Geological History of the Earth

1
Geological History of the Earth
2
Hadeon Eon

• No rocks because the Earth was molten

3
Archean Eon

• Earths crust cooled enough that rocks and
  continental plates began to form.
• Two theories
• Because the Earth was hotter, plate tectonic
  activity was more vigorous than today and
  prevented cratonization and continent formation
  until the mantle cooled and convection slowed
  down
• Because the mantle was too buoyant, subduction
  would not occur.

4
Proterozoic Eon

• Featured massive, rapid continental accretion,
  supercontinent cycles, and orogenic activity.
• Glaciations occurred

5
Phanerozoic Eon

• Current eoncovers roughly 545 million years
• Divided into three eras
• Paleozoic
• Mesozoic
• Cenozoic

6
Paleozoic Era

• Started shortly after the breakup of a
  supercontinent called Pannotia at the end of a
  global ice age
• At the beginning, Earths landmass was broken up
  into a large number of small continents
• Toward the end, the continents gathered together
  into a supercontinent called Pangaea

7
Mesozoic

• Pangaea gradually split into a northern continent
  Laurasia and a southern continent, Gondwana
• Later, Laurasia and Gondwana broke up into
  modern-day continents, but their locations were
  much different than they are today.

8
Cenozoic

• Laurasia became North America and Eurasia
• Gondwana split into South America, Africa,
  Australia, Antarctica and India, which collided
  with the Asian plate.

9
Pangaea Breaking Apart