VALIDITY OF KOLYMA-OMOLONSKYI SUPERTERRANE OR KOLYMA REGION (NORTHEAST EURASIA) FROM THE VIEW POINT OF MIDDLE PALEOZOIC PALEOGEOGRAPHY AND BIOGEOGRAPHY

The “Kolyma-Omolonskaya superterrane” (“Kolyma region”) is believed to represent a collage of “terranes” of different genesis and formation times. The Kolyma region is mistakenly shown on palinspastic reconstructions of the Middle Paleozoic as being separated from the Siberian Shelf platform. The autochthonous Tas-Khyaktakh and Selennyakh “terranes” located on the frontal part of the “Kolyma-Omolon superterrane” substantiates patterns of structural and facies of the Yana-Indigirkay carbonate platform to which they belong. In the Middle Paleozoic of Northeast Eurasia and North America was located an epicontinental basin and shelf which extended around the Siberian Platform. In the north, it can be traced to the Canadian Arctic, and to the east into Alaska, Western Canada and Nevada. A unified shelf to the north of the Eurasian and American continents indicates lithological marker levels and general observations of brachiopods. The late Ludford on the territory of northern Eurasia and North America is marked by accumulation of red and sulfate beds, and in the early Pridoian by the beginning of transgression accompanied by the expansion of pioneer species of the brachiopods Atrypoidea phoca (Salter) and Collarothyris canaliculata (Wenjukow), which forms the layers of gray-colored lumpy clayey shale deposits, traced from Novaya Zemlya, Vaigach and Dolgyi Islands, southeast Siberian Plate, Northeast Asia, the Canadian Arctic, and southeastern Alaska. This subglobal event can be called the “Lower Pridolian Event.” Thus “Kolyma-Omolonskyi superterrane” or its synonym “Kolyma region” in the middle Paleozoic was part of a unified shelf of the Siberian and North American platforms which existed until the Middle Mesozoic and moving terranes within their composition over large distances in the late Paleozoic and their subsequent return to the same location in the Late Mesozoic is unlikely.