> 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 earlier post to you.
> 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. 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; 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 requiring 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 50,000 times its weight. Note that the process for manufacturing gypsum mortar 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 original 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.
How can any of us ever know, when all we can do is think?