Известия высших учебных заведений: Геология и разведка (Dec 2017)
Evolution of the plants and invertebrates in the north of the Middle Siberia and environs at the Permian - Triassic boundary
Abstract
Five adjacent eco-stratigraphic units have been considered (listed here, from the bottom to the top): eco-zones Cordaites clercii ... Abiella subovata (7 dominants of the plain sedtmentation level), Quadrocladus pachyphyllus ... Bipemphigus gennisi (29 dominants of the mountain, plain, lowland sedimentation levels), Quadrocladus pachyphyllus ... Echinolimnadia mattoxi (15 dominants of the plain sedimentation level), Elatocladus linearis ... Cornia vosini (13 dominants of the mountain, plain, lowland sedimentation levels), eco-series Ferganiella ... Cornia vosini (11 dominants of the plain and lowland sedimentation levels). The lower eco-zone belongs to Vishkilian (Severodvinian) stage (Upper Permian), the upper one - to the Triassic. The age of the deposits included in the other eco-zones, has been discussed. A complete set includes dominants of the arborescent layer, slope herbaceous cover, lowland herbaceous cover, standing basins, semi-flowing water basins, flowing water basins, coastal basins of mountain, plain, and lowland levels. In the names of the eco-zones the dominant of the arborescent layer of mountain (or plain) level is written to the left, flowing water (or coastal) basin of the lowland level is to the right (through the dot). Eco-zones clearly differ from each other in the composition of the dominants. The clearest boundary is the boundary of the two upper eco-zones. The boundary of the two lower eco-zones is less clear. The least clear boundaries are the boundaries of the eco-zones Quadrocladus pachyphyllus ... Bipemphigus gennisi, Quadrocladus pachyphyllus ... Echinolimnadia mattoxi, Elatocladus linearis . Cornia vosini. It may be prompted to include these three eco-zones in the Taimyrian region-stage, returning its originally suggested volume. It corresponds to the zones from the Clarkina bachmanni to the Stepanocites mostleri.
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