orogeny

The process of mountain building — the large-scale deformation and uplift of the earth's crust by tectonic forces, producing mountain ranges over millions of years. An orogeny is not an event but an era: the Laramide orogeny built the Rocky Mountains over roughly 30 million years; the Alleghenian orogeny raised the Appalachians 300 million years ago. The word names the slow, crushing, folding force that turns seafloor sediment into summits.