An ophiolite is a section of oceanic crust and upper mantle that has been uplifted and exposed above sea level due to tectonic processes. Ophiolites are important geological features because they provide a window into the Earth’s interior and allow scientists to study the composition and structure of the oceanic crust and upper mantle, which are normally hidden from view beneath the ocean floor.
Ophiolites typically consist of a sequence of rock types that mirror the layering of the oceanic crust. These include:
- Serpentinite: a rock composed of the mineral serpentine, which forms when the mantle rocks are hydrated and altered by seawater.
- Gabbro: a coarse-grained, intrusive igneous rock that is the plutonic equivalent of basalt.
- Sheeted dikes: narrow, vertical sheets of basaltic rock that intrude the gabbro and represent the feeders for lava flows on the ocean floor.
- Pillow lavas: bulbous or pillow-shaped structures formed by the eruption of lava on the ocean floor.
- Sediments: layers of fine-grained sediment that accumulate on the ocean floor.
The study of ophiolites has played a crucial role in the development of the theory of plate tectonics, which explains how the Earth’s crust is divided into a series of plates that move and interact with each other. Ophiolites are also valuable sources of minerals such as chromite, which is used in the production of stainless steel
