GeologyRocks

I'm with you Benauld, I think it's a combination of events (which may be related -  eg massive lava outpourings brought about by the proximity of something massive approaching the Earth).  But it's nice to see a piccy which looks like something from a 1950's B-movie included in the article.  And how about the asteroid being 5 times faster than a speeding bullet?  I don't suppose it really matter how fast it goes, it's still going to make a big dent.

I prefer the quote from one of my colleagues at Imperial:

Mmmm....chargrilled dino-steak. Yum!

But what about those reports in Geoscientist which state that dating of the Chixulub (apologies for the spelling) impact place it approx 0.5Myr too early for the mass-extinction if it were to be the apocolyptic trigger event that it was supposed to be?

Surely 500,000 years is sufficient for the after effects of the impact to dissipate, even the dust would settle after a few 10s of years.

However, one item that I've never been sure of is the rate of extinction at the K-T boundary. I suppose it depends on the resolution of the rocks and the numbers of fossils found but if the data suggests a decline over 100,000 - 1,000,000 years then surely this disproves the 'hollywood' meteor theory. Although no doubt the imapct would have further stressed the environment and may have been the incident that pushed life over the edge.

I guess what I'm trying to get at in a roundabout way is that a group of scientists (no doubt highly respected) have apparently shut-off all debate about the K-T extinction whilst there is still some uncertainty about the exact mechanism. Due to the imperfect rock record I'm sure some uncertainty will always remain (as is the case in all science) and I think that the scientists who made this announcement would have better served science by explaining the uncertanties rather than making a (very unscientific) decree of absolute truth.

Most, if not all, people on this forum probably have been, are in the process of or will be educated to degree level in a science and will understand error and uncertainty to a reasonable degree. I feel the challenge is in communicating this to the public (and journalists). Currently, when scientific knowledge is updated and refined because more data has become available or new techniques are invented the public response is that what was previously accepted was 'wrong' therefore why should they trust what is now 'right'. Therefore now that an announcement has been made that Chixulub is the trigger event with no doubt, uncertainty or counternance of other proposals given how will it be possible to retract this position should further evidence come to light in the future that casts doubt on this interpretation?

And seeing as I'm on a bit of a rant here can someone please stop journalists and news reports using terms like 'Scientists believe....' or 'According to scientists...' as if science is faith-based rather than evidence-based. This leads to the public talking about 'so-called-experts' as soon as predictions are out by a few percent.

 And politicians who think that by saying something, or by winning a hypothetical argument, they are correct and what they have said is true. I think this is because they are generally lawyers who are trained to win arguments regardless of the facts. We need more scientists and engineers in government! Who's with me?!

Erm, sorry, kind of went a bit off-topic just there - but it feels good to get it off my chest!

Well Done!  It's good to see a rant now and again.

For a while they thought the impact had triggered the Deccan activity, until they realised it pre dated the asteroid impact. That blew that idea out of the water.

My opinion is the Earth was undergoing pretty severe flood basalt volcanism that was contributing noxious gases into the atmosphere slowly killing off certain forms of life. The impact then sealed the deal so to speak. 

Don't forget BBC 4 at 9  this evening Ali - they might tell us.  Or it may turn out to be the usual TV/journalism sensationalistism (is that a real word????)

John

“Civilisation exists by geological consent, subject to change without notice.” -  Will Durant

I am working tonight but I will have it on record

It seems these programmes never reach a solid conclusion anyway but they usually make good tv :) 

Well, I didn't think that was too bad at all.  Obviously the whole thing had to be at a fairly low level to allow for non geologists, but I didn't think it was condescending.

What other opinions have we got?

John

“Civilisation exists by geological consent, subject to change without notice.” -  Will Durant