Double whammy link to extinctions | BBC

[Ediacara]

Double whammy link to extinctions

By Paul Rincon
BBC News Online science staff


What are the chances of such great
events occurring together?

The chances that asteroid impacts and huge bouts of volcanism coincide randomly to cause mass extinctions may be greater than previously imagined.

UK researchers conducted statistical tests to determine the probability of such catastrophic events happening at the same time in Earth history.

They found massive releases of lava and space collisions should have overlapped three times in the last 300 million years.

Details will be published in a future issue of the geological journal Lithos.

More at the BBC

[starroute]

1. I read a book years ago that suggested a causal link

The author's theory was that asteroid impacts somehow speed up continental drift, and that in turn gives rise to greatly increased volcanism. I've been waiting to see when the idea would surface in a more mainstream context, but apparently they're still going with "coincidental."

[damnraddem]

2. I thought the idea about 65MYA was that the hit on Yucatan ...

was on the other side of the world from India, where the shock might have set off the volcanoes already in existence as India rammed Asia, forming the Himalayas.

[Cessna Invesco Palin]

3. ?

The syntax of your sentence suggests either:

a) volcanism formed the Himalayas
b) asteroid collision was instrumental in forming the Himalayas

I don't think either of these is true, but I think I'm probably, uh, misunderestimating what you're trying to say.

--Logan

[megatherium]

4. I've also heard the theory that the Yucatan impact triggered the volcanism

in India (the Deccan Trapps, a huge, unbelievably enormous flood basalt episode). Before the evidence for the asteroid came to light in the 1980s, that volcanic episode was the leading theory for what did in the dinosaurs.

The Himalayas I gather were the result of the Indian subcontinent sliding into the Asian continent. If I remember correctly, they're not very old, a few tens of millions of years old, not as old as the dinosaurs. Someone here who actually knows geology will correct me I hope.

[Cessna Invesco Palin]

6. I believe deccan traps came first...

>I've also heard the theory that the Yucatan impact
>triggered the volcanism

The deccan traps actually began erupting prior to impact, and continued afterwards. I believe that they were active for millions of years before and after, but I'm not quite sure on that point. I believe this is well documented - the ejecta layer from impact is somewhere in the middle of the deccan sequence.

[Ediacara]

5. Not the Himalayas

But the Deccan traps, which were huge flood basalts.