Parent Material and Soil Formation Created by Jim Ippolito & Mike Hanna College of Agricultural Sciences Colorado State University Next

a discussion of the type of soil parent material 1 2 8 3 6 5 7 Click a number to view a discussion of the type of soil parent material 4 Click here to end

Type of Parent Material: Colluvium Mode of Transportation: Gravity Colluvium Photo: Source: http://pubs.usgs.gov/of/2002/of02-437/gallery.htm Type of Parent Material: Colluvium Mode of Transportation: Gravity Degree of Sorting by Particle Size: Low Additional Information: The term colluvium classifies parent material transported by gravity. Colluvium is made up of a heterogeneous mixture of boulders, rocks, pebbles, and soil from upslope areas. Thus the degree of particle sorting is low. Background Photo Source: Jim Ippolito; Northern boundary of Rocky Mountain National Park, Colorado

terminal moraine Type of Parent Material: Glacial Till Glacial Till Photo Source: Peter Fletcher http://www.nesoil.com/images/newport.htm terminal moraine Type of Parent Material: Glacial Till Mode of Transportation: Ice Degree of Sorting by Particle Size: Low Additional Information: Parent material transported by ice is called glacial till. This parent material is found where glaciers have deposited material, such as in terminal or lateral moraines. Ice is a poor sorter of particles, and thus glacial till contains everything from the smallest clay-sized fraction to rocks, pebbles, and boulders. Background Photo Source: Jim Ippolito; Northern boundary of Rocky Mountain National Park, Colorado

Type of Parent Material: Tephra Mode of Transportation: Wind Background Photo Source: http://hvo.wr.usgs.gov/volcanoes/haleakala/1koolau_large.jpg Type of Parent Material: Tephra Mode of Transportation: Wind Degree of Sorting by Particle Size: High Additional Information: Parent material transported via volcanic ejecta is called tephra. The mode of transportation is wind. Wind is a good sorter of particles. Larger particles tend to bounce on the Earth’s surface while smaller particles are transported greater distances. Soil developed from volcanic ejecta. Soil Profile Source: http://soils.usda.gov/technical/classification/orders/andisols.html

Type of Parent Material: Loess or Aeolian Mode of Transportation: Wind Aeolian Photo: Source: Dr. Paul McDaniel; http://soils.ag.uidaho.edu/soilorders/entisols_06.htm Type of Parent Material: Loess or Aeolian Mode of Transportation: Wind Degree of Sorting by Particle Size: High Additional Information: Parent material transported by wind is called loess or aeolian. Wind is a good sorter of particles. Larger particles tend to bounce on the Earth’s surface while smaller particles are transported greater distances. Background Photo Source: http://www.nps.gov/grsa

Type of Parent Material: Alluvium Mode of Transportation: Water Degree of Sorting by Particle Size: High Additional Information: Parent material transported by flowing water (streams, rivers) is called alluvium. Water is a good sorter of soil particles. Larger particles (i.e. sands) settle out of water first, and smaller particles (i.e. clays) settle out of water last. Thus, you tend to find sand-sized particles closer to the water source and clay-sized particles further away. Soil developed from alluvium. Source: http://www.mo15.nrcs.usda.gov/features/gallery/houlka.html

Type of Parent Material: Lacustrine Mode of Transportation: Lake Degree of Sorting by Particle Size: High Additional Information: The term lacustrine classifies parent material transported by a lake. Water is acting on the parent material and thus there is a high degree of particle sorting. Lacustrine Deposit Profile Source: NRCS staff, http://houzi.org/lacustrine.html

Type of Parent Material: Marine Mode of Transportation: Ocean Degree of Sorting by Particle Size: High Additional Information: The term “marine” classifies parent material transported by oceans. Water is acting on the parent material and thus there is a high degree of particle sorting. Soil Profile Source: http://www.mo15.nrcs.usda.gov/features/gallery/ocilla.html

Degree of Sorting by Particle Size: Low Soil Profile Source: http://www.mo14.nc.nrcs.usda.gov/features/goldston.html Type of Parent Material: Residual or Residuum. Mode of Transportation: In place; none. Degree of Sorting by Particle Size: Low Additional Information: The terms residual or residuum classify parent material formed in place (i.e. non-transported). The degree of sorting is low because no other factors have influenced soil movement.