What goes up...
Dec. 9th, 2007 06:51 pm![[personal profile]](https://www.dreamwidth.org/img/silk/identity/user.png){kind=small}
andygatesAt the end of the Cretaceous, lots of dinosaurs died off. We all know that. And the mainstream says that an impacting object from space hit the Yucatán peninsula and the resulting massive devastation was wot dunnit. Less well known is that at around the same time there was a massive series of eruptions in the middle of India which went on to form the Deccan Traps, a huge stepped basalt plateau. Those eruptions came about because of a mantle plume - a hotspot like the well-known Hawaii one. The eruptions were so big that some people think they could have done for the dinosaurs instead.
The coincidence of the big hit and the big eruptions along with the big die-off is vexing, and it has been speculated that the impact triggered the eruptions.
But it could be the other way around.
Here's where the coolness comes in. A Cornell professor called J Phipps Morgan has proposed that gas pressure at a mantle plume could build up to such bonkers levels that when it does finally blow, it could blow a chunk of crust almost into orbit. On a ballistic path, it would go up... and come down with an almighty dino-splattering bang. This supergun showboating has been christened a Verneshot.
Just take a moment to bask in the nerdy glory of that: Verneshot. From the Earth to the, er, Earth again. Mmm, yes.
There are two bits of good evidence to back up the theory, which otherwise sounds a touch kooky. First, it predicts that you'd find depressions at the blast site and pipes of intruded rock - and Kimberlite pipes have been detected from gravity anomalies, under the Deccan Traps. Second, the iridium anomaly at the Cretaceous -Tertiary boundary layer could have come from the mantle plume. It's currently under Réunion, still active, and fat with Iridium.
The coincidence of the big hit and the big eruptions along with the big die-off is vexing, and it has been speculated that the impact triggered the eruptions.
But it could be the other way around.
Here's where the coolness comes in. A Cornell professor called J Phipps Morgan has proposed that gas pressure at a mantle plume could build up to such bonkers levels that when it does finally blow, it could blow a chunk of crust almost into orbit. On a ballistic path, it would go up... and come down with an almighty dino-splattering bang. This supergun showboating has been christened a Verneshot.
Just take a moment to bask in the nerdy glory of that: Verneshot. From the Earth to the, er, Earth again. Mmm, yes.
There are two bits of good evidence to back up the theory, which otherwise sounds a touch kooky. First, it predicts that you'd find depressions at the blast site and pipes of intruded rock - and Kimberlite pipes have been detected from gravity anomalies, under the Deccan Traps. Second, the iridium anomaly at the Cretaceous -Tertiary boundary layer could have come from the mantle plume. It's currently under Réunion, still active, and fat with Iridium.
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Date: 2007-12-09 08:49 pm (UTC)The evidence for a big impact around the Yucatan is very good. The K-T Iridium line is widely acknowledged to come from this impact, but if you examine the deccan traps you find that they straddle the KT iridium spike, which precludes them being responsible for it.
My best guess, neither of these things were very good for the dinosaurs and both contributed to an extinction event.
no subject
Date: 2007-12-09 08:50 pm (UTC)no subject
Date: 2007-12-10 09:35 am (UTC)no subject
Date: 2007-12-10 07:22 pm (UTC)