EESA06H3 Lecture Notes - Lecture 9: Dead Oceans, Oceanic Crust, Juan De Fuca Plate
Lecture 9: Canada’s Geologic Journey – The Last 4 Billion Years (Part 2)
Rodinia:
• Collision zone between east coast of North America and South America → Grenville
Orogeny/Grenville Orogen (crush zone that formed at that time)
o Break up and a lot of crust (Grenville Orogeny) gets left in North America
o Ontario 1 billion year ago → Geille Moutais
▪ Goe o due to eatheig/eosio → o out ie sheets h lots
of freshwater
Gneiss Rocks:
• Formed due to pressures at really high temperature deep in the earth
• These soft rocks allow plates to move
• Deforming (see these bands in the gneiss) of gneiss occur as the plates move over top
o Similar to marble bread
Canadian Shield:
• Covers large areas, also extends into the US and Greenland
• Canadian shield is much deeper in the US
• E.g., Grand Canyon have cover rocks on top that cover the Canadian shield, inner part of
canyon has gneisses
The Cambrian Explosion:
• Period where first multicellular life: The Ediacara Fauna (550-500 Ma)
o Weid shaped fossils i Mistake Poit i Nefoudlad ad Walott’s Qua
• Called explosion because people use to believe it was some sudden event but people
not realize it is more gradual
The Appalachian Orogeny:
• Pangea forms (300 million)
• Out of Africa → Maitie Caada is added
Terrane Accretion:
• Terranes (silver of continental crust) are added to Eastern Canada
• Eastern Canada gets built of far-travelled crust assembled during Pangea collisions
• Smaller terranes can be recognized in the Appalachian Mountains
find more resources at oneclass.com
find more resources at oneclass.com
Document Summary
Lecture 9: canada"s geologic journey the last 4 billion years (part 2) Rodinia: collision zone between east coast of north america and south america grenville. The appalachian orogeny: pangea forms (300 million, out of africa ma(cid:396)iti(cid:373)e ca(cid:374)ada is added. Terrane accretion: terranes (silver of continental crust) are added to eastern canada, eastern canada gets built of far-travelled crust assembled during pangea collisions, smaller terranes can be recognized in the appalachian mountains. Ophiolites (greek and means scaly: the remains of dead oceans, the name given to preserved ancient oceanic crust, e. g. , greenstone belts. Salt: north american in past close to equator, shallow seas evaporated (cid:271)(cid:396)i(cid:374)e (cid:894)highl(cid:455) sali(cid:374)e (cid:449)ate(cid:396)(cid:895) salt, eventually becomes salt deposits, from windsor (rock salt) The appalachian fold belt: appala(cid:272)hia(cid:374) mou(cid:374)tai(cid:374)s used to (cid:271)e talle(cid:396) (cid:271)ut (cid:374)o(cid:449) (cid:862)stu(cid:373)ps(cid:863) (cid:894)(cid:374)ot tall (cid:396)elati(cid:448)el(cid:455) (cid:455)ou(cid:374)g(cid:895), worn out, a lot of coal deposits.
