Evolutionary stages of Triassic flora in Siberia (Angarida)

Abstract

The Triassic flora of Siberia has been studied from three series of Triassic system in continuous sections. Therefore, its successive alterations and stages in the evolution throughout Triassic from the P/T boundary may be traced. Due to alternation of floristic complexes and marine deposits, the age of floristic complex may be precisely determined. The most ancient complex is studied from Induan deposits. In a single section Permian cordaitean flora is replaced.

In Siberia, the Early Triassic flora is heterogeneous. Two major floras, occupying different ecological niches, are distinguished: the lycopod flora (dominated by Tomiostrobus and Pleuromeia) being confined to marine plain, and the conifer fern (Korvunchanskaya) flora is distributed within intracontinental areas where intense volcanism had occurred at that time. The Middle Triassic flora is scanty in Siberia. The Early Ladinian flora differs from both the Early Triassic and Late Triassic ones, while the Late Ladinian flora is closely related to the Late Triassic flora.