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 زمین.
One of the key events in the history of زمین is afforestation or transition to forested سیاره 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 زمین.
اولین درختان فسیلی مستقل متعلق به Cladoxylopsida هستند که در اوایل دوره دونین تکامل یافته اند. را درختان کلادوکسیلوپسید (کالاموفیتون) بودند کمتر چوبی در مقایسه با لیگنوفیت‌های اولیه باستان‌بین (archaeopteridalean) که بعداً در اواخر اواسط دونین تکامل یافتند. از اواخر اواسط دونین، فلور لیگنوفیت های چوبی شروع به تسلط بر زمین کردند (لیگنوفیت ها گیاهان آوندی هستند که از طریق کامبیوم چوب مقاوم تولید می کنند).
در یک مطالعه اخیر، محققان یک چشم انداز جنگلی کلادوکسیلوپساید اوایل دوره میانی دوین را که قبلاً شناسایی نشده بود در سازند ماسه سنگی جلاد در سامرست و دوون در جنوب غربی شناسایی کردند. انگلستان. 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 زمین – 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.
La کلادوکسیلوپسید 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 زمین that tree-driven changes influenced course of rivers and non-marine landscapes of the سیاره برای همیشه تغییر کرد
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مرجع:
- Davies N.S., McMahon W.J., and Berry C.M., 2024. زمین 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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