Re: Geology Question (KRS related)


"Eric Stevens" <eric.stevens@xxxxxxxxx> wrote in message
news:a5o4u1976i53sqoi460vttpl16g10g1d8j@xxxxxxxxxx
On Thu, 2 Feb 2006 05:34:46 -0500, "Steve Marcus"
<smarcus_spamout_@xxxxxxx> wrote:



"Eric Stevens" <eric.stevens@xxxxxxxxx> wrote in message
news:rgt2u1t88kk0bgh61ve7td4sed4utej2j9@xxxxxxxxxx
On Thu, 2 Feb 2006 01:21:58 +0100, "Peter Alaca" <P.Alaca@xxxxxx>
wrote:

Steve Marcus wrote:
"Hayabusa" wrote
, "Steve Marcus" wrote:
Steve Marcus wrote:

And, of course, Wolter's Maine-tombstone-to-KRS comparison
depends upon a fundamental assumption, that
the KRS has not experienced any factors which might
"accelerate the weathering rate of biotite mica".
In suggesting that weathering rate of the Maine tombstone biotite
might have been accelerated, Wolter is treating the KRS
as if it were the control sample in the comparison
(which is not the way to do the comparison),

I think that' a fair assumption. Biotite doesn't weather easily. -
Take into account that I know little about weathering, but I am a
hardrocker. I have seen biotite bleached by acidic soils - swamps and
bogs; these conditions are usually much stronger than any rain can
provide, and the bleaching was caused over 10.000 years or so. If you
leave biotite in a jar of humous acid for 100 years I would be
surprised if you get any observable effect.

Interesting. The authors state that at least some of the Maine
tombstones (although they don't positively state it for the three
samples they used in their dating of the KRS) had lichens on them
and that acid produced by these lichens would
"accelerate the weathering rate of biotite mica."

The KRS was discovered buried in soil that one might safely predicate
was a bit "swampy" or "boggy"; that condition was used to support
consideration of Runestone Hill as fitting the term "island" which
appears on the KRS. Do I conclude from your post that burying a
stone in swampy or boggy conditions would not accelerate the
weathering of biotite so as to impart a "200 year old appearance" to,
let's say, a 100 year old inscription that had been buried for 50
years?

For the effect of lichens and more, see
"Biodegradation of Cultural Heritage:
"Decay Mechanisms and Control Methods"
http://www.arcchip.cz/w09/w09_tiano.pdf
[300 kb]
(Lichens on page 6)

I'm not quite sure that this is entirely relevant to the KRS which is
made of greywacke which is not mentioned at all. Basalt is mentioned
only once and then only in reference [103]. There is no mention of
granite or slate. The materials of primary interest are sandstone,
limestone and marble..

But, the difference between slate and greywacke seems to have caused no
concern.

Hmm. While no doubt you will disagree, you are changing the subject
from that of the rate of biological attack.

Obviously you didn't read my entire post before writing the above sentence.
I was not changing the subject, but was merely pointing out that in the
sentence above mine, you stated that an article on decay mechanisms and
control methods didn't seem to you to be relevant to the KRS because the
materials "of primary interest in the article included sandstone, limestone
and marble" while greywack and slate weren't mentioned. In other words,
*you* introduced the idea that rates of biological attack seemed, at least
to you, to be dependent on what type of rock was being discussed.

Yet you seem to have no issue with a comparison between comparing biotite
weathering of slate and greywacke. That seems inconsistent to me. I invite
you to explain why those positions are not inconsistent.


The point is that it isn't clear whether biotite degradation and/or
removal
from greywacke can be measured in terms of biotite degradation and/or
removal from slate, when the slate and greywacke have been "sitting" in
different geographical areas with different climates and amounts of
precipitation, and the greywacke is alleged to have been underground for
at
least 30 years in soil which might be acidic enough to accelerate the
"weathering" of the biotite.

Well, what say you? Do you agree or disagree with the sentiment expressed
in the above sentence?


None of the above says Wolter's wrong in his approach or his conclusions;
only that there are holes in what was presented that are picked up simply
by
applying logic to the material. If the logic is inapplicable because of
some sort of geologic knowledge that I (and most other laymen) lack, then
it
was Wolter's burden to address that lack in the book if the book was
intended (as it clearly purports to be) for laymen.

You should be able to discern from the above two sentences that I'm not
condemning Wolter's work out of hand. I am merely:

1. Asking questions;

2. Pointing out that these questions should not have been permitted to
arise in a work purporting to adhere to scientific principals; and

3. Noting that the the fact that these types of questions remain should
keep one from accepting Wolter's work out of hand..

If I'm wrong, I invite all attempts to educate me.



And also, with an other view:
Irish Stone Monuments study
http://www.heritagecouncil.ie/publications/stone/conc.html

" Patinas of biological origin were studied on
limestone and sandstone. Microscopic study
showed evidence of carbonate and quartz
particles being removed by the lichen and
incorporated into biological tissue in limestone
and sandstone respectively.
...
However, biological coats also provide protection
against rainfall dissolution, wind abrasion,
atmospheric pollution and salt weathering. The
rate of particle removal by lichen can be lower
than the rate of material loss through the above
decay processes and agents, especially in the
exposed environments of the west coast. ..."

This too seems to primarily focus on sandstone and limestone.

See above ...



Eric Stevens

Steve



Eric Stevens

Steve



.

Relevant Pages

  • Re: Geology Question (KRS related)
    ... In suggesting that weathering rate of the Maine tombstone biotite might have been accelerated, Wolter is treating the KRS as if it were the control sample in the comparison, ...
    (sci.archaeology)
  • Re: Geology Question (KRS related)
    ... In suggesting that weathering rate of the Maine tombstone biotite ... Wolter is treating the KRS ...
    (sci.archaeology)
  • Re: Geology Question (KRS related)
    ... "accelerate the weathering rate of biotite mica". ... In suggesting that weathering rate of the Maine tombstone ... Wolter is treating the KRS ...
    (sci.archaeology)
  • Re: Geology Question (KRS related)
    ... "accelerate the weathering rate of biotite mica". ... In suggesting that weathering rate of the Maine tombstone biotite ... Wolter is treating the KRS ...
    (sci.archaeology)
  • Re: Geology Question (KRS related)
    ... >>> is that a weathering comparison was used to date the inscription ... >> graywacke is a sedimentary rock; ... as slate is produced from shale. ... >> The KRS is best described as metagraywacke, ...
    (sci.archaeology)
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