Re: deep water = less ejecta?

[john bois <jbois@verizon.net>]

----- Original Message ----- 
From: "MICHAEL HABIB" <habib@jhmi.edu>
To: <dinosaur@usc.edu>
Sent: Sunday, January 27, 2008 12:12 PM
Subject: Re: deep water = less ejecta?


> >My reading of this is that they infer deep water from the shallow nature 
> >of the crater--meaning (I think) that the water >absorbed enough energy 
> >to blunt the force on the ocean floor.
>
> It could also mean that the floor filled and rose more rapidly immediately 
> after impact than it would have in a terrestrial setting, leaving a more 
> shallow depression post-impact.
>
> > In any case, if the crater is shallow it follows that less ejecta was 
> > blown out (right?)
>
> Maybe, but not necessarily.  Even if it is true, that would only refer to 
> the melted rock ejecta; the rest would be water (which probably isn't much 
> better for the global ecosystems), and the total ejected mass would likely 
> be similar.
>
> > If the water/rock ratio was appreciably different this should have a 
> > different effect than previously believed.  For example, heat >energy in 
> > water vapor would have a more local effect...at least versus the re-entry 
> > of solids globally.
>
> The effect might be different, but I'm not sure we have reason to think it 
> would be more local (perhaps fewer actual forest fires and more general 
> broiling?).  The heat energy in the water vapor would still be transferred 
> to the atmosphere, and thanks to the high heat capacity of water, it would 
> be able to travel further before completely unloading its heat energy. 
> So, I think we need more information before assessing if this would make a 
> major difference in the global scale.
>
> Cheers,
>
> --Mike
>
>
> Michael Habib, M.S.
> PhD. Candidate
> Center for Functional Anatomy and Evolution
> Johns Hopkins School of Medicine
> 1830 E. Monument Street
> Baltimore, MD 21205
> (443) 280 0181
> habib@jhmi.edu