Weathering and Soil Formation Flashcards
Vocabulary Practice and Understanding.
The process that breaks down rock and other substances at Earth’s surface.
Weathering
The removal of rock particles by wind, water, ice, or gravity.
Erosion
What are the two types of weathering?
Mechanical and Chemical
What type of weathering causes rocks to be physically broken into smaller pieces.
Mechanical Weathering
Name 2 causes of mechanical weathering.
Freezing and Thawing
Release of Pressure
Plant Growth
Actions of Animals
Abrasion
What is abrasion?
The term abrasion refers to grinding away of rock by rock particles carried by water, ice, wind, or gravity.
The process that breaks down rock through chemical changes.
Chemical Weathering
Name two causes of chemical weathering.
Action of Water
Oxygen
Carbon Dioxide
Living Organisms
Acid Rain
What is the most important cause of chemical weathering?
This type of chemical weathering causes rocks to dissolve.
Water
The oxygen gas in the air is an important cause of chemical weathering in rocks that contain iron. What is the process called when Iron combines with Oxygen?
Oxidation
Oxidation creates rust and rust makes rock soft and crumbly and gives it a red or brown color.
What type of rock weathers more easily?
Permeable
Permiable means that the material is full of tiny, connected air spaces that allow water to seep through it.
What is the loose, weathered material on Earth’s surface in which plants can grow?
Soil
One of the main ingrediants of soil comes from __________.
___________ is the solid layer of rock beneath the soil.
Bedrock
Once bedrock is exposed at the surface, it gradually weathers into smaller and smaller particles that are the basic material of soil.
What is the composition of soil?
Soil is more than just particles of weathered bedrock. Soil is composed of a mixture of rock particles, minerals, decayed organic material, water and air.
What is the dark-colored substance that forms as plant and animal remains decay?
Humus
Humus helps create spaces in soil for air and water that plants must have. It also contain nutrients for the plants growing in the soil.
What does fertility tell us about the soil?
Fertile soil is rich in the nutrients that plants need to grow and be healthy. The fertility of the soil is a measure of how well the soil supports plant growth.
Soil that is made up of about equal parts of clay, sand, and silt is called?
Loam
Loam has a crumbly texture that holds both air and water.
Gradually, soil develops layers called?
Horizons
A soil horizon is a layer of soil that differs in color and texture from the layers above and below it.
The A horizon is made up of what type of soil?
Topsoil
Topsoil is a crumbly, dark brown soil that is a mixture of humus, clay, and other materials.
The B horizon is called?
Subsoil
Subsoil usually contains clay and other particles washed down from the A horizon, but little humus.
