The Day the Dinosaurs Died

NewYorker.

Talk aboucher Serendipity: a Tale here well told ..along with the IF?s and the time-coordination of so momentous a Find to all paleo-folk
(+ Usn's too: who wouldn't be here) ... if that collision hadn't occurred.
Hmm--planet would be healthier though, sans homo-sapus. So if we could Rewind: who wants the sucker to fly-on-by? or are ya all homo-sap/chauvinist pigs?

[. . .]

The Tanis site, in short, did not span the first day of the impact: it probably recorded the first hour or so. This fact, if true, renders the site even more fabulous than previously thought. It is almost beyond credibility that a precise geological transcript of the most important sixty minutes of Earth’s history could still exist millions of years later—a sort of high-speed, high-resolution video of the event recorded in fine layers of stone. DePalma said, “It’s like finding the Holy Grail clutched in the bony fingers of Jimmy Hoffa, sitting on top of the Lost Ark.” If Tanis had been closer to or farther from the impact point, this beautiful coincidence of timing could not have happened. “There’s nothing in the world that’s ever been seen like this,” Richards told me.

[. . .]

https://www.space.com/what-killed-dinosaurs-asteroid-volcanoes.html

[...]

That paper's authors also uncovered a surprise: Their new dating showed that about 75 percent of the lava created by the Deccan Traps erupted after the impact. If further research confirms it, that's a novel finding, as previous studies suggested that only 20 percent of the lava flowed after the asteroid or comet hit.

The scientists used a precise dating method called argon-argon dating to measure rocks formed around the same time as the mass extinction at the end of the Cretaceous and beginning of the Tertiary period. This area in the geological record is called the K-Pg boundary (formerly known as the K-T boundary).

In the new paper, this team built on previous research they'd done pinpointing the date of the impact, which rocks collected in Montana suggested occurred 66,052,000 years ago, give or take 8,000 years.

They have also tackled the Deccan Traps dating conundrum before, in a 2015 investigation of Indian samples that showed that in at least one location, the eruptions happened within 50,000 years of the impact. Now, the scientists have obtained similar dates from a total of 19 rocks found at other locations in the Deccan Traps.

If most of the lava shot out after the impact, this has large implications for how the extinction played out. Here's what the standard narrative has been: If most of the Deccan Traps lava burst out before the impact, then the gases it generated could have caused global warming during the last 400,000 years of the Cretaceous. Observations show that global temperatures increased by about 14.4 degrees Fahrenheit (8 degrees Celsius), which would have forced species to evolve to live in these warmer temperatures. Then the disturbed ecosystem would have collapsed amid sudden global cooling after the impact kicked up dust (blocking the sun) or the volcanic gases cooled the climate.

The new scenario suggests climate change happened even before the eruptions peaked. If this happened, gases would have trickled out from underground magma chambers over a long period , similar to what is observed today at Mount Etna in Italy and Popocatepetl in Mexico.

"This changes our perspective on the role of the Deccan Traps in the K-Pg extinction," lead author Courtney Sprain, a former Berkeley doctoral student who is a postdoctoral researcher at the University of Liverpool in the United Kingdom, said in the same statement. "Either the Deccan eruptions did not play a role — which we think unlikely — or a lot of climate-modifying gases were erupted during the lowest volume pulse of the eruptions."

There are many open questions with this research, though, particularly since volcanoes can produce both cooling and warming gases. And scientists have never been able to measure the output of a massive flood basalt eruption like the one at Deccan Traps in real time — the last such eruption finished about 15 million years ago, in the Pacific Northwest.)

The second new study also complicates matters, calculating slightly different date estimates for the Deccan Traps eruption. (The two groups analyzed different minerals; furthermore, one focused on the lava flows themselves, and the other on sediments found between lava flows.)

(Emphasis added.)

Fascinating stuff, but there's still an awful lot that is unknown.

Cheers,
Scott.

Post #428,189 by Ashton 4/1/19 3:04:25 PM 4/1/19 3:04:25 PM Reply	The Day the Dinosaurs Died NewYorker. Talk aboucher Serendipity: a Tale here well told ..along with the IF?s and the time-coordination of so momentous a Find to all paleo-folk (+ Usn's too: who wouldn't be here) ... if that collision hadn't occurred. Hmm--planet would be healthier though, sans homo-sapus. So if we could Rewind: who wants the sucker to fly-on-by? or are ya all homo-sap/chauvinist pigs? [. . .] The Tanis site, in short, did not span the first day of the impact: it probably recorded the first hour or so. This fact, if true, renders the site even more fabulous than previously thought. It is almost beyond credibility that a precise geological transcript of the most important sixty minutes of Earth’s history could still exist millions of years later—a sort of high-speed, high-resolution video of the event recorded in fine layers of stone. DePalma said, “It’s like finding the Holy Grail clutched in the bony fingers of Jimmy Hoffa, sitting on top of the Lost Ark.” If Tanis had been closer to or farther from the impact point, this beautiful coincidence of timing could not have happened. “There’s nothing in the world that’s ever been seen like this,” Richards told me. [. . .]
Post #428,190 by lincoln 4/1/19 4:03:58 PM 4/1/19 4:03:58 PM Reply	ICLRPD “It’s like finding the Holy Grail clutched in the bony fingers of Jimmy Hoffa, sitting on top of the Lost Ark.” Satan (impatiently) to Newcomer: The trouble with you Chicago people is, that you think you are the best people down here; whereas you are merely the most numerous. - - - Mark Twain, "Pudd'nhead Wilson's New Calendar" 1897
Post #428,192 by Another Scott 4/1/19 6:02:25 PM 4/1/19 6:02:25 PM Reply	Relatedly... https://www.space.com/what-killed-dinosaurs-asteroid-volcanoes.html [...] That paper's authors also uncovered a surprise: Their new dating showed that about 75 percent of the lava created by the Deccan Traps erupted after the impact. If further research confirms it, that's a novel finding, as previous studies suggested that only 20 percent of the lava flowed after the asteroid or comet hit. The scientists used a precise dating method called argon-argon dating to measure rocks formed around the same time as the mass extinction at the end of the Cretaceous and beginning of the Tertiary period. This area in the geological record is called the K-Pg boundary (formerly known as the K-T boundary). In the new paper, this team built on previous research they'd done pinpointing the date of the impact, which rocks collected in Montana suggested occurred 66,052,000 years ago, give or take 8,000 years. They have also tackled the Deccan Traps dating conundrum before, in a 2015 investigation of Indian samples that showed that in at least one location, the eruptions happened within 50,000 years of the impact. Now, the scientists have obtained similar dates from a total of 19 rocks found at other locations in the Deccan Traps. If most of the lava shot out after the impact, this has large implications for how the extinction played out. Here's what the standard narrative has been: If most of the Deccan Traps lava burst out before the impact, then the gases it generated could have caused global warming during the last 400,000 years of the Cretaceous. Observations show that global temperatures increased by about 14.4 degrees Fahrenheit (8 degrees Celsius), which would have forced species to evolve to live in these warmer temperatures. Then the disturbed ecosystem would have collapsed amid sudden global cooling after the impact kicked up dust (blocking the sun) or the volcanic gases cooled the climate. The new scenario suggests climate change happened even before the eruptions peaked. If this happened, gases would have trickled out from underground magma chambers over a long period , similar to what is observed today at Mount Etna in Italy and Popocatepetl in Mexico. "This changes our perspective on the role of the Deccan Traps in the K-Pg extinction," lead author Courtney Sprain, a former Berkeley doctoral student who is a postdoctoral researcher at the University of Liverpool in the United Kingdom, said in the same statement. "Either the Deccan eruptions did not play a role — which we think unlikely — or a lot of climate-modifying gases were erupted during the lowest volume pulse of the eruptions." There are many open questions with this research, though, particularly since volcanoes can produce both cooling and warming gases. And scientists have never been able to measure the output of a massive flood basalt eruption like the one at Deccan Traps in real time — the last such eruption finished about 15 million years ago, in the Pacific Northwest.) The second new study also complicates matters, calculating slightly different date estimates for the Deccan Traps eruption. (The two groups analyzed different minerals; furthermore, one focused on the lava flows themselves, and the other on sediments found between lava flows.) (Emphasis added.) Fascinating stuff, but there's still an awful lot that is unknown. Cheers, Scott.
Post #428,198 by scoenye 4/1/19 7:41:17 PM 4/1/19 7:41:17 PM Reply	Wait, wait! The Ark really was in Tanis?!

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