AmericaA microscopic fragment of an asteroid that struck Earth 66 million years ago may be in the amber at the Tanis site in the Hell Creek Formation, North Dakota.
Naturalist David Attenborough and paleontologist David Attenborough describe the find in the documentary “Dinosaur Apocalypse”. DePalma, a graduate student at the University of Manchester, UK and an assistant professor at Florida Atlantic University, began working at Tanis in 2012.
The excavation site is a rocky plain in stark contrast to the late Cretaceous. At that time, the American Midwest was a swampy rain forest with an inland sea called the Western Interior Seaway that stretched from the Gulf of Mexico today to Canada. Tanis is more than 3,218 km from the Chicxulub impact crater (caused by an asteroid that crashed off the coast of Mexico) more than 3,218 km. But the initial findings here make DePalma confident the site can provide rare evidence of the end of the dinosaur era.
Most of the first spherical crystals that reveal traces of asteroid impacts are preserved in clay, the result of many geological processes over millions of years. However, DePalma and his colleagues also found some spheres lying in the sap above the surface of the log on the day of the dinosaur’s extinction and were preserved by visiting tigers. “In that amber we found some spheres that looked like they were frozen in place. Like perfectly preserved insects, when these spheres fall into the amber block, water cannot enter. They also never turn into clay and are kept intact,” DePalma said.
The researchers were able to identify some pieces of unmelted rock inside the glass sphere. Much of the tiny piece of rock is rich in calcium, most likely from limestone below the Yucatan Bay. According to DePalma, two of the rocks have extremely different compositions with skyrocketing amounts of chromium and nickel and a few other elements that are normally only found in meteorites. Based on preliminary analysis, the team believes that they have an extraterrestrial origin.
DePalma said he and his team hope to be able to confirm what materials the asteroid is made of and where it might have come from. DePalma presented the discovery in April at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. The team will publish a peer-reviewed paper on the preliminary finding in the coming months.
An Khang (According to CNN)
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