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Re: Ichthyosaurus fossilised in mid-birth ??



What about an earthquake? A seismic event might
collapse many dunes suddenly, making fossilization of
all the local 'lee scarp' animals more probable than
an single fortuitous dune collapse during a flood.
Seismicity also resolves the behavioral questions
raised previously...

--- Phil Bigelow <bigelowp@juno.com> wrote:

> 
> 
> On Sat, 23 Jul 2005 08:47:51 +0100 (BST) Aidan
> Karley
> <aidan_karley@yahoo.co.uk> writes:
> > 
> > --- Phil Bigelow <bigelowp@juno.com> wrote:
> 
> > > The burial has been interpreted to be the result
> of a sudden 
> > massive
> > > dune
> > > collapse.
> > > The Ankie baby clutch is also thought to have
> been buried by a 
> > dune
> > > collapse. 
> 
> 
> >     Something would have been necessary to change
> the structural
> > strength of the dune to get a collapse flow of
> some metres of
> > thickness. The normal lee scarp flows on aeolian
> dunes are what? - a
> > few mm thick? I'm trying to work up a scenario to
> generate such a
> > strength change.
> 
> 
> Ever since the dune-collapse idea first arose, I
> have thought that its
> hypothesized sediment mechanics characteristics
> would make a good masters
> thesis.
> 
> Lee scarp stability depends on grain size, grain
> shape, grain wetting,
> geometry of the grain packing (random, imbricated,
> face-centered,
> body-centered, close packed, tight packed, etc.),
> overburden (if any),
> angle of repose, and who knows what else.
> 
> This would be a good old-fashioned sediment
> engineering study, the way
> your grandpa used to do it***.  It could be a major
> contribution, all
> done by an enterprising student.
> 
> ***Walking 16 miles to school in the snow every
> morning, with no shoes,
> and with only a slide rule and a stale crust of
> bread for companionship
> at night.
> 
> <pb>
> --
> 
> 
> 
> 
>