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74 Cards in this Set
- Front
- Back
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What is the definition of a river (or stream)?
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Flowing body of water
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Define a channel
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A river that flows downhill with a definite path
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What is the name of particles and dissolved minerals that are carried by rivers?
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Load
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How can you identify a tributary?
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It is a contributing stream that is always diminishing in size upstream
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What are areas that a river and all its tributaries define?
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The drainage basin
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What 5 major rivers have important drainage basins?
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Mackenzie, Mississippi, Amazon, Nile, and Yangtze
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How can you determine the current direction of a river or stream?
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Using geometry
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What is the boundary between drainage basins called?
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Drainage divide
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What is the difference between a drainage divide and a continental divide?
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A continental divide is where a drainage basin drains in different directions off the continent
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What defines a Endorheic basin?
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A place where water can't get out, such as the Nevada Great Basins.
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Identify the 4 types of drainage patterns and know the difference.
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Dendritic- Gentle slope with uniform materials
Trellis- Resistent ridges Radial- Central uplift Rectangular- 2 directions of structural control |
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What is the definition of discharge and how do you figure it out?
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Discharge is the volume of water passing by in 1 second.
Q= W x D x V Answer is usually in cubic meters |
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What is a hydrograph and what does it do?
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It is an instrument placed adjacent to streams
A hydrograph plots amount of discharge vs. time |
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What is basin lag?
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The time elapsed between rainfall and peak discharge by the river.
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What are the two types of particles transported by rivers?
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Silt/clay
bed loads |
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What are the 3 channel types and what are their characteristics?
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Straight- self explanatory and uncommon
Meandering- Very common (snake shaped) Braided- Where there is lots of sediment that cause river channels to break off and join together, making it look braided |
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What is a flood plain?
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A flat valley bottom
Usually full of alluvium Marks extremes of meandering Prone to flooding so bad for building |
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Where can Deltas and Alluvial Fans be found?
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Where rivers end due to the dropping of sediment
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What weather patterns cause alluvial fans?
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Water sinking or evaporating
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Where are alluvial fans most commonly found?
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In mountainous and desert areas
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What are stream branches called?
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Distributaries
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What is the fundamental concept of groundwater?
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The upper crust is saturated with water from the "water table" down to approximately 10km
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What is the 1st step of groundwater accumulation (infiltration)?
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Water "soaks in" and moves through the Zone of Aeration. This water then continues to move within the Zone of Saturation
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What is the significance of porosity?
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It voids pores within rocks or sediments
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What can be found within pores?
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Air or fluids (water, oil, etc.)
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Permeability is defined by what?
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The ability of sediment or rock to transport fluids. (How connected are the pores)
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What allows permeability?
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Channels between pores (Like rivers are to lakes)
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How quickly does groundwater move downhill?
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Slowly (approximately 1 m/day) but highly variable
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What does groundwater flow fastest through?
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fractures and joints
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What is the Zone of Saturation?
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The area where sediment or rocks is saturated with water (no air filled pores)
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What is the top of the Zone of Saturation called?
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The water table. It directly replicates the topography as well.
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What is above the Zone of Saturation?
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The Zone of Aeration
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Whats the significance of surface water?
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It is basically an "outcropping" of the water table
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What is a perched water table?
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An area where the water can't penetrate. It usually sits above the main water table.
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Where is the water table located?
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Generally at the surface where there's surface water
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What is an aquifer?
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A water bearing layer
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Can aquifer's recharge (water into)?
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Yes, in the form of precipitation. It takes time though.
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What is water that is removed or leaking from an aquifer called?
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Discharge
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What is the name of the large aquifer in the Great Plains.
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Ogalala aquifer
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What is an artesian system?
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An underground area where water flows freely.
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What are springs and seeps?
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"Leaks" in an aquifer. They are where groundwater returns to the surface.
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Ground subsidence has what as an example?
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Sinkholes... Areas where the ground underneath the surface erodes.
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What changes can lead to an ice age?
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Global temperature drop, formation of ice sheets, etc.
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What is the definition of a glacier?
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System of flowing ice that originates on land through accumulation and recrystallizations of snow and ice.
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Why do glaciers move?
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Gravity
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What helps glaciers form?
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More snow accumulating in winter than melting in the summer
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When was the last max extent of global glaciation?
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Approximately 218 ka
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What is the fundamental change that makes glaciers possible?
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Snow--> Firn---> Glacier ice
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What are valley glaciers?
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Narrow tongues of ice in the mountains
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Define continental glaciers?
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1000's of M thick
Covers significant % of continent |
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How fast do glaciers move?
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Typically 0- several M a day.
Sometimes a surge of 200 m/day possible |
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Whats the name for the edge of a glacier?
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Termines
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What do glaciers do to the lithosphere?
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They depress it through isostacy
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How many known ice ages are there?
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5 major ones
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What period of glacial events are we currently in?
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Holocene
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What theories do we have about the forming of ice ages?
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1.Astronomical
suns output Variation in Earth's orbit (Eccentricity, tilt, precession) Interstellar dust clouds blocking sun 2.Atmospheric changes changes in greenhouse gas content volcanic dust in the atmosphere 3.Plate tectonics and ocean currents |
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What do all hypotheses about ice age formation have in common?
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They all address cooling
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What are fossil fuels?
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Remains of plants and animals trapped in sed. rock used for fuel
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What is the key to the formation of fossil fuels?
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Photosynthesis and decay
Leftover carbon is key |
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What is an important step in making sure that organic matter can become a fossil fuel?
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It has to be buried before it has time to decay
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What organic materials form different types of fuels?
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Bacteria and Plankton form oil and natural gas(liquid)
Plans form coal (solid) |
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What is coal?
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A black (biogenic) sedimentary rock
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What percentage of coal is organic material?
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>60%
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Where is coal formed?
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Swamps. And it originates as peat
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What produces higher grade coal?
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Higher % of Carbon
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How much coal is required for a coal bed to be considered economical?
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A few M thick to approximately 30m
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Compaction, drying and heating do what?
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Form better quality coal
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When and where was the first petroleum well made?
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1847 in Pittsburgh
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Describe the oil window.
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From ~80-150 C
Natural gas up to 225 C |
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What is natural gas?
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Gaseous fossil fuel, primarily methane (CH4 70-90%)
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What is oil?
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A mixture of hydrocarbons and organic molecules
(usually ~85% C and 12% H) |
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What percentage of oil is converted to fuels?
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~84%
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What two types of erosion are glaciers responsible for?
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Plucking: Ice picks up rock and soil and incorporates it into the base
Abrasion: ice polishes, scratches, and grooves bedrock |
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What is the definition of load in a glacier?
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Rock and sediment that is suspended in the glacier
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