Download Unconformities, Geologic Time Scale, and Uniformitarianism

Unconformities,GeologicTime
Scale,andUniformitarianism
Ms.P
Science2016
DoNow– duetomorrow!
1. Compareandcontrastrelativedatingto
absolutedating.
2. TheLawofSuperpositionstatesthat
“youngerrockslieaboveolderrocksinan
undisturbedsequence.”Whatdoestheword
undisturbed mean?
3. Howdoyouthinkrocklayersbecome
“disturbed”?
TheLawofSuperposition–Oldestrocksareatthe
bottom,newestrocksareatthetop!
• Inhorizontallayers
(original
horizontality) of
sedimentaryrock,
eachlayerisolder
thanthelayer
aboveit and
younger thanthe
layerbelowit.
Gapsintherecord…
• Sometimesrocklayersaremissingalltogether
creatingagapinthegeologicrecord.
Unconformities:themissingevidence
• Missingrocklayerscreatebreaksintherocklayer
sequencecalledunconformities.
• Anotherwayofthinkingaboutanunconformity is
thatitisasurfacethatrepresentsamissingpartof
thegeologiccolumn.
CausesofUnconformities
• Non-deposition- whenthereisNOsediment
depositedbecausethesupplyofsedimenthas
beencutoff.
• Erosion– movementofsedimentsfromone
placetoanother.
C.F.U.
1. Whatissuperposition?
2. Explainwhatanunconformityis.
3. Whatcausesunconformities?
4. Howdounconformitiesaffectsuperposition?
Whatispaleontology?
• Paleontology: Thescientificstudyofearth’spast,particularly
fossils.
• Paleontologistsarescientistwhostudytheearth’sfossils.
• Whatisitcalledwhenananimalspeciesiswipedoutfromthe
earth’ssurface.
GeologicColumn
• Notallrocksequenceshavebeenundisturbed.
Somerockforcesaredisturbed(moved)byforces
withintheearth.Thismakesithardforgeologist
todeterminetherelativeageofarock.
• Todeterminetherelativeageofarockscientist
useageologiccolumn
• Ageologiccolumn isanarrangementofallthe
differentrocklayersfromaroundtheworldin
whichtheoldestrocksareatthebottom.
Howwastheearthformed?Geologic
History
• Uniformitarianism—
– Thesameprocess thathavechangedtheearthinthepast
continuetochangetheearthtoday overalongperiodof
time.
– Basically,thethingsthatchangedtheearthinthepastare
changingtheearthtoday.
Evidencesupportinguniformitarianism
• Uniformitarianism
– Weathering,erosion,anddeposition haveshapedthe
earth’ssurfaceinthepastandarecontinuallyshapingthe
earth’ssurfacetoday
– Rocksthatwereformedinthepastlooksimilartorocks
today
GeologicTimeScale
• Thegeologiccolumnrepresentsthethousandsof
yearsthathavepassedsincethefirstrocksformed
onEarth.
• Altogether,geologiststudyyears,andyears,and
YEARSofEarth’shistory.
• Tomakethingseasier,scientistshavedevelopedthe
geologictimescalewhichisascalethatdividesthe
earth’shistoryintodistincttimeintervals.
CFU
1. WhatdoesUniformitarianismmean?How
wouldweapplythistermtotheearthtoday?
2. Whatisthegeologictimescale?
3. Accordingtothegeologictimescale
organismsstartedout_________and
becamemore_________overtime.
4. Howdidorganismsreallystartoutthough?
DoNow- day2– QUIZtomorrow!
1. Whatisanunconformity?
2. Whatarethecausesofunconformities?
3. WhatdoesUniformitarianismmean?How
wouldweapplythistermtotheearthtoday?
4. Whatisthegeologictimescale?
5. Accordingtothegeologictimescaleorganisms
Simple
startedout_________andbecamemore
Complex
_________overtime.
6. Howdidorganismsreallystartoutthough???
PaleontologyQuiztomorrow!
• Packetsyouneedtostudy—
– Fossils
– LawofSuperposition
– Unconformities,theGeologictimescale,
andUniformitarianism
GeologicColumnActivity
• Readthedirectionsonyoulabsheetsilently
asIreadthemaloud.
• DoNOTwriteonyourdirectionssheet.
• Oneyouarefinishedcoloring,pleaseraiseyou
handtoaskforscissors.Gluesticksareinyour
basket
GeologicColumnActivity
• Shapes=fossils
• Background=sediment
• Wavylines=depositionwasnotcontinuous
(maybeanunconformity!)
• Straightlines=depositionwascontinuous
• Coloreachlayeradifferentcolor.Layersthatare
thesameshouldbethesamecolor.
• Matchupthedifferentoutcropsaccordingtothe
fossils(shapes)andsediment(background)
Catalyst
1. Accordingtothegeologictimescale
organismsstartedout_________and
becamemore_________overtime.
2. WhatisthelawofSuperposition?
3. Whatisthegeologicscale?
4. Whatisanindexfossil?
5. HowcanfossilstellusaboutEarth’spast?