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Lecture 1 - intro to glg105

Earth Sciences
Course Code

of 4
September 13 2010 Lecture 1
Instructor: Charly Bank (U of T department of geology) room 2107, Earth Science
building (Huron & Russell)
Office hours: W 3:30-4:30, after class, by appointment,
(PDLO (please mark as GLG105)
2x 20% term tests
Final exam 45%
One homework assignment
Two page essay focusing on one scientist
- Who is she? (how did she become a scientist?)
- When (in what context did she live?)
- What did she contribute
- Why is this contribution significant to geology
- Inge Lehmann, Mary Anning, Alice Wilson, Florence Bascorn
Text on website à notes by Dick Bailey
Links to trustworthy websites
Tell us the correct answers and wrong answers of the past
Perspective maybe the concept that we are learning might not be considered
correct in the future
A controversy active about 60 years ago will be discussed
The scope of this course is to study the ideas of the pasts
What can we learn?
Ideas about how our planet works
Thoughts that prevailed at the tine are to be studied by this course
Historic ideas about origin and development of Earth
Contributes to Earth science by famous scientist within a historic context
Maps of earth
Thought process in science
Earth science as an example
Earth science has evolved over time
Story of ideas
How did they adapt these, how did they refute them?; Why do scientist think in a certain
way? What evidence do they use to back up their claims?
How did they counter act them? Why did ppl rethink these ideas?
knowledge built over the centuries
Connection to ppl and to time
Personalities representative of certain ideas
We will spend as much time on wrong ideas than on correct ones (why were these
ideas wrong and what refuted such ideas?)
"Treasure of scientific knowledge built over centuries"
-Clair Patterson
1- Where do rocks come from?
Firemen "versus" watermen
2 schools of thought provided by James Hutton (Scotland) & Abraham Gottlieb Werner
Hutton à there is an ancient volcano in Edinburg
Lots of volcanic rock
2- How old is planet Earth?
Cooling, deposits, radiometric dating
Lord Kelvin
Temperatures, he looked at heat
Earth has been cooling down
Fresh water becomes salty bc of erosion
Why do we feel earthquakes? Why do we have volcanoes?
3-How does Earth work?
Continental drift versus plate tectonics
; Came up with idea of super continent Pangaea
Continents were together and after broke apart
Why do have mountains? Volcanoes?
Keith Runcom
Used magnetic properties of rocks to argue that the oceans are opening and
that the Atlantic ridges are areas that are opening up
Plate tectonics
Evolution 150 years ago, relatively 100 years ago and plate tectonics in 1960's
4-How has life and Earth evolved?
First life: Fossils à when was first life on earth? How to get that info
Mass extinctions à Events in time a lot of life died off and new life was able to
Life changes conditions on the planet that allows life to flourish
Climate change à humans including climate change
Disturbing statistics à many ppl believe this is not happening which is bad
Lynn Margulis: endosymbiosis
The endosymbiotic theory concerns the origins of mitochondria and plastids
chloroplasts), which are organelles of eukaryotic cells. According to this theory, these
organelles originated as separate prokaryotic organisms that were taken inside the cell
as endosymbionts. Mitochondria developed from proteobacteria (in particular,
Rickettsiales or close relatives) and chloroplasts from cyanobacteria.
5-Is today's change of climate unique?
Ice ages and holt houses, "Snowball Earth"
:KDt is Science?
Compare these two statements
§ 1-The hairy woodpecker population in the NW USA is declining
§ 2- Over the past 5 years the hairy woodpecker population in NW USA declined
by 11%
according to the Institute of Bird Populations ** NB
Robert Hooke (1635-1702)
Proposed the following procedure
1-Make puzzling observation
2-propose hypothesis to explain observation
3-deduce testable consequence for each hypothesis
4- carry out tests to find most satisfactory hypothesis
5-propose further hypotheses and test them
Built first microscope
2 NB things à be able to verify, make a claim someone has to prove it
How does Earth's magnetic field originate?
Friends Patrick Blackett and Teddy Bullard
Met in Rutherford' s lab (Cambridge UK)
Blackett directed Bullard's doctoral research in 1930
They went their own ways
Worked together in the British Navy during WWII
Both became interested in magnetism of the Earth
Tested how the Earth's magnetic field originates by using a golden cylinder
Cosmic Theory by Patrick Blackett
Magnetic field of stars and planets seems to be related to the rotation of the body
Faster rotation = stronger field
Proposed in 1948
Tested in lab with rotating 15kg gold cylinder and 1/2 ton aluminum sphere (but
magnetometers were not fine enough)
Did not get good results
Consequence à field should become weaker as one moves deeper into the Earth
(eg: in
deep mine) NO
Geodynamo Theory by Bullard
Earth's magnetic field originates in liquid metallic core of the planet (proposed in
Liquid can move around à move the metallic in circles
Modeled using the very best computers
Dig through 1000 km of earth closer and closer to the core
The field gets stronger
Consequences à field should become stronger as we go deeper YES