Ophiolite is also known as an ophiolite suite. It does not refer to a specific rock but rather to a unique combination of rocks. From bottom to top, ophiolite is composed of olivine, layered sedimentary rocks, a sheeted dyke swarm, pillow lava and a set of marine facies siliceous rocks containing radiolaria fossils. Ophiolite suites are considered to be the remnant oceanic crust from the collision of ancient plates. They are important for the determination of ancient plate boundaries. For example, the ophiolite zone along the Yarlung Zangbo River and the Xiangquan River in Tibet, which is 1,400 km long, is considered to be a suture zone that formed by the collision between the Indian Plate and the Eurasian Plate.