This glacial cooling event we call the most recent ice age, was forming over the northern extent of North America, and specifically along the extent of British Columbia and Alberta, pressing into Washington, Idaho and Montana globally starting 2.6 million years ago, but it was only starting to break apart about 11,700 years before present.
As glacial ice broke, water and ice were destined to overtop flood basalt lands, located downstream of the melting glaciers, scraping off soils, plants, animals, and everything else accumulated on these surfaces. It happened as the flowing icebergs and glaciers scrapped off surface lands. This slurry of organic and inorganic materials ultimately became recycled at new resting places. Some as glacial erratics, and some as fresh soils on new surfaces.
