ИСТИНА

The Mesozoic and Cenozoic fold belts compose most of the North-Eastern Russia. Blocks of high grade polymetamorphic complexes (granulite and amphibolite facies which is closely intertwined with each other) exist within the Mesozoic belts. They are covered with unconformity by stromatolites-bearing Middle to Upper Riphean sediments in Okhotsk and Omolon areas. Accessory zircons from Omolon gneisses (amphibolite facies) have U-Pb age about 3650 Ма (Bibikova, 1989). Okhotsk mafic granulites have 3700 Ма zircon age (Kuzmin, 2005). Rb-Sr isochron age on rocks as the amphibolite and granulite facies of Omolon is about 3800 Ма (Kotlyar et al., 2001). Eoarchean gneisses of Omolon area include small tectonic bodies of amphibole eclogites. These eclogites thus are the most ancient geologic formations, exposed in the Mesozoic fold belts of the North-Eastern Russia. Amphibole eclogites, very similar to Omolon one, we examined in some Cenozoic belts (Taigonos, Pekulney). Here they are associated with ophiolite belts, and put to modern erosion cut with ultramafic protrusions. We interpret amphibole eclogites as fragments of the oldest mafic protobase of North-Аsian Craton