Chapter 15

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Transcript Chapter 15

Chapter 15
The Late Paleozoic
World
Guiding Questions
• How did marine life of late Paleozoic time
differ from that of middle Paleozoic time?
• How did terrestrial floras change on a
global scale in late Paleozoic time?
• What changes occurred in terrestrial faunas
during late Paleozoic time?
• What major biotic changes occurred in the
latter part of Permian time?
251 Million years
299 Million years
318 Million years
359 Million years
Late Paleozoic
• Carboniferous
glaciation
– Abundant swamps
• Permian drying
Late Paleozoic Life in the Sea
• Marine
– Ammonoids
abundant
• Highly mobile
– Brachiopods
• Productids
• Cone-shaped shells
• Produced reefs
Late Paleozoic Life in the Sea
• Crinoid meadows
– Significant
contribution to
early Carboniferous
(Mississippean)
limestone
Late Paleozoic Life in the Sea
• Bryozoans
– Sheetlike colonial
animals
– Trapped sediment
in mounds
– Important
contribution to
limestone
Late Paleozoic Life in the Sea
• Fusulinids
– Foraminifera
– Late Carboniferous
radiation
– Up to 10 cm in
length
– Guide fossil for
Upper
Carboniferous and
Permian
Late Paleozoic Life in the Sea
• Higher Mg-Ca ratio
• Aragonitic algae
– Important in late
Carboniferous
reefs
• Aragonitic sponges
– Play important
role in Permian
reefs
Late Paleozoic Life on Land
• Extensive swamps developed
• Coal swamps dominated by lycopods
– Lepidodendron
• Up to 30 m tall
– Sigillaria
Late Paleozoic Life on Land
• Seed ferns
– Abundant
– Small bushy plants
– Large and treelike
• Glossopteris
Late Paleozoic Life on Land
• Sphenopsids
– Not found in coal swamps
– Levees and floodplains
Late Paleozoic Life on Land
• Cordaites
– Upland plants
• Gymnosperms
– Naked seed plants
– Formed woodlands
– Conifers
• Cone bearing plants
Late Paleozoic Life on Land
• Permian
– Gymnosperms came to dominate terrestrial environments
Late Paleozoic Life on Land
• Winged insects
– Dragonflies
– Mayflies
Late Paleozoic Life on Land
• Amphibians
• Reptiles
Late Paleozoic Life on Land
• Reptiles
– Requires amniote
egg
– Protects embryo
– No longer needs
water for
development
• Pelycosaurs
– Dimetredon
– Eryops
Late Paleozoic Life on Land
• Therapsids
– Similar to mammals
– Legs no longer
sprawling
– Complex jaws
– Endothermic
• Warm-blooded
– Ectothermic
• Cold-blooded
Late Paleozoic Paleogeography
• Continents clustered • Early Carboniferous
near each other
– High sea level
– Warm, shallow seas
• Abundant limestone
• Evaporites on western North American
continent
Late Paleozoic Paleogeography
• Mid-carboniferous
– Mississippian
– Pennsylvanian
• Gondwanaland collided
with Eurasia (Hercynian)
– Extended Appalachians
• Alleghenian mountains
– Formed Ouachita Belt
• Oklahoma, Texas
– Glaciers; Sea level drops
• Later Carboniferous
– Increased latitudinal
gradients
– Glaciation expanded
Late Paleozoic Paleogeography
• Permian
– Interior
• Low moisture
– Pangaea nearly
• Evaporites and dunes
complete
• Ural Mountains – Reduced carbon burial
• Led to higher atmospheric CO2
• Global warming ended glaciation
Late Paleozoic Paleogeography
• Western dunes
Alleghenian Orogeny
• Mountain building
shifted to Eastern
US
• Valley and Ridge
– Thrust faults
• Blue Ridge
– Grenville age rocks
Alleghenian
Orogeny
• Continued
molasse
deposition
Southwestern U.S.
• Ouachita Mountains
– Westward continuation
of Appalachians
– Fold and thrust belt of
offshore deposits
Southwestern U.S.
• Microplates also accreted to Central America
Fountain Arkose
• Eastern flank of Front Range
Cyclothems and Coal
• Cycles in coal beds
that contain marine
sediments
– Slight change in sea
level
– Alternating
transgressions and
regressions
Cyclothems and Coal
• Transgression
– Deposition of
marginal marine
peat on top of
nonmarine deposits
– Capped with marine
sediments
Cyclothems
and Coal
• Regression
– Reversed the
sequence
• Oscillating glaciers
led to changes in
sea level
Delaware Basin
• In Texas and
New Mexico
• Economically
important
Delaware Basin
• Only flooded
region in Permian
• Significant
petroleum source
• Midland Basin
– Filled with
sediment
Delaware Basin
• Delaware Basin
– Carbonate and
evaporite
deposition
– Reef grew upward
– Waters receded and
stranded reef
• Capitan Limestone
Delaware Basin
• Early on, benthic
organisms
received oxygen
• When basin
deepened,
bottom waters
deepened,
stagnated
Glacial Striations
• South Africa
Fossil Wood
• Antarctic Wood
– Growth was
interrupted in
winter
Late Paleozoic Unconformity
• Global
unconformity in
marine sediments
Late Phanerozoic Life
• Rates of
Origination and
Extinction
Late Permian Anoxia
• Japan
• Uplifted rocks
• Gray chert replaced
oxidized hematite
Carbon
Isotope Ratios
• Negative shift at
Permian/Triassic
boundary