S. Karato, INTERACTION OF CHEMICALLY STRATIFIED SUBDUCTED OCEANIC LITHOSPHERE WITH THE 660 KM DISCONTINUITY, Proceedings of the Japan Academy. Series B Physical and biological sciences, 71(7), 1995, pp. 203-207
Subducted oceanic lithosphere is composed of two chemically distinct l
ayers, namely basaltic (crustal) and peridotitic (mantle) layers. Rece
nt mineral physics observations suggest that the crustal and mantle co
mponents of subducted oceanic lithosphere have distinct densities and
viscosities. The deformation of such stratified oceanic lithosphere as
it collides with the 660 km discontinuity is examined using a simple
analytical model. It is shown that the separation of the crustal compo
nent can occur through a small scale folding (10-20 km) if the viscosi
ty of the crustal (garnetite) layer is significantly higher than that
of the surrounding mantle (similar to 10(21) Pa s) but is less than si
milar to 10(23) Pa s, leading to a garnet-enriched transition zone beh
ind subduction zones.