Exam 1 Flashcards
Particle sizes, Largest to smallest
Sand, silt, clay
Why is organic matter necessary for good soil
better drainage, softer, resists erosion, biodiversity
Weathering definition
break down (and chemical transformation) of rock
What are the two types of weathering
Physical and Chemical
Characteristics of physical weathering
Disintegration by mechanical means, can be heat driven, tree and shrub roots can break down rock
Characteristics of chemical weathering
Decomposition chemically
Main agents of chemical weathering
water, CO2, O2, acid rain, biological substances
3 types of rock
Igneous rock, metamorphic rock, sedimentary rock
Characteristics of igneous rock
formed when lava or magma cools
high in Fe and Mg
Includes volcanic ash
Characteristics of metamorphic rock
Made when continental plates collide
causes heat and pressure
transforms sedimentary and igneous rock into something new
Characteristics of sedimentary rock
rocks are broken down into smaller pieces
weathering depends on original rock comp
Define parent materials
The original rock a soil is made from
What are residual parent materials
materials not transported
Define colluvium
rock fragments carried down steep slopes
define alluvium
rock fragments carried by rivers and streams
Define glacial till
material transported by a glacier
define aeolian
rock fragments transported by wind
loess
silt carried by air
marine
coastal sediments
lacustrine
lake sediments
peat
a compressed form of organic matter
5 major factors that contribute to soil development
parent material
climate
topography
biota
time
Order of horizons (Top to bottom)
O
A
E
B
C
R
O horizon
organic layer, forest floor
A Horizon
dark color, decayed organic matter, known as top soil
E Horizon
Eluviated (Washed out)
B horizon
material washed out from E horizon
C horizon
on top of parent material, retains structural features of underlying material, limited biological material
R horizon
rock layer
