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