Physical Geography

Geography
All processes related to river flow
erosion, transportation, deposition
river flows are affected by
climate, solar insolation, bedrock
alluvium
all material deposited by rivers
surface runoff is affected by
spring melt, infiltration capacity, and interception, intensity/duration (of the storm), topography, evaporation, and soil
Sheet erosion
initial down slope, unchannelized flow
rill erosion
turbulence causes increased erosion
gully erosion
rills coalesce and become larger
stream flow
erosion by stream or river channel
perennial flow
a stream that flows all year round
ephemeral flow
a stream that only flows at certain times
drainage basin
region that contains a river and all of its tributaries
source of the river
mouth, the start of the system, headwaters
base level of a stream
ultimate level, sea level
drainage divide
the zone or line where water drains in separate directions; perimeter of a basin often marked by ridges
continental divide
marks major changes in flow directions of major river systems
six types of drainage patterns
dendritic, trellis, multiple channels, centripetal, rectangular, deranged
drainage pattern
spacial arrangement of stream distributions
stream discharge
volume of water flowing in a stream at any given time (Q = width * depth * average velocity)
stream discharge is affected by
shape, topography, climate, vegetation, rock type, and land use
stream erosion
removal of rock material by flowing water
hydraulic action
physical process of water alone removing pieces of rock
abrasion erosion
fragments of rock grind each other
stream transportation
all streams and rivers, regardless of speed of flow, will move sediment
dissolved load
minerals carried in stream (dissolved)
suspended load
sediments moving in the flow without contacting the bottom of the stream bed
bed load (saltation)
sediments bounce along the bottom of the stream bed
bed load (traction)
sediments rolling along the bottom of the stream bed
stream deposition
rivers deposit sediments within channels or on their flood plains
types of stream deposition
alluvium, flood plains, levees, sand bars
levees
occur when rivers overtop their banks and deposit sediments in a ridge next to the channel
flood plains
over bank deposits only occur when rivers flood their banks
bars
any deposits with a discernible shape deposited through bed load; usually composed of sand or gravel
kinetic energy in streams
ability to erode and transport sediment; energy of motion
stream gradient
elevation change; headwaters
stream roughness
friction at the bottom and sides of channel
stream load
sediment being transported
stream competency
maximum particle size of sediment
stream capacity
total load ability of sediment
straight stream channel
very stable but highly unusual
meandering stream channel
occurring on relatively flat terrain, frequently have broad flood plains
braided stream channel
occur on relatively steep terrain
meandering stream
most common in humid climates; swings back and forth across a valley
stream hazards
mostly from flooding events; flash floods and long term floods
glaciers
large mass of ice that flows slowly from its origin to its margin due to gravity and other factors
glaciation
a period of extended ice cover
causes of glaciation
milankovitch cycles, tectonic activity or catastrophic events
ice sheets and ice caps
continental glaciers that engulf entire landscapes
valley glaciers
can emit from ice sheets and ice caps or have their source in a single cirque
marine glaciers
those that terminate in water such as an ocean or lake
glacier mass balance
related to the growth and decay of glaciers, accumulation and ablation zones
creep/ice deformation flow of glaciers
weight of the ice pushes it along
sliding flow of glaciers
water is melted out of the ice onto its bed, lubricates the bed and allows the ice to move, more water the faster the movement
types of glacial erosion
plunking and abrasion
types of glacial transportation
freeze on the ice and then melt out; meltwater flow
type of glacial deposition
outwash plains, end moraines
glacial plunking
chunks or rocks are plucked from their sources and frozen into ice; occurs commonly on down flow of small hills and results in oversteepened downflow slops
glacial abrasion
the dragging of ice and rock along rock surfaces creating striations
alpine landforms
formed by valley glaciers and outlet glaciers
continental landforms
formed by ice sheets
glacial depositions
end moraines, till plains, outwash plains
cirques
head of the glacier; frost shattering and ice movement carves this
tarns
lakes that are created at the bottom of glaciers
arete
where cirque walls adjoin from opposite sides to form this knife-like ridge
horn
the intersection of three or more aretes to form a point
end moraine
deposit of glacial material laid down as a ridge that marks the furthest extent of glacial ice
recessional moraine
marks the retreat positions of glacial ice
interlobate moraines
moraine that forms between two lobes of ice
drumlins
elongated mounds that form parallel to ice movement
eskers
deposition of ridges of sand and gravel from a river that moved in or beneath the ice
kettle hole
a lake resulting from buried ice that has melted
p-waves
compressional waves, back and forth movement
s-waves
transverse waves, up and down movement
structure of the inner core
iron and nickel, solid due to pressure
structure of the outer core
liquid iron
structure of the mantle
largest of interior zones of the earth; contains the asthenosphere and lithosphere
asthenosphere
(without strength) molten plastic material
lithosphere
upper mantle and crust; movement causes tectonic activity
mohorovicic discontinuity
moho! boundary between crust and mantle, designates differences in density
structure of the crust
exterior of the lithosphere, density differences (continental crust [granite] and oceanic crust [basalt])
minerals
naturally occurring substances with unique forms
ways to distinct difference in minerals
hardness, luster, cleavage, shape, and color
rocks…
aggregation of various minerals and pieces of minerals
three types of rock
igneous, metamorphic, sedimentary
igneous rock
molten rock solidifies; extrusively formed from volcanic activity at the earths surface; intrusively formed within the earths surface
sedimentary rocks
accumulation of sediments that is either compacted or cemented together
clasitic rocks
fragments of pre-existing rocks formed together
organic rocks
lithified organisims (fossils)
chemical rocks
dissolved minerals
stratification
process of layering
bedding planes
boundary between sedimentary layers
cross-bedding
substantial angles as opposed to parallel layers
unconformity
irregular or discontinuous boundary
metamorphic rock
changed state, formed due to heat or pressure; very hard and compact
foliation
wavy bands in metamorphic rocks
relief
high or low features in the earth
endogenic process
originates within the surface and increases relief
exogenic process
originates at the surface and decreases relief
lava flows
dome of magma, flood basalts, fissure regions, small potential to be explosive
shield volcanoes
large and gently sloped, mostly composed of lava flows, hawaii
cinder cones
small cone shaped hills that form ash and pyroclastic flow explosions
composite cones
explosive, lava and pyroclastic flows, concave slopes that are gentle at base and then steep at the top; composed of alternative layers of solidified lava, ash, and cinders
calderas
sunken central portion of a volcano, often contains a lake, sides are very steep
hypocenter
zone in the earth where the earthquake originates
epicenter
zone on the surface where the earthquake originates
scale used to measure earthquakes
richter scale

Leave a Reply

Your email address will not be published. Required fields are marked *