Mesozoic Geology Beginning of the Modern World
Mesozoic 248-65 Myr P r e c a m b r i a n Eon P h a n e r o z o i c Proterozoic Archean Hadean Era Period Age (Myrs) Epoch C e n o z o i c M e s o z o i c P a l e o z o i c Geologic Time Scale Tertiary Quaternary Cretaceous Jurassic Triassic Permian Pennsylvanian Mississippian Devonian Silurian Ordivician Cambrian Neogene Paleocene Age of the Earth 4600 Myrs (4.6 Byrs) Source: Geological Society of America (1999) 0.01 1.8 5.3 23.8 33.6 54.8 65 144 206 248 290 323 354 417 443 490 543 2500 3800 Holocene Pleistocene Pliocene Miocene Oligocene Eocene Paleocene
Highlights of Mesozoic Geology 1. Pangea was breaking up to form the modern continents 2. East Coast of NA rifted to become a passive margin, while the West Coast became active 3. Sea level went from a Phanerozoic low in the Triassic to a Phanerozoic high in the Cretaceaous 4. Dominated by warm climate (no ice ages)
Mostly Oceanic Deposits Mostly Orogenic Rocks Mostly Rift Rocks Mesozoic Rock
The Breakup of Pangea 1. Rifting of Laurasia and Gondwana to expand the Tethys Sea 2. Rifting of Gondwana to form Indian Ocean 3. Rifting of South America & Africa forming southern Atlantic 4. Rifting of North America and Europe to form North Atlantic 5. Rifting of Australia & Antarctica
Beginning of the Triassic
Late Triassic
1 Jurassic
Early Cretaceous 2
Middle Cretaceous 3 4
Late Cretaceous 5
What s Happening in the West? Orogenies
Mesozoic Batholiths
Convergent Boundary: Subduction Melting Produces More Felsic Magma Results in the formation & growth of Continental Crust and destruction of Oceanic Crust
West Coast
Divergent Boundary Results in the formation of Oceanic Crust
Terrane Accretion & the Growth of North America
The Aleutian Island Chain
As Plates Move - Islands Accrete to Form Larger Islands
High Mesozoic Seas Low Transgression Regression
Sedimentary Sequences of NA Blue = No deposition
Cretaceous Seaway
Mesozoic Climate - Hot Times Triassic: Arid and Warm Why? Largely continental Cretaceous: Warm and Wet Why? Break up of Pangaea and rising seas means more ocean and less continental
Evidence - Triassic/Jurassic Fossils Dunes Redbeds Evaporites
Evidence - Cretaceous Arctic Dinosaurs Arctic leaves Arctic Coal
What Led to Cretaceous Climate? 1. High Sea Level Holds more solar energy, moderate temperatures, change latitudinal exchange of heat 2. Increased Carbon Dioxide - Greenhouse Effect; possibly 10X present concentration Increased Sea Floor Spreading Superplumes?
Superplumes & Large Igneous Provinces (LIPS) Several Oceanic Plateaus formed around 125 Myrs
Mesozoic Extinctions
Mesozoic Extinctions When (End of ) Species Loss** Major Loses to Triassic 80 ± 4% Most synapsids Cretaceous 76 ± 5% Dinosaurs, marine reptiles, ammonites Triassic Extinction led to Dominance of Dinosaurs
Mesozoic Life Highlights Oceans repopulated with Modern Fauna Dominant land animals - Dinosaurs First Flowering Plants & Social Insects First Mammals First Birds Two Mass Extinctions (end-triassic and end-cretaceous)
Phytoplankton Erupt
Coccolithophores: calcareous phytoplankton (photosynthetic/autotrophs)
Foramifera: calcareous (CaCO 3 ) heterotrophs http://www.ucl.ac.uk/geolsci/micropal/calcnanno.html
Foramifera: calcareous (CaCO 3 ) heterotrophs http://www.ucl.ac.uk/geolsci/micropal/calcnanno.html
http://www.ucl.ac.uk/geolsci/micropal/calcnanno.html Foramifera: calcareous (CaCO 3 ) heterotrophs
Diatoms: siliceous (SiO 2 ) phytoplankton (photosynthetic/autotrophs) http://www.ucl.ac.uk/geolsci/micropal/calcnanno.html
http://www.ucl.ac.uk/geolsci/micropal/calcnanno.html Diatoms: siliceous (SiO 2 ) phytoplankton (photosynthetic/au totrophs)
Radiolarians: siliceous (SiO 2 ) heterotrophs http://www.ucl.ac.uk/geolsci/micropal/calcnanno.html
Radiolarians http://www.ucl.ac.uk/geolsci/micropal/calcnanno.html
Paleozoic vs. Mesozoic Rugosa & Tabulata Corals Hexacorals
Reefs - Hexacorals
Reefs - Rudists
Paleozoic vs. Mesozoic Brachiopods Bivalves & Gastropods
Inoceramids
Paleozoic vs. Mesozoic Crinoids Echinoids (Sea Urchins)
Paleozoic vs. Mesozoic Trilobites Crustaceans
Life was Adapting to Major Marine Predators http://www.youtube.com/watch?v=3d4aa_l6c3w&feature=related
Ammanoids - Parapuzosia
Bony Fish - Xiphactinus
Marine Reptiles
Placodonts
Plesiosaurs: Elasmosaurus
Kronosaurus
Ichthyosaurus
Largest- 150 ft long! Mosasaurus
Marine Reptile Relations
Giant Sea Turtles
The Green Report Flower Power Add Color to the Earth
Angiosperms
First Flowers Cretaceous Flower Magnolia What are the advantages to being a flower?
Are there advantages to co-evolution? Flowers and Insects Cretaceous
Paleozoic vs. Mesozoic Large Amphibians Frogs and Salamanders Paracyclotosaurus
Triassic Frogs
Mesozoic Reptiles Crocodiles Pterosaurs Dinosaurs & Birds Synapsids (Mammals) Anapsids (Turtles) Marine Reptiles Lizards & Snakes Archosaurs Diapsids
The Amniotes Diapsids (Includes lizards, dinosaurs & birds)) Classified based on skull structure Synapsids (Includes mammals) Anapsids (Includes turtles)
Anapsids & Diapsids (True Reptiles) Early Permian - Labidosaurus
Early Synapsids (Mammal-Like Reptiles)
Archosaurs: Early Diapsids
Big Dinosaur Questions Why were Dinosaurs so successful? What do we know about Dinosaur behavior? Where dinosaurs warm-blooded (endotherms) or cold-blooded (ectotherms)? Did birds evolve from dinosaurs? What caused the extinction of the dinosaurs?
Dinosaurs vs. Reptiles 1. Upright posture Legs beneath the body rather than to the side 2. Unique arrangement of ankle hinge (and other skeletal differences)
The 2 Major Lines of Dinosaurs
Russel Gooday & John Hughes Critters Gallery critters.pixel-shack.com
Ornithischia Bird-Hipped Dinosaurs 1. Stegosaurs 2. Hadrosaurs 3. Ankylosaurs 4. Pachycephalosaurs 5. Ceratopsids All Herbivores Less mobile, pubis facing backward, horny toothless beak, powerful grinding teeth, lattice of bony tendons reinforce the spine, largely four-legged, dominated Late Mesozoic.
Hadrosaurs - Duck-billed Dinosaurs Ouranosaurus
Hadrosaurs Parasauralophus
Hadrosaurs Maiasaurus
Laellynasaura
Stegosaurs Stegosaurus
Ankylosaurids - Natures Tanks Euoplocephalus
Ankylosaurids ankylosaurus
Pachycephalosaurs - Bone Heads Pachycephalosaurus
One of the last to evolve, became quite numerous. Like many dinosaurs became larger over time. Ceratopsids Horned Dinos Torosaurus
Triceratops Ceratopsids
Saurischia Reptile-Hipped Dinosaurs 1. Sauropods (Herbivores) 2. Theropods and Coelurosaurs (Carnosaurs) Aves (Birds) Herbivores and Carnivores Generally more mobile, pubis facing forward teeth on the rims of the jaws, two-legged and four-legged, dominated Early Mesozoic
Sauropods Seismosaurus X 20 Up to 90 feet long and 10 tons, lizardfeet (five toes like a reptile, nostrils sometimes on top, small brain (size of a kitten s), used gastroliths for digestion, herding animals
Barapasaurus Sauropods
apatosaurus Sauropods
Theropods Tyrannosaurus: up to 30 feet in length, several tons, size of a large elephant, Slow rambling gait?, large mouth for swallowing
Theropods Velociraptor
allosaurus Theropods
Small Theropods: coelurosaurs Compsognathus
How do we know about Dinosaur Behavior?
Dino Nests
Dinosaur Trackways
How do we know about Dinosaur Color and Soft Stuff?
Skin Imprints Triceratops
Feathers
Brain Casts & Gizzard Stones Emphasizes smell and senses, not planning gastroliths
Ceratosaurus Color?
Horner (2001) Dinosaurs under the Big Sky
Warm vs. Cold Blood (Endotherms vs. Ectotherms) http://www.youtube.com/watch?v=ialpzhopjta http://www.youtube.com/watch?v=fo-yfw6voyw&feature=related
Predator/Prey Ratios What limits how many animals can exist on a patch of ground or seafloor?
Upright Posture & Fast Speeds
Problems - Food & Heat Loss & blood pressure
Fossilized dinosaur heart 4-chambered
Bone Structure
Bottom Line Some dinosaurs were endotherms (small theropods) and others were ectotherms (large sauropods)
Adapting to the Skies
First in Flight - Pennsylvanian Cretaceous dragonfly
Meganeura monyi (roughly to scale) The largest insect in history
Pterosaurs Winged Reptiles Pterosaurs Actually predated dinosaurs offshoot of archosaurs skin membrane for wings Criorhynchus
Therapsids (Mammals) Synapsids Anapsids (Turtles) Marine Reptiles Lizards & Snakes Crocodiles Pterosaurs Archosaurs Diapsids Dinosaurs & Birds
Pterodactyl Winged Fingers Pterosaurs Pteranodon
Pterosaurs: Pterodaustro
Third - First Birds (Aves); Jurassic Descended from Saurischians!!! Feathers insulate birds from water and cold temperatures. The individual feathers in the wings and tail play important roles in controlling flight. These have their own identity and are not just randomly distributed. Some species have a crest of feathers on their heads. Although feathers are light, a bird's plumage weighs two or three times more than its skeleton, since many bones are hollow and contain air sacs. Color patterns serve as camouflage against predators evolved from the scales of reptiles
archaeopteryx
Share Characteristics with Theropods Deinonychus
( Tail feather") is an early genus of peacock-sized theropod dinosaurs that lived in the early Cretaceous Period (about 127 million years ago). They were feathered and remarkably birdlike in their overall appearance Caudipteryx
Feathered Dinosaurs Dilong paradoxus Dilong paradoxus is one of the earliest (Early Cretaceous) and most primitive known tyrannosaurids and had a covering of simple feathers
Last Mammals (Cenozoic) Bats
Mesozoic Mammals Therapsids (Mammals) Synapsids Anapsids (Turtles) Marine Reptiles Lizards & Snakes Crocodiles Pterosaurs Archosaurs Diapsids Dinosaurs & Birds
The Amniotes Diapsids (Includes lizards, dinosaurs & birds)) Classified based on skull structure Synapsids (Includes mammals) Anapsids (Includes turtles)
Triassic - Lystrosaurus Shovel reptile (synapsid) Dominated the land in the Early Triassic: 90% of land animals
Mammals vs. Reptiles 1. Development of jaw and ear bones 2. Secondary palate 3. Teeth differentiate 4. Evidence for warm-blood
Mesozoic Mammal Teeth Develop complexity within a single mouth and between species, e.g. grazing and predation.
Cynodonts (Triassic) One of the first common mammal-like reptiles. Name means dog teeth Differentiated teeth, more upright, bulging braincase, BUT it laid eggs!
Small Insectivores First mammals
Mesozoic Mammals: Bigger than previously thought Repenomamus More with the Cenozoic
Endothermy (warm-blooded) Internally heated High metabolic rate Can hunt at night and in cold climates Have to eat/breathe constantly Ectothermy (cold-blooded) Externally heated Low metabolic rate Can t hunt at night or live in cold climates Eat (and breathe) when you can Requires some anatomical changes: bones, mouth, lungs Lots of implications for lifestyles