Geology 311

Where did dinosaurs live?

• Every continental landmass, including Antarctica
• not all prehistoric creatures are dinosaurs
    * plesiosaurs, not dinosaurs but in the fossil record

What are dinosaurs

• did they fly?
    * no, unless specifically talking about birds
• did they swim?
    * swimming present, would have been able to, with different specialization and abilities
    * marine reptiles, however, were spending their whole lives/days in water
    * dinosaurs are terrestrial, but can swim

Pterodactyls: not a dinosaur, flying-reptile related to dinosaurs

Duck-billed dinosaurs seen having nesting grounds they returned to in “Egg Mountain” Montana

• social behaviour→ parental investment by certain types of dinosaurs

Niche partitioning:

Grey Areas

• Archaeopteryx
    * has feathers, which most people attribute to meaning flight
    * not all feathers are flight! Could be used for thermal regulation
      * flight would then be an adaptation
    * considered a “dino-bird”
    * could have been a “missing link” between dinosaurs and birds
    * has features of dinosaurs: boney tail and teeth
    * and features of birds: wings and feathers
• Microraptor
    * 4-winged dinosaur
• Amboteryx
    * dino-bat
    * some derived theropods might have been capable of short glides, but not real flight
• Spinosaurus
    * had adaptations for semi-aquatic lifestyle
      * flat feet to paddle
      * retracted nostrils→ pushed father up snout
      * dense bones to regulate buoyancy → other animals eat rocks
      * broad tail to act as a rudder
    * likely did most of its hunting in rivers

Plate Tectonics

Earth’s interior is made up of three sections: crust, mantel, and core

Pressure, temperature and density increase with depth along with mineral compositions

- more nickel, magnesium and iron farther down, aluminum and silica higher up

Crust

• rigid and solid
• where the people are
• Continental
    * thick: 20-80km
    * rich in Si + Al
    * relatively low density
    * ex. granite
• Oceanic
    * thin: 5-10km
    * rich in Fe + Mg
    * relatively high density
    * ex. basalt

Mantle

• below crust, solid
• split into several layers
• Uppermost mantle
    * rigid/brittle solid
    * stuck to base of crust
    * lithosphere = rigid uppermost mantle + crust
    * lithospheric plates move during plate techtonics
• Asthenosphere
    * ductile solid
• Deep mantle
    * less ductile solid due to pressure

Core

Two parts: inner and outer

• outer- liquid
• inner- solid

Geological Hazards

• Volcanoes
    * distributed along convergent plate boundaries
• Earthquakes
    * follow plate boundaries
    * can happen due to seismic activity due to fracking, landslides, bombing, etc. not just plate tectonics

Divergent boundaries

Plates moving away from each other

• mostly on seafloor
• hot rocks rise and cool, creating new crust
• plate movement has rock getting older as you move away from the ridge
• seafloor spreading produces continuous row of subsea volcanoes called mid-ocean ridge that wraps around the Earth
• \

Convergent boundaries

Plates move towards each other

Oceanic-continent

• oceanic layer subducted beneath continental layer, as its less dense
• deep trench formed
• leading edge of continental crust compresssed and deformed produces mountains
• volcanic arc above subducting plate

Ocean-ocean

• older, colder, denser plate subducts
• arc of volcanic islands forms on the overriding plate

Continent-continent

• produces very large mountains
    * ex. Himalayan mountains: convergence of Indian+Eurasian plates

Transform boundaries

Plates grind past each other laterally

• sliding by
• some destruction via friction, not really creating or destroying crust
• commonly formed along divergent boundaires to relieve stress
    * where plates move
• most connect at spreading ridges
    * Queen Charlotte fault: connects to subduction zone
    * Nootka fault: connects same direction at different rates
    * San Andreas is a transform fault