EESA06H3 Lecture 9: lecture 9
EESA06H3: Lecture 9.
• Caada’s Geologial Histoy i 5 pats:
▪ Main themes:
▪ A: Continents grow through time
▪ B: North American Continent has grown in 5 stages, Each phase adds crust to the continent
▪ 1. Arctica (2.7 Ga)
▪ 2. Nena (1.8 Ga)
▪ 3. Rodinia (1.0 Ga): Most of basement that underlies the Ontario and across Canada is added
during this time.
o Note ++ =Make the supeotiet aed, Rodiia
o ++ = Cato Caadia “hield —>Saw the building of the Canadian Shied
(Underlies Greenland and USA also)
o Ontario is a collision zone between East coast of America and South America:
o Peru has matching rocks
o Called the Grenville Orogen, formed Grenville mountains (Have eroded down by ice
sheets)
o Gneiss: Highly Deformed rocks. Deformed because squeezed at great depths (25 KM
down, around 800 degrees Centigrade)
o Soft rocks = Allows plate tectonics to move over top of it.
o Orogeny Vs Orogen
• Orogeny: mountain Building, Collision event—>The process
• Orogen: The actual rocks.
▪ 4. Pangea assembly (350 Ma):
o Maritime Canada is added during Appalachians Orogeny (Appalachian Mountains).
o Added much of eastern Canada Eastern US/Maritime Canada added during this.
Terrane Accretion: Slivers of oceanic/continental crust that have been added.
o Fa taelled ust.
o Ophiolites: Remains of Dead Oceans now preserved within continents , Greek for
“aly
o Newfoundland composed of Oceanic Crust
o 3 Zones:
▪ Continental Margin of Ancient NA plate. Now comprises the Humber Zone
▪ Island-Arc Volcanic Rocks and Lapetus Ocean Sediments consisting of Dunnage
and Ganger Terranes
▪ Rock left Behind when Eurasian/African Plate Wrenched loose from Pangea
(Avalon Terrane)
▪ Lage foelad asis eated y tetoi ollisio duig the foation of
Pangea c 400 million years ago result in extensive interior seas.
▪ Foelad Basi: Whe you fo ooge = thikeig ust. Tigges
depression of edge of the plate. Creates low areas within the plate.
▪ 5. Pangea Break Up (<200 Ma):
o British Columbia is added during Cordileran Orogeny (E.g Rockies)
o NA starts to be pushed to the West. West coast become active plate margin—>Have
subduction/collision
o Fusilinids From China and now in Western Canada
o When Terranes collide with continent a lot of pre-existing rocks get pushed towards
the centre.
o There are Thrustbelts in Alberta —>Record processes that were going on in the west
coast of NA
o Mount Rundle: Used to be one stamp
o Righting/writing?-table mountains that are gently sloping. pushed to right.
o Castle Mountain: Guards the bow river
o Mount Yamnuska: First mountain seen when you drive out of Calgary.
o Made of Old Cambrian Limestone
o Valley of the Ten Peaks:
▪ Peak #5: Mount Tuzo (Tuzo Wilson/OG name John Wilson) named after his mom.
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
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