PHYSICAL DETAILS OF MAGMA FORMATION IN SUBDUCTION ZONES

It has been shown that the subducting slab is in fact the large foliat ion zone along which the crust and subcrust matter of the lithosphere moves down to the mantle. This slab is a self-regulating dispersed adi abatic system. Decreasing temperature of the slab is kept due to the l imited heat conducting during its quick dipping as well as due to endo thermic process of foliation-induced surface formation initiated by fl ow stress. However, this does not preclude intensive magma formation i n the subduction zones because high dispersion of the foliated rocks a nd high stresses decrease substantially their melting temperature that initiates melt formation inasmuch as high pressure in the subduction zone. Rock melting is connected with the relative extension regions wi thin the subduction zone plane characterizing by drastic diminishing o f interphase boundaries and abrupt energy discharge leading to melting of the substrate. These high-temperature, high-pressure seats accumul ate much thermal energy which transform to mechanical upwards moving o f the melt during temperature decreasing in the system.