Abstract: | An ophiolite is an association of igneous and metamorphic rocks, including basalts, dolerites, gabbros and peridotites, which may be a fragment of crust and mantle formed by spreading at a ridge beneath an ancient ocean. This remarkable conclusion is supported by many features of the structure, field relationships, petrology and geochemistry of ophiolites. Although recent research has led to a degree of disillusionment with the idea that ophiolites are fragments of typical ocean floor, these rocks have a good deal to tell us about processes of ocean floor construction and mountain building. |