Chapter 3 Weathering Flashcards
What does the Gradational Process do?
Reduction of the land’s surface through:
Weathering
Mass Movement
Erosion
When does Mechanical Weathering occur?
When physical forces break rocks into smaller pieces without changing the rock’s mineral composition
What are the 3 physical process that are important causes of weathering?
Frost wedging
Unloading
Biological Activity
What is Frost Wedging?
Mechanical breakup of rock caused by the expansion of freezing water in cracks and crevices.
What is Talus?
Sections of rocks that are wedged loose by frost wedging that are then tumbled into piles (typically formed at bases of steep, rocky cliffs).
What is Unloading?
Reduced pressure on igneous rocks that causes it to expand and allow slabs of outer rock to break off in layers. (this creates a process called exfoliation).
What is Biological Activity?
Activity of organisms (plants, burrowing animals, humans) that causes mechanical weathering.
What is Chemical Weathering?
Transformation of rock into one or more new compounds.
What is the weathering of silicate Minerals?
It produces insoluble iron oxides and clay minerals.
What are the chemical weathering of Granite?
Weathering of potassium feldspar minerals, soluble salt (potassium bicarbonate), and silica in solution.
(quartz remain substantially unaltered)
What does Spheroidal Weathering cause?
Causes the corners and edges of rock to be more rounded.
What are 2 other factors affecting the rate of weathering?
Rock characteristics = Mineral composition and solubility, physical features such as joints.
Climate = Temperature and moisture are the most crucial factors, chemical weathering is most effective in areas with high temperatures and abundant moistures
