Ophiolites are fragments of oceanic crust and upper mantle that have been uplifted and emplaced on continental margins. They consist of five main layers: sediment, pillow basalt, sheeted dikes, gabbro, and peridotite. Ophiolites provide evidence for seafloor spreading and plate tectonics. While similar in composition, ophiolites differ from oceanic crust in thickness, age, density, and composition due to uplift and emplacement processes. Ophiolites in Pakistan are found in collision zones from the Indian plate colliding with the Eurasian and Afghan plates.