EESA06H3 Lecture Notes - Lecture 9: Alleghanian Orogeny, Appalachian Mountains, Ophiolite
Canada’s Geologic Journey : The last 4 Billion years
● Canada’s geological history is a long journey in 5 parts
● A. continents expand
● Ga (billions of years)
● Rodinia → most of the basement were added to North America
○ Key event for Ontario
● 1, 2, 3 = Canadian Shield
○ Old core of North America
● 4 → added most of Eastern Canada
● 5 → western North America
○ Added around the core of North America
○ Orogeny →
mountain building
■ Collision event
■ process/event
○ Origin
■ The crust that was added
■ Usually highly deformed
● Produced in magma
● Contain unstable uranium isotope
○ These break down and are used in radiometric imaging
○ Break down to produce lead → once lead is produced, it can’t escape
● To measure how old that rock is
● Use lithoprobe to measure up to 70km down (seismic activity)
●Concentric relationship
→ oldest rocks in the middle
● The light grey is youngest rock
● Point of subduction is to recycle oceanic crust into continental crust
● There are freshly made zicons and magma but they break up
○ Found in these rocks
Document Summary
Canada"s geologic journey : the last 4 billion years. Canada"s geological history is a long journey in 5 parts. Rodinia most of the basement were added to north america. 4 added most of eastern canada. Added around the core of north america. These break down and are used in radiometric imaging. Break down to produce lead once lead is produced, it can"t escape. To measure how old that rock is. Use lithoprobe to measure up to 70km down (seismic activity) Concentric relationship oldest rocks in the middle. Point of subduction is to recycle oceanic crust into continental crust. There are freshly made zicons and magma but they break up. Most mineral deposits can be found in sepcific tectonic settings. Adding to euroasia to create larger land mass. Himalayan orogeny expect to find a lot of marine rocks. Ancient pillow lavas volcanic eruptions underwater. Grey area are continental crust in between. Great thickness of pillow basalts between blocks of continental crust.
