THE LATE PALEOZOIC
THE CARBONIFEROUS 360-286 MY
W.D. Conybeare & W. Phillips 1822
MISSISSIPPIAN>> Mississippi River Valley
PENNSYLVANIAN>> Pennsylvania
T.C. Chamberlain & R.D. Salisbury 1906
THE PERMIAN 286-248 MY
PERM>> Central Russia
Roderick Murchison 1841
INTRODUCTION
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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
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
Paleogeography
Paleogeography
PALEOGEOGRAPHY
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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
PALEOGEOGRAPHY
• Pangea formed a large U-shaped supercontinent stretching from pole to pole
• Tethys Ocean formed an equatorial
reentrant basin on the east
• The Panthallassic Ocean covered the
rest of the globe
PALEOGEOGRAPHY
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 Orogeny>> Ural Mountains
• The final formation of the Appalachians
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
Location of the Principal Highland Areas of the
SW US During the Pennsylvanian
Orogenic
Development
Of the
Eastern
US
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
Physiographic Provinces of the Appalachian Region
Late Paleozoic Continental Collisions
Highland Areas
Associated with
the Antler
Orogeny of
CaliforniaNevada
Collision of Antler arc with
North American craton
during the Mississippian
creating the Roberts Mountains
An interpretation of conditions in the
Cordilleran orogenic belt in Early
Mississippian time, shortly after the
Antler orogeny.
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
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)
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
Coal Bearing Cyclothem: Idealized Sequence of 10 Layers
Illinois Cyclothem
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
Permian
of West
Texas
Reef front- Phylloid
Algae, sponge frame
work
Black carbonate mud
deep water sedimentation
with some reef ruble
Lagoonal sediments
and evaporites
Economic Deposits
• Coal- Rapid accumulations of partially
decayed vascular plant tissue in anoxic
conditions: peat>lignite>bituminous
– Pennsylvanian: Appalachian and Illinois Basin
• Oil & Gas
– Permian: West Texas & North Sea
Coal Seams in fluvial cross-bedded Mississippian Sandstones
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
Formation of Oil and Gas
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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
Hydrocarbon Needs
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Source Rock
Reservoir Rock
Trapping Mechanism
Timing
Economic Deposits
• Sodium & Potassium salts
• Phosphates (Fertilizers)
– Phosphoria Fm.
• Metal ores (tin, copper, zinc, lead,
silver, gold, platinum)
– Appalachian Orogeny
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
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
Paleoclimatic Indicators
Red- Coal
Blue-Tillites
Green- Evaporites
LATE PALEOZOIC LIFE
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Land Plants
Radiation of the Insects
Radiation of the Amphibians
The Origin of Reptiles
Mammal-like Reptiles
– Pelycosaurs and Therapsids
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
Life of the
Mississippian
Crinoids
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
Evolution of
Amphibians
10’s of million of years
of evolutionary history
between crossopterygian
fishes and true amphibians
Reptilian evolution from
amphibian ancestor took
22 my
First reptile in Late
Mississippian
4 major groups of reptiles
Anapsida
Synapsida
Diapsida
Euryapsida
Reptilian
Amniote
Egg
Anapsids
no opening
(Turtles)
Synapsids and
Euryapsids
one opening; low/
high
(therapsids- ancestors
to mammals/ ichthyosaurs
Diapsids
two openings
(lizards, snakes,
dinosaurs)
Pelycosaur
Dimetrodon
Mammal-Like ReptilesCynognathus (carnivorous)
Kannemeyeria (plant eating therapsid reptile)
Mammals acquired most characteristics (50%)
in the last 8 my of Permian
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
Mass
Extinctions
Permian Mass Extinction
• 90% of marine species became
extinct
• 54% of the families
• Final 10 my of Permian
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%