A fossilised forest comprising of fossil trees (known as Calamophyton), and vegetation-induced sedimentary structures has been discovered in the high sandstone cliffs along the Devon and Somerset coast of Southwest England. This dates from 390 million years ago which makes it the oldest known fossil forest on Земля.
One of the key events in the history of Земля is afforestation or transition to forested планета following evolution of trees and forests in the Mid–Late Devonian Period, 393–359 million years ago. The tree sized vegetations fundamentally changed the land biosphere in terms of stabilisation of sediments on flood plains, clay mineral production, weathering rates, CO2 drawdown, and the hydrological cycle. These changes had profound impact on the future of Земля.
Найдавніші окремо стоячі викопні дерева належать до Cladoxylopsida, що виникли на початку середнього девону. The кладоксилопсиди (calamophyton) були менш деревні порівняно з ранніми лігнофітами археоптерідалеана (archaeopteris), які еволюціонували пізніше в пізньому середньому девоні. З пізнього середнього девону флора деревних лігнофітів почала домінувати на суші (лігнофіти є судинними рослинами, які утворюють міцну деревину через камбій).
У недавньому дослідженні дослідники виявили раніше невідомий ранньодовінський кладоксилопсидовий лісовий ландшафт у формації піщаника Hangman у Сомерсеті та Девоні на південному заході. England. The site contains free-standing fossil trees or fossil forest dating from 390 million years ago which makes it the oldest fossilised forest known on Земля – about four million years older than the previous record holder fossil forest found in New York State. The study sheds light on the impact of the oldest forests.
Команда кладоксилопсид trees resembled palm trees but lacked leaves. Instead of solid wood, their trunks were thin and hollow in the centre and their branches were covered in hundreds of twig-like structures that dropped on the forest floor as the tree grew. The trees formed dense forests with very high abundance of plant debris on the floor. There was no growth on the floor as grass had not evolved yet but abundance of droppings by the densely packed trees had a big impact. The debris supported invertebrate life on the floor. The sediments on the floor influenced the flow of the rivers and resilience against floods. This was first time in the history of Земля that tree-driven changes influenced course of rivers and non-marine landscapes of the планета changed forever.
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Посилання:
- Davies N.S., McMahon W.J., and Berry C.M., 2024. Земля earliest forest: fossilized trees and vegetation-induced sedimentary structures from the Middle Devonian (Eifelian) Hangman Sandstone Formation, Somerset and Devon, SW England. Journal of the Geological Society. 23 February 2024. DOI: https://doi.org/10.1144/jgs2023-204
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