EESA06H3 Lecture 10: Part 2
Introduction to Planet Earth
March 14th, 2016
Lecture 10: Canada’s Geologic Journey: The Last 4.5 Billion Years (Part 2)
Weeks 10 and 12: Chapters 16 and 20
Acasta Gneiss (NWT)
- 4 billion years’ old
- The oldest continental crust in the Slave craton (oldest rocks in Canada)
- Detrital: means they are not fresh so they were derived/formed by older rocks and
reworked into younger rocks
Great thicknesses of pillowed basalts between blocks of continent crust
- Pillowed basalts are typically formed underwater and on ocean ridges
- It will penetrate into the seawater through fractures and it gets heated so the temperature
is well above boiling and it moves through the rocks and what it does is concentrates
metal (e.g. silver, zinc)
What we now call Labrador is added to Canada 2 billion years ago
- Use the information of Rifting, subduction, Obduction to interpret it
Stromatolites
- Google shark bay, Australia
- Oxygenation of Earth’s atmosphere (c. 2 Ga)
- There’s a famous gunflint chert in Canada (c. 11. Ga)
- Simple Bacterial Filaments (c. 3.3 Ga)
Shatter cones
- What happens to a rock when it gets impacted by a meteorite?
o A dramatic shock
o A big bolt comes in and shatters the rock
- Squeezing of the Sudbury impact basin by later tectonics as the Grenville Province was
added about 1.4 billion years ago
- Sudbury impact was really important in terms of mineral life
Ontario 1 billion years ago: The Grenville Mountains
- A lot of big mountains
Saglak Fiord, Labrador
- Highly deformed rocks underneath
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Lecture 10: canada"s geologic journey: the last 4. 5 billion years (part 2) Weeks 10 and 12: chapters 16 and 20. The oldest continental crust in the slave craton (oldest rocks in canada) Detrital: means they are not fresh so they were derived/formed by older rocks and reworked into younger rocks. Great thicknesses of pillowed basalts between blocks of continent crust. Pillowed basalts are typically formed underwater and on ocean ridges. It will penetrate into the seawater through fractures and it gets heated so the temperature is well above boiling and it moves through the rocks and what it does is concentrates metal (e. g. silver, zinc) What we now call labrador is added to canada 2 billion years ago. Use the information of rifting, subduction, obduction to interpret it. Oxygenation of earth"s atmosphere (c. 2 ga) There"s a famous gunflint chert in canada (c. 11.
