Early Periods of the Early Paleozoic

► : 438-408 mya

► : 505-438 mya

► : 570-505 mya ► Gondwanaland ► Laurentia ► formed in southern ► hemisphere Lay on equator

► consists of S. America, Africa, ► rotating counter clockwise and other shields

► Drifting south to polar position Continental framework

► Stable interior

► Arches

► Synclines

► Basins

► Domes ► Orogenic Belts

► Cordilleran Mtn

► Appalachian Mtn Clues to Paleogeography

► Paleomagnetic evidence

► Lithologic evidence

► Limestone

► Evaporites

► Lithic and greywacke

► Arkose

► Tillites

► Quartz sandstone

► Shales 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 Major Tectonic Events

► Break-up of Rodinia

►broad sequences as result of deglaciation and rapid spreading ► Eventual closing of oceans (wilson cycle) and orogeny lead to formation of Pangaea

. Taconic orogeny

. Acadia orogeny

. Alleghenian orogeny Cratonic Sequence of Paleozoic

► Sauk Sequence: Late Proterozoic to early Ordovician ► Tippecanoe Sequence: Early Ordovician to early ► Kaskakia Sequence: Early Devonian to end of ► Absaroka Sequence: Pennsylvanian to Early Jurassic 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 Early Paleozoic History

► 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

► As a Result: . Late Cambrian seas: MT to NY

. Deposits: Tapeat Sandstone (oldest), Bright Angel Shale, Mauv Limestone (youngest) Time and Facies (Slight tangent)

► Bright Angel Shale: good example of time transgression of facies

Middle Cambrian Early (AZ) Cambrian (CA) 50 million years Arches and Basins

How would these two structures differ throughout the transgression and subsequent regression? Back to the Sauk Sequence

► By the early Ordovician sea regresses and deposition ends

.as result of regression vast continental-scale uncomformity created .Karst topography Tippecanoe Sequence

Massive separates the Tippecanoe from the Sauk Sequence Key deposits:

the “Super Mature” Sandstone, St. Peter Sandstone

What does “Super Mature” mean?

Carbonate deposits contain abundant marine fauna Life of the Tippecanoe

► Unlike the sauk deposits the shallow marine limestones contain abundant fauna . Brachiopods . Bryozoans . Echinoderms . Mollusks . Corals . Algae Close of the Tippecanoe Landlocked, reef-fringed basins develop in Great Lake region 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 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 (aulocogen) filled with thick sediments

. Belt supergroup (MT, ID, BC)

. Uinta Series (UT)

. Pahrump Series (CA)

. Canadian Rockies (BC, Alberta) 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) 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 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 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 as a result of the rapid closing of the Iapetus; coastal and volcanic arc developed

► Millerburg Volcanic ash bed formed (454 my; 1-2 m thick) Taconic Orogeny

► The Taconic Orogeny is the first stage of deformation leading to the ►Occurs as a result of collision with part of western Europe ►folded shelf sediments composing accrectionary wedge thrusted landward to form mountains (48 km displacement known as Logan’s Thrust) Taconic Orogeny

► As deformation continued giant granitic batholiths produced by Taconic melting caused mtns to rise

. Taconic Mountains weathered to form vast of PA, WV, OH, and NY Climates

► Transgressions= Mild Climates, windswept low terrains

► Regressions and Orogenic Episodes= Harsher more diverse climates; winds diverted by mountains

► In early Paleozoic no land plants

. Solar Radiation reflected, not absorbed

. Sever temperature differences between night and day

► 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 Ordovician

► Sea Level changes 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 Silurian Climate

► Temperature Zonation . Glacial deposits above 65o latitude . Reefs, evaporates, eolian sands below 40o latitude Late Paleozoic

Devonian (480-360 m.y.a.) Mississippian (360-320 m.y.a.) Pennsylvanian (320-286 m.y.a.) (286-245 m.y.a.) 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 Absaroka Sequence

Yet another transgression Unique cyclical sediments Cyclothems: cyclical deposition of marine and nonmarine sediments

Shale

Limestone

Shale

Limestone

Coal Caused by either eustatic rise in sea level (Glacial melting) or by subsidence. Pangea During Silurian Iapetus sea closes - joins Baltica and Lauretia (Caledonian Orogeny) Pangea

Devonian: Orogeny continues to south forming Laurussia (Acadian Orogeny) Catskill Delta forms to west of Acadian Mtn Pennsylvanian: Collision of Africa with east coast of N. America joins Gondwanna Land and Laurussia (Hercynian in Europe, the Alleghenian in N. America By the Late Permian Pangea is complete Pangea

Devonian: Orogeny continues to south forming Laurussia (Acadian Orogeny) Catskill Delta forms to west of Acadian Mtn Pennsylvanian: Collision of Africa with east coast of N. America joins Gondwanna Land and Laurussia (Hercynian in Europe, the Alleghenian in N. America By the Late Permian Pangea is complete Climate Zonation paralled latitude Warm to hot within 40o of equator

Reduced CO2 in late Paleozoic causes cooling and then late Paleozoic Ice Age Mineral Deposits

Fossil Fuels Coal Present in all post Devonian rocks Oil and Gas Devonian Reefs Alberta, MT, SD Appalachian basin PA, WV