How is lithosphere formed?

Shouldn't the question be “how was the lithosphere formed”? What we see of plate tectonics' activity mostly recycles the oceanic part of a lithosphere that has now existed for much of Earth's history, but only appeared after it acquired its core and Moon. read more

Underneath continents, the lithosphere is deepest and the roots of mountain ranges go down tens of miles (like an iceberg, there is more underneath). The compositions of each type of crust change at plate boundaries, where new rocks are formed from common minerals in both crusts or one is metamorphosed into other rocks. read more

Tectonic activity is responsible for some of Earth's most dramatic geologic events: earthquakes, volcanoes, orogeny (mountain-building), and deep ocean trenches can all be formed by tectonic activity in the lithosphere. read more

New lithosphere is commonly formed at mid-ocean ridges, hot spots, and where there are active volcanoes. read more