Ophiolite

An ophiolite is a slice of oceanic crust and upper mantle that has been thrust onto a continent rather than subducted, exposing the deep-sea section on land. A complete ophiolite shows the full pseudostratigraphy from top down: deep-sea sediment, pillow basalts, a sheeted dike complex, layered gabbro, and mantle peridotite below the fossil Moho. This sequence is the main on-land evidence for how oceanic crust is built at a spreading ridge. Emplacement, called obduction, happens when an ocean basin closes during the Wilson cycle. The Troodos massif in Cyprus and the Semail ophiolite in Oman are the classic complete examples.