INTERNAL STRUCTURE OF THE OPHIOLITES OF CAPE KAMCHATSKIY (EAST KAMCHATKA)

Abstract

The identifying property of ophiolite is the pseudostratified grouping from the bottom up of ultramafics, gabbro, basalt and cherty sediments. In many ophiolite complexes these rocks have been tectonically separated, and the original relationships between them must be reconstructed. So separated ophiolites are typical of the Kamchatka foldbelt, and are most completely represented on Cape Kamchatskiy. During 1986-87 field work in the area, the author obtained new data on the gabbro and cherty volcanic rocks. These data suggest that the make-up of the section is more complicated than was previously thought. The ophiolite association of Cape Kamchatskiy consists of at least three genetically different rock bodies, oceanic basement, their mantling rocks, and island-arc basalt. They were tectonically superposed during the multistage thrusting to the northeast in post-Cretaceous time.