Geological time scale By Rcole9 5 BCE bison come to North America 2 BCE humans come to North America 1 BCE origin of the praries Period: 1 CE to 4600 geological time scale 2 ice age begins covering sk except cypress hills area 50 climate changes sask plateau developes 65 extinction of dinosaurs 66 Triceraptops roam sk 70 swamps rivers and lakes form badlands 75 shallow sea begins to retreat 100 diamonds are brought to surface is sk volcanic pipes 213 sk is covered by shallow sea 220 first mamal 245 first dinosaur 248 mass extinction in oceans 90% od specis disappear 355 First amphibians 385 Winnipegosis reefs are deposited, later become a trap for oil deposites. 470 tyndall stone deposited as massive limestone 478 meterite hits sk leaving behind Carswell meterite crater 544 sk covered by the epicontinetial sauk Sea hard shelled invertebrates 1300 uranium deposited 1700 Erosion of mountains 1800 Orogeny (mountain building) trans hudson orogen earth changes from anoxygenic environment to an oxygenic environment 1850 wathaman batholith (an intrusion of magma under the surface) 1900 Volcanoes in Sk 2100 break up of the ancient continent, creation of large continent 2500 Saskatchewan is a large part of a large ancient continent 4600 earth is formed