Glossary of Geology test 3
Other Decks By This User
- Mass Wasting
- Movement, caused by gravity, in which bedrock, rock debris, or soil moves downslope in bulk.
- Most mass wasting that takes place will not be noticable in a lifetime
T or F
- Mass wasting characteristics
- -large volume of material wasting away (declining)
-may be landslides
-movement of material downslope (gravity)
-gravitional pull causes things to move down inclines
- Agent of mass wasting
Help gravity in Mass wasting
- -slope of landscape (flat, gently rolling. steep will cause landslides)
-water involved-if landscape is wet, landslides is more likely to happen here, lubrication
-earth vibrations (earthquakes)
- shear strength
- In mass wasting, the resistance to movement or deformation of material.
- Common types of mass wasting
- 1. flows
-common difference is the mov't of the material
- -drops vertically down; freefall
-just single rocks fall not usually large volumes
- -Rock or sediment moves down the slope with a bit of contact with the slope (not freefalling)
-water does not really play a role
- -a soupy mixture of rock and sediment that forms a lump and moves downhill.
- -many rocks fall
-happens in fall and spring when freezing or thawing tends to happen
- ______ could cause erosion of underneath rock and make the above rocks fall because they have no support.
- Slip/slide characteristics
- -slumps happen in slides
-slips are dry, skip down slopes
-ex. rock slide, landslide, debrislide
-large volume of materials can be involved
-avalanches (some call it this)
- -occur in softer sediment
-material develops a slope that is too steep and mother nature brings it back to a manageable slope through a slow mov't of sections of rocks
- explain forming slopes with sand
- -cannot get steep slopes with sand unless the sand is wet (can only get a 35 degree slope).
-this is part of the processof nature getting huge slopes back to gentler ones.
- explain a Wyoming incident that happened in the 1930's involving a landslide/mudslide
- a shale layer got wet and the land on top of it slid down the slope and became like clay and caused many people to be killed
- Avalaches/landslides made up of __________
- rocks mixed with ice and snow
- Slide is a rapid mov't of loose material
T or F
- Slumps involve large material that is intact. Moving in one clump of material
T or F
- __________ is a good reason to never build close to cliffs
- Mass Wasting (ie slumps)
- Earthquakes can generate _______
- What to flows involve?
- -more water
-water saturated mass
-can take place over a long period of time (creep)
-can cause poles, gravestones to move
- natural downslope movement
- Flows may be called ________ or _________
made up of?
- Debri flows
-made up of fine grain materials and can move 60-70 mph and the flows eventually solidify.
- Ancient flows can be discovered by what?
- the area surrounding it
(vegetation is different)
- Streams usually get ther source from where?
- mountains and then empty into lakes, oceans, etc
- How does the load of the stream differ as you go from the source (mt) to mouth (lake)?
- gets finer as you go from left to right
Gravel->Sand->Silt and clay
- The source has gravel why?
- because the source has the most powerful force and the force lessens as you move away from mountains
- the slope of the stream is usually _______atthe source of the stream than at the mouth
- Stream Loads
- Bed Loads
- -have boulders
-stream not strong enough to move boulders.
-only a flood can move them great amounts.
- Temporary Streams
- -occur where upland meets lowlands
-look for alluvial fans
-it's only a stream when it rains
-the rain brings sediment down and it is added to the alluvial fan.
- Braided Stream
- -channels that twist this way and that b/c there is too much sediment to continue one way. (In alluvial fan)
- When could a permanent stream occur?
- When the water eventually picks one direction to travel.
- -erosional incisions into the landscape that are temporarily occupied by water (when it rains)
-they have the possibility of forming a stream
- -when rills grow in size
-still not a stream, only flows when it rains
-gullies eventually grow and could become streams as they get deeper.
- Where do streams mostly occur?
- they occur in all areas but most form in the mountains where there are steep slopes
- Flat lands
- take awhile for streams to form
- Streams change their appearance over time
T or F
(ex. Yellowstone River and Rocky Mt. Stream)
- Streams that flow from Mountains: their characteristics
- -V-shaped canyon
-no flat areas down at stream level
-relatively straight, controlled by underlying geology (fault lines or beds)
-have pretty steep slopes/gradients
-river will flow faster with many rapids and waterfalls (streams will run into points where erosion is slow to happen and it will be a waterfall that eventually will carve through it)
-rapids used to be streams-still eroding
-no tributaries(side streams)
- Flood Plain
- -overtime the stream starts to meander (erode)
-once meander starts (bends) this begins the flood plain.
-typical of rivers outside of mountains
-DEF. Flat area near stream
- Wide Valleys may occur in Mts.
T or F
(ex. some Pennsylvania mts.)
- In lower area of hills there will be ___ shaped valleys with flood plains carved by streams.
- Water Cycle
- -underground water
-don't typically see it
-ground water is everywhere beyond a certain point
-water fills in pores, spaces in bedrock (with wells this is usually where the water comes from)
- Differences between Surface and Subsurface Water
- 1. Not normally seen -unless pressure drives it out of geologic material
2. Doesn't flow in the same way. Ground water is everywhere and usually not in channels
3. Ground water does not flow in rapids and waterfalls. It really moves slow compared to surface water.
4.Gro. water will commonly be pure. Not bacteria infested but there may be compounds in it that make it taste bad.
5. Temp. in ground water is consistent. Surface water differs at various depths.
6. Gro. water can move up hill (flows up slopes). Surface water cannot b/c of pressure
- 2 major parts of ground water system
- Unsaturated Zone and Saturated Zone
- Another name for Unsaturated Zone
- Vatos Zone
- Unsaturated Zone
- -pores and cracks
-some are wet but they aren't totally full of water
-soil and upper bedrock part still has room for water.
- The deeper you go into the ground the more ________ the rocks become
- Saturated Zone
- -lots of water starts flowing (in a hole)
-could be soil or bedrock
-every pore and crack is filled with water
-cannot get anymore water in there
-the water then continues down and eventually stops existing in a liquid form (become too hot)
-this is where we get ground water
- Water Table
- -Area b/t Uns. Zone and Sat. Zone
-Upper surface of the Sat. Zone)
- The water table is where you _______ see the water
- If the water table comes to the surface where a lake or stream is, what happens?
- -It isn't considered a water table anymore
-only called water table beneath the surface
- What eventually happens to the ground water?
- -it makes it to the ocean and goes back into the atmosphere
- What happens in areas of lower elevation?
(Atmospheric Pressure and Collums of Sediment)
- -they have lower pressure and ground water is moving toward it. (if you have a mt, gro. water moves away)
- Ground Rock
- -gets more pressure than a surface body of water because it has atmospheric pressure and collums of sediment pressing down on it
- Why is ground water slow moving?
- B/c it is soaking from one place to another
- How can you have a well?
- -if the right type of geologic material is present
-you have to drill a long way down if the right kind is present close up
- -A geologic material that readily releases ground water
ex. sedimentary rocks, course grains, conglomerates, sandstone, brechits, sand, pebbles, gravel)
- Sometimes ________ and ______ are good aquifers because it has holes, etc.
- limestone and dolostone
- Poor Aquifers
- Igneous and Metamorphic rocks
- -a geologic material that does NOT readily release groundwater.
-shale, budstone, fine grains
- The only way to get Igneaous and Meta rocks to be good aquifers is to what?
- -they must have fractures
- How were some earthquakes in Denver formed?
- -Igneous rocks had many fractures and water came into the pores
- What do you do to ensure you will have enough water when you have a well?
- -drill deep into the rock because water tables fluctuate
- Water tables at the surface cause_________
- Artesian System
- -rise in water level b/c the water is already experiencing great pressure so water could flow out of the well (higher than anticipated)
-water in well simply has to be at a higher level than the normal water table (doesn't have to be flowing)
- How do aquitards react to rain water?
- they reject it cause they don't hold much water
- How do aquifers react to rain water?
- they absorb it
- Cone of Depression
- -ground water system changes over time (causes a cone of depression)
-this is where the water level lowers.
-over time you'll have to dig deeper.
- What happens if there is overuse of a well?
- -the water table and entire water level decreases and the well may dry up
- Pollution of ground water
- -surface water can be cleaned easily by stopping sources of pollution and let mother nature finish cleaning it.
-difficult to clean up b/c pollution is in all the pores and cracks
-it will take eons to clean it
-so slow moving that it will take years to discover if the ground water in certain areas is polluted
- what is a common contaminate of ground water?
- -dumps (toxic chemicals seep into the ground)
-oceans cause salty ground water
-gas can leak into gro water
- Ground water and dissolve bedrock and form _________
- How do caves form?
- -rain water mixes with CO2 and causes carbonic acid and then that begins mixing with the soil which allows it to mix with more CO@. Eventually this is strong enough to corrode limestone, dolostone, and other bedrock
- For caverns to happen you need 4 things
- 1. Limestone or dolostone have to be present and close to the surface
(caves are vertical first and then go lateral)
2. Sufficient rainfall-helps if the climate is a little warm in summer so best in tropics.
3. Need active streams with in the region that are causing downcutting. necessary to keep the water table moving.
4. We need geologic time for caves to develop. (most occured in cenozoic time)
- Water does what in order to form caves?
- -carves through soil to form shafts then water goes lateral and begins the caves
- Caves at the water table will be what?
- filled with water and unexplorable
- potholes on the earth's surface
- Sinkholes develop in 2 ways
- 1. slow sinking variety-dissolving of rock in ground
2.collapse sink holes-may collapse (disolved rock)-bug cave may sink
- Sink holes could:
- -cause houses to sink
-could happen suddenly (in front yard for instance)
- caverns only develop where?
- in soluble rock
- -a hill
-refers to landscape features that are related to ground water
- In a lot of karst systems, what is happening?
- there are not any streams on the surface; they are all running into the caves.
- stream coming up from down below
- -Iciclelike pendent of dripstone formed on cave ceilings
-made of calcium carbonate
- cone-shaped mass of dripstone formed on the cave floor, generally directly below a stalactite.
- If a cave is dry, then what?
- it is dead; it's not growing anymore
- Calcite precipatated by flowing water on cave walls or floors.
- Where will you find water in karsts?
- -won't know it's one until you see disappearing streams
-may find water in the depressions
-ponds may go directly into caves
- terra rosa
- -reddish-brown to orangish soil the often indicates a karst landscape .
-when you combine H2O and CO2, the rust begins and colors the soil rust colored.
- __________ is the largest cave system in the world
- Mammouth Cave
- Tropical Karst
- -water leaves little mountains standing because that rick was resistant to dissolving
(pic in china)
- Soda Straws
- -the beginnings of stalactites that eventually get plugged up
- How can some ground water be hot?
- there is magma underground in some places like Yellowstone that causes the water to heat and geysers to form and hot springs.
- explain geysers
- they explode through igneous rock and recipitates as geyserite (not a carbonate)
- Most of North America was formed with ____________
- How do glaciers form?
- -form in mountains and flow down valleys
-formed in polar latitudes (canada, etc) then went down to Ohio River
- a moving mass of ice that must me a minimum of 300-500 ft thick
- Glaciers begin where?
- 1. high up in mountains
2. polar latitudes (north or south poles)
-somewhere where the temp is low overtime and there is lots of snow
- steps to forming a glacier
- 1. Need snow-that sticks around all year so it will accumulate
2. after it reaches several feet thick, the snow begins to gradually form a granular snow (not snowflakes anymore)-occurs because of pressure
3.then it changes to Firn-an icy type of snow. tiny particles that move around. (several hundred feet)
4. Firn begins to melt into each other to form glacier ice. needs to be thicker still. need around 250 ft of thickness and then glacier can move in plastic flow
- Plastic Flow
- -glacier moving like plastic
-oozes from one place to another
- The slope of glaciers do what?
- decrease from the center (the source)
- Glaciers are moved by what?
- -gravity and pressure
- Continential Ice Sheets
- -what covers Anartica
-expand and will move out of region
-will get a great ice age
-Antar. has almost 4 miles of ice
- Ice Shelf
- -an area of floating ice
-makes continental look bigger than it actually is
-movement of ice is similar to ground water (begins vertical at the top then goes lateral)
- When glaciers get to the ocean level, pieces break off to form _________.
- Alpine Glaciers
- -AKA mountain and valley
-glaciers found in mountains
-glaciers are restrained by the landscape
-can tell a glacier was in a mountain range if there is a U-shape valley instead of a V-shaped one
-don't get thick enough to flow out of valley
- Rigid Zone
- -upper part of glacier (AKA the brittle zone)
-Ice up there is solid and tends to break
- Zone of Plastice Flow
- -In lower part of glacier that seems like plastic
-pressure is great enough to create a plastic flow (the part of the ice that moves)
- -long, vertical breaks
-open fissure in a glacier
-lower part of a glacier can flow around big masses of rock while the rigid zone has many cracks from it
- glaciers prolly move how much during a year but a few can actually move how much?
- prolly move a few inches
some move a couple hundred feet
- Explain the friction felt by glaciers
- -More friction is byt he valley walls and at the bottom of glaciers so that the ice doesn't flow as fast as the ice in the middle
- Surging Glaciers
- -glaciers that could move a couple hundred feet in a matter of months
-usually riding on water, not attached to the ground with ice
- _________ cut the inital valleys and _______ come later
- Where does glacier development happen the most?
- -in the north part of the mountains
-prolly the NE side because little wind
- -where most glaciers begin
-enlarges overtime by water freezing on the rocks in the deep U-shaped valley
-upper most part of glacier
-high in mountains, walla of rocks
- Glacial Valley
- -when the glacier becomes too big for the cirque it flows into the adjacent valley.
- What is the result of the snow and ice being removed from a cirque?
- -a deep U-shaped depression
- Hanging Valley
- -valley occupied by smaller glaciers that have not been deepened as mich as others
-you'll presently see a waterfall there.
-the valleys cannot carve theirs as deep as the main valley
- One glacier flows into other glaciers like a little stream flowing into a larger one
T or F
- There are all types of erosion
- -glacier valleys
- -sharp mountainous peak
-develop from alpine glaciers
-created by glaciers eroding away (in the cirque)
- -a long ridge (sharp)that come to a bladed edge
-ridges that radiate out from a horn and form the sides of a glacial valley
-separate adjacent galcial valleys
- Lakes are associated with ______
- -a glacial lake that is in a crique
- Pater Noster Lakes
- -a series of glacial lakes
-look like a chain of blue beads
-each at a slightly differnet elevation
-streams link the pater noster lakes together
- Alpine glaciers change the landscape ___________
- Running water is the most important geologic agent in ______, _________, and ______________
- Almost every landscape on earth shows results of _________________ or __________.
- stream erosion or deposition
(dominant processes of this are streams and mass wasting)
- Hydrologic Cycle
- the movement and interchange of water between sea, air, and land
- Solar radiation provides what?
- the necessary energy for evaporation
- a body of running water that is confined in a channel and moves downhill under the influence of gravity
- longitudinal profile
- a typical stream viewed from the side
- the upper part of a stream near its source in the mountains
- where the stream enters the sea
- cross section
- a V-shaped valley cut into solid rock
- sediment deposited by the stream
- a thin layer of unchanneled water flowing downhill
- drainage basin
- the total area drained by a stream and its tributaries
- tributaries that have a pattern that resembles branches of trees or nerve dendritics (V or Y)
- radial pattern
- streams diverge outward like spokes of a wheel, forms on high conical mountains, such as composite volcanoes or domes.
- rectangular pattern
- tributaries have frequent 90 degree bends and tend to join other streams at right angles, develops on regularly fractures rocks
- trellis pattern
- parallel main streams with short tributaries meeting in right angles.
- stream erosin and deposition are contorlled primarily by what?
- a river's velocity and to a lesser extent its discharge
- velocity is controlled by what?
- a stream gradient (the downslope of a bed), channel shape, and channel roughness
- the volume of water that flows past a given point in a unit of time
- hydralic action
- refers to the ability of flowing water to pick up and move rock and sediment
- the grinding away of the stream channel bu the friction and the impact of the sediment load
- bed load
- course particles that wind can move over the surface of the earth (sand and small pebbles)
- movement by rolling, sliding, or dragging
- a series of short leaps or bounces off the bottom (to move downstream)
- suspended load
- sediment that is light enough to remain lifted indefinitely above the bottom of the water turbulence
- dissolved load
- the portion of total sediment load in a stream that is carried in a solution.
- a ridge of sediment
- placer deposits
- found in streams where the running water has mechanically concentrated heavy sediment
- the capacity if a rock to transmit a fluid such as water or pertoleum through pores and fractures
- vadose zone
- the unsaturated zone above the water table
- Depositional features
- the deep gashes made by frozen rocks in the glacier running over a softer rock (scratches)
- lakes that have formed in criques
- unsorted and unlayered rock debris carried by a glacier
- a landform made up of tills
- Till Characteristices
- -mixed up substance (rock, stone, and fine grain material)
-in glacial deposited material
-everything stays together
-the ice does not sort these materials like water does
-has different sized and kinds of substances (like igneous, sedimentary, and metamorphic in it-not just sedimentary)
- moraines are often visable even if what happens?
- even if ice is still there.
(may be sitting on top of the ice)
- lateral moraines
- -tehy are on either side of the valley
-made of debri sliding off mountains and landing on glaciers
- medial moraine
- -if glaciers come together, 2 of the lateral morraines (each glacier only has 2) become one and go down the center of the glacier
-could have more than one medial moraine
- end moraines
- -till that runs across the bottom of glaciers
-perpendicular to the glacier
-typically occur at the end of the glacier
-could be more than 1
- How do glaciers usually move?
- they flow from the crique (source) to end
- what is really happening when it looks like a glacier is moving uphill?
- it really isn't it just cannot keep up with the melting and they appear to then be moving up
- advancing glacier
- as long as the glacier is accumulating more than it's melting the glacier will grow
- if a glacier is advancing or retreating, there cannot be what?
- an end moraine
- receding glacier
- if there is more melting, the glacier will decrease over time
- what is the true equilibrium of a glacier?
- when it never seems to be receding or advancing over time
(melts at same pace as it accumulate)
- when is the only time you will really get an end moraine?
- when the glacier is at equilibrium
- recessional and terminal moraines are what?
- special end moraines
- terminal moraines
- the furthest the glacier goes
- recessional moraines
- the place that a glacier recedes to
- ground moraine
- -till that is laying underneath a glacier (unseen until ice melts away)
-not very thick layer
- As glaciers melt, what kind of water will be running off of them?
- strong torrents that carry sediment with them
- -water deposited materials that some from melting glaciers
-sand and gravel usually
- Outwash ______layering while till_________
- good examples of glaciers dropping into the ocean and breaking off into icebergs
(some till goes with the icebergs and everything settles eventually on the ocean's bottom)
- Scandanavia and Norway
- kettle lakes
- as glacier recede they may leave huge pieces of ice that leave depressions in the land that water eventually fills adn they become lakes
- sandy, gravely hills formed from till and outwash going into holes in the glaciers
- what won't you find on continental ice sheets?
- horns, sheet, end moraines
- COntinental ice sheets are not stopped by landscapes so what won't you see? what may you see?
- -horns, etc
may see striations and glacial groups
- -sinuous ridges
-tunnels that weave into ice.
-they drain the melt water
- -pills of till
-usually thick hills
-usually have a steep slope or a very gentle one
- Outwash Plain
- -not till
-better sorted debri
-beyond the end moraine
- Glacial Erratics
- -large hunks of till that glaciers leave behind after they melt
- Where is there many hills formed by glaciers and their deposits of till?
- SW Michigan
- the last age began how long ago? when did it end?
- -a couple million years ago
-a few thousand years
- the north american glacier covered how much of US?
- the upper part, not the southern states
- how can you track a glacier?
- by checking the end moraines
- ___________ can erode rock
- sandblasting (sand storms)
- wind usually has what kind of load and explain it
- a suspended load and this means it carries smaller particels than sand and overtime this can erode rocks
- Why does wind have it's greatest affect in deserts?
- because there is little vegetation
- wind abrasion
- -wind constantly abraids the rock
-rock may have a skinny center (hour glass)
-crazy shaped rocks
-can cause overhangs
- Holes in rocks are caused by what?
- they have been gauged out of that part of the rock
- Sand Dunes
- material eroded from rocks that are being blown around by wind
- -caused by wind.
-moves material like sand
- form of a dune migrates how?
- in the direction of the wind
- dunes typically have what kind of angles?
- 30-34 degree ones
- 4 types if dunes
- tips of the cresent point in the direction the wind is blowing
- tips in the direction from which the wind is coming (opposite)
- dune ridge is perpendicular to wind flow
- dune is parallel to wind flow
- 3 features that determine what type of dune develops
- 1.vegetation covering the surface
2.strength of wind
- ________ and ___________ dunes are seen where?
- parabolic and transverse
- ________ and _________ dunes are formed where?
- barchan and longitudinal
- cross bedding
- -tells us that the dunes are continually migrating.
-the layers run into each other
- complex sand dune
- -cannot figure out what type of dune they are
- a steep slope is always _______ of the way the wind is blowing
- dunes can be present in mountains, shorelines, and deserts
T or F
- -fingerlike projection where one end is attached to land and the others are in just water
- wind comes in and moves vast amounts of sand (blowouts)
- Blowout Area
- area that used to be covered by great amounts of sand
- Desert Pavement
- -what's left after the wind blew away everything it could move
-rocky sand-chunks of rock and little sand, no dunes
-may happen after deflation
- -wind abraided rocks or stones
-wind cannot move them so it abraids them
- -silt material
-sometimes associated with deserts or glaciers
-people can dig houses into them
- Rain Shadow Deserts
- -a few deserts associated with rain like the Rockies
-happens because clouds lose all rain in the mountains and do not have any for land so this causes some deserts
- -lots of valleys and gullys
-almost no plants
-when it rains there are torrents and mass erosion that cause jagged, irregular shapes
- Southern rocks are pretty flat and develop isolated knobs of rocks called what?
- plateaus, mesas, buttes, or pinnacles
-these happen where there is low vegetation and rain
- In southern areas, stream channels may be what?
- an up-raised block bounded by normal faults
- downdropped block bounded by normal fault
- horst blocks
- graben blocks
- overtime what happens to the uplifted rocks?
- they wear down
- -loose material that builds up so you can't tell alluvial fans from one another
- Rock in which sediment (Bajhada)sits on
- -temporary pond or lake that may develop in the lower lying land.
- What controls wind?
-does it always go the same direction?
-erosin features as well as depositional features are associated with wind
- shorelines are a _________________
- depositional agent
- what happens in long standing bodies of water?
- waves are cause by what?
- -wind or gravitational pull (tides)
-most important depositional feature in lakes and oceans
- currents are often present in lake and oceans
T or F
- What kind of motion do water particels travel in on there way to the shore ( in waves)?
- Water molecules closer to the surface of the water have a ________ radius
- Wave Base
- -where water no longer moves
- Circular movements of waves help the waves do what?
- -go up and down
- wave length
- -the distance between 2 crescent waves
- wave base = ___________
- 1/2 wave length
- water doesn't cause much erosin unless what?
- it's moving
- Long Shore Currents
- -are present when the waves come in at an angle
-they move out of the acute angle
-these are strong enough to carry sand
-this is why the sand is spread so evenly
-where the waves are breaking
- When the wave base equals the depth of the water, the waves will ________
- slow down
- Waves are forced to break and collapse when?
- -when the water on the bottom of the wave hits the bottom of the ocean (shallow bottom) and slows down and the water on top keeps going
- What happens to waves in shallow water?
- -the wave height increases and speed (velocity) slows down because there is still the same amount of water but less room for it
-there is more friction on waves so they don't move as fast
- sand moves in a zigzag pattern because ____________
- waves both carry it on and off the beach
You must Login or Register to add cards