Geomorphology Flashcards
What is Geomorphology dependent on?
Reoccurrence intervals and recovery time
What is Weathering?
Physical break down and chemical alteration of minerals
What is Chemical Weathering?
Destruction of unstable substances, forming stable ones
What are examples of chemical weathering?
Oxidation, hydration, hydrolysis, ion exchange
What is Saprolite?
Chemically altered rock
What is Regolith?
Broken down rock
When are minerals most stable?
When there are in a low temperature, and exposed to low pressures. They are most resistant to weathering consequently
What is Physical Weathering?
The break down of rock into smaller pieces
What are examples of physical weathering?
Unloading, hydration, thermal expansion, salt growth
What is erosion?
Removal of rock or regolith from the earth’s surface
What are the two types of erosion?
Continuous - occurs in the grass
Episodic - big slides
What is mass wasting?
The downslope movement of a hill
What are the two types of mass wasting stresses?
Shear stress - diagonal outwards
Normal Stress - diagonal inwards
What is mass movement defined by?
Defined by material and movement
What is Talus?
Coarse, angular debris
What is characteristic of sheer materials?
Need water (sliding materials)
What is creep?
Expansion and Contraction of soil particles
What is creep dependent on?
Climate
What are the factors that increase running water?
velocity, discharge, channel size
What are the factors that decrease running water?
Gradient and channel roughness
What are the two types of flow?
Laminar: Smooth
Turbulent: Rough
What is velocity?
Proportional to the cross-sectional area of a slope + resistance
What is stream power proportional to?
Discharge x slope
What is abrasion?
Wearing away of the rock sediment with sediment
What is plucking?
The removal and transportation of bedrock
What are knick points?
Over steep sections of a river
What is competence?
Maximum grain size that a river can carry
What is capacity?
Total load of a river
What is the percentage of dominant discharge of a river?
90%
What is aggradation?
Continued filling of sediment
What is a delta?
Depositional progradation of shorelines at a rivers mouth
What channels have low sinuosity and step pools?
Straight Channels
What channels have high sinuosity and erosion?
Meandering channels
What channels have wide flood plains which are rapidly adjusting?
Braided Channels
What channels are separated by stable islands?
Anastomosing Channels
