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