Isotope analysis has revealed three age groups of zircons in massive eclogites fromStolbikhaIsland: 1) short-prismatic igneous - 2752±16 Ma (AR I); 2) rounded metamorphic with Omp inclusions – 2683.1±7.8 Ma (AR II); and 3) Proterozoic prismatic, scarce rounded metamorphic – 1895.5±9.5 Ma (PR). The REE distribution spectra of AR 1 zircons are of igneous type and that of AR II zircons is comparable with that of eclogite. PR zircons were produced mainly by gradual and complete replacement of AR zircons, and their REE distribution spectrum displays an inherited pattern, which is due to proportional dilution provoked by the growth of additional crystals.