GEOG 205 final Flashcards
define geomorphology
the study of the form of the earth
describe the driving mechanisms of geomorphology
climate/atmosphere, tectonics, biotic, gravity
describe the difference between uniformitarianism and catastrophism
uniformitarianism (James Hutton) believes changes are due to continuous, smaller-scale actions, catastrophism (Georges Cuvier) believes changes are due to sudden, catastrophic, large-scale events
define the processes and forms
processes operate on variable time and space scales, forms are the result of process, driving forces, and setting
understand why studying geomorphology is relevant
hazard assessments, water quality, planetary studies of landforms, climate records, and agriculture
define and provide examples of isolated, closed, and open systems
isolated - energy cannot cross system boundaries (universe)
closed - energy can cross, but no substantial change (earth)
open - both matter and energy can cross boundaries (river)
define negative and positive feedbacks
negative - discourages change in system, self-regulates
positive - encourages change in system
understand the concept of thresholds and equilibrium
thresholds - intensity that must be met for a certain reaction or result
equilibrium - the idea of a self-correcting balance
describe the relationship between drivers and resistances to landscape change and list the forces of each
increase driving force and/or reduce resting force = rate increase and vice versa
drivers - climate, gravity, internal heat/tectonics
resistances - lithology, vegetation, structure
describe the role of time, magnitude, and frequency in landscape change
time - variable levels of time are required for products of change
magnitude and frequency - frequent events have low magnitude (strength), high-magnitude events are more rare
define denudation
any process that wears away landforms and results in decreasing the elevation and relief of a landscape
describe differences/similarities between weathering and erosion
weathering - in-situ breakdown of earth forming materials
erosion - relies on transporting agents and gravity
describe key factors that control weathering
parent rock material, climate/setting, soil, and length of exposure
define the two types of weathering
physical - mechanically breaking down materials
chemical - chemical alteration of composition through different reactions
describe the six types of physical weathering
pressure stress release, thermal expansion and contraction, salt weathering, hydration, freeze-thaw, plants
describe the different types of chemical weathering and provide an example for each
oxidation (iron -> hematite), hydrolysis (water), carbonation (carbon), cation exchange (holding + ions), chelation (materials binding together)
explain why weathering is important in geomorphology
it plays a large process in the creation of soil and landforms
understand the role of weathering in soil formation
need both physical and chemical breakdown to make soil
define soil forming factors
climate, organisms, relief, parent material, and time
define cohesion and adhesion
cohesion - attraction of water molecules to other water molecules
adhesion - attraction of water molecules to solid surfaces
describe differences between clay and sand particles
clay - flat, disc shaped, high surface area, high adhesion, water moves slowly
sand - round, more conductive pore network, low surface area, low adhesion, water moves faster
define mass movements in force balance terms (driving vs resisting forces)
collective term for all gravitational downslope movement of materials, with little or no transporting agent (reference diagram)
what are the basic forces involved in slope stability
shear force - pushing downslope
normal force - pushing into slope
differentiate the main categories of mass movement processes and landforms
heaves - soil creep, solifluction, gelifluction
falls - rock falls, rock topples
slides - translational, rotational
flows - debris flow, mud flow, earth flow, lahars avalanches
define source and sinks in a geomorphology context
sources are where sediment starts moving (erosion) and sinks are where sediment stops moving (deposition)
define key characteristics of a watershed
topographically defined, inputs do not always equal output, watersheds drain into a single common outlet, reference diagram
describe the importance of watershed morphology in understanding geomorphologic processes
watersheds can show key processes at play (weathering and erosion) and parent material and its resistance
what is the equation for calculating drainage density?
drainage density = (channel length)/(area)
describe different drainage patterns and where they might form/what controls their morphology
dendritic - tributaries join larger streams at acute angles
parallel - tributaries form parallel to slope surface
trellis - synclines form valleys
radial - tributaries extend headward reaches upslope toward top of elevation
rectangular - tributaries make sharp ends to enter main channel
centripetal - stream flows downwards towards a central depression
deranged dendritic pattern over run by glacier
define hydraulic actions and abrasion and where they occur in the system
hydraulic action - erosion due to flowing water only (upstream tributaries at highest elevations)
abrasion - debris movement, particles grinding out the stream bed (downstream)
what are the driving and resisting forces in channels?
gravity, planes of weakness, friction of grains, bedforms, channel shape, vegetation