1. Early Paleozoic

2. Periods of the Early Paleozoic
Cambrian: mya
Ordovician: mya
Silurian: mya

3. Overview of Paleozoic Broad Sequence of Events
Gradual Marine invasion of low continents
Wide epeiric (shallow) seas; moderated climate
Wide shallow habitats for marine organisms
Epeiric seas retreated; instability occurred
Thick sedimentary layers and Volcanic deposits developed
Collisional Mountain ranges built

4. Plate Tectonic Events Break-up of Rodinia
Oceanic closing and orogeny to form Pangaea
Taconic orogeny
Acadia orogeny
Alleghenian orogeny
Caledonian Orogeny
Hercynian Orogeny

5. Clues to Paleogeography
Paleomagnetic evidence
Lithologic evidence
Limestone
Evaporites
Lithic Sandstone and greywacke
Arkose
Tillites
Quartz sandstone
Shales
Shallow Sea
Equatorial Drying conditions
Mountain Building
Arid conditions-deserts

6. Laurentia (N. America) and Gondwanaland (first stage of Pangaea )
formed in southern hemisphere
consists of S. America, Africa, and other shields
Drifter south to polar position
Laurentia
Lay on equator
rotated counter clockwise

7. Continental framework
Stable interior
Arches
Synclines
Basins
Domes
Orogenic Belts
Cordilleran Mtn
Franklin Mtn
Appalachian Mtn
Caledonian mnt

8. Paleogeography of Laurentia
Equator: North-central Mexico to Ellsmere Island, Canada
Vast epeiric Sea (30o Latitude; vast carbonate deposits)
Vast lowlands of Canada Shield were exposed (desert)
Volcanic Mnts: Texas and New England

10. Seaways Appalachians (on east) Cordilleran (on west)
Franklinian (on north)
Caledonian (on northwest)
Extensive Sediment belts
Shales in seaways
limestone in empieric seas
Quartz sand on shoreline and deserts

11. Cratonic Sequence of Paleozoic
Sauk Sequence: Late Proterozoic to early Ordovician
Tippecanoe Sequence: Early Ordovician to early Devonian
Kaskakia Sequence: Early Devonian to end of Mississippian
Absaroka Sequence: Pennsylvanian to Early Jurassic

12. Early Paleozoic History
Synopsis of Sauk Transgression
Canadian Shield eroded for 50 my prior to transgression
Gradual transgression covered shield
Transcontinental Arch (highlands) became island chain in shallow epeiric sea
Transcontinental Arch: Ontario to Mexico, parallel to Cambrian equator
As a Result:
Late Cambrian seas: MT to NY
Cordilleran deposits of Grand Canyon
Tapeat Sandstone (oldest)
Bright Angel Shale
Mauv Limestone (youngest)

13. Back to the Sauk Sequence
By the early Ordovician sea regresses and deposition ends
Vast continental-scale uncomformity
Karst topography on carbonates rocks

14. Tippecanoe Sequence
Massive unconformity separates the Tippecanoe from the Sauk Sequence
Known for:
the “Super Mature” Sandstone, St. Peter Sandstone
What could “Super Mature” mean?
Carbonate deposits contain abundant marine fauna

15. Fauna found in Tippecanoe
Shallow Marine limestones with vast fauna
Brachiopods
Bryozoans
Echinoderms
Mollusks
Corals
Algae

16. Close of the Tippecanoe
Landlocked, reef-fringed basins develop in Great Lake region

17. Evaporite region In some areas evaporites accumulated to 750 meters
If this occurred due to evaporation of a single body of water, the water would have to have been ~1000 kilometers deep
Barred Basin

18. Cordilleran Region History
Sauk Interval
Passive Margin on opening ocean; deep marine basin on west
Western ocean opened; block rotated out; included Siberian region of Asian continent
Arms of rift filled with thick sediments
Belt supergroup (MT, ID, BC)
Uinta Series (UT)
Pahrump Series (CA)
Canadian Rockies (BC, Alberta)

19. Tippecanoe Interval
Conversion to active margin with subduction (Wilson Cycle)
Volcanic Chain formed along western trench
Trench deposits; greywacke and volcanics
Western ocean deposits: Siliceous black shales and bedded cherts with graptolites (graptolite facies)
East of subduction zone: shelly facies- deposited in back arch basins (fossiliferous carbonates)

20. Appalachian History
Appalachian Trough: Deformed three times during Paleozoic
Subdivisions of trough:
Eastern sediment belt: greywacke, volcanic siliceous shale
Western sediment belt: Shale, sandstone, limestone
Physiographic region of today
Eastern belt: Blue Ridge and Piedmont
Western Belt: Valley and Ridge and Plateau

21. Sauk Interval Trough was a passive margin on opening ocean
Shelf sediments: sandstone and limestone
Oceanic sediments: shales
Transgression spread deposits westward across craton; thick carbonates formed on subsiding shelf
Abrupt end with onset of subduction and ocean closure during Middle Ordovician

23. Tippecanoe Interval
Carbonate sedimentation ceased; platform downwarped by subduction
Thick graptolite black shale and shoreline immature sands spread west
Volcanic flows and pyroclastic beds formed when volcanoes emerged on coast
Rapid closing of eastern ocean (Iapetus); coastal and volcanic arc developed
Millerburg Volcanic ash bed formed (454 my; 1-2 m thick)

24. Taconic Orogeny
Appalachian Mountains built in collision with part of western Europe
Compression folded shelf sediments into mnt and Logan’s Thrust formed (48 km displacement)

25. Taconic Orogeny

27. Giant granitic batholiths produced by Taconic melting
Taconic Mountains weathered to form vast sandstones of PA, WY, OH, and NY
Great clastic wedges spread westward (age tracts deformation)

28. Climates Transgressions= Mild Climates, windswept low terrains
Regressions and Orogenic Episodes= Harsher more diverse climates; winds diverted by mountains
Earth Rotation was faster (shorter days, greater tidal effects)

29. Climate
No land Plants
Solar Radiation reflected, not absorbed
Sever temperature differences resulting
End of Late Proterozoic Glacial Cycle: Cool beginning for Early Paleozoic
Melting Polar Caps= Rising sea levels and warming
Equitorial Position= tropical climates for Laurentia, Baltica, and Antarctica
No Ice caps= warm polar seas

30. Climate Cross Bedding in Desert Sand Deposits
Shows wind blew NE to SW across eastern

31. Ordovician Sea Levels and Biotic Extinctions
African Glaciation lowered sea levels and cooled global temperatures
End-Ordovician extinctions in many families
Bryozoans
Tabulate corals
Brachiopods
Sponges
Nautiloid cephalopods
Crinoids

32. Silurian Climate Temperature Zonation
Glacial deposits above 65o latitude
Reefs, evaporates, eolian sands below 40o latitude

33. Late Paleozoic Devonian (480-360 m.y.a.)
Mississippian ( m.y.a.)
Pennsylvanian ( m.y.a.)
Permian ( m.y.a.)

34. Pangea
During Silurian Iapetus sea closes - joins Baltica and Lauretia (Caledonian Orogeny)
Devonian-Orogeny continues to south forming Laurussia
Pennsylvanian collision joins Gondwanna Land and Laurussia (Hercynian in Europe, the Alleghenian in N. America
By the Late Permian Pangea is complete

35. Forming Pangea
Pennsylvannian
Silurian
Mississippian
Devonian
Permian

36. Kaskaskia Sequence Oriskany sandstone- initial transgression
Devonian Clastics- material shed off rising Appalachians
Upper Devonian-Mississippian
Massive marine deposits
Late Mississippian- Regression
Widespread erosion and development of Karst topography

37. Absaroka Sequence Yet another transgression Unique cyclical sediments
Cyclothems
Shale
Limestone
Coal
Caused by either eustatic rise in sea level (Glacial melting) or by subsidence.

38. Climate Zonation paralled latitude
Warm to hot within 40o of equator
Reduced CO2 in late Paleozoic causes cooling and then late Paleozoic Ice Age

39. Mineral Deposits Fossil Fuels Limestone- used to produce cement’
Coal
Present in all post Devonian rocks
Limestone- used to produce cement’
Silica- glass production
Silver, gold- mountain building events