Abstract
The rocks of various metamorphic complexes from Archean to Mesozoic-Cenozoic age have been found in the Pacific marginal seas. Those formations are represented by the rocks from high temperature granulitic facies to high pressure glaucophane schist facies.
The Archean-Early Proterozoic rocks of the gneiss-migmatite complex were found in the western part of the Japan Sea. That complex has been formed under conditions of granulite and amphibolite facies (Ps: 5.5-7.5 kbar, T: 630-800°C).
There were Middle Paleozoic schists and amphibolites dredged in the northern Japan Sea. They have been a result of metamorphism of oceanic tholeiites under greenschist facies conditions. The zonal schist complex of the Philippine Sea has been formed on the oceanic tholeiites at constant temperature (500-515°C) and variable pressure (Ps: 4.0-6.5 kbar). Metamorphic rocks of the Okhotsk Sea have been formed at a temperature of 550°C and pressure 5.1 kbar. In the East-China Sea we found Late Paleozoic metamorphic rocks, represented by two complexes. The lower complex is composed of amphibolites and gneisses which had been formed under conditions of glaucophane schist facies (P more than 9.5 kbar, T= 540°C). The schists of the upper complex have been formed at T = 380°C and Ps = 4 kbar. Metamorphism in the marginal seas had been developing along with decrease of the heat flow in time. That is why the high temperature metamorphism of the Precambrian complexes was changed to low temperature greenschist metamor-phism of Phanerozoic rocks which took place in linear zones of high pressure.
