streams Flashcards
the initial driving force
evaporation and then condensation
sun
mountain range
a streams beginning
source
a streams end another body of water ocean lake River
mouth
landform at mouth that projects into another quiet body of water
Mississippi
Nile
delta
a River and all of its tributaries
River system
a stream that ends in the main River
tributary
the area of land drained by a River system
drainage basin
watersheds
all of the water that falls in a certain watershed will remain in the watershed
basins
ridges that separate watersheds
two major divides (continental) in the US
Appalachians and Rocky Mountains
divide
V-shaped
down-cutting
few tributaries
youthful- stage 1
floodplain develops
more tributaries
mature- stage 2
meandering channel, lots of tributaries
wide floodplain
oxbows and cut-offs
old stage- stage 3
channel and v-shaped valley floodplain point bar cut bank tributaries source mouth and delta meanders and oxbow lakes
parts of a River
water overflows banks and floods the floodplain
caused by heavy rainfall, snow melt
most pronounced in the spring
most erosion occurs during this
flooding
large material carried alon the bed or bottom of the stream
boulders, pebbles, and sand
bed loads
material that is held in suspension
clay and silts
suspend load
minerals that have been dissolved by the water
can’t be seen, must be tested chemically
dissolved load
the amount of water moving by a certain point of a stream
multiply the volume of a River by its velocity and you will get discharge
usually measured in cubic feet per second
speed depends mostly on a streams gradient
volume usually depends on amount of rainfall and drainage basin size
discharge
a period in which ice extends farther than normal
last one began about 1 million years ago
returned to normal about 12000 years ago
Ice ages
cool summers
little or no ice melts
period of cooling
what causes cooling
change in Suns energy
earths tilt, orbit
change in positions of continents
volcanos
leads to cooling of the polar regions
milankovitch cycle
changes CO2 content
less CO2
less global warming gases
reef building
limestone
form in mountains
rivers of ice
alpine valley
ice sheets
cover 100-1000 square miles
Greenland and Antarctica
continental glaciers
grinding of bedrock
Rock is carried by glacier and scratches bedrock
glacial grooves
abrasion
glacier grabs rocks and pulls them out of the ground
pucking
huge, flat areas
Great Plains