Topic 1 Flashcards
active tectonics
ongoing deformation of earth’s crust
passive tectonics
indirect influence on processes and forms through spatial distribution of lithology and structure
does lithology and structure play an important role in active tectonics?
no
magnitude of isostatic compensation of erosion and the spatial scale is related to ___ of the crust
flexural rigidity
Secondary uplift through flexure
load is added at a distance away, resulting in lowering of the crust underneath the load and elevation of the crust
what do climate cycles do across the globe?
they distribute climate systems
attributes of a climate system are
precipitation, temperature, wind speed and relative humidity (RH)
glacial geomorphology
glacial moraines, trimlines, polished surfaces, forebuldges and isostatic response.
coastal geomorphology
sea level RISE: marine terraces
sea level FALL: barrier islands
fluvial geomorphology
fluvial terraces, river knickpoints
how does a river respond to a lowering sea level?
by incising. incision propagates upstream; causing a narrowing of the river valley and formation of terraces
plate tectonics
controls distribution of landmasses and ocean circulation through opening and closing of passages
ice sheets and glaciers
increases albedo
mountain topography
windward side: precipitation, increased runoff, increased mass wasting and lower snow line
leeward side: decreased runoff, rain shadow
volcanic eruptions
brings matter, aerosols, CO2 into the atmosphere. Increasing cloud coverage and decreases solar radiation coming in.
weathering
removal of carbon from the atmosphere, soluble cations and bicarbonate carried into rivers and calcium carbonate formation in the ocean.
weathering
physical and chemical break down of materials
importance of weathering is due to the production of ____, ____ and ____
sediment, by products and soils
what makes weathering a disequilibrium response?
conditions at the surface are very different from those during rock formation
what are 6 types of physical weathering?
pressure release, freeze thaw, thermal expansion, salt crystal growth, biotic, hydration
what are 4 types of chemical weathering?
solution, oxidation, hydrolysis, ion exchange
physical weathering is
the break down of materials into smaller pieces, allowing more surface area for weathering. No chemical composition change.
chemical weathering is
decomposition of minerals through chemical alteration.
driving forces of physical weathering
water and temperature. (climate controlled)
resisting forces of physical weathering
lithology and structure. (rock controlled)
driving forces of chemical weathering
water and temperature
resisting forces of chemical weathering
silicates (look at bowens reaction series)
chemical weathering is strongest with
high precipitation and temperature
physical weathering is strongest with
low precipitation and moderate temperature
soil mantled landscapes form when
rate of soil production > erosion rate
bedrock landscapes form when
rate of soil production < erosion rate
mass movements
form of dominant transport for how weathered materials make it way down to the valley floor
shear strength
magnitude of shear stress that a soil can sustain or overall resistance to movement/deformation.
what happens when water fills the pore spaces?
normal stress decreases
factor of safety
stability of a slope and is the ratio between the forces resisting movement to those drivers
what are 3 types of stresses?
tensile, compressive and shearing
what are 3 common types of strain-stress responses?
elastic, plastic and viscous fluid
dilatant
viscosity increases with shear stress
pseudoplastic
flows as grains re-arrange and pore water escapes
liquefaction
loss of soil strength under shock and leads to fluid behaviour
toppling
brittle failure or plastic rotational stability depends on aspect ratio
slides
failure on distinct shear surfaces with little internal deformation
spreads
more cohesive material sinks into deformable layers underneath
creep
upward heave with downslope displacement
