The Chicxulub asteroid, which kills dinosaurs, struck Earth at a 60-degree angle. At the end of the Cretaceous period, about 66 million years ago, a 10-kilometer asteroid struck Earth near the site of the small Mexican town of Chixulub.
The Chicxulub asteroid
The impact unleashed an incredible amount of climate-altering gases in the atmosphere, triggering a chain of events that led to the extinction of non-avian dinosaurs and 75% of life on the planet. According to new research, this was likely made worse by the fact that the Chicxulub asteroid collided at an angle of about 60 degrees, one of the deadliest angles possible.
The Chicxulub asteroid struck Earth at an angle of about 60 degrees, one of the worst-case scenarios for an impact fatality from the production of climate-changing gases. Image credit: Chase Stone. For dinosaurs, the worst-case scenario is exactly what happened, “said lead author Professor Gareth Collins, a researcher in the Department of Earth Sciences and Engineering at Imperial College London.
Our simulations provide compelling evidence that the asteroid struck at a steep 60-degree angle above the horizon and approached its target from the northeast. We know that it was one of the worst-case scenarios for a fatality on impact, as it threw more dangerous debris into the upper atmosphere and scattered it everywhere; this was what caused the nuclear winter.
Professor Collins and his colleagues examined the size and composition of the crater’s subsoil, using geophysical data to feed simulations that helped diagnose the angle and direction of the impact. Their analysis was also based on recent drilling results in a 200-kilometer-wide crater, which brought rock evidence of extreme forces produced by the impact.
Important in diagnosing the angle and direction of the impact was the correlation between the center of the crater, the center of the peak ring, and the center of dense uplifted rocks, about 30 km below the crater. At Chicxulub, these centers are aligned in a southwest-northeast direction, with the center of the crater midway between the elevation centers of the mantle and the summit ring.
The team’s 3D simulations at a 60-degree angle made these observations almost exactly. They reconstructed crater formation in unprecedented detail and gave us more clues about how the largest craters on Earth form.
“Despite being buried under about a kilometer of sedimentary rocks, it is remarkable that the geophysical data reveals a lot about the structure of the crater, enough to describe the direction and angle of the impact,” said co-author Dr. Auriol Rai. said one researcher. Department of Earth Sciences and Engineering of Imperial College London and the Institute of Geology of the University of Freiburg.
“Large craters like Chicxulub form in minutes, and the bottom of the crater involves a spectacular rock bounce,” said co-author Dr Thomas Davison, from the Department of Earth Sciences and Engineering at Imperial College London.
Our findings can help advance our understanding of how this bounce can be used to diagnose the details of the impacted asteroid. The research is described in an article in the journal Nature Communications.
Giant meteorite landed in Ukraine 650,000 years after the Chicxulub event that killed the dinosaurs. About 66 million years ago, a 10 km (6.2 miles) wide asteroid struck Earth near the site of the small town of Chixulub, in what is now Mexico. While this effect is strongly related to the extinction of non-avian dinosaurs at the end of the Cretaceous and 75% of life on the planet.
Giant meteorite landed
The temporal relationship of the lesser known Boltish impact structure in Ukraine to these events is uncertain, although it is believed to have occurred between 2000 and 5000 years before the mass extinction. A new study published in the journal Science Advances shows that the Boltish impact occurred 650,000 years after the end of the Cretaceous mass extinction; At the time, the weather was recovering from the effects of the Chicxulub effect and the Deccan Traps volcano.
A part of the Boltish-influenced formation near the village of Bovatishka in the Kivorohradska Oblast, Ukraine. Image credit: views / CC BY-SA. The Boltysh impact structure is approximately 24 km (15 miles) in diameter with a central rise 6 km (3.7 miles) in diameter. Located in Ukraine’s Kivorodsk Oblast, the structure is now buried under more than 500 meters (1,640 feet) of post-impact sediment. Previous analysis of Boltish samples conducted decades ago suggested that the meteorite may have struck Earth 2,000 to 5,000 years ago from the Chicxulub asteroid.
The Chicxulub impact is widely believed to have caused the mass extinction event that extinguished non-avian dinosaurs and the climatic event that created the geological signature known as the Cretaceous-Paleogene boundary. However, the question remains whether Boltish’s influence may have been close enough in time to have had an impact on both. The new analysis shows that, in fact, the Boltysh impact occurred some 650,000 years after the Chicxulub event.
Researcher Dr Annemarie Pickersgill said: “The results give us a more accurate view of what happened to Earth in the aftermath of the Cretaceous mass extinction event and our timeline to better understand our deep history. geological “. at the Faculty of Geographical and Earth Sciences at the University of Glasgow.
To determine the date of the Boltish impact more precisely than ever, Dr. Pickersgill and her colleagues selected four samples of two rock cores taken from Boltish Crater, which contained rocks and sediments from the lake produced during the impact event that had accumulated over time. after the crater. constituted.
They determined the age of the samples using the argon-argon dating function. Argon-argon dating measures the radioactive decay of potassium to argon. The level of disintegration serves as a ‘rock clock’, advancing through geological time and today allowing researchers to determine when the rocks formed during the Boltish impact event.
“Our analysis shows that the impact occurred about 65.39 million years ago,” Dr. Pickersgill said. This places it firmly in place after the Chicxulub impact and the formation of the Cretaceous-Paleogene boundary, evidence of which is found in geological records around the world. Researchers make connections for the first time between the new dating of the Boltish impact and evidence for a known ‘hyperthermic’ event found in the Earth’s sediment record, a period of extreme global warming called the lower C29N hyperthermic.
At that point in Earth’s history, Indian volcanoes, known as the Deccan traps, were releasing massive amounts of greenhouse gases into the atmosphere, accelerating a period of global climate change. “The purpose of the Paleolithic is to help us understand and adapt to today’s changing climate by studying how our environment responded to environmental stressors in the past,” said Dr. Pickersgill.
“Being able to link the sediments from Lake Boltish to the hyperthermic lower C29N is another piece of the puzzle that will produce a clearer picture of how our planet has responded to climate change in the past.”