# How do they Carbon date stone carvings? **URL:** \ **Category:** Factual Questions\ **Created:** [March 2, 2017, 12:05am UTC](https://boards.straightdope.com/t/how-do-they-carbon-date-stone-carvings/781148 "2017-03-02T00:05:32Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![Mrdeals](https://avatars.discourse-cdn.com/v4/letter/m/ea666f/32.png) [@Mrdeals](https://boards.straightdope.com/u/Mrdeals)\ **Post date:** [March 2, 2017, 12:05am UTC](https://boards.straightdope.com/t/how-do-they-carbon-date-stone-carvings/781148/1 "2017-03-02T00:05:32Z")
I was watching a show on the History channel and they showed these large stones in Nevada, the stones had symbols carved directly into the rock. They then state “these carvings have been dated to more than 10,000 years ago” I understand how cave paintings can be dated based on the substance added to the rock. In this case however, nothing is being added. ---
**Author:** ![bob\_2](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/bob_2/32/3341_2.png) [@bob\_2](https://boards.straightdope.com/u/bob_2)\ **Post date:** [March 2, 2017, 12:11am UTC](https://boards.straightdope.com/t/how-do-they-carbon-date-stone-carvings/781148/2 "2017-03-02T00:11:36Z")
Dating is a complex question and conclusions are drawn from an assessment of a whole load of data relating to the place and the surroundings. > [@](#): > > There is no way to date a stone carving based on just the stone itself, because the chemistry of the situation is too variable and too complex. For example, moisture and temperature fluctuation will have a big effect on how a stone weathers. So, one excavated stone might look brand new, and another one very ancient and degraded. > > Usually stone carvings are dated either on the basis of style or on the archaeological context they are found in. > > [methodology - How can one reliably date a carved stone item or structure? - History Stack Exchange](http://history.stackexchange.com/questions/25561/how-can-one-reliably-date-a-carved-stone-item-or-structure) ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [March 2, 2017, 12:17am UTC](https://boards.straightdope.com/t/how-do-they-carbon-date-stone-carvings/781148/3 "2017-03-02T00:17:44Z")
Did they say “carbon dated”, or just “dated”? ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [March 2, 2017, 12:30am UTC](https://boards.straightdope.com/t/how-do-they-carbon-date-stone-carvings/781148/4 "2017-03-02T00:30:40Z")
\*Radiocarbon testing dated the carbonate layer underlying the petroglyphs to roughly 14,800 years ago. Geochemical data, sediment and rock samples from adjacent Pyramid Lake show they were exposed to air from 13,200 to 14,800 years ago and again from 10,500 to 11,300 years ago. ‘Whether they turn out to be as old as 14,800 years ago or as recent as 10,500 years ago, they are still the oldest petroglyphs that have been dated in North America,’ said Benson, a national research scientist emeritus for the U.S. Geological Survey and curator of anthropology at the University of Colorado Natural History Museum in Boulder. \* > **[Rock of ages! Ancient carvings unearthed on Nevada boulders could be the...](https://www.dailymail.co.uk/sciencetech/article-2394340/Ancient-petroglyphs-Nevada-oldest-rock-carvings-North-America.html)** > > The petroglyphs were found on limestone boulders near Pyramid Lake in northern Nevada's high desert and feature geometric designs. ---
**Author:** ![Banksiaman](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/banksiaman/32/3334_2.png) [@Banksiaman](https://boards.straightdope.com/u/Banksiaman)\ **Post date:** [March 2, 2017, 7:26am UTC](https://boards.straightdope.com/t/how-do-they-carbon-date-stone-carvings/781148/5 "2017-03-02T07:26:32Z")
Geochemical carbonates can form on stone surfaces in some conditions. A rock engraving may overlie the carbonate or cut through. Having carbon content C14 dating of the carbonate is a possibility. In the first case the date of the carbonate provides a _terminus post quem_ [date after which the art was done], while in the second case its a _terminus ante quem_ [date before which]. Exactly how long the art was executed before or after the carbonate is another question. It could be days or centuries. C14 dates represent a probability range and it is common practice to use the mean date plus or minus 2 standard deviations to reasonably represent the likely possible date range. ---
**Author:** ![Banksiaman](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/banksiaman/32/3334_2.png) [@Banksiaman](https://boards.straightdope.com/u/Banksiaman)\ **Post date:** [March 2, 2017, 10:59am UTC](https://boards.straightdope.com/t/how-do-they-carbon-date-stone-carvings/781148/6 "2017-03-02T10:59:39Z")
Oops - if the engraving is overlain by the carbonate, then that provides the terminus ante quem. Didn’t see my error back there. ---
**Author:** ![Isilder](https://avatars.discourse-cdn.com/v4/letter/i/cc9497/32.png) [@Isilder](https://boards.straightdope.com/u/Isilder)\ **Post date:** [March 2, 2017, 12:40pm UTC](https://boards.straightdope.com/t/how-do-they-carbon-date-stone-carvings/781148/7 "2017-03-02T12:40:47Z")
yep, and they fit it in with knowledge of the local geography, climate ,etc to be sure that there wasn’t some other event that disturbs the dating technique. They didnt have to date the carbonate that was laid over the top, they just had to determine when the lake level was high enough to lay the carbonate on the carvings. Whether they get that directly from the carbonate or from other techniques. (eg dating wood in the layers of sediment around the place… ) … they do as much as they can to be sure that they aren’t missing something. ---
**Author:** ![CalMeacham](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/calmeacham/32/35_2.png) [@CalMeacham](https://boards.straightdope.com/u/CalMeacham)\ **Post date:** [March 2, 2017, 12:51pm UTC](https://boards.straightdope.com/t/how-do-they-carbon-date-stone-carvings/781148/8 "2017-03-02T12:51:31Z")
> [@Mrdeals](#): > > I was watching a show on the History channel and they showed these large stones in Nevada, the stones had symbols carved directly into the rock. > > They then state “these carvings have been dated to more than 10,000 years ago” > > I understand how cave paintings can be dated based on the substance added to the rock. In this case however, nothing is being added. I’ve got books on Southwestern Rock Art that devote entire chapters to the dating of carvings. In short, you’re right that you can’t carbon date something with no carbon in it. As others have pointed out, “these carvings have been dated to more than 10,000 years ago.” doesn’t say they were _carbon_ dated. Even more cynically, I’ll point out that the statement doesn’t say they were _correctly_ dated, either. Some dating methods: 1.) Rock _paintings_ , or carvings with painted parts may contain carbon datable pigments or binders 2.) Nearby campsites may have artifacts that are datable. It’s still a question if the site and the carving are related. 3.) Other items (like a tree growing through the carving) provide datable items after the carving 4.) geological events (like the carvings were buried by a datable rockslide or covered in a datable flood 5.) The subject matter itself may be datable (like it contains a man riding a horse. Or an automobile – yes, these really occur. Or someone claims the carving represents an astronomical event, like a nova.) 6.) Guessing.