V. K. Kuzmin

Upper Maya uplift (Okhotsk massif): Geological structure, composition, age, tectonic position

Abstract. The Upper Maya uplift of the Okhotsk massif contains the Eoarchean Ancient Maya, Neoarchean Upper Maya, and Paleoproterozoic Iskra complexes. For the Maya complex, the author obtained the Eoarchean and Hadean Nd-model dating — 3.76, 3.77, and 3.99 Ga. In gneiss, zircon cores present the Hadean concordant age as 3,949 ± 11 Ma and 11 Eoarchean datings as 3,862–3,757 Ma. The Upper Maya complex has granulite and amphibolite facies rocks. As the Sm-Nd isotope system suggests, the lower age boundary of the complex’s rock formation is 3.0 Ga. Gneiss zircons have the Neoarchean concordance age of 2,651.9 ± 8.9 Ma (U–Pb, SHRIMP-II). The uplift’s western margin locates the Iskra complex of garnet-biotite, sillimanite-cordierite-biotite schists with the Paleoproterozoic model ages of TNd(DM) from 2.28 to 2.19 Ga.

Keywords: Early Cambrian, geochronology, gneiss, granulite, amphibolite