Term
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Definition
*age of rocks/ geologic features/ events relative to each other
*sequence of events |
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Term
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Definition
| age of rocks, etc in yeras before present |
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Term
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Definition
*younger sediments are deposited atop older sediments
*in an undisturbed sequence of sedimentary rocks older layers will occur deeper in the sequence |
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Term
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Definition
*sediments are deposited in essentially flat-laying layers
*tilted layers indicate events after deposition |
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Term
| cross cutting relationships |
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Definition
*younger features cut across older features
*faults, igneous intrusions |
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Term
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Definition
| *rock unit containing inclusions formed after rock unit providing inclusions |
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Term
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Definition
*fossils succeed (follow)each other in a well defined order
*fossils not randomly distributed through the rock record
*fossil content of a sedimentary rock is charactersistic of the time when that rock formed |
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Term
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Definition
*(1800)
*england
*canal builder |
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Term
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Definition
*a gap in the geologic record
*a buried erosional surface
*a buried landscape |
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Term
| examples of simple uncomformities |
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Definition
*deposit sediment layer
*lithify sediment
*uplift/erode
*subside/deposit new sediment
*lithify new sediment
*uplift |
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Term
| examples of angular uncomformity |
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Definition
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Term
basics of absolute dating
one |
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Definition
| *normally applied to igneous rocks (date the time when a particular crystal formed and radioactive elements within the crystal serve as internal "atomic clock" |
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Term
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Definition
| *spontaneous ejection of capture of subatomic particles by an atomic nuclues |
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Term
| process of radioactive decay |
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Definition
*composition of nucleus changes
*therefore one element changes into another
*energy released |
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Term
| examples of radioactive decay |
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Definition
*alpha emission: nucleus ejects 2P+2N
*beta emission: neutron ejects electron and turns into proton
*electron capture: proton absorbs an electron and turns into neutron |
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Term
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Definition
| elements with same number of protons but different number of neutrons |
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Term
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Definition
| radioactive isotope that decays |
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Term
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Definition
| what the parent isotope turns into |
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Term
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Definition
*time for half the quantity of a radioactive isotope to decay
*geometric rate process |
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Term
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Definition
*linear rate- constant amount in a given time interval
*geometric- constant fractions in given time interval |
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Term
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Definition
*orthoclase- KAlSi3O8
*contains K, NO Argon
*contains some radioactive K-40.
*K-40-----Ar40 half life 1.3 B.Y. |
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Term
| assumptions for radiometric dating for crystals |
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Definition
*know 1/2 life
*invariant 1/2 life= basic principle for physics
*parent isotope lost only through radioactive decay and no additional parent isotope added after the mineral forms
*daughter isotope is formed only through radioactive decay of parent isotope and no daughter isotope lost from the crystal |
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Term
| applied assumptions to K-Ar method |
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Definition
*orthoclase crystal inside of granite
*potassium gradually decays into Argon
*heat up atoms and apply pressure
*argon is out of there
*no longer a closed crystal system |
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Term
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Definition
*choose an unaltered rock
*use more than one radiometric dating method
*date more than one mineral |
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Term
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Definition
C-14 radioactive isotope of carbon decays to N-14
*forms in upper atmosphere and its breathed in/consumed by organisms
*1/2 life is 5730 yrs
*normal stable carbon is C-12
*when alive organsims have constant C-14/C-12 ratio, after death ratio diminishes |
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Term
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Definition
*fragmentation and chemical decomposition of rock
*physical (mechanical weathering)
*chemical weathering |
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Term
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Definition
| layer of weathered rock mineral fragments and soil that blankets most of earths surface (dirt) |
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Term
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Definition
*clay rich regolith formed from intense in place chemical weathering of bed rock
*retains appearance and structure of the original rock
*commonly red or orange
*commin in west ga area |
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Term
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Definition
*combo of mineral grains, organic matter, water and air that supports plant growth
*dark color.. organic matter |
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Term
| mechanical weathering process |
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Definition
*frost wedging--expansion of water to ice, cracks rocks apart.
-talus (talus slope)
**exfoliation/sheeting/unloading-- cracks form paralledl to land surface as overlying rock is stripped away
*common in exhumed igneous intrusions |
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Term
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Definition
| chemical decomposition of mineral into other minerals or non mineral substance |
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Term
| types of chemical weathering |
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Definition
*ionic dissociation
*hydrolysis
*oxidation |
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Term
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Definition
"dissolution"
*minerals dissociate in water ex- halite, NaCl
*major factor only for evaporite minerals |
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Term
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Definition
-main process for silicates
*H or OH replace atoms w thin minerals
*aided by acidic conditions
*examples- calcite plus carbonic acid--- cations plus carbinate ions
** orthoclase feldspar plus carbonic acid-- kaolinite |
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Term
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Definition
combined iron metal with oxygen (iron oxides)
*red color bc of iron being oxidized hematite |
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Term
| what controls the weathering rate? |
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Definition
*minerals
*rock structure
*climate |
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Term
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Definition
some are more resistant
quartz- highly resistant
calcite- dissolves in water |
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Term
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Definition
| determining the rate fractures, porosity, etc |
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Term
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Definition
| the most important factor of the wearthering rate (ex- water, wind, temp, humidity/rainfall) |
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Term
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Definition
*generates a lot of sediment
*movement of rock or regolith downhill under the direct influence of gravity
*important bc it could be deadly
*expensive |
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Term
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Definition
*rock slide
*slumping
*flow
*creep |
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Term
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Definition
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Term
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Definition
| occurs in unconsolidated material |
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Term
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Definition
*sediment and water moving as a fluid (mud flow)
*ex- mud flow, debris flow, earth flow |
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Term
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Definition
| very slow movement caused by cyclic expansion of the sediment and it could be a freeze/thaw or wetting/drying contraction of sediment |
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Term
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Definition
*oversteepening
*water
*vegetation loss
*eathquakes |
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Term
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Definition
*river erosion
*sea waves
*construction/digging activity |
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Term
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Definition
*at the simplest level
*adds weight or can weaken clays
*running water can cause erosion
*water pressure force pores or fractures open and decreases friction
*"hydrolic jack" (bean can demo) |
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Term
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Definition
| no roots to anchor your soil, no cover to absorb water |
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Term
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Definition
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Term
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Definition
*rivers
*gradient
*velocity
*discharge
*alluvium |
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Term
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Definition
*slope of stream channel
*controls velocity of flowing water |
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Term
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Definition
*speed of current
*controls size of sediment particles that water can carry |
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Term
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Definition
*volume of water flowing past a point in a stream during a given time interval
*measured in volume per unit time gallons per minute (GPM)
cubic feet per second (CFS) |
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Term
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Definition
*detrital sediment deposited by running water
*(sand gravel mud) |
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Term
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Definition
*flat floor of a valley built uo with flood deposits of alluvium
*created by repeated flooding |
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Term
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Definition
*stram that wanders back and forth with broad looping curves
*typically located of floodplain |
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Term
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Definition
*velocity of water
*most important
*meandering stream |
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Term
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Definition
| former portion of the stream channel, now cut from stread water-filled |
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Term
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Definition
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Term
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Definition
| sediment choked stream, made of many intersecting channels |
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Term
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Definition
*bed load
*suspended load
*dissolved load |
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Term
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Definition
(coarsest sediment) bounced dragged, rolled along stream bed; sand and gravel
*can even move boulders during large floods |
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Term
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Definition
| (fine sed) carried suspended by moving water- silt and clay and mud |
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Term
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Definition
material chemically dissolved in H20
*chemically weathering products (Ca, Na, HCO3, SO4)
*pollution (Ca, HCO3, Na) |
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Term
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Definition
*river/stream delta
*alluvial fan
*stream channel/floodplain |
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Term
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Definition
*located where a river mets the sea
*river flows into the sea and velocity drops and sediment is deposited
*as sediment is deposited, the river shifts position-- delta lobes |
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Term
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Definition
"delta on dry land"
*delta forms when a stream exits a mountain valley
*water velocity decreases |
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Term
| stream channel/floodplain |
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Definition
*point bars
*braided streams- flow across comp sed channel
*backswamp- flood plain away from channel (fine grain sediment like mud)
*natural levees- on floodplain adjacent to channel (coarse sed) ridges of sand parallel to channel cross section |
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Term
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Definition
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Term
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Definition
parallel to the river-small streams
*prevent flooding by the river
*built out of sed rock |
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Term
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Definition
*largest source of easily accessible fresh water
*naturally purified
*remains in ground for X period of time
*occurs dispensed in tiny pores within rock and sed, not unergound rivers/lakes |
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Term
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Definition
*giant groundwater reservior
*water constantly added to resevior
*recharge- water constantly leaving underground
*discharge= balance |
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Term
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Definition
measure of open space within material
*determines amount of water that rock of sed can hold |
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Term
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Definition
ease with which a fluid can flow through a solid
*determines how easily you can extract water from ground |
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Term
| water table and related terms |
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Definition
*unsaturated zone
*saturated zone
*water table |
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Term
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Definition
| area of subsurface in which pores are not saturated with water |
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Term
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Definition
| pores saturated with water |
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Term
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Definition
*boundaries between sat and unsat
*level to which ground is filled up w water
*rises and falls with changes in recharge and discharge
*not always flat |
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Term
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Definition
*gaining streams
*losing strams |
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Term
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Definition
*streams receive water from undre ground
*most streams are gaining streams
*naturally all streams are gaining |
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Term
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Definition
*stream that loses water into undergound
*found in deserts, arid climates, a lot of bedrock |
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Term
| aquifers and related terms |
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Definition
*aquifer
*confining layer
*unconfined layer
*unconfined aquifer
*confined aquifer
*artesian well
*perched aquifer
*well
*spring
*seep |
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Term
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Definition
a water saturated geologiv unit that can transmit significant amounts of water units normal hydrologys conditions
*rock alluvium saprolite etc
*useable amounts of water |
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Term
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Definition
| a low permeability unit that acts as a barrier to groundwater flow |
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Term
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Definition
(water table aquifer)
*an aquifer bounded on its top surface by the water table |
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Term
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Definition
| an aquifer capped by a confining layer (also referred to as an artesian aquifer) |
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Term
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Definition
*a well in which water rises above the top of aquifer
*occur in confined and unconfined aquifers
*flowing well |
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Term
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Definition
| a small aquifer above main water table |
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Term
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Definition
| a hole dug or drilled below water table to extract water |
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Term
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Definition
| a location of concentrated groundwater discharge |
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Term
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Definition
| a location of deffused groundwater discharge |
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Term
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Definition
*mostly metamorphic rock
*AL-NJ (includes west ga)
*metamorphoc rocks overlain by saprolite
*wells |
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Term
| metamorphic rocks (piedmont) |
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Definition
*saprolite= high porosity low perm
*bedrock= low porosity, fractures so high perm |
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Term
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Definition
*10 ft to 60 ft
*dug, bored (augured)
*2ft- 4ft diameter |
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Term
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Definition
*80 feet to 600 feet deep
*drilled
*6 in diamter well |
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Term
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Definition
*karst- provence of slovenia
*landscape underlain by water- soluble bed rock |
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Term
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Definition
*limestone (most), gypsum, rocksalt
*features-caves, sinkholesm losing streams
*subsurface erosion- water dissolves bedrock, few to no surface streams
*large springs |
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