Here's a breakdown of the typical rocks found in an ophiolite sequence from top to bottom:
* Sedimentary Cover: This layer is often missing, eroded away, or represented by thin remnants. It consists of deep-sea sediments like pelagic clays and cherts.
* Pillow Lavas: These are characteristic features of ophiolites. They form when lava erupts underwater, creating rounded, pillow-shaped structures.
* Sheeted Dikes: This layer is composed of numerous, parallel, vertical intrusions of solidified magma (dikes).
* Gabbro: This is a coarse-grained igneous rock that makes up the bulk of the oceanic crust.
* Layered Gabbro: This layer shows a layering of different minerals within the gabbro.
* Ultramafic Rocks: These rocks, like peridotite, are very rich in magnesium and iron and represent the upper mantle.
So, while ophiolite is not a single type of rock, it's a complex assemblage of rocks that provide valuable insights into the processes that form oceanic crust and the dynamics of plate tectonics.
