Re: ophiolites and minerals
Ophiolite is an older term for a mixture of metamorphosed basaltic lavas. They have a great deal of variation (i.e. poorly defined), but generally are thought to represent early stages of tectonic activity. Many appear to have been deposited as submarine pillow basalts, rich in olivene, pyroxenes, and amphiboles. These minerals alter to serpentine, chlorite, epidote, and etc. usually giving an overall dark greenish color. In contrast, rare earth minerals are usually found in late stage, siliceous magmas (i. e. granites, pegmatites) and in sedimentary accumulations of weathering products of these rock types, especially playa lake deposits. Diamonds appear to form in deep ultra-basic magmas that do not reach the surface before cooling. So in answer to your questions - anything is possible, but neither rare earth minerals nor diamonds are likely to be found in ophiolites.
From MikeR - October 06, 2011 at 02:12:56