North America

History

The past. The last ice age: the Laurentide and Cordilleran ice sheets grew from 30,000 years ago, held their peak from 26,576 to 19,076 years ago, and melted back by 11,726 years ago. The land beds turn to ice, all at once, and only across those spans.

4 billion years ago

Rocks among the oldest known on Earth formed, now found in northern Canada.

1.8 billion years ago

Older continental blocks collided and welded together into the core of North America.

201.5 million years ago

Huge lava floods erupted as Pangaea began to break apart, at the time of the end-Triassic mass extinction.

55.5 million years ago

Greenland, which rides on this plate, split from Europe and the northeast Atlantic Ocean began to open.

30 million years ago

The Pacific plate first reached this plate's western edge, and the San Andreas fault system began to grow.

6.3 million years ago

The Gulf of California began to open, and Baja California moved over to the Pacific plate.

Sources: Clark et al. 2009, Science 325:710 · Bowring and Williams 1999, Contributions to Mineralogy and Petrology 134:3 · Hoffman 1988, Annual Review of Earth and Planetary Sciences 16:543 · Blackburn et al. 2013, Science 340:941 · Storey, Duncan and Swisher 2007, Science 316:587 · Atwater 1970, GSA Bulletin 81:3513 · Oskin and Stock 2003, Geology 31:23