geology of Canada Flashcards
what are the main geological building blocks of North America? How did the continent evolve?
where can we find dinosaurs in Canada
- Western Interior basin (alberta)
- fluvial, shallow marine environment
- approx 100-60 million years ago
- fossils are well preserved
- lots of oild and gas in the region
- Drumheller, alberta. dinosaur captial of the world
how did the canadian rockies form
- collisions on the west coast when Pangea was breaking up which also formed BC
- in mid jurassic period; collison and accretion of terrnes ith western N. America
when did the ice sheets develop
- global cooling in cenozoic (65 Ma- present)
- growth of major icesheet in northern hemisphere (about 3 million years ago)
- we have been shaped by glaciation. glaciers left aquifers
- about 20,000 years ago, Laurentide ice sheet covered most of Canada and some of USA
- less than 12,000 years ago, Toronto was under 2 km of ice
- we are still in an ice age altough glaciation is not as extensive as it once was. we have a large extensive ice sheets (50 000 km^2)
why is it important to understand the geologic history of Canada**
- understand past conditions to understand current formations
- learn about types of rock etc.
- for example, learning about rocks which make up areas can determine what is built/not built there. ie. dont really want to build on highly erosional surface
where are the oldest rocks in canada located
- Canadian shield
- Acasta Gneiss (4.03 billion years old), Northwest territories
how did the north american cratonform
- smaller continents joined together
- throughout geologic times, things have moved together and apart due to plate tectonics. Movement is slow and dynamic
United Plates of America
- the original N American continent, Arctic, started to form about 2.5 billion years ago from smaller continents
- southern province added during the formation of Nena about 1.9 billion years ago
- Torontoish area addded during the formation of rodinia about 1.3 billion years ago
what is the canadian shield
- the exposed part of the north american craton
- it is an ancient erosion surface: peneplain
- cover of younger rocks
- about 1 000 000 000 years old
- lots of erosion has occurs
- metamorphic rock
craton
the stable interior portion of a continent characterisitically composed of ancient crstaline basement rock
oldest canadian life forms
Mistaken Point, Newfoundland
- ediacaran biota
- 565 to 543 million years old
Burgess Shale
- exposed near Mt. Wapta, BC
- extermenly rich fossil record
- strange organisms
- about 540 million years old
- organisms such as hallucigenia, anomalocaris, pikaia, and opabinia
where did atlanic provinces come from? what did this cause?
- collosion of smaller continents from east
- added during formation of pangea, 600-300 million years ago
-formed the taconic mountains (niagrar escarptment rocks) - growth of the super contient Pangea
- they formed as micro-contients added to the east. folded rocks on newfoundland
- Newfound land is a part of N. America with old sea floor, and a piece of Africa
what were the conditions of the time when atlantic provinces were added? what did these conditions cause the formation of?
- extensive swamps, equitorial
- semi equitorial to tropical environemtn
- lots of swamps
- these conditions casued lots of coal formation as vegetation grew and expanded
how was British Columbia added
- pangea breaks apart about 150-200 million years ago
- atlantic ocean forms
- N. america drifts westward and collides with micro-continents which forms BC
- collisions also form structure of the rocky mountaitns
- there is manny terranes in BC which are all due to a seperate collision event
climate in cenezoic
climate has flutuated repeatedly during the past 3 million years; from cold ‘glacial’ conditions to warmer ‘interglacial’ conditions; currently interglacial
- 8-10 glacial-interglacial cycles in past 800,00 yeras. however, the rate of change of temperature change currently is alarming
