The Late Jurassic – Early Cretaceous and Paleocene swamp plant communities of Transbaikalia and the Russian Far East|
Eugenia V. BUGDAEVA & Valentina S. MARKEVICH
Institute of Biology & Soil Science FEB RAS, Vladivostok, Russia
On the territory of Transbaikalia, Amur River region, and Primorye region three
stages of development of swamp vegetation, where the abundant plant material
accumulated, can be distinguished: the Tithonian-Valanginian, the Barremian-
Albian, and the Paleocene. The main Tithonian-Valanginian coal-forming plants
were cyatheaceous ferns, conifers, and extinct ginkgoaleans (Pseudotorellia,
Eretmophyllum, and Sphenobaiera). The coal formation at the second stage was
the most significant being manifested over vast areas of Siberia and the Far East.
During the Barremian-Albian,the main coal-forming plants varied in composition
depending on environments: in sea-side marshy plains they were represented by
gleicheniaceous and cyatheaceous ferns, as well as taxodialeans, in intracontinental
basins - cyatheaceous ferns, conifers (Miroviaceae, Cheirolepidiaceae, Araucariaceae,
and Pinaceae) and ginkgoaleans (Baierella, Sphenobaiera, Pseudotorellia).
The coal accumulation of the third stage took place in Zeya-Bureya Basin
(Amur River region). The mire plant communities were dominated by taxodialeans
and polypodiaceous ferns. The composition of the Jurassic and Cretaceous mire
communities shows their conservatism, probably due to similar palaeoenvironments.
Conifers and ginkgoaleans were critically importantelements of swamp
plant communities. Nevertheless, at the Mesozoic-Cenozoic boundary their composition
changed drastically. Miroviaceae, Cheirolepidiaceae, and ginkgoaleans
disappeared. Taxodialeans replaced them in swamp plant communities. Our research
was supported by Russian Academy of Sciences (grant no. 12-I-P28-01),
Far East Branch of RAS (grant no. 12-III-À-06-075, 12-III-À-06-070).
© 2012 Organizing Committee