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Lecture

GG101 Lecture Notes - Mass Wasting, Geomorphology, Carbonation


Department
Geography
Course Code
GG101
Professor
James Hamilton

Page:
of 3
GG101 Week 10 Lecture 2
Geomorphology
study of landforms and landscapes and the processes that are responsible for their
development
Scale of Inquiry
Spatial
Temporal
2 main types of processes
1) Endogenic Processes
internal earth processes
deepseated (not hydrologic cycles, etc)
volcanism, seismic activity, mountain building
energy source comes from radioactive isotopes
these processes can be described by the model of plate tectonics
energy source is geothermal heat (radioactive decay of certain isotopes generates the
heat)
Fig 11.2 a - c
2) Exogenic Processes
on the surface of the earth
energy source comes from the sun (solar radiation)
weathering, mass wasting,
Weathering
set of processes that act to break down materials at the surface and in the shallow
subsurface
Weathering Processes
o Physical
mechanically break materials apart mainly through expansion and
contraction
Freeze Thaw (frost action)
o water in pores and fissures in bedrock rapidly freezes and
expands
exerts pressure (stress) on surrounding rock causing
the rock to fracture
o What type of environment?
won't work in warm/dry climate
Salt Crystal Growth
o saline water in pores and fissures evaporates
salts crystals develop in pores
crystals expand (as they absorb water or are heated)
o What type of environment?
tend to be a marine shoreline, seaspray
Pressure Release
o expansion of bedrock may occur if confining pressure is
released
o produces fissures that are parallel to the surface
o Exfoliation
bedrock fracturing as a result of removing the
pressure that was previously exerted on the rock
o Chemical
chemical decomposition of mineral materials
Solution
disassociation of a mineral into its constituent ions in the presence
of water
o e.g. dissolving salt
Carbonation
action of carbonic acid aiding solution of carbonate or other
materials
o e.g. calcium carbonate
o Biological
can be complex
can see this in action at a cemetery
Model of Plate Tectonics
boundaries and margins
o read textbook
Convergent margins = 2 plates coming together
o thinner/denser oceanic crust goes under the thicker continental crust, produces
magma plumes which may lead to volcanoes or earthquakes
Divergent boundary = plates separating / moving apart
o most common is 2 plates of continental move apart
o as 2 plates move apart, we get magma and volcanic activity
o on reading on plate tectonics analyze basic anatomy and how the structure is laid
out, focus on convergent, divergent, and transform boundaries