DETRITAL ZIRCON CHRONOLOGY OF MIDDLE-UPPER PALEOZOIC SANDSTONES AROUND THE KHANKA BLOCK (FAR EAST RUSSIA): A NEW CONSTRAINT TO GREATER SOUTH CHINA

Middle Upper Paleozoic shallow marine/non-marine sandstones from the Sergeyvka belt adjacent to the Khanka block (Primorye, Far East Russia) were analyzed by LA-ICPMS U-Pb dating of detrital zircons. The age spectra of detrital zircons from the Devonian Lytorgian Formation, Lower Carboniferous Shevelevka Fm, and Permian Lyudyaza Fm in the Nakhodka area share more or less the same pattern. The majority of detrital zircons are of 500-400 Ma (Cambrian to Silurian). These ages are common in arc granitoids in Primorye and also in Japan, thus suggest the probable derivation from the subduction-related Paleozoic batholith belts along the proto-Pacific margin. In addition, all these Paleozoic terrigenous clastics constantly contain a small amount of Proterozoic zircons, in particular, Neoproterozoic ones, which range in 1860-550 Ma, with prominent dominance in 950-800 Ma (Early-Middle Neoproterozoic). The provenance of the Middle-Late Paleozoic basins around the Kahnka margin had Early Paleozoic arc rocks together with Proterozoic continental crusts. Although minor in amount, the occurrence of these Neoproterozoic grains is significant in regional correlation because continental crusts with the correlative ages are rather rare in modern East Asia, except for South China. It is noteworthy that these age spectra are similar to those of the coeval sandstones in Japan and South China. These support the idea of “Greater South China” (Isozaki, 2014 GFF) that included the conterminous South China and its NE extensions in Primorye/Japan in accordance with their mutual similarity in the Paleozoic fauna. In the paleogeographic reconstruction of Rodinia, S. Chine requires a much larger space than previously imagined.