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About 92 million years ago, in what is today the center of Utah, a terrible storm blew on a huge blooming tree, which was washed away in a river and in an old delta. The sediments buried a portion of the tree trunk, which then mineralized, preserving a fossil that is currently breaking records.
In a new study published Wednesday in Scientists progressResearchers present the oldest indices of large flowering trees in North America. The record fossil is a petrified log nearly six feet wide and 36 feet long. Researchers say the tree was about 170 feet tall, about twice the size of Utah's highest living tree.
The fossil tree trunk probably belongs to Paraphyllanthoxylon, an ancient genus known from other fossils. But this tree has lived and died 15 million years before the oldest North American fossils of large flowering trees. (See the oldest living tree in Europe and find out why there is a growth spurt.)
Outside experts say that the existence of the tree makes sense. Flowering plants, also called angiosperms, appeared about 135 million years ago. A hundred million years ago, the smaller ones dominated some lowlands, and about 75 million years ago, there were obvious traces of massive flowering trees. About 90 million years ago, angiosperms had to start reaching the sky.
"This is not necessarily surprising because we know that there is a rich flora of angiosperms at this time," says Nan Crystal Arens, a paleobotanist from Hobart and William Smith Colleges who n & # 39; 39; was not involved in the study. "But that's the concrete proof, put your hands over-that those tall trees were there."
Finding fossils of this time, called the Turonian, was a challenge because the sea level was high at the time, which means that most turonian sediments capture what was happening in the water, not on Earth. Less than one hundred known angiosperm wood fragments are over 84 million years old and most come from small trees less than four inches in diameter.
"This corresponds to a period that is really under-sampled … so it was really nice to see that coming out," added paleobotanist Dori Lynne Contreras, PhD student. student at the University of California, Berkeley.
Logging history
Finding the massive log was a stroke of luck. With funding from the National Geographic Society, paleontologist Adelphi University, Michael Emic, went to the center of Utah in 2014 to research long neck dinosaur bones. One day, a local official of the US Bureau of Land Management, John Reay, made Emic visit the area and showed him interesting geological features that the BLM had long noted, including the petrified marble .
First, Emic did not know what to do with it. On the one hand, petrified logs are not uncommon in the western United States, especially coniferous ones. But on the other hand, the log was an impressive sight. (Learn more about Petrified Forest National Park in Arizona.)
How trees speak secretly in the forest
What are trees talking about? In Canada's Douglas fir forests, see how trees "talk to each other" by forming underground symbiotic relationships – called mycorrhizas – with fungi to relay stress signals and share resources among themselves.
"You're out there in the desert, and with an untrained eye, you're just looking at a lot of sand and sandstone," says Emic. "But I could see then that there had to be some crazy monsoon storms to move a tree [such as this one] on one of these deltas at this time. I saw the environment come to life.
Dr. Emic asked Reay if he could take samples of the newspaper, which he posted to paleobotanist Nathan Jud, who is now a professor at William Jewell College. Jud first thought the fragments belonged to a large conifer tree. But once he examined them under a microscope, he realized that the log of Utah was not only huge – it was a rare find.
"My jaw dropped," says Jud, the lead author of the study. "I immediately knew that it was the oldest log of angiosperms more than one meter in diameter anywhere in the world." He quickly congratulated Emic by SMS .
Fragment of a large sheet of Ferron Sandstone limb in Utah.
Photograph of Nathan Jud
The team has some follow-up studies in mind to determine where different plants lived in the turonian landscape near the newspaper's resting place. Meanwhile, Dr. Emic hopes the new study will draw more scientific attention to member Ferron Sandstone, the rock formation of Utah who produced the fossils. Not only did the team study the petrified marble, but during subsequent expeditions into the region, they also found pollen, leaves and vertebrate fossils, including a shark tooth and bones. dinosaurs.
"Before our article, there are three journals of member Ferron Sandstone; it's just seen as this sterile unit, "says Emic. "I'm not saying that it's the next big thing or anything, but what it does is encourage other people to prospect for fossils."
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