EAPS 111 Exam 3
Within a glacier what is the primary force driving its motion? (This force acts on all of us.)
Gravity
What role does friction and cohesion play in slope stability?
FIND ANSWER
What kinds of areas near Purdue are prone to slope failures and why?
FIND ANSWERS
What is flood stage in terms of height and discharge?
Flood stage- amount of discharge required for stream to overtop its bank and spill out onto the floodplain
Lateral moraine
Forms along sides of glaciers, dark fringe of rocks and other debris
How is most freshwater used in the United States?
Irrigation, thermoelectric power, public and domestic use, industrial use, aquaculture, mining, livestock
Medial moraine
Sediment rich belt in the center of the glacier, forms where 2
What occurs in the major processes of the hydrologic cycle (Precipitation), and where do they occur and how are they related?
a. Driven by the sun b. Clouds cool perhaps when they rise over a mountain, the water molecules become less energetic and bond together and fall as rain, snow or hail depending on temp, it may reach ground, evaporate as it falls or be captured by leaves an dother vegetation before reaching ground
What occurs in the major processes of the hydrologic cycle (Inflitration) and where do they occur and how are they related?
a. Driven by the sun b. Some precip seeps into ground through fractures and pores in soil, sediment and rocks, some becomes groundwater, some remains in soil, and some rises back to surface
What occurs in the major processes of the hydrologic cycle (runoff)
a. Driven by the sun b. runoff- rainfall or snowmelt can make water that flows across surface as runoff, (from direct precip it can be joined by runoff from melting snow and ice and by the flow of groundwater onto the surface and this runoff is carried into ocean by rivers where it can be evaporated
What occurs in the major processes of the hydrologic cycle (Evaporation)
a. Driven by the sun. b. evaporation- water is heated by sun and molecules become energized and break free of attractive binding forces and they rise into atmosphere as water vapor
What is wave refraction and how does it contribute to generating longshore drift of sediment?
a. Refraction is the bending of waves because of varying water depths underneath. The part of a wave in shallow water moves slower than the part of a wave in deeper water. So when the depth under a wave crest varies along the crest, the wave bends. b. waves bend if they approach shore at angle- waves almost always approach shore at angle. i. as waves begin to encounter bottom the segments closest to shore are slowed more in segments in deeper water and difference in velocity causes initially straight waves to refract (bend), becoming more parallel to the shore c. if waves approach coast at angle the sediment is moved laterally (longshore drift) i. forms sandbars, barrier islands, spits (waves and longshore currents transport sand and other beach sediment along the coast making a long and low mound of sediment that lengthens in the direction of prevailing longshore current, if it cuts off a bay it becomes a baymouth bar, if sea level rises the bar wil become a sandy barrier island)
How do river terraces form, and what do they signify?
a. They are older stranded floodplains perched above current floodplain b. terraces- flat benches that are perched above a river or stream and stair step up and out from active channel, made of river derived sediment and are abandoned floodplains and alluvial plains c. step one- deposition of sediment (on floodplain), here, river is nearly at same level as floodplain d. step 2- change in conditions like drop in base level causes river to downcut through floodplain deposits forming second lower floodplain, 1st floodplain is stranded on both sides of river and are unlikely to be flooded again e. step 3- more downcutting and river abandons second floodplain making a third lower one, 1st floodplain is now high and dry and downcutting events makes a stair step appearance to the land (lower and higher terraces)
Why are glaciers sensitive indicators of climate change, given the parts and processes you described in #9?
a. They are sensitive climate indicators because amounts of snowfall and melting are delicately balanced in galciers, so max ice extent is a sensitive climate indicator b. isotopic compositions of ice on land and on water in sea are indications of increases and decreasesin amt of snow and ice on land. ice holds lighter isotopes and heavy ones are left in sea until it melts c. oxygen and carbon isotopes in fossils to infer changes in seawater temp and chem over time to infer times of glaciation or times when melting of glaciers released freshwater into ocean d. ice cores show oxygen isotope compositions so you can tell temp, same with marine shells
What are climate proxies and how do they help us extend the instrumental record?
a. a measurement interpreted to reflect past conditions, some are straight forward and others are more difficult to interpret b. ice core proxy (analyze gas in the ice cores), tree ring proxy, glacier length, thermometer record
What are the main differences between an alpine from a continental glacier?
a. alpine- glacier that moves down from a high valley, confined to valley b. continental- larger than alpine, very large sheets of ice, cover entire continent
What are the ways that plate tectonics can affect climate?
a. altering land elevation, pumping volcanic gases into atmosphere, rearranging the configuration of landmasses and ocean currents, and changing sea level via changes in seafloor spreading rates (displaces water form ocean basns flooding low parts of conts) b. current arrangement and topography of the conts and ocean basins help guide wind and ocean currents that redistribute heat around earth. volcanic activity with the plate boundaries releases gas and particles into atm changing chem and affecting global temp c. uplifts mountains
What is the angle of repose and why is this an important quantity for understanding slope failure?
a. angle of repose- steepest angle at which a pile of unconsolidated grains remains stable i. controlled by frictional contact between grains ii. loose dry material about 30 degrees iii. higher angle for coarser material, wet stuff or gangular iv. angle of resulting slope is at angle of repose, if more is added the bile becomes wider and higher but angle remains the same v. slope failure occurs when slope is too steep for its material to resist pull of gravity
What kinds of rocks or earth materials make the best aquifers in terms of these two qualities?
a. aquifer is large body of permeable, saturated material through which groundwater an flow well enough to yield significant volumes of water to wells and springs (saturated zone) b. to be good material it must have high permeability as occurs in poorly cemented sand and gravel, most sandstone, cavernous limestone, or highly fractured rocks of nearly any type c.has to be permeable and porous d.confined- separated by earth's surface by rocks w/ low permeability e. unconfined- rain or surface water can seep unimpeded through unsaturated
Where in a stream profile would you most likely expect to find the base level, the most active erosion, and a meandering/flood plain portion of the river.
a. base level- the lowest level to which a river can erode (high above base level=much erosion) sea level is ultimate base level (ocean) b. meandering/flood plain- down stream
How does climate influence tectonics?
a. climate conditions control speed of erosion (causes uplift of deeper parts of mtn, removes rocks at surface) i. uplifted mountains force wind belts to flow around and over them and uplift of mtn leads to regional climate changes which act to lower the range through increased erosion
How and where is river discharge calculated? How does this change through time after storm events?
a. cross sectional area=width x Depth b. discharge= Cross sectional area x stream velocity c. increased discharge, peaking after a storm d. collected at a gauging station at a cross section
8) Illustrate how the factors in #11 above combine to generate meander growth and downstream migration.
a. curve starts to form when a slight difference in roughness on channel bottom causes water to flow faster on one side of a channel than another and that fast side erodes faster making a slight curve on the slow side sediment is deposited and meanders start to form and erode its banks and this causes streams to migrate toward sides and downstream positive feedback ensues (system where process once started results in more of the same) b. as meanders migrate back and forth across lowlands thay continuously erode and deposite loose sediments in floodplain and channel and this is main way floodplain flroms and old meanders remain as scars in floodplain c. sometimes meanders join and cut it off (cutoff meander) d. meanders migrate until they encounter a resistant riverbank, until vol and velocity of flow drop too low for erosin to continue or until 2 pts of meanter intersect
What is a drainage basin?
a. drainage basin- an extent or area of land where surface water from rain, melting snow, or ice converges to a single point at a lower elevation (area drained by a stream) (land area that contributes runoff to a given point in a stream or river) i. mapped to overall topography, raindrop to base level ii. better unit of analysis for understanding hydrology, flood hazards, total discharge iii. larger?
How do changes in Earth's orbit drive short-term (less than 1 million years) climate change? Is it predictable and cyclic? What are the three components of orbital variations that generate much of cyclic climate change?
a. eccentricity= noncircular shape of earth's orbit around the sun b. changes in orbit cause variations in the amount of solar radiation reaching earth c. 3 components= tilt, precession (wobble of rotation axis like a spinning top slowing down) and eccentricity (shape of orbit) d. they can be predictable, they are Milankovitch cycles
How would you recognize a coastline shaped primarily by erosion vs. one shaped largely by deposition of sediment?
a. erosion- has relentless pounding of waves, not uniform, concentrated at specific locations and certain elevations i. sea cliffs, wave cut platforms, caves and sea arches, pinnacles and sea stacks ii. on hard bedrock b. deposition-moved sediment, can accumulate in places where water velocity is slower, mostly sandy features i. sandbar, barrier island, spit
Why are glacial erratic's and striations evidence of past glaciers and what do they signify?
a. erratic is an out of place huge block that is carried very far by a glacier to an area where that type of rock may not even exist b. striation- smoothed rocks that are shiny and polished on the surface and have scratch marks and grooves cut into bedrock by stones carried along the base of a glacier, polish and marks are clues that glaciers once covered this region
How is a barrier island formed, and why is these not generally fabulous features on which to build structures intended to be permanent?
a. first a spit forms when waves and longshore currents transport sand and other beach sediment along coast building a long low mound of sediment that lengthens in direction of prevailing longshore current b. if spit grows long enough it may cut off a bay becoming a baymouth bar which shelters bay from waves and bay may fill in with sediment and low lying marsh may form c. then if sea level rises, former spits and bars may become long, sandy barrier islands. they may also form if mounds of sediment deposited by rivers when sea level is lower, become islands when sea level rises d. it is low lying can be underwater, waves can be bad, storm surge or strong winds bad
What is a flood plain?
a. flood plain- an area of low-lying ground adjacent to a river, formed mainly of river sediments and subject to flooding., area covered w/ water when stream floods out of its channel
Compared to stream valleys, what shape do glacially carved valleys have? Why?
a. glaciers form U shape valleys and rivers form V shape valleys b. running water cuts a v shape, deposit sediment inside, cut away outside, meander c. glaciers focus grinding on inside of bends, they go down easiest paths which is paths cut by streams usually and the stream valleys transform into broad steep sided troughs, straight paths
How does the physical behavior of glacial ice change with depth from top to bottom in a glacier (where does the ice flow and where does it break)?
a. glaciers form where accumulation of snow and ice exceeds loss, glaciers lose ice and snow by melting, wind erosion and sublimation, equilibrium line: losses equal accumulations, ice melts away at lower elevations, on land or in water b. white up high and blue lower down c. fractures in top d. upper part of glacier flows faster than lower part
We have evidence that earth has been much warmer in the past and much colder. Why are we concerned about climate change today given this information?
a. global temp from coldest to warmest of Holocene in last century i. the rate is unprecedented b. co2 concentrations racing up now b/c of human activities- planet is warming more than it should as a result
What is the primary force acting to cause slope failure events?
a. gravity pulls material downhill, tends to pull everything toward earth's center i. it acts vertically so a block will not move on a flat surface ii. it pulls a block at an angle so block can move on an angled slope
How does groundwater accumulate?
a. groundwater flows down slope of water table, steeper slope=faster flow b. groundwater accumulates with rain or snowmelt that seeps into ground, reach water talbe and saturated zone and below water table groundwater may flow c. groundwater originates from precipitation and snowmelt that seeps from the surface down into the subsurface. The water accumulates in pores, fractures, and cavities w/in soil, loose sediment and rock d. groundwater seeps into subsurface passes through unsaturated zone and then saturated zone, it flows below the water table through the interconnected pore spaces, (water can't flow laterally in unsaturated zone b/c pores not connected enough but it can seep down
Which part of the earth systems are involved with the climate system?
a. hydrosphere (oceans, lakes, etc) have largest effect on climate (takes a lot of energy to heat up water) b. atmosphere- energy is absorbed by it, sunlight is reflected by it c. clouds and particles- energy is absorbed by it, sunlight is reflected by it d. land and oceans- sunlight is reflected by them (if light colored), energy is absorbed by it (if dark colored) e. infared energy radiates from earth f. other processes influence atmospheric temp i. sun varies in solar output over short and long time periods ii. greenhouse gases influence how much heat is trapped iii. variation from more circular to less circular orbit over long times
What conditions are needed for the terminus of a glacier to advance instead of retreat?
a. it needs to get cold again and snow needs to pile and turn into ice b. or it can float on the water if the sea or lake is deep enough
What's the relative role of land use (changing the permeability of the landscape), the rate of water entering the river system, or other factors?
a. land use- decreasing porosity decreases infiltration and increases floods b. rate of water entering river system- rate increases can lead to flooding
How does glacial till form and what does it look like?
a. layers or patches of poorly sorted till, it forms b. unsorted glacial sediment that is derived form erosion of material by moving ice of a glacier, it is deposited some distance down ice to form terminal, lateral, medial and ground moraines
What are the three major characteristics used to classify slope failures?
a. mechanism of movement (fall- slope failing in nearly vertical sense), (flow-moving as a fluid mass down some slope), how the material moved b. type of material (solid rock ie rock fall) or (unconsolidated material ie debris flow) c. rate of movement (fast) or (slow)
How can groundwater get contaminated, and why is this a serious problem?
a. mining and naturally mineralized rock, landfill, farm, septic tank, leaking tank in gas station, fuel storage tanks, dry cleaner, house holds, truck fuel spill, brought by river or outside area by groundwater, factory wells, spills, emissions b.it can spread out, moves w/ groundwater down water table, can be filtered if flows slowly like through sand but not filtered if flows rapidly like in limestone caves
What kinds of continental glacier features have been left in Indiana, especially as the last glaciation receded?
a. moraine b. smooth troghs that were once covered by ice sheets which smoothed underlying landscape c. ridges- piles of glacial sediment mark front of ice sheet as it melted back (recessional moraines) d. drumlin- streamline form of sediment e. esker- melt water river flowing through ice f. recessional moraine- glacier stops for a bit and deposits stuff g. kettle lakes- from till w/ bi chunks of ice in them
What is porosity, and how is it different from permeability?
a. porosity- proportion of volume of rock that is open space, determines how much water a material can contain b. permeability- measure of ability of material to transmit a fluid, related to size and interconnectedness of pore space (low porosity usually has low permeability) i. granite crystals have low porosity as does poorly sorted clasts ii. clay has low permeability as does porous volcanic rock with separate pores iii. well rounded and well sorted have high porosity as does clay rich sediments and sedimentary rocks iv. loosely cemented gravel and sand have high permeability and vesicular volcanic rocks do too
What kinds of things can trigger slope failures? What factors make mass wasting more likely?
a. precipitation b. changes in land use (if you are building houses on areas that were previously stable but you removed some vegetation so it became less stable) c. overloading slope (if you put too heavy things on a slope that's mass is greater than the ability of the slope to hold it) d. Undercutting slopes (blasting to make roads, rivers running through, oceans) e. sudden shock like from an earthquake f. volcanic eruption
Where do rainforests tend to be located on earth? Deserts? Why are these climate zones found where they are in general?
a. rainforests are in tropical places or close to the equator (where the NE and SE trade winds converge) high rainfall, no freezing temps, rich in plants, Intertropical convergence zone b. deserts are in arid regions, receive less precip than it loses to evap places with descending air and high pressure (coastal desert, subtropical desert, rain shadow desert, polar desert, cont desert), form from descending air in subtropical belts and from airflow associated w/ cold ocean currents, also in rain shadows associated w/ mountain ranges and in cold, dry polar regions
What is meant by the saturated vs. unsaturated zone of an aquifer?
a. saturated zone- deeper in subsurface zone where water fills nearly all pore spaces and fractures, where most water occurs I nsubsurface b.unsaturated zone- part of subsurface where most of the pore spaces are filled with air rather than water (upper part) (can become completely dry during long periods w/out rain
What does sea level change have to do with past glaciations? Explain this linkage.
a. sea level is lower during ice ages and higher in the past b. as the glaciers melt the sea level rises
In a figure of a stream profile where is the stream gradient the steepest? The flattest?
a. steepest- near their origin like hills and mountains b. flattest- downstream
What is the difference between emergent and submergent coastlines, how do they form? How might you recognize one from the other?
a. submergent coasts-form where land has been inundated by sea because of a rise in sea level or subsidence of land i. estuary- river vally that has been flooded by sea allowing freshwater from land to interact w/ salt water form sea ii. fjord- steepsided valleys carved by glaciers and invaded by sea as level rose b. emergent coasts- form where sea has retreated from the land due to falling sea level or due to uplift of the land relative to the sea i. submerged features may be exposed by falling sea levels like reefs, offshore sandbars, and underwater parts of deltas ii. coral reefs exposed on land are sure sign coast has emerged iii. sandbars can become coastal dunes
What is ground subsidence? How can ground subsidence be related to groundwater or oil pumping? How can one prevent subsidence when pumping groundwater from an aquifer
a. subsidence- gradual caving in or sinking of an area of land b. if you pump large volumes of water or oil out of one well it pumps so rapidly that the groundwater around the well can't flow in fast enough to replenish what is last and it causes local water table to drop forming a funnel shaped cone of depression around the well, direction of groundwater flow changes across the entire area c.. water table drops, aquifer compacts, land subsidence d. can prevent it by making sure withdrawal rate is less than the recharge rate
Land/sea interface along shorelines 1
a. swirl away loose pieces of bedrock or break off new pieces b. waves bend (refract) if approach shore at an angle i. part that encounters bottom slows, bending wave c. grind and break clasts, making sand and stones that promote erosion d. waves break directly on promontory from several sides i. bays are protected from largest waves by promontory e. as ground slopes upward the bottom of the waves slows down and wave breaks f. currents form when ocean or lake water flows in certain direction, single current can affect entire thickness of water or currents can push shallow water in one direction and deeper water in another
How do changes in tectonics determine if a stream will be erosional or depositional
a. tectonic- can uplift or subsidence an entire region i. differential subsidence- flatten or steepen gradients, can cuase widespread deposition as stream velocity decreased and stream lost capacity ii. uplift- causes streams to erode down to landscape cutting canyons and steepening topographic relief
What is a sinkhole and how are they related to caves?
a. the roof collapse of a cave forms a sinkhole of the surface b. karst topography- surface w/ sinkholes, limestone pillars, disappearing streams
What is the significance of methane and carbon dioxide in the climate system?
a. they explain the rest of the climate change b. can be traced back many years through ice cores
Understand what is meant by tributaries and trunk streams in dendritic-style drainage basins.
a. tributary- smaller subsidiary channel that feeds a main channel b. trunk stream- is the main stream
What is the difference between a confined and unconfined aquifer?
a. unconfined- open to earth's surface and to infiltration b. confined- overlain by less permeable materials
Can orbital variations explain all climate change? If not, what else is involved?
a. variation in solar radiance (solar input variation explain a lot of climate change) b. last 200 years global warming can't be explained by orbital variation
What influence does the ocean have on the climate of nearby continents
a. warm currents from tropics cause prevailing easterlies to bring warm moist air to land b. temp of surface currents combined w/ prevailing wind controls local climates.
In ocean wind generated waves what is the sense of motion of water particles? What is the importance of fetch in the size of wind-generated waves?
a. water molecules move up and down and from side to side but stay in about the same place b. also they do circular patterns deeper within the wave c. above the base it moves less and below it there is no wave action d. stronger the wind the larger the waves e. fetch- wind blows across the surface (for a long way to generate big waves) i. area of ocean surface over which wind blows in a constant direction generating waves ii. longer the fetch and faster the wind the bigger the waves
What is the water table and how does it relate to the topography?
a. water table is the top of the saturated zone (separates saturated and unsaturated zones) b. can intersect surface in lakes, streams or swamps c. water table generally follows topography but more subdued, water table cuts across rock units
7) How does the shape of a channel control the location of the maximum stream velocity?
a. water velocity is lower when channel is shallower on the inside of a bend so sediment is deposited on the inside of the bend (point bar) b. on outside of bend channel is deeper and water flows faster so outside is eroded into steep river bank (cutbank) inertia causes force of water to be directed toward outside of a bend
What is a wavelength, crest, and trough of a wave? What is wave base and how is that related to breaking waves and the depth that wave energy affects the sea floor?
a. wavelength- crest to crest (how far apart waves are) i. longer wavelengths move faster than shorter and can travel farther before dying b. crest- the high point of the wave c. trough- low point of the wave d. wave base- depth below which no wave action is felt, ½ the wavelength, depth above which waves interact w/ deeper water or the seafloor i. waves bread where wave base=1/2 wavelength ii. when wave reaches water that is shallower than wave base its lower parts begin shearing against the bottom and the waves slow, crowd together and get higher as their wavelengths get shorter
Why is freshwater important? How common is it relative to saltwater and where is most of this relatively rare resource?
a. we need freshwater to live b. it (3.5%) is less common than salt water(96.5%) c. it is mostly in ice caps and glacier (68.7) then groundwater (30.1%) then other (.9%) then surface water (.3%) surface includes (lakes, swamps, rivers)
What is the weather compared with climate?
a. weather- short term scales (days to weeks) b. climate- long-term average i. changes are noticeable and demonstrable over years of data ii. results in a change of average conditions around which weather varies iii. weather variance and weather types also change with climate change
How is a spring different than a well?
a. well- hole dug or drilled deep enough to intersect water table and if well is w/in aquifer, water will fill open space to level of water table and the water can be drawn out by buckets or pumps b. spring- place where groundwater flows out of ground onto surface, water table intersects surface, happens naturally, can happen with faults, where permeable rock encounters less permeable obstacle, unconformities, limestone aquifers i. geyser/hot spring- heated groundwater comes up to surface
Where are the zones of accumulation and ablation/melting on a glacier?
a. zone of accumulation- upper part of glacier or ice sheet where snow and ice are added faster than they melt b. zone of ablation/melting- at lower elevations, ice melts away faster than it can be replenished by downward mvt of ice w/in the glacier and by snowfall. this causes the glacier to end or terminate either on land or in the sea
What other factors besides angle of repose control slope stability?
angle of repose for the material, discontinuities (fractures, cleavage and bedding reduce mechanical strength of rock and may allow rock to slip down hill), amount of water (addition of minor amounts of water increases strength of soil but too much weakens soil by pushing grans apart, clay can flow)
Land/sea interface along shorelines (appearances)
appearance of shoreline reflects hardness of bedrock. hard resists erosin forms rocky cliffs and erosion sculpts softer sediment and rock into more gentle slopes and rounded hills
Which features and processes add or remove sand from a beach?
b. sand comes from erosion in land c. rivers provide sediment into shoreline d. coastal sand dunes are a net loss of sand from beach or may get sand from land and add it to shore, though many swap sand with beach e. current flowing along a coast (longshore) transports sediment parallel to coast and can add sand to beach, remove or keep at equilibrium f. waves erode reefs and offshore islands especially during storms and carry loose sediment to coast g. sediment generated by wave erosion and associated slumping of rocks along coast, waves can bring sand in from offshore, pick up and take sand to deep water or swash it back and fourth
How is flood plain related to meanders, the active channel, and terraces?
b. terrace- stranded floodplain perched above and outside current floodplain c. floodplain extends beyond meander belt d. levees form during flooding- sediment carrying floodwater rises above channel and spreads out and current slows and deposits sediment in large mounds next to and paralleling the channel and it remains as an elevated rise after the flood water receeds, they help keep floodwaters from spilling onto floodplains e. floodplains are next to the active channels
What is a watershed?
b. watershed area of land where all of the water that is under it or drains off of it goes into the same place. (land area that contributes runoff to a given point in a stream or river) i. associated w/ individual river systems at a convenient pol'l/management scale ii. most common unit of analysis for land managers (pollution control, water supply) iii. smaller areas?
How do man made structures like breakwaters enhance or retard beach erosion?
breakwaters-wall built out in water to bear brunt of waves and currents, built parallel to coast to protect beach from severe erosion and cause sand to accumulate on beach behind structures, but they only protect areas that they cover b. seawall- concrete or steel, rip rap, results in loss of beach in front of wall
How do changes in base level determine if a stream will be erosional or depositional
c. changes in base level/sea level-change in sea level changes location of shore and elevation of base level, i. if base level lowers (drop in sea level) stream will downcut to try to match new base level ii. if base level rises (rise in sea level) stream erodes inland, but will deposit sediment along coastline's new position
How do changes in climate determine if a stream will be erosional or depositional
climate- increase in rain/wet conditions- slopes have more vegetation so they can hold soil but increased discharge allows streams to carry sediment away, beveling the hills more than during dry period
Land/sea interface along shorelines (climate)
climate- wet- lots of precip for erosion, formation of soil and growth of vegetation which stabilizes soil and limits amt of material that can be picked up wy wind and water or moved downslope by gravity. dry climates result in less vegetation, less soil and less stable slopes
Be able to describe and/or recognize falls, slides, flows and slumps, and the differences between these if made of rock or loose earth material
d. falls- large blocks or smaller pieces of bedrock detach from a cliff face and fal until they smash into te ground, can be triggered by rain, frost wedging, thawing of ice that had held rocks to cliff, an earthquake, river erosion or humans e. slides- slab of relatively intact rock detaches from bedrock along bedding surface, preexisting fault, joint or other discontinuity that is inclined downslope f. flows- flowing masses of weak mostly finegrained material that flows like water i. avalanche is fast rock flow and creep is slow rock flow g. slumps- rotational slide- rock layers and other material rotate backward as they slide, move along one or more curved slip surfaces
Where does groundwater communicate directly with surface water?
e. surface and groundwater are interconnected and water flows through them, surface water can soak in and become groundwater if surface material is permeable and water table is deep enough so there is an unsaturated zone into which water can seep f. water table intersects surface groundwater can flow out onto land, forms springs and adds water to lakes and such g. when river is lower than water table the river gains water, when river is higher than water table it loses water h. most lakes mark where water table intersects and rises above land surface
What happens to the shape of the water table as groundwater is pumped?
forms a funnel shaped cone of depression
Terminal Moraine
forms at the termination of a glacier and marks glacier's farthest downhill extent
Land/sea interface along shorelines 2
g. faulting and other tectonic activity can raise parts of the coast above sea level or drop parts of land submerging areas along the coast h. wind can move sand and finer sediment away from toward, or along a beach depending on direction the wind blows relative to the orientation of the shoreline i. rivers can contribute sediment into shore system j. waves can erode rock and loose materials, deposit sand and other sediment or move sediment around i. strong waves cause greater erosion k. storms bring large waves, strong winds and intense rain l. slope of seafloor- steep slopes can allow large waves to break directly against rocks along shore and gentle slopes cause waves to break a short distance offshore
Why does groundwater dissolve limestone to make caves, while limestone is deposited in the first place in seawater?
groundwater is slightly acidic b/c of dissolved co2 and sulfuric acid and calcium carbonate dissolves in acidic conditions
Be able to predict the motion of sediment from longshore drift based on knowledge of incoming wave direction and downslope direction of the seafloor.
if waves approach coast from angle the sand can be moved laterally along the coast (laterally moving sand= longshore drift_
How does the flow rate in an aquifer compare to that of currents in an ocean or rates in a stream (faster or slower)?
it is slower because groundwater has to flow through soil material. it takes longer for the water to get through the pores than it does to flow through an open system
Why is a conveyor belt a good analogy for moving sediment through a glacier?
it moves ice and sediment forward to front of glacier, rubble is piled up at front and if ice advances over the pile the process starts again
How do man made structures like jetties enhance or retard beach erosion?
jetties-juts out into the water to protect bay, harbor or beach, built in pairs, can focus waves and currents on adjacent stretches of the coastand the directed waves and currents, deprived of their normal load of sediment by the wall, erode the adjacent areas as they try to regain an equilibrium amt of sediment
How do natural levees form?
levees form during flooding- sediment carrying floodwater rises above channel and spreads out and current slows and deposits sediment in large mounds next to and paralleling the channel and it remains as an elevated rise after the flood water receeds, they help keep floodwaters from spilling onto floodplains
How will seasonal changes in precipitation influence the level of the water table?
more rain raises the water table, less rain- the water leaves the water table and goes into water bodies so less water in water table
Land/sea interface along shorelines (coastal landsapes)
reflect amt and size of available sediment. coast can't be rocky if only present materials are soft and fine grained, rivers give fresh influx of sediment into shore
What is the "sand budget" for a beach?
sediment budget- amount of sediment available to the system, controls many factors of the shoreline
What factors lead to floods?
snowmelt, local heavy precipitation, regional precipitation, volcanic eruption, dam failure, urbanization
What is the primary energy source for the climate system?
solar energy is the biggest driver and co2 and methane drive the rest
How are lakes and rivers in relatively wet climates (like Indiana) related to the water table?
they are higher than the water table so the rivers lose water
Land/sea interface along shorelines (orientation of coastline)
waves approach from specific directions in response to prevailing winds and may change with season, some areas of coast are sheltered and receive less wave action b/c they are sheltered in a bay or protected by island barrier reef or other feacture