Hi guys, today I will discuss an exciting technology, which method can date stone and
concrete. It is called Luminescence Dating. People interested in the world-wide megalithic phenomenon
are often aware of how very challenging it is to date prehistoric stone buildings. The more
commonly used radiocarbon dating can not date stone because it’s limited to organic items. Now
this new method Luminescence Dating can possibly unravel the age mystery of these megalithic sites.
Luminescence dating techniques are most commonly applied to sand or silt sediments.
Methods have been developed in recent decades that also allow us to date rock
surfaces of ancient stone sites. One such study was done on the Giza Plateau
where the smallest great pyramid and three other structures were tested.
The data was published about 8 years ago. The researchers claimed that the resultant ages
have confirmed most conventional Dynastic dates, while in some cases, predating the
conventional dates by hundreds of years. “ So, does that mean the mainstream timeline
of the Giza complex is actually correct? Were the great pyramids really built by dynastic Egyptians?
Maybe not. Let me show you what I have found and why I don’t think these results are conclusive.
First let’s see the luminescence dating results of the Giza structures.
This chart is from a 2014 research paper: Surface luminescence dating of some Egyptian monuments.
The link to this paper is in the description section under the video. I did some digging and
found that the samples used for dating were taken before 2010 from four sites on the Giza Plateau.
Here is a simplified chart for easier viewing.
I will focus on the structures which mainstream Egyptologists have given suggested dating;
they are the Valley Temple of Khafre, the Sphinx Temple and the Menkaure Pyramid.
While we are reading the luminescence dating results, I want to point out a few things that
caught my eye. First of all, samples that came from the same structures strangely show very
different ages. For example, the granite sample of the Valley temple is dramatically older than
the limestone sample by over 2,000 years. Did the temple take 2,000 years to complete?
That’s the time difference from Julius Caesar’s era to now 2022. What type of construction could
take that long? Also, I would like to remind you as many have pointed out, that at the Valley
Temple, the granite blocks were placed to cover the limestone core and work as an exterior layer;
which means the granite blocks should date younger than the limestone. But the luminescence data
show the opposite with the granite sample predating the limestone by 2,000 years.
The limestone sample was taken from an inner wall of the roof. I wonder whether
that part of the roof was not original but moved or added during a later renovation.
The same thing happened with the dating of Sphinx temple.
We can see that the oldest dating is again about 2,000 years older than the youngest sample. Both
samples are granite and both were collected close to the temple floor and the bedrock.
Isn’t that peculiar? Mainstream academia states it took only 20 years to build the great pyramid made
up of millions of big blocks. If correct, then why would the two significantly smaller temples take
2,000 years to finish? It doesn't add up. I don’t think these temples would have taken 2,000 years
to build even though that’s what the luminescence dating suggests. The drastically different dating
results could be caused by external reasons - I will come back to this point later.
Let’s keep reading the chart. The Menkaure Pyramid is the only pyramid that got tested
at Giza Plateau and its dating reveals something very interesting. The paper
notes one sample was taken and tested from the granite casing stone at the base of the pyramid.
This sample dates to around 3450 BC with a larger error margin. The Menkuare Pyramid sample
is the most ancient of all the samples collected from Giza by a minimum of a few hundred years.
Mainstream academia claims the three great pyramids of Giza
were built during the Old Kingdom of Egypt which is the period spanning 2700-2200 BC;
this period is known as the "Age of the Pyramids" or the "Age of the Pyramid Builders". The smallest
pyramid, the Menkaure, was said to be the last great pyramid built at Giza at 2510 BC.
But the luminescence dating result is literally arguing that the Menkuare pyramid was built way
before the Old Kingdom period around 3450 BC. Based on the dating result and its error margin,
the Menkaure Pyramid is potentially almost 1,900 years older than the conventional date. So,
the "Age of the Pyramid Builders" might actually be the “"Age of the Pyramids Discoverers".
Moreover, the oldest dating results of the Valley temple and the Sphinx temple signify
that these two also predate the mainstream claim of the 4th Dynasty in the Old Kingdom period
by a few hundred years and potentially closer to 1,000 years.
Even though the paper states that the dating results are within the conventional timeline,
the real data is actually proposing earlier dates of construction.
It’s also quite surprising to see that samples taken from the same building
were found to have a huge age difference of 2,000 years. This makes me question how accurate
and reliable are these luminescence dating results. Now let’s take a look at that aspect.
Luminescence dating refers to a group of methods of determining how long-ago
mineral grains were last exposed to sunlight or sufficient heating. Certain minerals such
as quartz and feldspar store energy within the lattices of the mineral's crystals.
High enough levels of heat or light can empty these crystals stored energy to zero,
after which time the mineral begins absorbing energy again which can be measured in a lab.
This method works as follows: in the distant past, people were building stone structures.
During the process such as cutting and transporting stone blocks, the solar radiation
bleached away the luminescence signal down to zero to a certain depth hence it resets the
time clock. When the masonry blocks were laid in areas where the block surfaces received no
light, “shielding of the surface occurs and re-accumulation of luminescence is initiated
due to irradiation from ambient radioactivity and continues till excavation and measurement.”
By testing buried elements of foundations or walls in archaeological ruins,
luminescence dating is able to tell us the last time that buried stone was exposed to light,
and hence when the building was first built.
There are two fundamental factors in order to achieve an accurate dating. The 1st is the
resetting or bleaching of the luminescence signal. The rock’s old signal needs to be
sufficiently "bleached" before it gets buried for its dating. Bleaching of the luminescence signal
is mainly dependent on light intensity, light spectrum and duration of exposure.
Material properties such as grain size, grain coating and mineralogy
may also influence bleaching efficiency. Short daylight exposure, from 1-100 seconds
of direct sunlight on quartz can effectively reset the time clock.
A few years ago, scientists found that besides sunlight, artificial light sources, including
some darkroom lights, can also bleach rock samples to various degrees even when they were exposed as
short as 15 minutes. Therefore, the rock samples should only be worked on in a light-safe lab.
The 2nd paramount factor in luminescence dating is proper sampling techniques to avoid light
contamination. Because surface luminescence dating methods determine the last time a mineral has been
exposed to light, it is imperative that samples must be collected in a light-proof container
since any exposure would result in apparent age underestimation.
I’ve read multiple recently published papers on luminescence dating and all of them stress how
critical it is that the sample be collected under safe lighting conditions, otherwise the sample is
at risk of age underestimation and will show a considerably more recent date due to loss of
the natural signal. The accuracy and precision of luminescence dating results are directly related
to the type and quality of the material sampled and sample collection methods in the field.
Researchers have done outdoor experiments to study the bleached level of rock samples. One experiment
took place in Southern Sweden. The testing results proved that the samples exposed to daylight were
bleached relatively rapidly in both sunny and cloudy days. The initial bleaching was more rapid
in direct sunlight than under cloud cover with average bleaching rates of 15 %/s and 9 %/s,
respectively, for the first 5 seconds of exposure. This means that even if the sample is exposed
for just 1 second in a cloudy day in Sweden, the light can still bleach 9% of the natural dose
which would result in a younger reading of the rock’s burial age.
On this global solar map, we can see the Nordic country Sweden is at the lower spectrum regarding
average received solar irradiation, while Egypt is endowed with much more abundant solar resource.
This indicates that the masonry block surfaces at the Giza Plateau would be easily bleached
to zero for luminescence dating which is good. But the sunlight is a two-edged sword
since it would require extra care when collecting samples in Egypt,
because intense sunlight or even reflective light can bleach and contaminate a sample.
In order to avoid light contamination, special tools are used to safeguard the sampling process.
Currently sampling tubes are the most common method of collecting a luminescence sample.
Sampling tubes are light-proof and typically hammered into the side of an archaeological trench
to collect samples. After the tube is fully inserted, it is then excavated back out,
and the light-exposed ends are sealed with opaque plastic, tape or a cap.
Experts say that if light contamination cannot be prevented using sampling tubes or cores,
a sample may be collected under an opaque tarp or at night.
Finding tarp material that is truly light-safe can be tricky, and multiple layers may be necessary.
Ok, so collecting and processing rock samples for luminescence dating is a
delicate job since any light exposure would affect the dating accuracy.
With this information in mind, let’s see how the Giza samples were collected.
Here are the photos showing where the samples were collected and that they were taken during bright
daytime. According to the paper, “Surfaces were detached from walls gently by a hammer and chisel
and pieces of inner surface with an area around 2 × 2 cm. The procedure is made with due caution and
by the moment the detached piece becomes loose the external part is covered by a black plastic bag
which covers the whole removed piece marking the outer part and with an arrow the inner surface.”
It’s a little confusing but basically the researchers used
a hammer and chisel to remove rock pieces instead of a sampling tube.
Sampling tubes were not available when these samples were taken over 11 years ago.
Comparing to the recent sampling techniques,
the collection method used at Giza was not very sophisticated and not up today’s standards. The
unsatisfactory sampling could have affected the Giza dating results.
We just heard about how crucial proper sampling and processing are in surface luminescence dating.
However, at the Giza plateau, “By the moment the detached piece becomes loose the external part is
covered by a black plastic bag”. So, there is a gap between when the rock sample came loose
and when it got covered with a bag. How brief was this gap?
Don’t forget that even a second of daylight will influence the reliability of the dating result.
If one second of exposure in a cloudy day in a low solar region like Sweden can bleach 9% of a rock
sample’s natural dose, then how much damage can 1 second of strong sunlight do at the Giza Plateau?
I’m also curious how the sampling work was practiced. Was it done by two people as one
holds the chisel and hammer while another prepares the bag to cover the sample?
Since the samples were pretty small and they were all taken from buried or corner areas,
it would not be easy for two people to work side by side especially when one was raising a
chisel and hammer. The other person would need to wait until the holder of the hammer cleared
the premise in order to grab the sample. If the sampling was done by one person, then he/she
would need to chisel first then drop the tool and get a bag to wrap up the piece. Either way the
sample would likely be exposed to light therefore bleached and contaminated to a certain level.
I’m not going to scrutinize other factors such as the depths of samples, the bags
or lights used during the sampling, the sample preparation and examination with older techniques.
I think the chisel and hammer method alone could be sufficient to question the reliability
of the published dating results. Maybe that’s part of the reason why the samples from the same
building show vastly different ages because some samples were more bleached than others.
In luminescence dating, when a sample received unwanted light exposure it would result in age
underestimation, in other words, a younger age. Since the Giza samples were probably contaminated
due to an earlier sampling method; that means the dating results from the paper
could be considerately younger than the actual ages of these sites. Therefore,
the real ages could be much more ancient. Even with the possible bleached samples, the Menkaure
Pyramid was still dated to be over 900 years older than the conventional time. Meanwhile,
the two temples are likely to have been built long before the Egyptian Old Kingdom period as well.
What does this tell us? That the pyramids, along with the Valley Temple and Sphinx temple are not
the works of dynastic Egyptians. These magnificent structures have a much longer history than
mainstream academia has given them credit for. My last question is this: can we do another sampling
at the Giza Plateau with the most cutting edge technology and if so what might that reveal? If
you have any insights, please leave me a comment. If you like my video, please give me a thumbs up
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to share with you. This is Curious Being, I’m Tina. Thanks for watching and see you next time.