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The Okinawa Trough is different from other typical backarc spreading basins because the acidic vol-canic rock(pumice)is extensively distributed in it.Systematic mineralogical and petrochemical study on arepresentative core(Z14—5)to characterize the magmatic evolution of the Trough during its early spreading stage showed that the pumice magma was originally from the mantle,but underwent full crystallizationdifferentiation and was possibly contaminated by crust-derived material.With time,the acidic volcanic ac-tivities of the Okinawa Trough have an evolutional tendency of shifting to relatively basic magma activity.With further spreading of the Trough the magmatic activity will be intensified and the crust of the Troughwill develop from the transitional type to the oceanic type.
The Okinawa Trough is different from other typical backarc spreading basins because the acidic vol-canic rock (pumice) is extensively distributed in it. Systematic mineralogical and petrochemical study on are present core (Z14-5) to characterize the magmatic evolution of the Trough during its early spreading stage showed that the pumice magma was originally from the mantle, but underwent full crystallization differentiation and was possibly contaminated by crust-derived material. Time of the acidic volcanic ac-tivities of the Okinawa Trough have an evolutional tendency of shifting to relatively basic further activity of the Trough the magmatic activity will be intensified and the crust of the Troughwill develop from the transitional type to the oceanic type.