The marine Permian of East and Northeast Asia: an overview of biostratigraphy, palaeobiogeography and palaeogeographical implications

The Permian marine biostratigraphy, faunal successions and mutual correlations (where possible) throughout East and Northeast Asia are synthesized, region by region, based on both published literature and the author's field observations in certain parts of the region. The correlation of the Permian marine successions of NE Asia with the Permian international timescale and, in particular, with Gondwanan Permian marine sequences remains a major challenge, due to profound marine provincialism during the Permian. However, by employing biogeographically mixed faunas from East Asia (SE Mongolia, NE China, South Primorye of Far East Russia and the South Kitakami Terrane of Japan) as ‘biostratigraphic gateways’, coupled with some bipolarly and bi-temperately shared Permian marine taxa and faunas, it has been possible to correlate, with reasonable confidence, some of the high-palaeolatitude Permian marine rock units and faunas of NE Asia with those of the Tethyan region and Gondwana.Palaeobiogeographically, the Permian marine faunas of East and NE Asia are assigned to four major provinces: Verkolyman, Sino-Mongolian–Japanese, Cathaysian and Panthalassan provinces, on the basis of their palaeogeographical distribution patterns and characteristics of faunal assemblages. Of these, the Sino-Mongolian–Japanese Province has considerable significance for regional palaeogeographical, plate tectonic and palaeoceanographical reconstructions during the Middle Permian, because of its conspicuously mixed cool- and warm-water marine biota. The origin of this biogeographically mixed marine biota is interpreted to have resulted from a combination of some key factors, including the increased tectonic convergence between the Bureya–Jiamusi Terrane and the Sino-Korean Platform during the Permian and the intermingling of both warm- and cold-water ocean currents off the eastern coastal areas of the Bureya–Jiamusi Terrane and the Sino-Korean Platform during the Middle Permian.