From: Glenn Morton <firstname.lastname@example.org>
> This is not surprising at all and this mud layer has no analogy with what
> is seen in the Haymond.
> First, a look at the picture shows that the vast majority of the area is
> covered by the mud. In the Haymond and other turbidites, the shale is
> and widespread.
> SEcondly, any tsunami water trapped in a puddle on top of the sand will
> contain some shale. The water will flow through the porous sand, filtering
> the shale out and leaving it on the surface of the sand. This is why the
> shale doesn't cover the entire deposit.
There is a simularity with the Haymond deposits in that the tsunami
deposited consisted of two layers: the bottom one of sand, the top one of
clay/silt. To be sure the quantites of each are certainly different than
the Haymond deposits.
The article also makes the following points:
1. "The recently deposited tsunami sand is believed to have come from
offshore of the beach as numerous sand dollars were found near the surface
of the deposit."
2. "Another common characteristic of recently deposited tsunami sand was
normal grading (a decrease in the size of the sand grains from the bottom to
the top in the deposit)"
3. "The deposit fined landward (near the shore the sand particles were
larger than the sand farther inland)."
Lets start with point 1.
In this case, as the tsunami swept ashore it picked up beach sand and nearly
simultaneously deposited it as it swept inland. What if, instead of a sandy
beach, the wave had swept across a muddy delta? What would be the major
load carried by the wave? What would be the major deposition? Obviously,
The point being that tsunami deposition reflects the compsition of the soils
across which the tsunami came as it swept ashore. So it could consist of
lots of sand/little clay, or some sand/some clay, or little sand/lots of
One of the major means of identifying turbidite deposition is the fact that
it has normal grading (although reverse grading is sometime noted), from
sand through silt to clay. At the New Guinea tsunami depsition site the
deposit displays "normal grading" (including clay/silt on top). This
confirms an off hand statement from a non-creationary geologist I heard once
who said that tsunami and turbidite depositions were nearly
The tsunami deposition also display landward fining. It is curios to note
that ALL Grand Canyon formations display horizontal fining in one direction
or another. I wonder if anyone has checked to see if the Haymond desposit
layers graded horzontally. I would not be the least bit surpried to find
that they do grade horizontally.
> Thirdly, this is a tsunami deposit which is above sea level which allows
> shale-containing water to flow down through the porous sand as noted
> Below sea level, this won't happen. The water will not flow through the
> like it does on land.
This is a good point. I like it! It makes deposition of clay/silt even
faster than I had thought. It is still note worthy that the clay/silt was
there because the tsunami picked it up and carried it into place.
> So, this has nothing to do with a turbidite.
If it is true that turbidite and tsunami deposits are nearly
indistinguishable, then whos to say that the Haymond deposits are not
tsunami rather than turbidite deposits?
This archive was generated by hypermail 2b29 : Sun Feb 10 2002 - 11:52:34 EST