Origyptian Wrote:
-------------------------------------------------------
> Thanos5150 Wrote:
> --------------------------------------------------
> -----
> > Modern contamination happens in the lab, not in
> the
> > field, so are we to expect all of these labs to
> be
> > tainting their samples in the same way sample
> > after sample little different 11yrs apart? This
> > does not seem reasonable if even possible.
>
> It doesn't seem reasonable to you because you're
> making an incorrect assumption. Modern
> contamination can be accounted for by at least two
> possible sources other than the lab (I never
> claimed the lab introduced any contamination):
>
>

1. Contamination definitely
> has been happening since the casings were removed
> centuries ago and the ancient mortar has been
> exposed to the more modern atmospheric pollution,
> tourists, robbers, animals, windblown organic
> matter, etc., all of which have had their way with
> the surface chemistry of those exposed core blocks
> and mortar,
>
> 2. The mortar may have been introduced in the
> early/pre- Dynastic period during restoration
> projects and not as original construction. While
> this might contain some smaller amount of date
> "contamination", it's an enormous
> contamination in the presumption that the
> dates refer to the original construction of the
> structure.

>
> > And regardless, modern contamination affects a
> > sample less and less the younger it is and no
> > matter what isn't going to tack on thousands of
> years.
>
> Modern contamination most certainly can take
> off thousands of years, the more and more
> older the original sample really
> is, as I've explained in my
> [url=http://grahamhancock.com/phorum/read.php?1,10
> 54014,1055124#msg-1055124]earlier post to
> you[/url].
>
>
>
> > For convenience I quote Wikipedia:
> > "Any addition of carbon to a sample of a
> > different age will cause the measured date to
> be
> > inaccurate. Contamination with modern carbon
> > causes a sample to appear to be younger than it
> > really is: the effect is greater for older
> > samples. [b]If a sample that is 17,000 years
> old
> > is contaminated so that 1% of the sample is
> modern
> > carbon, it will appear to be 600 years
> > younger[/b]; for a sample that is 34,000 years
> old
> > the same amount of contamination would cause an
> > error of 4,000 years. Contamination with old
> > carbon, with no remaining 14
> > C, causes an error in the other direction
> > independent of age – a sample contaminated
> with
> > 1% old carbon will appear to be about 80 years
> > older than it really is, regardless of the date
> of
> > the sample."
>
> > So if a 17,000yr (15,000BC) old sample appears
> > only 600yrs younger with 1% modern
> contamination
> > it would take 18-20% contamination to get that
> > sample to appear to be 5,000yr (3,000BC) old.
> > There is no stretch of the imagination to make
> > this plausible.
>
> How do you know how much modern carbon could have
> seeped into the surface of that mortar and/or has
> been chemically exchanged with, or absorbed by,
> that surface "charcoal" over the past 700 years,
> considering all organic substances that could come
> in contact with those surfaces over such 24/7
> exposure? The RCD studies made a fundamental error
> of not only taking surface samples, but actually
> [i][u]requiring[/u][/i] that all of the samples
> be taken from the surface without offering any
> explanation at all for that requirement other than
> stating that all samples were biased to only those
> that contain a visible 1 mm clump of surface
> charcoal, the content of which is anyone's guess
> after being exposed to surface carbon for almost a
> millennium if not much longer.
>
> And that's not the only thing that's causing a
> skewed result. Let's not forget the outlier math
> apparently presumes a univariate normal
> distribution when no such sample distribution was
> mathematically characterized. This results in an
> incorrect "best fit" statistical method that
> forces the data into a preordained "expected"
> range. That seems clear with the '95 study (which
> included the '84 data).
>
> By the way, depending on the source of the
> charcoal in the samples and the process used to
> manufacture the mortar, charcoal can attract/trap
> a relatively huge volume of environmental carbon
> which can add significantly to the contaminant
> effect. For example, modern activated charcoal
> (which can be created simply by heating it above
> 250C within oxygen steam) absorbs not merely 20%
> of its weight, but up to [i][u]50,000
> times[/u][/i] its weight. Note that the process
> for manufacturing
> [url=https://books.google.com/books?id=Mtth5g59dEI
> C&pg=PA1081&lpg=PA1081&dq=process+to+make+%22gypsu
> m+mortar%22&source=bl&ots=tE_OhyPZRz&sig=DhgGtN2jN
> gPyAx8_g9zmCu_3-c4&hl=en&sa=X&ved=0ahUKEwiTgeDz1bT
> NAhXHZj4KHT9RCP8Q6AEIODAE#v=onepage&q=process%20to
> %20make%20%22gypsum%20mortar%22&f=false]gypsum
> mortar[/url] is about 250C to get the "sweet spot"
> between a slow drying but hard gypsum (120C-180C)
> and a fast drying, brittle gypsum (300C). So it's
> quite possible that the process created a lot of
> activated charcoal that served as a target for a
> great deal of modern contamination.
>
>
>
> > > Also, we need to consider the possibility that
> the
> > > sampled mortar might have been applied by the
> OK
> > > long after the original date of
> construction...
> >
> > As I said before, the joints of many blocks are
> > slathered with mortar which you can see where
> it
> > has oozed out between them. Romer estimates
> over
> > 500,000 tons of mortar was used in
> construction.
>
> Not sure how he has determined it was used during
> the "construction", vs. restoration, etc., long
> after original construction.
>
>
> > For this to be the work of restorers thousands
> of
> > years after the fact it would equate to them
> > refacing nearly the entire exterior of the
> core,
> > if not all of it, and this is assumes of course
> > the casing stones were not there.
>
> Not necessarily. It could simply mean that the
> restoration projects used mortar with big chunks
> of charcoal and the investigators biased their
> sampling to that batch of mortar applied during
> the restoration projects during dynastic times. We
> have no reason to assume the RCD studies selected
> randomly across that entire "500,000 tons" of
> mortar. By the way, considering G1 has been
> calculated to weigh a total of 6 million tons, I
> doubt Romer was talking about a half million tons
> of mortar on G1 alone.
>
> Meanwhile, it's not unreasonable to propose that
> throughout the dynastic era, they may very well
> have applied 500,000 tons of mortar as part of
> their reconstruction projects up and down the
> Nile. That's obviously a lot less work than
> building all that stuff from scratch. And it
> certainly would account for why the RCD studies
> are relatively consistent in dating the mortar to
> the dynastic period.
>
> Meanwhile, how can we know with certainty which
> mortar was applied during the
> [i][u]original[/u][/i] construction, if any,
> perhaps other than G1's casing stones which I'm
> not aware were ever sampled (again, I'm referring
> to deep samples, not the far more problematic
> surface samples).
>
>
>
> > > And of course, there's the artifacts
> introduced by
> > > the assumptions made in the "expected"
> distribution
> > > to ensure the data samples fit that
> distribution
> > > (as hinted by drrayeye's post in this thread).
>
> >
> > Other than drilling into the interior to
> hopefully
> > find a sample or two, there is nothing else
> that
> > is going to be any better than the samples
> > collected. Again, over 400 samples were taken
> > which all tell the same story which just so
> > happened to not be the story Egyptologists
> wanted
> > to hear. Twice.
>
> Perhaps it's simply a garbage-in-garbage-out
> effect? Do we have any reason to consider that the
> Egyptologists changed their methodology
> significantly between the various studies? Hawass
> was very clear that the only RCD studies he would
> approve are those that are run under the auspices
> of Egyptologists. So are there studies that were
> allowed to take deep samples, or that go into
> better description of the sample treatment to
> remove modern contamination, or that don't
> automatically presume a univariate normal
> distribution within the dynastic date range as a
> way to skew the data and omit those pesky
> "outliers"?
>
>
>
> > Again, over 400 samples say the same thing
> which
> > the '84 study in particular clearly gave
> results
> > Egyptologists did not want to see.
>
> And even though that Cayce study showed dates that
> were about 200 years older than the '95 study,
> it's not clear that the contamination in the '84
> samples still didn't make those dates far newer
> then they really are. The math allows those
> samples to be many millennia older than the
> investigator's methodology would lead us to
> believe.


Hey , Ori, what direct experience do you have with radiocarbon dating?

Thank you.