Historical Geology

• Dinosaurs during Mesozoic Era
• Fossil formation


  1. Quick burial - organism is buried suddenly preventing decay

  2. Replacement - as layers accumulate, minerals in the remains such as bones are replaced (calcium phosphate is replace by pyrite)

  3. Movement - uplift causes the fossil layer to surface

  4. Erosion - fossil is exposed to the surface
• Petrified fossil


  All or part of an organism is replaced by minerals (petrified wood)
• Cast


  Result of mold
• Trace fossils


  Activities of organisms
• Preserved remains


  Preserved in/ close to their original state (ice, tar, amber)
• Precambrian Eon is exhibited by extreme environments, little to no tectonic activities, early presence of life


  True
• HADEAN ERA


  Marked by extreme magmatism, no tectonic activities (Earth is still differentiating); heavy meteorite bombardment
• Stromatolite - built up by ancient cyanobacteria that may have introduced oxygen to the atmosphere

• Silurian fauna


  • fishes
  • arthropods
  • vascular plants in land
• Devonian Period - "age of fishes" - variety of fish species like armored fish, jawless fish, sharks, lobe and ray-finned fishes

• Carboniferous forest


  • tall ferns and ancient vascular plants
• Permian Extinction/ PT Extinction - worst mass extinction in earth's history
• Mesozoic Era


  Marked famously by gigantic dinosaurs and Pangaea
• Evolution of dinosaurs and starting to dominate the Mesozoic Era
• Dinosaurs continues to dominate in Jurassic Period
• KT extinction lead to the demise of dinosaurs
• Mammals thrived after the KT extinction
• Mammalian diversity marks Cenozoic Era


  • distant relatives of modern horses
  • distant relatives of modern rhinos
  • distant relatives of modern tigers
• Great American Faunal Exchange


  Pliocene