On Sat, 27 Mar 1999 17:15:36 +1100 Jonathan Clarke
<jdac@alphalink.com.au> writes:
>Obviously I need to read the dreaded Gastaldo! Where is this paper
found? I
>am not sure of the relevance of this citation though. My understanding
of
>the roots of vegetation growing in waterlogged ground is that they are
>commonly (though not always) shallow. The citation you give seems
consistent
>to me with that. What is your point?
Gastaldo's paper is: A CASE AGAINST PELAGOCHTHONY: THE UNTENABILITY OF
CARBONIFEROUS ARBORESCENT LYCOPOD-DOMINATED FLOATING PEAT MATS, by Robert
A. Gastaldo, Department of Geology, Auburn University, Alabama 36849
I posted a summary of it at:
http://www.calvin.edu/archive/asa/199804/0389.html
and http://www.calvin.edu/archive/asa/199805/0030.html. These were
followed by my comments in the ASA archives from May 25, 1998. If you
would like, I can send you a copy of the paper by s-mail (but I will need
your address).
>The coals I have seen and most of those I read about have splits and
dirt
>bands. They also have zones where there is coaly sediment, shale,
sandstone
>etc., with coal debris in it, but surrounded by clastic sediment. To me
that
>indicates a complex interplay of autochthonous and allochthonous
processes.
>They might not exist in the coals you are familiar with of course.
I see exactly what you describe. I don't see anything about these
features that suggests autochthonous processes.
>Which coals have you examined?
I've looked at probably several dozen seam outcrops or exposures in north
Alabama, and several of the Kentucky seams which Steve Austin studied
when I joined Steve and his students while they were on a field trip.
The only difference I have noticed in the seams is that some have no
rootlets below and some do; otherwise they are rather monotonous.
>What features lead you to think you are
>mistaken? How confident are you in your own observations?
Very confident. My strength is field geology, mapping and synthesis of
data.
>Last year you
>hadn't recognised rootlet horizons, one of the simplest and most
important
>things to look for in any succession of coaly sediments. I don't want
to
>sound too critical here, but what else are you missing? Other
geologists had
>known about roots etc. beneath Carboniferous coals for over 100 years.
Yes, but I was looking for roots that would support tall trees - the type
described by Gastaldo. In his paper, Gastaldo included a picture of a
stigmarian axial root system. What I had observed beneath coals was tiny
carbonaceous ribbons, which look more like grass roots. Now that I have
recently seen what the stigmarian axial root systems really look like, I
realize that I was looking at rootlets. It is important to note that
large root systems and stumps are found _associated_ with these coals in
B'ham, but not in the strata immediately below the coal (for the large
roots) and the stumps are not in the coal seams - where they would have
to be if they formed the coal in situ.
>Unless they others are all idiots,
No, these are very intelligent men.
>the weight of opinion should always count for something. Of course, you
might be >right for individual seams. Maybe you are right about the
seams you are talking about.
You don't want to go there. The seams I am talking about are not
atypical. If I am right about the seams I am talking about, then there
is something very wrong with the big picture (uniformitarianism).
>Thank you for being so honest. So let me ask you another question. If
it
>were not for this hermeneutic, would you really feel pushed towards the
YEC
>position? Or would you be comfortable with the geological evidence for
an
>old earth?
At this point I'm not concerned about the age of the earth, just coal.
The hermeneutic (and Steve Austin) prompted me to look for myself, having
seen the fit of the data, I no longer need the hermeneutic.
>If you don't want to take Genesis 1-3 figuratively, that is fine, so
long as
>you acknowledge that the Church fathers and the Jewish rabbis thought
>differently. Gordon Brown has pointed out the most likely way Jude 14
was
>meant to be taken.
OK, so maybe instead of Enoch being the seventh, maybe he was the tenth
from Adam. But I still don't see a case for making Adam 250,000 years
ago, nor for making the flood local.
>We have to be careful about what we mean by the word "literal". The
literal
>meaning is the actual meaning, the meaning that the author intended.
Agreed.
>The other interpretation is that it represents a catastrophic collection
of
>floating plant debris.
This is the model I envision.
>I have seen rafts of this type on rivers, shorelines
>and in the geological record.. But they don't have the density of
organic
>mater to form coal. Such agglomerates of plant debris are also quite
weak
>structurally, and it is hard to imagine a raft of that size forming in a
>turbulent environment. They could survive in a low energy environment.
But
>when they sink their relatively low organic content would not result in
them
>forming coal, only a wood rich sediment.
That would depend upon the relative rates of organic and inorganic
settling rates.
>I like the following section, because in it you mention specifics. You
need
>to be more specific though. Which coals are you referring to in it?
The Upper Cliff in Blount County, Alabama which Gastaldo referred to, the
Pratt, Mary Lee, Blue Creek, Jefferson, Black Creek, Jagger, Nunnally
Group, Nickle Plate, and a few others I can't remember right now (all in
north Alabama) and the Kentucky No. 9, 10,
11 and 12 (I think we saw all of these) when I was with Steve Austin in
Kentucky. From what we read, the Pittsburg would also fit.
>Absence of rootlets in the underlying stratum
>is good (though not conclusive) evidence for a coal being allochthonous
>deposit. In my experience the nature of the underlying lithology is not
>significant. I have seen transported plan material overlying both
sandstone
>and shale. I have also seen rootlets in sandstone as well in shale.
However
>you should remember blurring of boundaries in soils is largely due to
>bioturbation by soil invertebrates. I would think these are rare in
>waterlogged soil beneath peat. The environment is too hostile -water
>saturated, low oxygen, and low pH.
Root penetration and decay over thousands of years would blur the
boundary, unless you are talking about a moss peat.
>I don't see why this is a problem. The rootlets you see are the last
ones to
>have formed. This is true whether you are looking at a modern soil, a
>historically buried one, or an ancient ones in the geological record.
When
>you look at a soil in a the side of a ditch you only see the roots
currently
>present (and perhaps a few relicts). These will only be a small
proportion
>of all the roots that have infiltrated the soil. Also remember the
surface of
>peat accretes upwards. So there is not an infinite amounts of time for
roots
>to penetrate into the underlying substratum. Eventually the root zone
will
>be entirely within the peat.
Not according to Gastaldo.
>If only small rootlets are preserved, then the plants growing there had
only
>small roots.
Jonathan, this is true only if we assume your autochthonous model is
true. You have unconciously limited the range of possibilities by
assuming one model. Close your eyes and repeat after me, "I am a YEC"
ten times a day, and eventually you will see other possibilities. :-)
>If large roots are preserved, then plants with large roots are
preserved.
You need to get out of that box. Large roots are preserved, as are
plants with large roots. But the large roots are not directly beneath
the coal and the large stumps are not in the coal.
>We must go by what the evidence says. I can't see the problem
>here.
It's crystal clear to me. Keep thinking about it.
>>I have seen stumps and tree trunks
>> above and below coal seams, but never in the coal, and I don't recall
>> ever seeing a coal seam with a "pothole" interrupting the continuity
of
>> the seam. It looks like the stumps and trunks were floating in water
and
>> settled out.
>
> That is a good point, however, if the hole is filled by peat, it would
be
>hard to see. It would only clearly show up if the overlying sediment
was
>distinctive in character.
Overlying light gray sandstone and gray shale are quite distinctive from
black, vitrain coal. Vitrain coal with vertical joints is easy to follow
because the light reflects off the joints which tend to be parallel. I
have seen a coal seam which appeared almost totally reflective (white
reflected light). If there were any infills from the overlying sediment,
they should be obvious because of the reflective character of vitrain
coal, which is common in Alabama.
>There is layering and layering. Layering formed by physical sedimentary
>processes looks very different to that formed by compression. The coal
thin
>sections I have seen are layered. The layers are defined by compressed
plant
>material, such as cuticle, not by transported sediments. What is the
nature
>of the laminae that you have seen, are they mainly the result of
traction
>currents
What are "traction currents"? If these are impurities introduced by
turbidity currents, then, yes. If these are stream channel cut-and-fill
structures, I have heard of them in coal seams, but have never seen one.
>, or compression of compressive material?
I have seen these laminae in pure vitrain. I suppose they form between
sheets of vegetation.
>Have you seen them in thin section?
No, but I had assumed coal would be too dense to see through. I thought
it was studied in reflected light. I've done neither, but what is the
best method?
> That sounds fair enough. But please define "intensely" and "deeply
>rooted". The literature would suggest that such horizons are common.
The underclay should look like a topsoil which is black at the surface
(from rotted roots) and gradually transitions to native, inorganic soil.
>Is the
>"little or no interbedded material" in the substrate or in the coal?
Sorry, I don't remember my point with that.
>Partial preservation of lamination in the underlying material simply
means
>that there was insufficient root activity to destroy it.
Exactly. So how long would it take a swamp to form 12 inches of coal.
>As I mentioned, the lack of a soil fauna in peat would minimise the
mixing
>between the peat and the underlying material. I have commonly seen
sharp
>contacts between modern peats and underlying substrates.
Moss peats? Have you ever looked at the contact between organics and
substrate in a swamp with tall trees and large, deep roots?
> So what is the problem? Four feet (1.2 m in real measurements)
People who get up with their feet pointing in the direction their head
should be are not qualified to determine what is real. :-)
>suggests that
>there were some deeply rooted plants in the overlying seam. I have no
>problem with that, do you? Os this "deeply rooted" enough to meet your
criteria?
I'm still thinking about that. These roots were all "rootlets" and were
all vertical as far as I could see. I'm not convinced that they were all
connected to the coal. My impression was they were truncated at bedding
planes about 6 inches apart beneath the coal. I would like to think that
they may have floated in.
>Not trying to steamroller anybody, just trying to help you see your
>methodology and the task ahead of you.
This is very helpful and I very much appreciate your time.
Good night, and God bless,
Bill
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