Flashcards
Proterozoic (15)
Cards in this deck (9)
- 1The Proterozoic Eon covers what parts of Earth history? (when to when?)2.5 Ga to 544 Ma
- 2When did most of Earth's continental crust get formed?In the proterozoic?
- 3How did most of Earth's continental crust form?Repeated collisions of numerous small terranes
- 4What is the Wopmay Orogeny? What is the significance of the Wopmay Orogeny in northwestern Canada?-Very old, very eroded mountain belt in nw Canada.
-It's a good example of an early mountain-building event in the continental growth history of the Laurentia. - 5☼What is Laurentia☼North America + Greenland - Florida
- 6Did Laurentia experience many mountain-building events from 1.6 to 2.0 billion years ago?Yes there were six (or more)
- 7Explain the Mid-Continent Rifting event1.2-1.0 Ga
North America tried to rip apart but failed. A rift valley formed, but is now filled in with lava and sed. rocks.
(like the east African rift valley today) - 8Explain the Reelfoot Rifting event~late Proterozoic to Cambrian
North America tried to rip apart again but failed.
A rift valley formed.
From the Mississippi river valley area to KY to WV.
Earthquakes occur along these old faults - 9What is the Grenville Orogeny? When did it occur?-Old eroded mountain belt in eastern USA & east Canada. (Owebec to Texas)
-Lots of metamorphic rocks
-Formed by South America colliding into Laurentia
-occured 1.1 Ga