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 near each other Early Carboniferous 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 Pangaea nearly complete Ural Mountains Interior Low moisture Evaporites and dunes Reduced carbon burial Led to higher atmospheric CO 2 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