THE LATE PALEOZOIC

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THE LATE PALEOZOIC

• THE CARBONIFEROUS 360-286 MY
• W.D. Conybeare W. Phillips 1822
• MISSISSIPPIANgtgt Mississippi River Valley
• PENNSYLVANIANgtgt Pennsylvania
• T.C. Chamberlain R.D. Salisbury 1906
• THE PERMIAN 286-248 MY
• PERMgtgt Central Russia
• Roderick Murchison 1841

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INTRODUCTION

• Mississippian- 40 MY
• Pennsylvanian- 34 MY
• Permian- 38 MY Duration
• Suturing of Pangea
• Alleghenian and Hercynian Orogenies
• Western terrane accretions in North America
• Formation of the Ural Mountains

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INTRODUCTION

• Tropical Climates around the Tethys Ocean
• High stands of sea level (Mississippian
  epicontinental seas)
• Tropical swamps during the Pennsylvanian (coal
  measures)
• Land plant diversity, insects evolved, reptiles
  evolved
• Permian redbeds (tropical desert climate)
• Glaciations in Gondwana

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Paleogeography
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Paleogeography
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PALEOGEOGRAPHY

• Opening of the Tethys Ocean
• Kazakhstan closed on Baltica
• Continuation of Antler Orogeny
• Other terranes collided with Canada
• Beginning of Hercynian Orogeny in southern Europe
• Final collision of Gondwana to Laurentia in
  Pennsylvanian
• Alleghenian (E US) and Ouachita Orogenies (S US
  S. AM)
• S. Am collided with TX forming ancestral Rockies
• Well defined Tethys Ocean in the Permian

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PALEOGEOGRAPHY

• Pangea formed a large U-shaped super-continent
  stretching from pole to pole
• Tethys Ocean formed an equatorial reentrant basin
  on the east
• The Panthallassic Ocean covered the rest of the
  globe

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PALEOGEOGRAPHY
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Paleogeography

• Pangea almost complete by the Permian except for
  a few microcontinents that assembled in the
  Triassic and Jurassic
• Late Paleozoic most widespread period of
  collisional mountain building
• The major orogeny of the Permian was the Uralian
  Orogenygtgt Ural Mountains
• The final formation of the Appalachians

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TECTONIC EVENTS

• The Hercynian Orogeny
• Southern Europe-Baltica
• 6000km long, lasted 30my, intense metamorphism,
  volcanism and plutonism
• The North American Cordillera
• Continuation of Antler Orogeny
• Ellesmere Orogeny (Canada and Alaska)
• The Alleghenian and Ouachita Orogenies
• Final phase of Appalachians- Thrust sheets
• Ancestral Rockies uplifted
• The Uralian Orogeny

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Location of the Principal Highland Areas of the
SW US During the Pennsylvanian
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OrogenicDevelopmentOf the EasternUS
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The Appalachians

• Valley and Ridge
• folded faulted sedimentary rks
• Blue Ridge Province
• metamorphosed Precambrian and Paleozoic Rks
• Inner Piedmont
• high grade metamorphic rks intruded by granites
• Charlotte Carolina Slate Belt
• metamorphosed folded late Proterozoic
  Cambrian sediments and volcanics

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Physiographic Provinces of the Appalachian Region
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Late Paleozoic Continental Collisions
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Highland Areas Associated with the Antler Orogeny
of California- Nevada
Collision of Antler arc with North American
craton during the Mississippian creating the
Roberts Mountains
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An interpretation of conditions in the
Cordilleran orogenic belt in Early Mississippian
time, shortly after the Antler orogeny.
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NEOPROTEROZOIC TO CENOZOIC TRANSGRESSIONS AND
REGRESSIONS OBSERVED ON THE CRATON
Variable sea level represented sequences of
sediments bounded by unconformities on all of the
cratons -
Major unconformity due to regression
Craton remained intact while collisions occurred
on all sides Sea levels remained high during the
Permo-Carboniferous and especially during the
Mississippian Sea level occilations on the
order of 200m and 1600km occurred 2 to 3 times
every million year
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CYCLOTHEMS

• Cratonic sediments dominated by cycles
• Rock types repeat in a cyclic manner
• Rock units of a meter or so can be traced for
  100s of kilometers
• Coal Measures- 10 to 20 m sections of 10 rock
  units showing a regression/transgression
  separated by a coal seam (typical, mid continent)

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CYCLOTHEMS

• 150-200m changes in sea level
• Represented in Illinois by 60 cyclothems
• Representing 20 to 25 my
• Representing a 300,000 year cycle
• Changes in global sea level caused by waxing and
  waning of Gondwana glaciations

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Coal Bearing Cyclothem Idealized Sequence of 10
Layers
Illinois Cyclothem
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The Permian Midland and Delaware Basins of West
Texas
750km of reefs sponges, algae, brachiopods and
bryozoans
Deep marine basins 400-1000m below sea level
Arid conditions represented by red beds and
evaporites
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Permian of West Texas
Lagoonal sediments and evaporites
Reef front- Phylloid Algae, sponge frame work
Black carbonate mud deep water sedimentation with
some reef ruble
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Economic Deposits

• Coal- Rapid accumulations of partially decayed
  vascular plant tissue in anoxic conditions
  peatgtlignitegtbituminous
• Pennsylvanian Appalachian and Illinois Basin
• Oil Gas
• Permian West Texas North Sea

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Coal Seams in fluvial cross-bedded Mississippian
Sandstones
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Formation of Oil and Gas

• Most Oil formed in marine environments
• Organic rich sediments are deposited fast and
  buried before decomposition
• These sediments are mainly younger than 500
  Million Years
• Organic material converted to oil and natural gas
  (hydrocarbons, e.g. CH4) upon burial, by
  geothermal heat (150- 200F)
• Oil and gas migrate from source rock to permeable
  rock
• If trapped oil and gas can be recovered

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Formation of Oil and Gas

• Decay of algae and bacteria
• Burial
• Cooking (temperature pressure)
• Formation of Hydrocarbon
• Favorable Preservation Conditions
• High organic production (over 10)
• Anaerobic depositional systems
• Moderate to low rate of sedimentation

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Hydrocarbon Needs

• Source Rock
• Reservoir Rock
• Trapping Mechanism
• Timing

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Economic Deposits

• Sodium Potassium salts
• Phosphates (Fertilizers)
• Phosphoria Fm.
• Metal ores (tin, copper, zinc, lead, silver,
  gold, platinum)
• Appalachian Orogeny

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Late-Paleozoic Climates

• Coal formation in low and high latitudes
• W. Europe and E. North America tropical climates
• cool moist climates in Siberia, China and
  Australia

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Late-Paleozoic Climates

• Strong zonation in climates
• Glacial climates in Gondwana
• Tillites and dropstones Africa, S. America and
  India
• Hot arid climates in low latitudes
• Redbeds and evaporites in central and western
  North America

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Paleoclimatic Indicators
Red- Coal Blue-Tillites Green- Evaporites
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LATE PALEOZOIC LIFE

• Land Plants
• Radiation of the Insects
• Radiation of the Amphibians
• The Origin of Reptiles
• Mammal-like Reptiles
• Pelycosaurs and Therapsids

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Marine Environment

• Radiation of brachiopods, ammonoids, bryozoans,
  crinoids, forams and calcareous algae after
  Devonian extinction
• Mississippian Age of Crinoids
• Phylloid Algal mounds of the Pennsylvanian
• Sponge-Bryozoan reefs
• Fusulinid foraminifera of the Pennsylvanian and
  Permian

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Life of the Mississippian
Crinoids
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Radiation of the Insects

• Co-evolution of plants, insects and amphibians
• Number of families appear in the Early
  Pennsylvanian
• Wingless insects (hexapods)
• Winged insects
• Fixed and folding wings

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Evolution of Amphibians
10s of million of years of evolutionary
history between crossopterygian fishes and true
amphibians
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Reptilian evolution from amphibian ancestor
took 22 my First reptile in Late Mississippian 4
major groups of reptiles Anapsida Synapsida Diapsi
da Euryapsida
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Reptilian Amniote Egg
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Anapsids no opening (Turtles)
Synapsids and Euryapsids one opening
low/ high (therapsids- ancestors to mammals/
ich- thyosaurs
Diapsids two openings (lizards, snakes, dinosaurs)
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Pelycosaur Dimetrodon
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Mammal-Like Reptiles- Cynognathus (carnivorous)
Kannemeyeria (plant eating therapsid reptile)
Mammals acquired most characteristics (50) in
the last 8 my of Permian
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The Bear Gulch and Mazon Creek Faunas

• Soft part preservation
• Bear Gulch Mississippian finely laminated
  limestone deposits of Montana preserving fish
  fossils
• Mazon Creek Pennsylvanian deltaic storm deposit
  of Illinois containing concretions with fossil
  plants and soft bodied marine fossils

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Mass Extinctions
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Permian Mass Extinction

• 90 of marine species became extinct
• 54 of the families
• Final 10 my of Permian

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Permian Mass Extinction

• Fauna Flora that became extinct
• All Paleozoic Corals, all Fusilinids, all
  Trilobites, Eurypterids and Blastoids and most
  sea urchins, brachiopods, crinoids, bryozoans
  Glossopteris flora and many insects
• Causes
• Glaciations (drop in sea level), reduction in
  area of shallow seas
• changes in climate due to Siberian flood basalts
  (CO3), drop in oxygen from 33 to 14