The appearance of the elements of the Protopteris floras: Paleogeographic constraints

The elements of the Protopteris floras were identified in lower Emsian deposits in areas of collision and rift-related volcanism in Gorny Altai, Tuva Trough, Khakassia, Rybinsk Depression, and the eastern Kuznetsk Basin. The appearance of this type of flora in Siberia was accompanied by short-term climatic transitions from humid to arid conditions and periodic shoreline oscillations. The eruptions of volcanoes brought chemical elements and compounds into the atmosphere, which were responsible for mutations in the plants. Natural selection, which was caused by changes in climatic conditions, also played an important role.