early paleozoic earth history - ccsf · 2010-11-11 · facies model cambrian rocks of the grand...
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Early Paleozoic Earth Early Paleozoic Earth HistoryHistory
William SmithWilliam Smith
First geologic mapFirst geologic mapStudied the early Paleozoic Rocks of EnglandStudied the early Paleozoic Rocks of EnglandCoal Mines and CanalsCoal Mines and CanalsLaw of Faunal SuccessionLaw of Faunal Succession
William Smith 1769 –1839)
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William SmithWilliam Smith’’s Maps Map
Breakup of Breakup of PannotiaPannotia
By the beginning of the Paleozoic, six major By the beginning of the Paleozoic, six major continents:continents:
LaurentiaLaurentiaBalticaBalticaSiberiaSiberiaChinaChinaKazakhstaniaKazakhstaniaGondwanaGondwana
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CratonsCratons and Mobile Beltsand Mobile Belts
The supercontinent began breaking apart The supercontinent began breaking apart sometime during the latest Proterozoicsometime during the latest ProterozoicBy the beginning of the Paleozoic Era, six major By the beginning of the Paleozoic Era, six major continents were presentcontinents were presentEach continent can be divided into two major Each continent can be divided into two major components components
a craton a craton and one or more mobile beltsand one or more mobile belts
Composition of Paleozoic ContinentsComposition of Paleozoic Continents
CratonsCratonsRelatively stable and immobile parts of continentsRelatively stable and immobile parts of continentsForm the foundation for sedimentationForm the foundation for sedimentationConsist of two partsConsist of two parts
Shield Shield –– exposed portion of igneous and metamorphic rocks of the exposed portion of igneous and metamorphic rocks of the PrecambrianPrecambrianPlatform Platform –– buried, extending outward from shieldburied, extending outward from shield
Mostly flat but some parts gently folded into domes and basinsMostly flat but some parts gently folded into domes and basins
Mobile BeltsMobile BeltsElongated areas of mountain building from plate Elongated areas of mountain building from plate convergenceconvergence
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Paleozoic Paleozoic PaleogeographyPaleogeography
Early Paleozoic Early Paleozoic -- CambrianCambrianThe six continents were dispersed in low latitudesThe six continents were dispersed in low latitudesNo polar iceNo polar iceEpeiricEpeiric seas on all platformsseas on all platformsHighlands on Highlands on GondwanaGondwana, eastern Siberia, central , eastern Siberia, central KazakhstaniaKazakhstania
EpeiricEpeiric SeasSeas
Widespread shallow seas that transgressed and Widespread shallow seas that transgressed and regressed across the platformregressed across the platformChanges in sea level caused transChanges in sea level caused trans-- and and regressionsregressions
GlaciationGlaciationPlate movement/spreading ratePlate movement/spreading rate
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Paleozoic Paleozoic PaleogeographyPaleogeography
Late CambrianLate Cambrian
Water circulated freely among ocean basins, and the Water circulated freely among ocean basins, and the polar regions were mostly ice freepolar regions were mostly ice free
By the Late Cambrian,By the Late Cambrian, epeiricepeiric seas had covered areas seas had covered areas of of LaurentiaLaurentia, , BalticaBaltica, Siberia, , Siberia, KazakhstaniaKazakhstania, China, China
Highlands were present in northeastern Highlands were present in northeastern GondwanaGondwana, eastern Siberia, and central , eastern Siberia, and central KazakhstaniaKazakhstania
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Late CambrianLate Cambrian
Late OrdovicianLate Ordovician
Plate movements played a major role in the changing Plate movements played a major role in the changing global geography global geography
Gondwana moved southward during the Ordovician and Gondwana moved southward during the Ordovician and began to cross the South Polebegan to cross the South Pole
AvaloniaAvalonia separated from separated from GondwanaGondwana and collided with and collided with BalticaBaltica
An active convergent plate boundary existed along its An active convergent plate boundary existed along its eastern margin during the Ordovicianeastern margin during the Ordovician
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Late OrdovicianLate Ordovician
Middle SilurianMiddle Silurian
BalticaBaltica, with attached , with attached AvaloniaAvalonia, moved northwestward relative to , moved northwestward relative to Laurentia and collided with it to form the larger continent of Laurentia and collided with it to form the larger continent of LaurasiaLaurasia
This collision, which closed the northern Iapetus Ocean, is This collision, which closed the northern Iapetus Ocean, is marked by the Caledonian marked by the Caledonian orogenyorogeny
The southern part of the Iapetus Ocean still remained open The southern part of the Iapetus Ocean still remained open between Laurentia and Gondwana between Laurentia and Gondwana
Siberia and Kazakhstania moved from a southern equatorial Siberia and Kazakhstania moved from a southern equatorial position during the Cambrian to north temperate latitudes by theposition during the Cambrian to north temperate latitudes by theend of the Silurian Periodend of the Silurian Period
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Middle SilurianMiddle Silurian
CratonicCratonic SequencesSequences
Large scale Large scale lithostratgraphiclithostratgraphic units representing units representing major major transgressivetransgressive and regressive cycles and regressive cycles bounded by unconformitiesbounded by unconformitiesCorrelatableCorrelatable across continents, basins and across continents, basins and mountain mobile beltsmountain mobile beltsRepresent sea level changes due to major Represent sea level changes due to major tectonic and/or glacial eventstectonic and/or glacial events
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Sequence Sequence StratigraphyStratigraphy
Allows for high resolution analysis of time and Allows for high resolution analysis of time and faciesfacies relationships in sedimentary rocksrelationships in sedimentary rocksStudy of rock relationships within timeStudy of rock relationships within time--stratigraphicstratigraphic framework of related framework of related faciesfaciesbounded by unconformities.bounded by unconformities.Sequence is the succession of rocks; boundaries Sequence is the succession of rocks; boundaries are the unconformities caused by regressionare the unconformities caused by regression
Evolution of North AmericaEvolution of North America
CratonicCratonicsequencesequence
Sequence Sequence stratigraphystratigraphy
Sauk Sauk SequenceSequence
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The Sauk SequenceThe Sauk Sequence
First major transgression onto the N. American First major transgression onto the N. American cratoncratonEarly Cambrian Early Cambrian –– shelfalshelfal sedimentation onlysedimentation onlyMiddle Cambrian Middle Cambrian ––epeiricepeiric seas transgress over seas transgress over the the cratoncratonLate Cambrian Late Cambrian –– epeiricepeiric seas cover most of N. seas cover most of N. America (except some shield and America (except some shield and transcontinental arch)transcontinental arch)
Early Paleozoic Evolution of North Early Paleozoic Evolution of North AmericaAmerica
TransTrans--continental continental ArchArch
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The Cambrian of the Grand Canyon The Cambrian of the Grand Canyon RegionRegion
The Cambrian of the Grand Canyon The Cambrian of the Grand Canyon RegionRegion
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The Grand Canyon: A The Grand Canyon: A TransgressiveTransgressiveFaciesFacies ModelModel
Cambrian Cambrian Rocks of the Rocks of the Grand CanyonGrand Canyon
Time Time TransgressiveTransgressive FormationsFormations
TimeLines
Faunal analysis of the Bright Angel Shale indicates that it is Early Cambrian in age in California
and Middle Cambrian in the Grand Canyon region.
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TimeTime--TrangressiveTrangressive Cambrian Cambrian FaciesFacies
Appalachian Appalachian Mobile BeltMobile Belt
Tippecanoe SequenceTippecanoe Sequence
Sauk Sea regressed exposing huge areas of Sauk Sea regressed exposing huge areas of carbonate to erosion = unconformitycarbonate to erosion = unconformityTransgression deposited The Tippecanoe Transgression deposited The Tippecanoe Sequence during OrdovicianSequence during OrdovicianWidespread pure quartz sandstone (St. Peter SS) Widespread pure quartz sandstone (St. Peter SS) with purity due to with purity due to resedimentationresedimentation of Sauk of Sauk sequence sandstonessequence sandstones
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Tippecanoe SequenceTippecanoe Sequence
Basal sandstones followed by extensive Basal sandstones followed by extensive fossiliferousfossiliferous carbonatescarbonatesOutboard of carbonate reefs are Outboard of carbonate reefs are shalesshales from from erosion of Taconic Highlands and erosion of Taconic Highlands and AppalacianAppalacianmobile beltmobile belt
Tippecanoe SequenceTippecanoe Sequence
TippecanoeTippecanoeSequenceSequence
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Transgressing Tippecanoe SeaTransgressing Tippecanoe Sea
Modern reef settingModern reef setting
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Cambrian Archeocyathid reef
Ordovician Bryozoan reef debris
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Stromatoporoids reef builders
Ordovician North American barrier reefs
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Ordovician reef outcrops
Ordovician Life
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EvaporitesEvaporites
Halite and Anhydrite deposits of early PaleozoicHalite and Anhydrite deposits of early PaleozoicLagoons behind barrier reefsLagoons behind barrier reefsMichigan basin Michigan basin –– limited circulationlimited circulation
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Halite from Evaporite deposits, Michigan Basin
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•Northern Michigan Basin sediments during the Silurian Period
End of the Tippecanoe SequenceEnd of the Tippecanoe Sequence
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Appalachian Mobile Belt and Appalachian Mobile Belt and Tectonic Tectonic OrogenyOrogeny
QueenstoneQueenstone Delta Delta ClasticClastic WedgeWedge
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