EESA01H3 Lecture 10: Lecture 10.docx
21 Apr 2012
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Document Summary
Canada"s geologic journey: the last 4. 5 billion years (chapter 20) Geology of north america known for 100 years but what put it together? (cid:173) tectonic plate paradigm. Paradigm - revolutionary idea that changes people"s views on data that have been around for many years (cid:173) cratons (orange colour) inner core of old crystalline (igneous metamorphic rocks) rocks from the pre- Similar to canadian shield (cid:173) cover rocks (blue/lime colour) cover the craton. Has a much greater extent because it"s under a large area of cover rocks (cid:173) continents start off as small piece of crust and by colliding with other micro continents, they grow in size. Older rocks are at the core (craton) while the newly formed rocks are at the outer layers. Rocks get younger as you go towards a margin of large continents (cid:173) over the last 4. 5 billion years, earth has been recycling oceanic crust into continental crusts. Obduction allows for continental crust to grow.
