30 terms

science study guide

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abrasion
The grinding away of rock by other rock particles carried in water, ice, or wind
fertility
A measure of how well soil supports plant growth.
Weathering
The breaking down of rocks and other materials on the Earth's surface.
erosion
Processes by which rock, sand, and soil are broken down and carried away (i.e. weathering, glaciation)
Inorganic
Not formed from living things or the remains of living things
organic
of, relating to, or derived from living matter.
Humus
material formed from decaying leaves and other organic matter
Oxidation
A chemical change in which a substance combines with oxygen, as when iron oxidizes, forming rust
o horizon
the uppermost horizon of soil. It is primarily made up of organic material, including waste from organisms, the bodies of decomposing organisms, and live organisms.
a horizon
topsoil
b horizon
subsoil horizon the rock has been weathered into fine grains, but no living things are present.
e horizon
The zone of leaching that forms under the O horizon or, less often, the A horizon.
r horizon
The bedrock, which lies below all of the other layers of soil, is referred to as the R horizon.
residual soils
parent materials formed in place
clay
A natural, earthly material that retains its shape and hardens when fired
silt
A mixture of rich soil and tiny rocks
sand
A naturally occurring grainy material made of finely divided rock and mineral particles; the most common ingredient is silica
ice wedging
Process that splits rock when water seeps into cracks, then freezes and expands.
What is soil a mixture of?
rock particles, minerals, decayed organic material, water and air
what are organic/inorganic parts of soil made of?
organic: decaying organic matter
inorganic: minerals and broken down rocks
what is the most important factor that effects soil formation?
climate
chemical weathering
The process in which rock is broken down by changes in its chemical makeup
mechanical weathering
The type of weathering in which rock is physically broken into smaller pieces
is sand fertile?
no.
the b horizon consists of ______
subsoil
what are three decomposers of soil?
fungi, bacteria, worms
five agents of erosion
gravity, running water, glaciers, waves, and wind
what are two ways in which glaciers erode Earth's surface?
plucking and abrasion
what causes the sediment in a river to move downstream?
human activity
How does glacial deposition occur?
Deposition occurs when the glacier melts and leaves rock and sediment on the land.