I was not trying to attempt to correlate any particular stratigraphic
sequence with another but just make some general observations about a
>Palynology, in my opinion, is a somewhat vague way to determine
>environmental influences in the stratigraphic record. Let me indicate why
>using one limited example. In the area that I live, the mountains contain
>primarily pines. At times during the year, great clouds of pine pollen
>exit the front ranges of the Rockies, and are deposited in the lakes and
>ponds of the area. The Foothills trees are primarily larches, aspens and
>cottonwoods, with some pines present in the mix. Depending on wind
>direction, time of year, plus other factors such as sediment influx, lake
>inflow/outflow, etc. many variables are introduced to alter sediment
>entrainment of pollen grains.
Agreed and though I am not expert in palynology I am a professional
botanist and do know my plants. When I see the complete dominance of
pollen from Spruce and Fir trees over a 2 meter section of the core and a
complete lack of pollen from pines over that same area I am not slow to
conclude that the forest not only near to the site but for many hundreds of
square miles surrounding the site, must have been dominated by spruce and
fir trees. Not only do they both produce pollen at the same time of year
but as you say even if there were pines within a 100 miles there should be
pine pollen in the record.
>If one were to core the lake and pond sediments, one would find a
>surprising stratification of a variety of pollen zones. One could surmise
>that a pine forest grew in the area at one time, then a mixed forest grew
>there, then at another, a deciduous forest grew there, then something
>else, all requiring great periods of time. One can be led to all kinds of
>explanations and interpretations, but it is very difficult to conclusively
>KNOW what events occured at the time. We can speculate, to no end.
>Further, there is an explanation within a short period timeframe for these
>sorts of observations as I have indicated.
Too simple: The pollen that is found at particular positions in the
stratigraphic record represent communities of plants that one would expect
to find together in different climatic zones. Why should such
stratification of pollen occur that is simply blown in? Why does it sort
into recognizable plant communities rather than simply types of pollen that
would be found in spring, summer, and fall for example? Also pollen
profiles in sediments above corresponding tephra layers in other cores in
other craters suggest the same succsession of plants at those sites.
Hypothesizing similar wind patterns or depostional rates at all of these
site over a large area would seem a stretch.
I do wish the major emphaisis of my post was not ignored. I pointed out
the positions of the tephra layers which are very distinct. The closest
one to the surface being 21 meters (70 cm thick) the second at 44 meters.
If depostion were occurring at a rather fast pace and this stratification
of pollen were occurring I would expect some disturbance of this tephra
layer. I don't see how these layers could have been deposited until well
after the Flood waters had completely subsided, thus depostion of the 23
meters of highly organic material had to be deposited at some point! This
70 cm tephra certainly wasn't deposited after 500 BC or we would have some
record of it.
Joel and Dawn Duff / | ' \ Spell Check?
Carbondale IL 62901 ( ) 0
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