Comments on: A Catastrophic Career http://blogs.discovermagazine.com/loom/2008/11/22/1365/ A blog about life, past and future. Written by DISCOVER contributing editor and columnist Carl Zimmer. Thu, 08 Jan 2009 06:04:06 +0000 http://wordpress.org/?v=2.3.1 By: Mike Clinch http://blogs.discovermagazine.com/loom/2008/11/22/1365/#comment-12499 Mike Clinch Mon, 01 Dec 2008 17:25:20 +0000 http://blogs.discovermagazine.com/loom/2008/11/22/1365/#comment-12499 Before you dismiss the Alvarez hypothesis for the Cretaceous extinctions too quickly in favor of volcanic eruptions, such as the Deccan Traps, consider that the very largest trap basalts seem to coincide with the mass extinctions, and that the trap basalt eruptions are located antipodally to the impact sites. It's possible that the shock wave from large asteroid impacts are focused antipodally, shatter the crust, and allow for voluminous basalt eruptions. Therefore, even if the eruptions caused the extinctions, the eruptions were in turn caused by the impact and we are back to Alvarez Before you dismiss the Alvarez hypothesis for the Cretaceous extinctions too quickly in favor of volcanic eruptions, such as the Deccan Traps, consider that the very largest trap basalts seem to coincide with the mass extinctions, and that the trap basalt eruptions are located antipodally to the impact sites. It’s possible that the shock wave from large asteroid impacts are focused antipodally, shatter the crust, and allow for voluminous basalt eruptions. Therefore, even if the eruptions caused the extinctions, the eruptions were in turn caused by the impact and we are back to Alvarez

]]> By: Vijay Sundaram http://blogs.discovermagazine.com/loom/2008/11/22/1365/#comment-12495 Vijay Sundaram Mon, 01 Dec 2008 09:32:25 +0000 http://blogs.discovermagazine.com/loom/2008/11/22/1365/#comment-12495 In the late nineties in San Francisco I read the book, Night Comes to the Cretaceous, by James Powell which was my first introduction to the solid science and evidence behind the dinosaur extinction theory. The book has an investigative and methodical approach that proposed, investigated and ruled out, through the preponderance of evidence, other potential reasons and causes for the catastrophe. The Alvarez father-son pair were the protagonists and I was in awe of their science and ingenuity. I am thrilled to see Walter's felicitation here. I recall the Deccan traps from about the same time (~65 mya) being one of the chief contenders for the cause of the extinctions. I live now in Bangalore which is in the Deccan plateau and whenever I drive around the rocky countryside I cannot help thinking about the role this countryside might have played in the evolution of this planet and its denizens. In the late nineties in San Francisco I read the book, Night Comes to the Cretaceous, by James Powell which was my first introduction to the solid science and evidence behind the dinosaur extinction theory. The book has an investigative and methodical approach that proposed, investigated and ruled out, through the preponderance of evidence, other potential reasons and causes for the catastrophe. The Alvarez father-son pair were the protagonists and I was in awe of their science and ingenuity. I am thrilled to see Walter’s felicitation here.

I recall the Deccan traps from about the same time (~65 mya) being one of the chief contenders for the cause of the extinctions. I live now in Bangalore which is in the Deccan plateau and whenever I drive around the rocky countryside I cannot help thinking about the role this countryside might have played in the evolution of this planet and its denizens.

]]> By: Todd Oakley http://blogs.discovermagazine.com/loom/2008/11/22/1365/#comment-12249 Todd Oakley Mon, 24 Nov 2008 00:13:11 +0000 http://blogs.discovermagazine.com/loom/2008/11/22/1365/#comment-12249 "But other than the end of the Cretaceous, there’s no compelling evidence at the moment for any impact coinciding with a pulse of extinctions." What about the deep sea crater near Australia that dates to the end Permian? http://www.sciencemag.org/cgi/content/abstract/1093925 I know there were a lot of other things going on then, too, but it seems like a good candidate. Also, I haven't followed that end Permian crater work very closely, so maybe the dates have changed, or I could be mistaken about something.... “But other than the end of the Cretaceous, there’s no compelling evidence at the moment for any impact coinciding with a pulse of extinctions.”

What about the deep sea crater near Australia that dates to the end Permian?

http://www.sciencemag.org/cgi/content/abstract/1093925

I know there were a lot of other things going on then, too, but it seems like a good candidate. Also, I haven’t followed that end Permian crater work very closely, so maybe the dates have changed, or I could be mistaken about something….

]]> By: CoffeeCupContrails http://blogs.discovermagazine.com/loom/2008/11/22/1365/#comment-12214 CoffeeCupContrails Sun, 23 Nov 2008 00:41:44 +0000 http://blogs.discovermagazine.com/loom/2008/11/22/1365/#comment-12214 Excellent article. "Sulfur and Chlorine in Late Cretaceous Deccan Magmas and Eruptive Gas Release" on ScienceMag is restricted access. Any chance of accessing it or a review would be good. Excellent article. “Sulfur and Chlorine in Late Cretaceous Deccan Magmas and Eruptive Gas Release” on ScienceMag is restricted access. Any chance of accessing it or a review would be good.

]]>