What happened on the day of dinosaurs?Idish knows the answer

66 million years ago, today, known as the prefecture of North Dakota in the United States, a bird's hip planting TheScelosaurus is walking along the coast.

Strange Dragon's skeleton model | ARV NM / Wikimedia

Suddenly he stunned, looking around nervously -the earth began to shock, and the sea water also rolled up. A surging wave that could reach 9 meters high was gradually forming from the south, all the way north, swallowing everything. Strange Dragon began to run in panic, but everything was futile. It and many animals were instantly involved in the devastating waves, mud and wreckage floods, and the waves ruthlessly pulled its legs from the body.

This strange dragon will never know that in the next 24 hours, the dinosaur family represented by it is facing a little "small" friction created by a foreign guest -this foreigner is the huge Hick who is huge Hick. Chicxulub Asteroid, people believe that it is the culprit of dinosaurs.

Imagination of meteorite impact event | Donald E. Davis

It does not know that after millions of years, its roasted legs have become an important evidence of this impact.

Strange Dragon: Poor charcoal grilled dragon legs

In 2021, Robert DEPALMA, a paleontologist at the University of Kansas, led the team to scientific research. At a fossil point named Tanis Site in the Hell Creek strata in North Dakota, they found a dinosaur leg. Although this leg is carbonized, the skin, muscles and bones are well preserved.

Unfortunately Strange Dragon's dry corpse fossil | Documentary "Dinosaur · Last Day"

In order to identify the identity of the fossil, Derma brought the fossil to London and solicited the opinion of Paul Barrett, an expert in bird's hip dinosaur. Barrett believes that this is a strange dragon's leg, that is, the victims mentioned at the beginning of the article. It is not particularly unusual to discover the dinosaur corpse. What makes Dipama shocked is the truth revealed by the details of this dinosaur leg -it is likely to be the person and victim of the asteroid impact.

Map of Tanis | Robert A DEPALMA et al. / Proceedings of the National Academy of Sciences

Due to the integrity of the fossils, Derma and Barrett could try to speculate what the dinosaurs had encountered during their lifetime. Barreta noticed that the pelvis of the dinosaur and the tail spine partly overlapted. They suspected that the animal may be rolled violently during his lifetime, and he was quickly buried like the victims of the ancient city of Pompeii. The biggest possibility is the flood caused by the impact of the asteroid. This poor animal constantly rolls and tears, and finally formed the fossil we see today.

However, why did Dipama and Barrett judge that the floods encountered by this unfortunate dinosaur were set off by asteroid hits the earth? This also starts with Tanis's origin.

Not always lucky survivors

The Tonis fossil point was first discovered by the team of Steve Nicklas, a professor at North Georgia University,. In 2012, Dpalma began to discover the location. In 2017, Dpalma published a striking research result here: the Tonisi fossil point is a witness place for dinosaur extinction.

Why can mammals survive from the shadow of dinosaur extinction and turn over the serfs to sing and become the master of the new era? In the past, the mainstream statement included small mammals, strong adaptability, non -picky eaters, constant temperature, and digging. Among them, digging theory is a more popular saying, because digging holes are quite common among modern small mammals, and it is an effective survival strategy. But this point has always lacked the support of fossil evidence.

Fossil discovered by Tanis Fossils | NASA Goddard Space Flight Center

And Dpalma's team announced that they found a fossil hole in Tanis, which will help support the theory: the entire structure of this hole is narrow, and there are several cavities in the shape of a bottle -shaped bottle; There are some small mammal fossils that are scattered as Cimolesta, which are called Cimolesta, which means "Bai Yan's little thief") -without doubt that they were residents of this cave system during their lifetime.

This cave is filled with sediments, which contains a lot of local ancient plants (such as pine, ferns, etc.) spores and pollen. This shows that when the sediment is poured into the cave, a large number of plants still retain the outside world. After the asteroid hit, the plants were destroyed, so the spores and pollen content outside the cave was small.

The imagination of the dinosaur extinction period, the world outside the cave has become a scorched earth | National Science Foundation, zina dertsky

According to plant sediments, people can guess the origin of this cave -in a very short time before and after the asteroid impact, the animal quickly tapped the cave and then abandoned it. Filial materials are like time capsule, retaining some substances before the catastrophe. The owner of this cave did not survive through the shelter of the cave, like other mammals. It was unfortunately blocked by the dust brought by the shelter by its asylum. Among them. The significance of this cave found that in addition to prove that ancient mammals can indeed survive the calamity through digging, it also implies that the animals in the Tanis area are likely to be the direct witness of the Hick Suruber meteorite impact!

Fish: Cradle of Death

At the end of the late Baiyan World, the rivers and swamps in the Tannis area were paradise for aquatic animals. The catfish fossils here will further reveal what happened before and after the asteroid impact.

Derma's colleague Melanie During, in 2017, went to the Tennis fossil to inspect many times. Daily catfish.

Gao Shouyu, of course, this is not a fish, but the history of the catfish family is indeed very long ｜ Cliff / Wikimedia

The data results of the fossil layer analysis of the imaging show that a large number of dust particles from aliens are preserved in the gill rakes of these catfish, and these alien particles have only one source -the scattered dust particles after the Hick Suruber meteorite is impacted.

These particles have been filtered out before the catfish, but they have not entered the mouth or further entered the digestive tract, indicating that they did not have time to send these things into their mouths, and they returned to the west. Their death is likely to cause severe lake shocks due to meteorite impact, which causes the river to suddenly surge, which causes these fish to die suddenly.

The skull fossils of catfish, small yellow dots in the green part, are the dust trapped in the gill cavity | Melanie Aranka Dominique During et al. / Nature (2022)

After using the micro X -ray technology to analyze the storage of the specimen with micro X -ray technology, Du Rui's team found that these catfish only experienced a very short -term rock, and fossils were formed, which is likely to be caused by the rapid burial after the meteorite impact. If these catfish are indeed "witnesses" who hit the day, paleontologists and geologists can touch the vine. Through the age of these fossil unearthed layers, it is more detailed and specific that 66 million years ago When did you hit the earth, even in what season.

Extinction occurs in a spring

66 million years ago, the huge Hick Suruber meteorite hit the Yicatan Peninsula in Mexico today. Its impact directly affected everything within 1500-4000 kilometers of the impact point, and the Tannis region located at 3,000 kilometers away from the impact point was completely covered.

A series of chain reactions caused by meteorite impact caused 75%of the Earth's species to be completely extinct, and also marked the end of the middle generation. In the past, people called this extinction as the Cretaceous-TERTIARY EVENT Event, referred to as K-T extinct; at the same time, it also regarded 65 million years ago as the end of the Baiji Period.

"K-T Extinction" deposited mineral layer (part of the white line) | Zimbres / Wikimedia

However, by 2004, due to the lack of accurate equivalent in the time span covered by the Third Period, the International Strangers Commission no longer recognizes the effectiveness of the Third Division, and disassembles the third discipline into ancient and new discipline. As a matter of course, the International Strangers Committee encourages the use of the Cretaceous – Paleogene Extinction Event, referred to as the K-PG extinction to replace the name "K-T extinction". The boundaries between Bai Yan and Gujinji have also been measured as 66 million years ago, but the public has not adapted to this new geological concept.

Back to Tennis, in order to figure out what season the K-PG incident happened, Du Rui and her colleagues measured Tannis's catfish fossils. They found that the main growth season of these fish was roughly spring (March-June) and autumn (September-December), because the number of snorkels of catfish at this time will reach its peak. Du Rui's team analyzes the carbon isotope content and judges these catfish growth, so that they can know the season when they are buried in the meteorite impact.

Thin slices of catfish tooth fossils | Melanie Aranka Dominique During et al. / Nature (2022)

The analysis results revealed that 66 million years ago, the Hick Suruber meteorite collided into the Gulf of Mexico, North America in the spring of the northern hemisphere.

Spring should be a season of recovery and vitality. But in this spring, almost all animals with more than 50 kg of body have been killed in the catastrophe brought by Hick Suruber. Because most of the animals in the northern hemisphere have just slowed from the lack of resources, they can no longer support the second severe winter brought by this foreign guest. Fortunately, after 66 million years of impact day, we finally discovered the first witnesses of the day -although it was a few fish and the remaining legs left by a dinosaur. It is believed that in the near future, in addition to the Tannis region, more in -depth evidence of fossils will be found around the world, and the puzzle left us with a meteorite left 66 million years ago.

references

[1] During, M.A.D., SMIT, J., Voeten, D.F.A.E. ET Al.

[2] DEPALMA RA, Oleinik Aa, Gurche LP, Burnham DA, Klingler JJ, McKinney CJ, Cichocki FP, Larson Pl, Egeton vm, Wogelius ra, edwards np, bergmann u, manning pr. (2021). Seasonal End-cretaceous Chicxulub IMPACT Event. https://doi.org/10.1038/s41598-021-03232-9-9

[3] DEPALMA, ROBERT A.; Smit, Jan; Burnham, David A.; Kuiper, Klaudia; Manning, Phillip L.; Oleinik, Anton; Larson, Peter; Maurrasse, Florentin J. A.; Gurche, Loren; Alvarez, Walter (2019). A seismical interest onShore Surge DEPOSIT at the KPG Boundary, north dakota. Https://doi.org/10.1073/pnas.18174071717171717171717170707070707070707070707070707071717170707171774

[4] DEPALMA, R. Et Al. (2017) Life after Impact: a Remarkable Mammal Burrow from the Chicxulub Aftermath in the Hello Creek Formation, North Dakota

[5] The Day The Dinosaurs died, Douglas Preston, March 29, 2019

[6] Marshall, Michael (1 April 2019).

[7] "Tanis: Fossil of Dinosaur Killed in Asteroid Strike Found, Scientist Claim". BBC News. 6 April 2022.

[8] AMOS, Jonathan (24 February 2022).

[9] Schulte, Peter (5 March 2010).

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