What is the meaning of ophiolites ?

O are claimed to be pieces of ocean crust and upper mantle that have been thrust up onto continental crust and are now found in mountains, mainly along continental margins.1,2 An ideal ophiolite suite consists from bottom to top of peridotite, gabbro, sheeted dikes, basalt with pillow lavas and sedimentary rocks. The peridotite is considered to be an upper mantle rock, while the remainder of the sequence consists of ocean crustal layers. Starting at the bottom of ocean crust, layer 3 is gabbro; followed by layer 2B, the sheeted dikes, which are closely-spaced nearly vertical dikes of diabase (an intrusive basalt); layer 2A, which is the extrusive basalt that is suppose to flow from mid ocean ridges; and layer 1, the sediments. Ophiolites can be over 10 km thick and sometimes of large scale, such as the impressive arc-shaped Oman ophiolite that is about 150 km wide and 550 km long (figure 1).3,4