Geology of Canada
canadian shield - stable tectonic province covering ? - contains some of the ____ rocks on earth - largely comprised of _____ rocks that formed during the _____ eon
- 8,000,000 km^2 - contains some of the oldest rocks on earth - largely comprised of precambrian rocks that formed during the archaean eon
describe geological features observed with interior platform
- basins formed by thermal subsidence - domes formed by buoyant uplift
interior platform
- extensive sediments have been deposited around periphery of canadian shield - precambrian basement rocks that underlie these sediments are an extension of canadian shield - both clastic and chemical/biological sedimentary rocks
canadian examples of greenstone belts
- flin flon (S/M) - abitibi (Q/O) - temagami (O)
describe the western boundary
- juan de fuca from north cali to van island is sub ducting and creates the cascadia subduction zone - pacific plate transform fault except in southern alaska
Flin-Flon greenstone belt
- precambrian greenstone belt formed by arc volcanism during paleoproterozoic period - composed of volcanic and sedimentary rocks that host extensive volcanogenicmassive sulphide desposits - several zinc, copper and gold mines
describe the craton of canada
- stable core of continent - consists of canadian shield; where precambrian rocks are exposed at the surface and which has been tectonically stable for nearly 1 billion years - consists of continental platform: precambrian rocks buried beneath flat lying phanerozoic sedimentary rocks
greenstone belts are zones of what ?
- within cratons - metamorphosed mafic and ultramafic rock - basalt, other volcanic rock - associated with sedimentary rocks
the second phase of appalachian mountain building is ?
acadian orogeny (390-370ma)
what is the oldest phanerozoic orogen ?
appalachian fold belt
where is the northern boundary of NA plate
basically past north pole in north east siberia
intercratonic basins
basins within and surrounding the canadian shield became filled with sediments during the phanerozoic
why do we care about greenstone belts
important source of metals - gold, copper, silver, zinc
decreasing intensity of deformation towards coast or inside continent
inside continent
coast region is mainly what type of rocks?
intrusive igneous and volcanic rocks
shield bedrock exposed during five major periods of ________ in past ______ years last glacial maximum was ______ years ago
major periods of glaciation in past 500,000 years last glacial maximum was 20,000 years ago
eastern boundary of north american plate
mid atlantic ridge
name the five proterozoic orogens
new quebec trans-hudson thelon tomgat wopmay
where is the queen charlotte transform fault
north of the triple junction ( pacific, NA, juan de fuca) meeting point north west of van island
Canada is situated largely within the ____ part of the NA plate which includes :
northern, northamerica, greenland, west north atlantic, western iceland
what to plates are responsible for cordilleran orogen ?
pacific and north A
the orogenic belts are regions formed during
phanerozoic eon
third phase of appalachian orogeny
third phase of appalachian orogeny (325ma-260ma)
rocky mountains are comprised of ______ and ______, ______ rocks
thrust and fold, sedimentary rocks
true or false: there is a passive boundary between the maritime (newfoundland) and the atlantic ocean floor
true
praire evaporite formed how many years ago
~ 385 Ma
describe the timeline for geological evolution of canada
1. archean cratons 2 . super continent nuna 3. rodina (greenville) 4. pangea - appalchian orogen 5. innuitian orogen 6. cordilleran orogen
innuition fold belt what orogeny ? what periods? what collision ? after about 200my of _______ and _____ the rocks were folded again during the _______ orogeny, when ______ collided with northeastern laurentia
Ellesmerian orogeny during devonian to carboniferous periods (360ma) attributed to collision with a terrane known as pearya .. after about 200my of subsidence and extension the rocks folded again during the eurekan orogeny (50Ma) when greenland collided with northeastern laurentia
describe the precambrian rocks found on the canadian shield
Igneous (granite) metamorphic (gneiss) highly deformed, metamorphosed sedimentary and volcanic rocks host valuable mineral deposits
name the six geological provinces in canada
cordilleran orogen continental platform canadian shield innuitian orogen appalachian platform continental shelf and slope
western canadian sedimentary basin under went _____ and ______ _____ during mountain building tectonically induced _______ produced broad foreland basin
deformation and crustal thickening subsidence produced broad foreland basin
the basins that eventually filled with phanerozoic sediments were created and destroyed by rising and _______ ______ levels and by ______ processes
falling sea levels and by tectonic processes
the canadian prairies are underlain by_______ -______ sedimentary rock
flat-lying sedimentary rock
what kind of rocks make up the innuition fold belt? time frame
folded sedimentary rocks ranging from cambrian to tertiary periods
what are the patterns of the geology of canada related to
formation of the supercontinents accretion of terranes, which consist of fragments of continental crust, island arcs or oceanic rocks
western interior seaway measured 1000 km across and 800m deep formed during _____ during subduction of _____ plate closed due to uplift associated with _______ orogeny 75-40ma
formed during cretaceous during subduction of farallon plate closed due to uplift associated with laramide orogeny 75-40 ma
describe the appalachian fold belt
series of different terranes made up of rock deposited along the edge of laurentia or amid islands that formed between laurentia and Gondwana
name the five archean cratons
superior slave rae hearn nain (Na)
what was the first phase of appalachian mountain building
taconic orogeny (~470 ma) - first phase of appalachian mountain building