Soil Layers Rock Layers and Minerals Flashcards
Rock layers are also called
strata
The Grand Canyon was formed in what era?
Cenozoic
A soil is composed of __% ____ _____
45% mineral matter
A soil scientist is called a
pedologist
The original mineral complex from which a soil is formed is called the soil’s
parent material
The amount and availability to plants of elements necessary for plant growth is called?
Fertility
In aquatic environments, lithification is preceded by
sedimentation
What is the descending order of the soil horizons?
O, A, E, B, C, R
The O Horizon consists of
The top, organic layer of soil, made up mostly of leaf litter and humus.
The A Horizon consists of
The topsoil, a dark layer where seeds germinate and plant roots grow. It is made up of humus mixed with mineral particles.
What is humus? NOT THE FOOD ITEM. That’s hummus. Note the second “m”. I would not recommend eating humus - it would taste like dirt. Hummus on the other hand, is fucking delicious.
Humus is decomposed organic matter. That’s why it would taste like dirt.
The E Horizon consists of
A light layer made up mostly of sand and silt, having lost most of its minerals and clay due to eluviation.
What is eluviation?
The transport of soil material from upper layers of soil to lower levels by downward precipitation of water across soil horizons.
The product of illuviation is?
An iluvial deposit
What is illuviation?
The accumulation of a material that is being transported downward.
The B Horizon consists of
The subsoil, which contains clay and mineral deposits that it receives from layers above it via eluviation.
What mineral deposits does the B Horizon primarily consist of?
Iron, aluminum oxides, and calcium carbonate
The C Horizon consists of
The regolith: slightly broken-up bedrock. Plant roots do not penetrate into this layer; very little organic material is found in this layer.
The R Horizon consists of
Bedrock: the unweathered rock layer beneath all other layer.
How many orders of soil are there in soil taxonomy? Can you name them all?
12: Alfisols, Aridisols, Entisols, Histosols, Inceptisols, Mollisols, Oxisols, Spodosols, Ultisols, Gelisols, Andisols, and Vertisols.
Gelisols are
Soils with permafrost within 2 m of the surface
Histosols are
Organic soils
Spodosols are
Acid forest soils with a subsurface accumulation of metal-humus complexes
Andisols are
Soils formed in volcanic ash
Oxisols are
Intensely weathered soils of tropical and subtropical environments
Vertisols are
Clayey soils with high shrink/swell capacity
Aridisols are
Calcium carbonate-containing soils of arid environments with subsurface horizon development
Ultisols are
Strongly leached soils with a subsurface zone of clay accumulation and
Mollisols are
Grassland soils with high base status
Alfisols are
Moderately leached soils with a subsurface zone of clay accumulation and >35% base saturation
Inceptisols are
Soils with weakly developed subsurface horizons
Entisols are
Soils with little or no morphological development
Plimsols are
A type of shoe
