Sixth extinction, rivaling that of the dinosaurs, should join the big five, scientists say

American Association for the Advancement of Science ^ | 16 April 2015 5:15 pm | Eric Hand

[Utilizer]

Earth has seen its share of catastrophes, the worst being the “big five” mass extinctions scientists traditionally talk about. Now, paleontologists are arguing that a sixth extinction, 260 million years ago, at the end of a geological age called the Capitanian, deserves to be a member of the exclusive club. In a new study, they offer evidence for a massive die-off in shallow, cool waters in what is now Norway. That finding, combined with previous evidence of extinctions in tropical waters, means that the Capitanian was a global catastrophe.

“It’s the first time we can say this is a true global extinction,” says David Bond, a paleontologist at the University of Hull in the United Kingdom. Bond led a study that was published online this week in the Geological Society of America Bulletin. He adds that in magnitude, the Capitanian event was on par with the dinosaur-killing extinction 66 million year ago. “I’d put this up there with it, albeit with slightly less attractive victims,” Bond says.

[gleeaikin]

Finally got my Google back and found this very nice time line article for all Earth’s history.

http://en.wikipedia.org/wiki/Detailed_logarithmic_timeline

Here are a great many interesting charts regarding extinction events and related. If you look at the first chart, first row, you can see a charted labeled Marine Extinctions in blue. It clearly shows a two phase, or ongoing series of extinctions toward the end of the Permian. The second chart in the second line, in orange allows shows a similar wide time period of extinctions for the late Permian. So it appears that the Capitanian falls in this period but the biggest extinction was at the 250 mya time line. I don’t know how to transfer these images. Perhaps someone else could do it?

https://www.google.com/search?q=permian+extinction+timeline+charts&num=50&newwindow=1&safe=off&tbm=isch&tbo=u&source=univ&sa=X&ei=01YzVbruMY6TsQTW6IHABw&ved=0CB4QsAQ&biw=1600&bih=775

[SunkenCiv]

Thanks gleeaikin. The Capitanian is aka Middle Permian.

http://en.wikipedia.org/wiki/Capitanian

Looks like a marine extinction, that is, zero to do with an atmospheric volcano — IOW, possibly a submarine volcano, but more likely a sea surface impact.

http://www.science20.com/news_articles/big_6_capitanian_extinction_gets_new_evidence-154854

[TigersEye]

Thanks gleeaikin. This is interesting stuff. I had no idea there were so many extinction events. They usually only talk about the big ones.

[gleeaikin]

Thanks for posting the charts. Also, you may want to look at the following FR link. I made an extensive and detailed comment there, #34, which may interest you and others concerned with natural disaster and volcanoes.

http://www.freerepublic.com/focus/f-bloggers/3280739/posts

[gleeaikin]

Note the smaller but distinct spike about 34 million years ago labeled “End Eocene”. That would be the Chesapeake Meteor that struck just north of Norfolk leaving a crater 60 miles in diameter. Norfolk and territory are on the south rim of the crater, the odd bends in the James and other rivers entering into the Bay are also traversing the western rim. The north rim is at Exmore on the Delmarva Peninsula.

[editor-surveyor]

.
Sci-Fi thread!

.