The emplacement of the Yarlung Zangbo ophiolites:A new analytical model

The emplacement mechanism of ophiolites is a scientific problem in the plate tectonics which has not been clearly explained till now, and such a situation restricts resolving many secondary questions. In this paper, a new analytical model is proposed on the basis of combination of the key published data and the field observations. The large length of the ophiolite belt suggests a close relation between its formation and the converging plate process; the two phases of arc magmatism in the Gandise magmatic arc indicate translation of the tectonic features at the converging plate edges; there are not sufficient geological, petrological and mineralogical constraints in the previous reports about boninite; the universal discovery of the strongly reduced crystal populations suggests that the obduction process of ophiolite was related to the large scale activity of the deep fluids. Accordingly, a new model of ophiolite emplacement is proposed and called fluid-assisting model, in which the processes such as rollback and break-off of the subducted plate, fluid-lithosphere interaction, and oceanic lithosphere dome seem to have been the essential factors controlling ophiolite emplacement.