Chixculub and volcanoes: dinosaurs die! (Introduction)

by David Turell , Saturday, July 16, 2016, 05:01 (3052 days ago) @ David Turell

What if Gulf Oil burned and produced so much soot the temperature dropped and dinosaurs died:-http://phys.org/news/2016-07-oil-dinosaurs.html-"A new study may get us closer to solving this mystery. The asteroid struck the Yucatan Peninsula, a region with vast quantities of crude oil buried underground. New data shows that the burning of the oil produced billions of tons of soot, enough to dim the sun for years and lead to a decade of global cooling.-"The Cretaceous-Paleogene (K-Pg) extinction event was severe, wiping out over 75% of all species, including not just dinosaurs but also many birds, mammals, snakes, lizards, plants, and even insects. It was global, hitting all continents and all oceans. And it was rapid, with species seeming to vanish overnight.-***-"But how does an asteroid impact in Mexico cause a worldwide extinction? Alvarez read about the 1815 explosion of Tamboro. Sulphate gas shot into the atmosphere caused a volcanic haze that reflected sunlight. It lead to the "Year Without a Summer", when freezing temperatures in summer lead to widespread crop failures and famine. Alvarez proposed that debris from Chicxulub had blocked out the sun. Without the sun, plants and plankton couldn't make food and the entire ecosystem starved.-"It was a clever idea but studies of the K-Pg boundary revealed a problem. The debris was mostly coarse and would have dropped out out of the sky in a matter of a few months or weeks - not long enough to starve giant dinosaurs. There wasn't enough fine debris that could stay aloft for years to cause an extinction. So what did?-***-"As the Chicxulub asteroid tore into the earth, it released the oil locked in the rock. The Deepwater Horizon spill produced 4.9 million barrels of oil from just a tiny hole in the ocean floor. The Chicxulub crater was 180 kilometers across. The intense heat of the impact would have burned the oil to create clouds of black soot and shot them into the stratosphere. Critically, tiny soot particles can stay up in the atmosphere for years. But was there enough to block out the sun?-"The researchers from Tohoku University in Japan studied the chemistry of soot at the K-Pg boundary and then estimated the amount of soot produced by impact. The total burned carbon produced was on the order of 1.8 to 60 billion tons.-***-"They then used computer models to estimate the effects on the climate. Their models showed that the soot would have been highly effective in blocking light. Depending on the amount of soot, sunlight would have been reduced by 50% to 90%, and the global temperature would have cooled by between 6°C and 18°C, with cooling being especially severe towards the poles. Cooler temperatures would have also reduced rainfall, leading to widespread drought.-"Critically, the soot cloud would stay aloft for years. The darkness and cooling were most severe in the first few years, but it would have taken a decade for light levels to slowly return to normal, and even longer for the climate to return to normal.-"The research also helps put a time limit on the dinosaur extinction, suggesting the bulk of it took place in a span of less than ten years.-***-"But the new study is one of the most exciting developments in years, and it suggests that we may be closer to finally understanding the extinction of the dinosaurs. It may be that their extinction was caused by pollution and climate change caused by burning oil.-"This could also explain why other asteroid impacts aren't associated with mass extinctions. It may have been the unlucky coincidence of a huge oil field and a giant asteroid impact that made Chicxulub so deadly. "-Comment: Fascinating new theory. The Gulf of Mexico is filled with giant oil reserves.