test 3 study guide Flashcards
drainage basin
Total area drained by a stream and its tributaries
meander
A pronounced sinuous curve along a stream’s course.
floodplain
A broad strip of land built up by sedimentation on either side of a stream channel.
saltation
A mode of transport that carries sediment downcurrent in a series of short leaps or bounces.
recurrence interval
the average time between floods of a given discharge
point bar
A stream bar (see definition) deposited on the inside of a curve in the stream, where the water velocity is low.
delta
A body of sediment deposited at the mouth of a river when the river velocity decreases as it flows into a standing body of water.
traction
Movement by rolling, sliding, or dragging of sediment fragments along a stream bottom.
Braided stream
A stream that flows in a network of many interconnected rivulets around numerous bars.
Alluvial fan
Large, fan-shaped pile of sediment that usually forms where a stream’s velocity decreases as it emerges from a narrow canyon onto a flat plain at the foot of a mountain range.
Passive margin (E)
A margin that includes a continental shelf, continental slope, and continental rise that generally extends down to an abyssal plain at a depth of about 5 kilometers.
mid-ocean ridge
A giant mountain range that lies under the ocean and extends around the world.
active margin (W)
A margin consisting of a continental shelf, a continental slope, and an oceanic trench.
turbidity current
A flowing mass of sediment-laden water that is heavier than clear water and therefore flows downslope along the bottom of the sea or a lake.
aseismic ridge
Submarine ridge with which no earthquakes are associated.
continental shelf
A submarine platform at the edge of a continent, inclined very gently seaward generally at an angle of less than 1°.
abyssal plain
Very flat, sediment-covered region of the deep-sea floor, usually at the base of the continental rise.
seamount
Conical mountain rising 1,000 meters or more above the sea floor.
Seamount
Conical mountain rising 1,000 meters or more above the sea floor.
Crevasses
Open fissure in a glacier.
artesian well
A well in which water rises above the aquifer.
Recahrge
The addition of new water to an aquifer or to the zone of saturation.
subsidence
Sinking or down warping of a part of the Earth’s surface.
sinkhole
A closed depression found on land surfaces underlain by limestone.
aquifer
A body of saturated rock or sediment through which water can move readily
discharge
In a stream, the volume of water that flows past a given point in a unit of time.
cone of depression
A depression of the water table formed around a well when water is pumped out; it is shaped like an inverted cone.
desert
A region with low precipitation (usually defined as less than 25 centimeters per year).
Mesa
broad, flat-topped hill bounded by cliffs and capped with a resistant rock layer.
Playa
A very flat surface underlain by hard, mud-cracked clay.
flash floods vs regular floods
flash flood covers smaller area and is over and done very quickly.
Understand how gradient affects velocity, and how velocity affects a streams ability to erode, transport, and deposit sediment
High velocity = large grains
high velocity streams are dominated by erosion and transport low velocity are dominated by transport and deposition
Name describe, and understand the different ways in which a stream transports sediment.
Bed load- gravel and sand
Suspended load- silt clay muddy water
Dissolved load- soluble products of chemical weathering, ions, invisible, present in all streams.
Understand the concepts of downcutting, base level, and lateral erosion, and how they are interrelated.
Downcutting- A valley-deepening process caused by erosion of a streambed.
Base Level- theoretical limit of downcutting
Lateral Erosion- Erosion and undercutting of stream banks caused by a stream swinging from side to side across its valley floor.
Understand the concepts of downcutting, base level, and lateral erosion, and how they are interrelated.
Downcutting- A valley-deepening process caused by erosion of a streambed.
Base Level- theoretical limit of downcutting
Lateral Erosion- Erosion and undercutting of stream banks caused by a stream swinging from side to side across its valley floor.
Know stream terraces’ relationship to base level.
Stream terrace is a response to drop in base level. When base level drops a stream that is meandering will renew downcutting and carve a new lower flood plane and leave the older one up high as a terrace.
Be able to identify three basic drainage patterns and what they indicate about the underlying geology.
Dendritic- horizontal sedimentary rock
Radial- volcanic landforms
Trellis- folded sedimentary rock
Know the definitions of and difference between porosity and permeability.
porosity- the amount of rock that is openings, ability to hold water
permeability- ability to transmit water, requires connected openings
Understand what the water table is, including its position in space and time.
its the underground level of water, upper surface of the saturated zone. Generally deeper at high elevations and shallower at low elevations.
Know and be able to identify the subsurface groundwater zones.
Water table- The upper surface of the zone of saturation.
Saturated zone- A subsurface zone in which all rock openings are filled with water.
Unsaturated zone- A subsurface zone in which rock openings are generally unsaturated and filled partly with air and partly with water; above the saturated zone.
unconfined aquifer- closer to surface, recharge can easily get in, fluctuates with weather
confined aquifer- separated from the surface by confining layer, recharge passes through aquitard, deeper fewer fluctuations.
Explain how some rock/soil can purify contaminated (sewage) GW and why others can’t. speed/velocity
Some soil/rocks are too permeable and the water passes through so fast the micro organisms don’t have time to cleanse.
Be able to explain the origin of caves, including information about rock type and relationship to fractures
Soluble rock: Gypsum, halite, dolomite, limestone
Groundwater
Fractures
List the three steps/phases in the formation of glacial ice.
Snow
Firn (takes about a year to form, is the partially compacted granular snow)
Ice
Understand the relationship of glacial budget to glacial advance/retreat.
Positive budget means glacier is accumulating more than losing so it grows
Negative budget means opposite so it shrinks
moraine
A body of till either being carried on a glacier or left behind after a glacier has receded.
till
Unsorted and unlayered rock debris carried by a glacier.
outwash
Material deposited by debris-laden meltwater from a glacier.
outwash
Material deposited by debris-laden meltwater from a glacier.
Sea Level
Sea level rises as glaciers retreat and drops as glaciers advance.
What is the dominant agent of land sculpture in deserts?
running water
What is the dominant rock structure (orientation) in the Colorado Plateau?
Horizontal sedimentary rock
Rock structure in the CO Plateau results in what types of landforms?
Canyons, mesas, and buttes
Explain two reasons that wind is more effective in deserts than humid regions.
wind is less dense than water, stronger, less vegetation, and wind can’t pick up wet seds
