GEOL 3000 Geologic MapsSlide 2Up isn’t always YoungingUp IndicatorsSlide 5Slide 6Slide 7Slide 8Slide 9Principles of Faunal Succession and Faunal AssemblageSlide 11Gaps in the Geological Record UnconformitiesCreating UnconformitiesSlide 14Slide 15Regional Correlation of Units Piecing the Rock Record TogetherRelative Time for Intrusive Igneous Rocks Principle of Cross-cutting RelationshipsGlobal Time Markers Volcanic Ash EruptionsSlide 19Slide 20Slide 21Global Time Markers Climate ChangeAbsolute Age Determinations Radiometric DatingRadioactive IsotopesRadioactive DecayRadioactive Decay Half-lifeSlide 27GEOL 3000GEOL 3000Geologic MapsGeologic MapsDetermining the Relative and Determining the Relative and Absolute Age of Map UnitsAbsolute Age of Map UnitsRelative Age Dating - SuperpositionRelative Age Dating - SuperpositionUp isn’t always Up isn’t always YoungingYoungingUp IndicatorsUp IndicatorsCross-beddingRipple MarksGraded BeddingAmygdaloidal Zones in LavasPillowed LavasSedimentary Facies – Time Trangressive UnitsSedimentary Facies – Time Trangressive UnitsPaleogeography of Middle Laurentia in the PaleozoicPaleogeography of Middle Laurentia in the PaleozoicAdvanced TransgressionAdvanced TransgressionRegressionRegressionPaleozoic Formations of the Upper MidwestPaleozoic Formations of the Upper MidwestPrinciples of Principles of Faunal SuccessionFaunal Successionand Faunal Assemblageand Faunal AssemblageIndex Fossils - Widespread distribution- Restricted, known time of existence- Common to many environmentsThe Jordan SandstoneThe Jordan SandstoneUnconformityUnconformityMissing FossilsMissing FossilsGaps in the Geological RecordGaps in the Geological RecordUnconformitiesUnconformitiesSiccar Point, Scotland“The mind seemed to grow giddy looking so far into the abyss of time”John Playfair – Illustrations of Huttonian Theory (1809)Creating Creating UnconformitiesUnconformitiesAngular UnconformityDisconformityNonconformityGrand Canyon StratigraphyUnconformities Unconformities or or Pinch-outs?Pinch-outs?Gaps in the Minnesota TimescaleGaps in the Minnesota TimescaleRegional Correlation of UnitsRegional Correlation of UnitsPiecing the Rock Record TogetherPiecing the Rock Record TogetherRelative Time Relative Time for Intrusive for Intrusive Igneous Igneous RocksRocksPrinciple of Cross-cutting RelationshipsGlobal Time MarkersGlobal Time MarkersVolcanic Ash EruptionsVolcanic Ash EruptionsGlobal Time MarkersGlobal Time MarkersMeteor ImpactsMeteor ImpactsK-T impact siteK-T Boundarycoalmudstone-impact layerThe 1.875 Ga Sudbury ImpactThe 1.875 Ga Sudbury ImpactThe First Major Extinction Event ??The First Major Extinction Event ??Global Time MarkersGlobal Time MarkersMagnetic ReversalsMagnetic ReversalsGlobal Time Global Time MarkersMarkersClimate ChangeClimate ChangeAbsolute Age DeterminationsAbsolute Age DeterminationsRadiometric DatingRadiometric DatingRadioactive IsotopesRadioactive IsotopesRadioactive DecayRadioactive DecayRadioactive Radioactive Decay Half-lifeDecay Half-lifeZirconZrSiO4U substitutes for Zr, but Pb does not.87Rb  87Sr; 86Sr is stableRb – chemically substitutes for KSr – chemically substitutes for Ca87Rb/86Sr87Sr/86SrCa-plagioclaseGranite whole rockK-feldsparBiotite (K-rich)t=087Sr/86Sr°t=1Metamorphismat t=1t=2Isochron87Sr/86Sr°(m)Rb-Sr Dating of a Rb-Sr Dating of a