Geochemistry of the Permian «kolymic» Limestones of the Omolon Massif (Northeast Asia)

Five types of carbonates were differentiated among the Middle Permian (Roadian-Wordian) deposits of the Omolon massif when studying rare-earth and rare element distribution and petrographic characteristics. New data were obtained on the geochemical features of the «Kolymic» limestones indicating their bacterial nature. The rocks were formed in shallow oxygen-rich environments under humid climate conditions. Possible sources of volcano-terrigenous admixture in the limestones were intermediate and basic volcanics (Okhotsk-Taigonos volcanic arc), as well as acidic igneous rocks (Devonian volcanics of the Kedon Series), which were located near the sedimentation basin.