(via SciShow) The North American continent used to have deep roots extending far into the Earth's mantle. They melted. Here's how scientists think they disappeared.

"A publication of the Decade of North American Geology." Title on envelope: Centennial continent-ocean transects : Tectonic section displays. Accompanies set of maps, sections and profiles with title: ...

7 continents of the world: The Earth consists of 71% and 29% of landmasses. These land masses are further divided into continents. The complicated geological process of plate tectonics led to the ...

There are seven continents on Earth, or so we learned in school. But it turns out that these designations are not as straightforward as they seem, and different scientists have different views on how ...