"The Micro Continent and the History of Land Formations in Eastern Washington"
Three billion years ago all the continents were all hooked together in one continent called Pangaea. Two billion years later Asia splits and floats off. Four hundred million years after Asia split, sediments on coastal plain will later form Kootenay arc.
Five hundred million years later a micro continent crashed into North America, crushing the plain into the Kootenay arc.
Fifty million years later another micro continent crashed into North Okanogan forming the Okanogan highlands.
Twenty to forty million years before now (1998) volcanoes erupted in Western Cascades going up through older Cascades.
Thirteen to twenty million years ago real dark black basalt lava flows around Southeast Washington along with layers of sediments called the Latah formation.
Two to three million years ago wind came North down across the Columbia Plateau and blew in loess---soil.
75,000 years ago higher Cascades formed and out maxed the old ones.
10,000 to 20,000 years ago ice age and glacial flooding came and made big holes in ground and ice melted which was glacial flooding. back to menu