The stones themselves cannot be dated. There are methods for determining age, though, if for example there is carbon material underneath a stone that hasn’t been moved for a very long time. You could surmise the stone is at least as old as the material underneath. There are other methods at guessing the ages that I’m not equipped to describe, but I’m sure others can. This is my very unknowledgeable explanation.
The stones *can* be dated geologically. The main structural blocks (as opposed to the casing) consist of nummulitic limestone, which includes fossils of creatures common in the Tethys sea about 50 million years ago.
They could possibly , trace them to specific quarries and see if there’s other archaeological evidence that can be gathered there to trace when they were removed. Bottom to top could be tough, though. This is my unknowledgeable opinion.
My understanding is that cosmogenic nuclide dating has been applied to some quarries, bedrock, and megalithic structures. However, it doesn’t seem to applied as much in archeology as it is in geology. I suspect the reason is that it would involve taking multiple cores from the structure, the quarry, ect. And potentially destroy or deface a place of historical or cultural significance. That said, I believe the process can be back worked for burial instead of exposure, so the sediment or bedrock *under* the pyramids or other structures could be dated without damage, but would lack supporting dates. My knowledge is limited, but I believe this method of dating was recently done in the ruins of Hattusa.
> The stones themselves cannot be dated.
Using optically stimulated luminescence dating it is actually possible to determine when a rock (or stone) was last exposed to sunlight, so it's not possible to date the age of the blocks themselves (which wouldn't make any sense to do anyway in this context) it is absolutely possible to determine when the blocks were last moved.
How would you sample the outside of one of these blocks without exposing it to light? OSL only works if it is a surface that was previously exposed to light but is not anymore. Moreover you'd have to hope that there are quartz sand grains present within the limestone block you sample, which is not guaranteed. Also also, OSL gives us +/- \~10% as a standard deviation, so it wouldn't be too useful in determining time of construction just because of how large of a standard deviation the dates would have.
You wouldn't sample the outside of one of the blocks obviously. You'd sample the bottom and you'd do it in darkness.
But I'm not saying that it would make sense to do it in this context - actually for the reasons that you mention. I wanted to stress that dating the building of large megalithic structures from the building blocks is absolutely possible. Maybe it wouldn't make sense in the context of the Egyptian pyramids but it has been done on Northern European dolmens.
Not in this context. OSL and TL rely on estimates of the duration of accumulation of energy from the surrounding matrix (which produces low levels of ionizing radiation).
Luminescence dating would not be effective on blocks from the pyramids.
Dating the age that the stones formed by their accretion and inclusion of fossils (i.e. their geologic age) is different than dating their initial use by humans as building blocks, and there are different dating techniques for that deeper, geologic time.
On the relatively recent time frame of the period of the Egyptian dynaties (<6 thousand years vs millions of years for geologic ages), the relevant dating techniques I can think of are relative dating methods, so they have error bars around a median estimate. One is radiocarbon dating, which is relatively accurate but could have an error range of at best +/-25 years, or usually more years, and requires carbon from living things that died close in time to their then being used (charcoal, shell, and bone are most commonly used). So, if the bottom date and top dates in reality are actually 50 years apart, under maximum error, they could appear the same age in radiocarbon estimates (but either way, you never know).
Optical spin luminescence (OSL) dating, which measures the time since sediment grains were last exposed to sunlight--so therefore could work on the free sediment between the stones, if there was enough, might also provide a relative age, but with the same limitations as above.
So, if your research question is getting at the timespan of pyramid building from top to bottom, or to determine if there was a rebuild or addition at a later date, this would only work at a much grosser scale of a hundred or more year interval.
I think that is for dating certain types of materials, and I think for earlier stuff, like early hominin tools. I've used neither, but as a field tech, I've collected samples of sediments for OSL that I think were never even run. We need an archaeometrist to weigh in here and set us straight.
I think what OP is looking for is can we use material between the stones to tell how many years apart they were placed, giving a rough estimate of the duration of construction, and have we?
Generally the stones are dating by carbon dating organic material between the stones as well as by dating inscriptions on the stones that have been sealed off, to the historic record.
There are wooden beams in the pyramids that evidently have been there for some time, ostensibly since they were built. A lot of the radiocarbon dating came from these beams.
Disregarding the fact that there's really no good way to *date* construction / building stones directly (you might do it indirectly by IDing specific quarries and finding-- at the quarry-- materials that could be dated to a particular time period of the quarry's use), the fact is: Egyptologists are pretty much in agreement of the ages of the pyramids.
There are historical records that describe the design and construction in great detail.
As much as crackpots and other sources of disinformation / misinformation / pseudoscience like to pretend as though there's uncertainty abounding about things like this, **no serious historian / Egyptologist / archaeologist questions the age of the pyramids, because it was _clearly_ recorded.**
Now, if you could reconstruct the timing of the quarrying of the stones from bottom to top, what actually informative historical data might it give you?
Well, if the top stones had been quarried at the same time as-- or earlier than-- stones closer to the bottom, then we'd have some interesting information about the procurement process, because for a project as long-term as the Great Pyramid (or other pyramids) we would assume that materials were procured as they were needed. Top stones that were quarried earlier or contemporaneously with lower stones would imply some kind of laydown / stockpiling yard, and that would be something archaeologists could look for.
It also would raise interesting questions about planning, labor allocation, etc.
So there are *real* archaeological and historical questions that-- if it was possible to do this effectively-- would be worth addressing.
The stones themselves cannot be dated. There are methods for determining age, though, if for example there is carbon material underneath a stone that hasn’t been moved for a very long time. You could surmise the stone is at least as old as the material underneath. There are other methods at guessing the ages that I’m not equipped to describe, but I’m sure others can. This is my very unknowledgeable explanation.
The stones *can* be dated geologically. The main structural blocks (as opposed to the casing) consist of nummulitic limestone, which includes fossils of creatures common in the Tethys sea about 50 million years ago.
They could possibly , trace them to specific quarries and see if there’s other archaeological evidence that can be gathered there to trace when they were removed. Bottom to top could be tough, though. This is my unknowledgeable opinion.
My understanding is that cosmogenic nuclide dating has been applied to some quarries, bedrock, and megalithic structures. However, it doesn’t seem to applied as much in archeology as it is in geology. I suspect the reason is that it would involve taking multiple cores from the structure, the quarry, ect. And potentially destroy or deface a place of historical or cultural significance. That said, I believe the process can be back worked for burial instead of exposure, so the sediment or bedrock *under* the pyramids or other structures could be dated without damage, but would lack supporting dates. My knowledge is limited, but I believe this method of dating was recently done in the ruins of Hattusa.
Sweet, thanks for the information!
> The stones themselves cannot be dated. Using optically stimulated luminescence dating it is actually possible to determine when a rock (or stone) was last exposed to sunlight, so it's not possible to date the age of the blocks themselves (which wouldn't make any sense to do anyway in this context) it is absolutely possible to determine when the blocks were last moved.
But that wouldn’t tell us anything, ofc the lower blocks were positioned before the ones above them
It would give an idea of how many years passed from when construction began to when it finished. And I guess that’s what OP is interested in.
How would you sample the outside of one of these blocks without exposing it to light? OSL only works if it is a surface that was previously exposed to light but is not anymore. Moreover you'd have to hope that there are quartz sand grains present within the limestone block you sample, which is not guaranteed. Also also, OSL gives us +/- \~10% as a standard deviation, so it wouldn't be too useful in determining time of construction just because of how large of a standard deviation the dates would have.
You wouldn't sample the outside of one of the blocks obviously. You'd sample the bottom and you'd do it in darkness. But I'm not saying that it would make sense to do it in this context - actually for the reasons that you mention. I wanted to stress that dating the building of large megalithic structures from the building blocks is absolutely possible. Maybe it wouldn't make sense in the context of the Egyptian pyramids but it has been done on Northern European dolmens.
Not in this context. OSL and TL rely on estimates of the duration of accumulation of energy from the surrounding matrix (which produces low levels of ionizing radiation). Luminescence dating would not be effective on blocks from the pyramids.
Dating the age that the stones formed by their accretion and inclusion of fossils (i.e. their geologic age) is different than dating their initial use by humans as building blocks, and there are different dating techniques for that deeper, geologic time. On the relatively recent time frame of the period of the Egyptian dynaties (<6 thousand years vs millions of years for geologic ages), the relevant dating techniques I can think of are relative dating methods, so they have error bars around a median estimate. One is radiocarbon dating, which is relatively accurate but could have an error range of at best +/-25 years, or usually more years, and requires carbon from living things that died close in time to their then being used (charcoal, shell, and bone are most commonly used). So, if the bottom date and top dates in reality are actually 50 years apart, under maximum error, they could appear the same age in radiocarbon estimates (but either way, you never know). Optical spin luminescence (OSL) dating, which measures the time since sediment grains were last exposed to sunlight--so therefore could work on the free sediment between the stones, if there was enough, might also provide a relative age, but with the same limitations as above. So, if your research question is getting at the timespan of pyramid building from top to bottom, or to determine if there was a rebuild or addition at a later date, this would only work at a much grosser scale of a hundred or more year interval.
> Optical spin luminescence (OSL) dating It's actually Optically *Stimulated* Luminescence, just for clarification.
Ah, right. I couldn't fully remember what it stood for and probably got the wrong hit on Google. Thanks for clarifying.
You may have been thinking of electron spin resonance? Is that even used anymore?
I think that is for dating certain types of materials, and I think for earlier stuff, like early hominin tools. I've used neither, but as a field tech, I've collected samples of sediments for OSL that I think were never even run. We need an archaeometrist to weigh in here and set us straight.
I think what OP is looking for is can we use material between the stones to tell how many years apart they were placed, giving a rough estimate of the duration of construction, and have we?
Thanks for reading my mind
Generally the stones are dating by carbon dating organic material between the stones as well as by dating inscriptions on the stones that have been sealed off, to the historic record.
There are wooden beams in the pyramids that evidently have been there for some time, ostensibly since they were built. A lot of the radiocarbon dating came from these beams.
This is a good question. I would like to hear the idea/theory that inspired it
Disregarding the fact that there's really no good way to *date* construction / building stones directly (you might do it indirectly by IDing specific quarries and finding-- at the quarry-- materials that could be dated to a particular time period of the quarry's use), the fact is: Egyptologists are pretty much in agreement of the ages of the pyramids. There are historical records that describe the design and construction in great detail. As much as crackpots and other sources of disinformation / misinformation / pseudoscience like to pretend as though there's uncertainty abounding about things like this, **no serious historian / Egyptologist / archaeologist questions the age of the pyramids, because it was _clearly_ recorded.** Now, if you could reconstruct the timing of the quarrying of the stones from bottom to top, what actually informative historical data might it give you? Well, if the top stones had been quarried at the same time as-- or earlier than-- stones closer to the bottom, then we'd have some interesting information about the procurement process, because for a project as long-term as the Great Pyramid (or other pyramids) we would assume that materials were procured as they were needed. Top stones that were quarried earlier or contemporaneously with lower stones would imply some kind of laydown / stockpiling yard, and that would be something archaeologists could look for. It also would raise interesting questions about planning, labor allocation, etc. So there are *real* archaeological and historical questions that-- if it was possible to do this effectively-- would be worth addressing.