Astro Blog

https://gizmodo.com/the-asteroid-that-killed-the-dinosaurs-spawned-a-monste-1849614930 By  Isaac Schultz , Gizmodo.  Excerpt: The impact created fast-moving waves nearly 3 miles high, a new study finds. A team modeling the aftermath of the asteroid impact that doomed the dinosaurs 66 million years ago say that the collision also created a global tsunami that devastated coastlines from North America to New Zealand. The researchers studied ancient sediments from over 100 sites around the world, to see how extreme waves resulting from the impact may have disrupted the geological record. Their work was  presented  at a meeting of the American Geophysical Union in 2018 and is  published  this week in the journal AGU Advances.… 

https://www.science.org/content/article/dinosaurs-thrived-until-moment-asteroid-hit-excavators-controversial-site-claim By Michael Price, Science Magazine.  Excerpt: ...Two years ago, a paleontologist claimed to have found evidence at a fossil-rich North Dakotan site called Tanis that dinosaurs were alive until moments after the impact, when floodwaters surged over them. But many paleontologists were skeptical, especially because the dinosaur data were first discussed in a magazine story rather than a peer-reviewed journal. Last week, at the annual meeting of the Geological Society of America (GSA) in Portland, Oregon, paleontologist Robert DePalma and colleagues added detail to their claims. They presented evidence of fossils from Tanis—including stunningly well-preserved bones, skin, and footprints from what’s probably a  Triceratops —that suggest dinosaurs were indeed witnesses to the asteroid that ushered them out of existence.…

https://news.berkeley.edu/2019/03/29/66-million-year-old-deathbed-linked-to-dinosaur-killing-meteor/ Source:   By Robert Sanders, Berkeley News, UC Berkeley. Excerpt: The beginning of the end started with violent shaking that raised giant waves in the waters of an inland sea in what is now North Dakota. Then, tiny glass beads began to fall like birdshot from the heavens. The rain of glass was so heavy it may have set fire to much of the vegetation on land. In the water, fish struggled to breathe as the beads clogged their gills. The heaving sea turned into a 30-foot wall of water when it reached the mouth of a river, tossing hundreds, if not thousands, of fresh-water fish — sturgeon and paddlefish — onto a sand bar and temporarily reversing the flow of the river. Stranded by the receding water, the fish were pelted by glass beads up to 5 millimeters in diameter, some burying themselves inches deep in the mud. The torrent of rocks, like fine sand, and small glass beads continued...

https://www.nasa.gov/press-release/international-team-nasa-make-unexpected-discovery-under-greenland-ice Source:   NASA RELEASE 18-099. Excerpt: An international team of researchers, including a NASA glaciologist, has discovered a large meteorite impact crater hiding beneath more than a half-mile of ice in northwest Greenland. The crater — the first of any size found under the Greenland ice sheet — is one of the 25 largest impact craters on Earth, measuring roughly 1,000 feet deep and more than 19 miles in diameter, an area slightly larger than that inside Washington’s Capital Beltway....   See also 2019-02-12. Radar reveals a second potential impact crater under Greenland’s ice. By Paul Voosen, Science Magazine. [ https://www.sciencemag.org/news/2019/02/radar-reveals-second-potential-impact-crater-under-greenland-s-ice ]

https://eos.org/articles/dinosaur-killing-asteroid-impact-made-huge-dead-zones-in-oceans Source:   By Lucas Joel, Eos/AGU. Excerpt: About 66 million years ago, an asteroid roughly 10 kilometers wide hit Earth in what is today the Gulf of Mexico. It brought annihilation: All the dinosaurs except for the birds went extinct; forests around the planet vanished temporarily, killing off all bird species that lived in trees; dust and other aerosols blocked the Sun, and global temperatures took a nosedive. The world plunged into a state analogous to nuclear winter. Another fallout effect of the impact, according to new work, was a depletion of oxygen in the oceans triggered by rapid global warming following the impact and nuclear winter. Such anoxia, the researchers behind the work report, devastated marine life. What’s more, this episode of anoxia may have parallels to the rapid global warming and resulting ocean anoxia being wrought by human-driven climate change today. “The global w...

Source:   Lynn Yarris, Lawrence Berkeley National Laboratory Excerpt: …an international panel of 41 experts in geology, paleontology  and other related fields, after an exhaustive review of the data, declared an end to a 30 year controversy over what triggered the extinction of the dinosaurs – an asteroid or volcanoes. The panel ruled in favor of the asteroid... the size of San Francisco, traveling faster than a bullet, slammed into Earth ...delivered a destructive blast thousands of times more powerful than the combined yield of all the world’s nuclear weapons, setting off earthquakes greater than 11 in magnitude and widespread tsunamis, and shrouding the globe for years in a thick cocoon of sky-blackening dust and debris.... newscenter.lbl.gov/feature-stories/2010/03/09/alvarez-theory-on-dinosaur/