Physical Geography Test #1 Flashcards
(29 cards)
What is Geologic time
History of the earth from its formation to the present that has been divided into major time periods
What is the age of the earth
4.543 billion years old
What are the four layers of the earth
Crust, mantle, outer core, inner core
What is the thickness of the earths crust
35-70km thick
What is the thickness of the mantle of the earth
2900km thick
What is the thickness of the inner core
1200 km thick
What is the outer core
2300 km thick
What are the four eras in order from oldest to current
Precambrian, Mesozoic, Paleozoic, Cenozoic
How long did the precambrian era last and what percent of the years history
4 billion years and 87% of the earth’s history
What life started in the Precambrian era?
Multi-celled organisms
What era did the Canadian Shield form
Precambrian era
How long did the Palaeozoic era last and what percent of the earths history is it
325 million years and 7%
What era was it when large parts of North America were covered in shallow seas
Paleozoic
What life developed in the Palaeozoic era
Fish, amphibians, land plants, and insects
What era did the Appalachian mountains form
Palaeozoic era
How long did the Mesozoic era last and what percent of the earths history was it
180 million years and 4%
What era did Pangea break up in
Mesozoic
What era did the Rocky Mountains begin forming in
Mesozoic
What life formed in the Mesozoic era
Birds and mammals
What era ended with a mass extinction + what went extinct
Mesozoic era with the dinosaur extinction
What is the current era
Cenozoic era
How long ago did the Cenozoic era start
66 million years ago
What era was the most recent ice age in
Cenozoic era
What era did the uplifting of the coastal mountains happen in
Cenozoic era
