.
Plant weathering
When an animal burrows in the ground and breaks up the rock. This is mechanical weathering.
Animal weathering
A combination of fungus and algae that lives on rock and produces a weak acid. This is chemical weathering.
Lichen weathering
What are 3 factors that affect the rate of weathering?
Climate, pressure, composition
How are humans changing soil formation?
Farming, mining and forestry
How does climate affect soil type? Why is climate the most important factor in developing the characteristics of a soil?
When the climate is warm, plants and animals die and produce soil. Also bacteria weathers down rock. It is most important because it can help the soil being produced.
What is the role of partially decayed plant and animal remains in a soil?
It gives nutrients in the soil and creates acid that helps with weathering
How many horizons does typical soil contain?
About 3
What is the A-horizon? What does it contain?
The a horizon is called top soil. It contains organic material
What are the characteristics of the B-horizon? What is leaching?
The b horizon is where soluble minerals and clay accumulate. Leaching is when minerals drain away from soil
What is the C horizon? How does it differ from the other layers?
The c horizon is a layer of partially altered bedrock. It is the lowest horizon and has rock in it
_____ is the loose covering of weathered rock particles and decaying organic matter overlying the bedrock of earth
Soil
When a hole is dug out of the ground, a vertical sequence of layers is exposed called a __________
Soil profile
A distinct layer or zone located in the soil profile is called a ______
Soil horizon
The rich, dark material from decayed organic material is called______
Humus
Weathering is the process by which rocks on or near earths surface break down and change.
True or false?
True
Mechanical weathering changes the chemical composition of rocks.
True or false?
False
The repeated thawing and freezing of water in the cracks of rock is called ice wedging.
True or false?
True
The chemical reaction of carbon dioxide with other substances is called oxidation.
True or false?
False
The horizons in order are…
A, b, c
The three horizons make up a soil____
Profile
What horizon contains the most humus?
A
What horizon is most like parent material?
C
The most leaching of minerals occurs from the ____ horizon to the ____ horizon
A, b
Top soil is the ____ horizon
A
How does soil form?
Decaying of loose organic debris
