Lecture 1: Jan 9, 2009
Introduction to Planet Earth
The course if focused on the history of planet earth, how it works internally and how continents and
oceans have evolved (the geosphere) over the last 4 billion years.
Rate of plate movement is the same growth of finger nails average 3.7cm/year.
“Earth history”: application of plate tectonic theory to the ancient past
-reconstructing past continent.ocean configurations
-paleoenvironmental reconstruction (e.g. climate) and paleobiology
-search for mineral resources
Challenges of environmental change
-effects of urban sprawl
-hardening of watersheds
-remediation of contaminated sites
-earthquakes; landslides & tsunamis
-climate warming and severe weather
-water shortages (i.e. drought cycles in Alberta. Tarsands consume huge amounts of water, very
-acid mine drainage
Lecture 1 and 2
How planet earth works and the plate tectonic “revolution”
Key concepts to remember:
-continental drift: 1912 (Wegener) “Pangaea”
-Sea floor spreading 1960 (Hess)
-Polar wander paths for continents 1965
-magnetic reversals and stripes 1965 (Vine)
-Mid-ocean ridges and hot spots (Wilson 1965)
-plate tectonics: 1967 (Wilson)
-oceanic vs. continental plates
-collisional (obducting and subducting) margins and divergent (rifted) plate margins
How did our solar system form?
-the universe is 15-20 billion years old (Ga)
-formed by a cosmic explosion, BIG BANG
-solar system formed after 5 billion years ago -oldest known rocks are 4.7 billion years old (meteorites)
-oldest rocks on Earth are 4.03 billion years old and occur in Canada (Acasta Gneiss) found near
Yellowknife in the Northwest Territories
-it’s hard to find really old rocks like these, because of the rock cycle. It is the fate of many rocks since
the environment forces always change it into other rocks.
Planetary Accretion: 4.5 billion years ago
-the formation of planets from dust
-ion meteorites tell us there is differentiation at this stage where planets develop at iron rich core and a
rocky mantel that surrounds the core.
Early development of planets
-olivane (check spelling) iron rich silky material which is the building blocks of this planet
-“The Hadean” = hell on earth.
-most of the earths water is from the de-watering of minerals deep in the earths crust