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Re: extinction

David Marjanovic wrote:

> the impact must have vaporized loads of seawater, so the presence of
> chlorine atoms/ions in the fireball which also contained the iridium is
> expected.

I've seen estimates that water was vaporised or worse for a radius of
about 200 miles around the impact point.  If true, and if the assumed
average depth of the sea in the vicinity was on the order of 500 feet,
then the volume of seawater placed into the atmosphere would be on the
loose order of 12,000 cubic miles.  Would that be enough to provide some

> In short... diffusion of Ir through waterlogged sediments doesn't seem
> impossible to me.

Placing a surplus 12,000 cubic miles of water into the atmosphere would
have increased the average rainfall rate for a while, which would have
caused erosion and loss of vegetation, which would have increased the
rainfall rate for a while, which would......

Seems to me that redeposition and associated diffusion, followed by more
redeposition and still more diffusion would continue for some time.

Dewey, how much water was actually placed into the atmosphere, and for
how long a time was the hydrologic cycle disrupted by the reduced
vegetative cover and increased erosion?

All in all, this is a very interesting conversation.

All the best,