NJDEP - NJGS - Geologic Map Series 06-3, Bedrock Geologic ...
Unconformities, Geologic Time Scale, and...
Transcript of Unconformities, Geologic Time Scale, and...
Unconformities,GeologicTimeScale,andUniformitarianism
Ms.PScience2016
DoNow– duetomorrow!
1. Compareandcontrastrelativedatingtoabsolutedating.
2. TheLawofSuperpositionstatesthat“youngerrockslieaboveolderrocksinanundisturbedsequence.”Whatdoesthewordundisturbedmean?
3. Howdoyouthinkrocklayersbecome“disturbed”?
TheLawofSuperposition–Oldestrocksareatthebottom,newestrocksareatthetop!
• Inhorizontallayers(originalhorizontality) ofsedimentaryrock,eachlayerisolderthanthelayeraboveit andyounger thanthelayerbelowit.
Gapsintherecord…
• Sometimesrocklayersaremissingalltogethercreatingagapinthegeologicrecord.
Unconformities:themissingevidence
• Missingrocklayerscreatebreaksintherocklayersequencecalledunconformities.
• Anotherwayofthinkingaboutanunconformity isthatitisasurfacethatrepresentsamissingpartofthegeologiccolumn.
CausesofUnconformities
• Non-deposition- whenthereisNOsedimentdepositedbecausethesupplyofsedimenthasbeencutoff.
• Erosion– movementofsedimentsfromoneplacetoanother.
C.F.U.
1. Whatissuperposition?
2. Explainwhatanunconformityis.
3. Whatcausesunconformities?
4. Howdounconformitiesaffectsuperposition?
• Paleontology: Thescientificstudyofearth’spast,particularlyfossils.
• Paleontologistsarescientistwhostudytheearth’sfossils.
• Whatisitcalledwhenananimalspeciesiswipedoutfromtheearth’ssurface.
Whatispaleontology?
GeologicColumn
• Notallrocksequenceshavebeenundisturbed.Somerockforcesaredisturbed(moved)byforceswithintheearth.Thismakesithardforgeologisttodeterminetherelativeageofarock.
• Todeterminetherelativeageofarockscientistuseageologiccolumn
• Ageologiccolumn isanarrangementofallthedifferentrocklayersfromaroundtheworldinwhichtheoldestrocksareatthebottom.
• Uniformitarianism—– Thesameprocess thathavechangedtheearthinthepastcontinuetochangetheearthtoday overalongperiodoftime.
– Basically,thethingsthatchangedtheearthinthepastarechangingtheearthtoday.
Howwastheearthformed?GeologicHistory
• Uniformitarianism– Weathering,erosion,anddeposition haveshapedtheearth’ssurfaceinthepastandarecontinuallyshapingtheearth’ssurfacetoday
– Rocksthatwereformedinthepastlooksimilartorockstoday
Evidencesupportinguniformitarianism
GeologicTimeScale
• ThegeologiccolumnrepresentsthethousandsofyearsthathavepassedsincethefirstrocksformedonEarth.
• Altogether,geologiststudyyears,andyears,andYEARSofEarth’shistory.
• Tomakethingseasier,scientistshavedevelopedthegeologictimescalewhichisascalethatdividestheearth’shistoryintodistincttimeintervals.
CFU
1. WhatdoesUniformitarianismmean?Howwouldweapplythistermtotheearthtoday?
2. Whatisthegeologictimescale?3. Accordingtothegeologictimescale
organismsstartedout_________andbecamemore_________overtime.
4. Howdidorganismsreallystartoutthough?
DoNow- day2– QUIZtomorrow!
1. Whatisanunconformity?2. Whatarethecausesofunconformities?3. WhatdoesUniformitarianismmean?How
wouldweapplythistermtotheearthtoday?4. Whatisthegeologictimescale?5. Accordingtothegeologictimescaleorganisms
startedout_________andbecamemore_________overtime.
6. Howdidorganismsreallystartoutthough???
SimpleComplex
PaleontologyQuiztomorrow!
• Packetsyouneedtostudy—– Fossils– LawofSuperposition–Unconformities,theGeologictimescale,andUniformitarianism
GeologicColumnActivity
• ReadthedirectionsonyoulabsheetsilentlyasIreadthemaloud.
• DoNOTwriteonyourdirectionssheet.
• Oneyouarefinishedcoloring,pleaseraiseyouhandtoaskforscissors.Gluesticksareinyourbasket
GeologicColumnActivity
• Shapes=fossils• Background=sediment• Wavylines=depositionwasnotcontinuous(maybeanunconformity!)
• Straightlines=depositionwascontinuous• Coloreachlayeradifferentcolor.Layersthatarethesameshouldbethesamecolor.
• Matchupthedifferentoutcropsaccordingtothefossils(shapes)andsediment(background)
Catalyst
1. Accordingtothegeologictimescaleorganismsstartedout_________andbecamemore_________overtime.
2. WhatisthelawofSuperposition?3. Whatisthegeologicscale?4. Whatisanindexfossil?5. HowcanfossilstellusaboutEarth’spast?