EESA06H3 Lecture Notes - Lecture 10: Acasta Gneiss, Gunflint Chert, Canadian Pacific Railway
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Lecture 10 – Planet Earth
- all the continents are constructed in a similar fashion
Slide 1:
- read properly
- gigaanam (Ga)
- craton is core of north American
- martime is added when pangea is forming
- western Canada added after pangea breaks up
- mostly sedimentary rocks added on Eastern and Western Canada
Slide 2:
- blue > is apalasian belt
- red > craton
Slide 5:
- zircons [2.7bys] > used for uranium lead dating > can’t say much about
geological area w/o knowing age of age
o new method
Slide 6:
- zircon > analyze it to know how much lead is there > help determine age
Slide 7:
- Acasta Gneiss > 4bya oldest crust found in Canada
- we’re only dating since when it was a gneiss > was a rock before that too
- detrital > having been derived from something else
- zircons originate in igneous rock then get weather > released in water
become metaphoric rock > gneiss
Slide 8 [diagram]:
- oldest rock Napier Complex
- oldest rock in the middle
o old rocks are embedded in the interior of continents
Slide 9:
- province > rock that have extended over a long period of time
o broad areas characterized by similar properties but have sharp
boudaries
- most common rock type found with orgen > gneiss
- provinces were microcontinents > microcontinents collided > separated by
oregens
- Greenland was apart of the NA continents then separated about 80mya
- arctica > oldest NA landmass > 2.5-2.7 bya
- nina Columbia > second growth stage
- 3. basement rocks gotta added at this time
- 1,2,3 > craton
- cordilleran > added during the breakup of pangea
- 5 parts to NA geology
Slide 10:
- Lithoprobe
o means ‘probing rocks’