Lecture 1 - Rocks And Minerals Flashcards
What are the macronutrients of soils
Nitrogen, phosphorus, potassium, calcium, magnesium, sulphur
Micronutrients of soils
Iron, manganese boron, molybdenum copper, zinc, chlorine, cobalt
Definition of parent material
Unconsolidated mineral or organic matter from which solum ( A and B Horizon) of soils is developed by pedogenic processed
What are the different parent material types
Residual: developed in place
Transported:
- gravity: collivium
- water: alluvium, lacustrine, marine
- wind: dune sands, loess, volcanic material
-glacierd: till, glaciofluvial, glacio-lacustrine, glacio-marine
Cumulose: pest, muck
Definition of minerals
An inorganic compound of defined composition, found in rocks
What are primary minerals
Minerals that has not been altered chemically since deposition and crystallization from molten lava
Eh: quartz mica, feldspar
What are secondary minerals
Minerals that are formed by the breakdown of a primary minerals
Where are secondary minerals found
Silicate clays; iron oxides
Most prominent in clay and sometimes in silt fractions
Definition of rocks
A solid, cohesive aggregate of grains of one or more minerals
Definition of weathering
The general process of rock and mineral disintegration / decomposition
Types of physical weathering
Temperature
- exfoliation - surface layers peel away
- ice forms in cracks and the volume increases
Water + ice + wind: abrasion + transport
What does physical weathering do
Decrease size of particles and increase surface area
Makes the particles more easily weathered by biogeochemical processed
Biogeochemical weathering
Chemical weathering enhanced by water, oxygen and organisms
Converts primary minerals to secondary minerals and release nutrient elements
What are the different types of biological weathering
Breaking up particles : plants roots and many soil dwelling organisms loosen the soil
Transfer and mixing : earthworms can move up to 50 tons of soil per hectare per year. Termites bring parent material to surface
Chemical effects:
Organisms respire and produce CO2
Carbonic acid - chemical weathering
