A volcanic eruption 39 million years ago buried a forest in Peru.Petrified trees now reveal the primitive history of South America


<スパンクラス="キャプション">Based on evidence found by paleontologists, an artist sketched El Bosque Petrificado Piedra Chamana, which may have been seen long before humanity.</span> <span class="帰属"><クラス="リンク ラピッド-noclick-resp" href="https://www.nps.gov/flfo/learn/nature/peru-eocene-forest.htm" rel="ノーフォローノーオープナー" 対象="_ブランク" data-ylk="slk:Mariah Slovacek/NPS-GIP">Maria Slovachek / NPS-GIP</a></span>“src =” https://s.yimg.com/ny/api/res/1.2/xIg4XIqjvkmJw8bf3wMKYA–/YXBwaWQ9aGlnaGxhbmRlcjt3PTcwNTtoPTQ1MS4zOTU4MzMzMzMzMzMzMz/https://s. B / aD05MjI7dz0xNDQwO2FwcGlkPXl0YWNoeW9u / https: //media.zenfs.com/en/the_conversation_us_articles_815/148d46693d23ade9d8ba254b9f398f89 “data-src =” https://s.yimg.com/ny/api/res/1.2/xIg4XIqjvkmJw8bf3wMKYA–/YXBwaWQ9aGlnaGxhbmRlcjt3PTcwNTtoPTQ1MS4zOTU4MzMzMzMzMzMz/https //s.yimg.com/uu/api/res/1.2/onTWidUyIYpOklGPXKlajQ–~B/aD05MjI7dz0xNDQwO2FwcGlkPXl0YWNoeW9u/https://media.zenfs.com/en/the_conversation_us_articles_815/148</div>
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Based on evidence found by paleontologists, an artist sketched El Bosque Petrificado Piedra Chamana, which may have appeared long before humanity. Maria Slovachek / NPS-GIP

On the hill outside the small village of Sexi, PeruThe fossil forest hides secrets about South America millions of years ago.

When we first visited these petrified woods over 20 years ago, little was known about their age and how they were preserved.We started Date with rocks Study of volcanic activity that preserved fossils. From there, from the day the volcano erupted in northern Peru 39 million years ago, we began to stitch together the stories of the forest.

That day, ashes fell into the forest, stripping the leaves. Then a stream of ash material passed through, crushing the trees, carrying them into the river like logs, and to the place where they were buried and preserved. Millions of years later Modern Andean roses Carrying fossils, the rocks were exposed to the forces of erosion, and the fossil forests and leaves were once again exposed to the sun.

This petrified forest, El Bosque Perificado Piedra Chamana, The first fossil forest from the tropical regions of South America to be studied in detail.I’m saved Paleontologist Like us Understanding the history of the vast diversity forests of the tropical regions of the New World and the past climate and environment of South America.

By observing the fossilized tree flakes under a microscope, we were able to map a combination of trees that had grown here long before humanity existed.

Illustrations of each artist of the most common types of wood found and cross-sections of fossil wood seen under a microscope

Illustrations of each artist of the most common types of trees found and cross sections of fossil trees viewed under a microscope

Petrified wood seen under a microscope

A thin sample of petrified wood that could be observed under a microscope was needed to identify the types of trees that were growing in the forest before the eruption. Due to the amount and variety of fossil wood in the field, it has never been so easy.

We sought to sample forest diversity, relying on features that can be observed with the naked eye or with a small handheld microscope. ship Carries water upwards in the presence of trees and annual rings. It was then possible to cut small blocks from the specimen and prepare petrological flakes from them in three planes. Each plane provides a different view of the structure of the tree. They make it possible to see many detailed features related to containers, wood fibers, and wood tissue components.

Three enlarged cross-sections of fossil wood

Three enlarged cross-sections of fossil wood

Based on these characteristics, refer to past studies and provide information. Wood database Find out what kind of tree exists.

Clue in the forest and leaves

Many fossil trees are closely related to today’s lowland tropical forests of South America.

One has the typical characteristics of Liana, a tree vine.Others appear to be large canopy trees, including modern relatives SaberI also found some of the most well-known trees in South American forests: Hula, Or a sandbox tree. Announcer, A type of cashew tree.And Ochroma, Or Barça. The largest specimen on the Sexi site – a fossil trunk about 2.5 feet (75 cm) in diameter – has the following characteristics: Shinometra, Bean tree.

Discovery of mangrove, Avicennia marinaThere was more evidence that the forest was growing at low altitudes near the sea before the Andes rose.

The fossil leaves we found provided another clue to the past. Everything had smooth edges, rather than the more common toothed edges and robes in cooler climates from mid-latitudes to high latitudes.We know that forests were growing when the Earth was once geologically growing Much warmer From today.

Leaves that have been fossilized to the smallest detail.

Leaves that have been fossilized to the smallest detail.

Although fossil forests and today’s Amazon forests have many similarities, some fossil trees have anatomical features that are unusual in the tropics of South America. One is the seed Dipterocarpaceae, Have a group The only other representative in South America But it is common today in the rainforests of South Asia.

Artists bring the forest to life

When we had the opportunity to collaborate with artists at, our notion of what this ancient forest looks like expanded. Floristant Fossil Formation National Monument Reconstruct forests and landscapes in Colorado. Elsewhere with fossil trees is the Floristant with huge petrified redwood stumps. Petrified Forest National Park In Arizona.

In partnership with the artist Maria SlovachekIs also a paleontologist and has made me think critically about many things. What was the forest like? Was the tree evergreen or deciduous? Which is taller and shorter? What did they look like in flowers and fruits?

Studies have shown that many fossil trees are likely to grow in streams and inundated forest areas, but what about vegetation growing from highland waterways? Hills covered with forests Was it, or was it supported by dry-adapted vegetation? Maria investigated today’s relatives of the trees we identified and what shapes and colors the flowers and fruits were. And so on, I found a clue to know what they looked like.

Large petrified logs on open ground against a backdrop of rugged hills

Large petrified logs on open ground against a backdrop of rugged hills

Fossils of mammals, birds and reptiles of the same period have not been found in the ruins of Sexi, but it is certain that ancient forests supported a variety of wildlife. By that time, birds had diversified and crocodile reptiles had long swam in tropical waters.

Recent paleontological discoveries have revealed two important groups of animals – Rodents of monkeys and guinea pigsIncluding guinea pigs arrived on the continent when fossil forests were growing.

This information allowed Maria to live in an ancient forest. result Is a lush waterside forest of tall flowering trees and vines with thick trees. Birds fly in the air and crocodiles fly offshore. You can imagine you were in the world 39 million years ago.

This article is reprinted from the following conversationIs a non-profit news site that aims to share ideas from academic experts. It was written by: Deborah Woodcock, Clark University And Herb Meyer, National Park Service..

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Deborah Woodcock is funded by the American Philosophical Society, the National Science Foundation, and National Geographic.

Herb Meyer is supported as an employee of the National Park Service on this project and is additionally funded by The Friends of the Florissant Fossil Beds, the National Science Foundation, and National Geographic.

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