Thread by @NaqadStudies

*UPDATE*
Offset for Mediterranean areas in Carbondating

We've had some helpful reviews (particularly by one expert) of this original thread.

We have one correction, as well as some added information from two recent papers provided by Dr Sidky, which we will go into presently...

https://twitter.com/NaqadStudies/status/1242651994789154819

At the outset, we should say that we used imprecise language when paraphrasing Youssef-Grob.

Thank you Dr Sidky for point this out.

https://twitter.com/therealsidky/status/1242792226595508224?s=20

Now for the longer update!

An offset of approx. 19 years was detected by Dee et al (2010) when carbon dating Egyptian artifacts.

This particular offset means that calendar date will be ~19 years younger than the raw radiocarbon dating.

The difference in flora growing seasons in Mediterranean regions cause small deviations in carbon dating, compared to European areas.

Generally, the Mediterranean growing season starts earlier than the European growing season.

However, this Egyptian offset appears to be episodic, rather than constant. It is therefore "not amenable to the application of a simple constant offset or error enlargement."

See the following paper:
advances.sciencemag.org/content/6/12/e…

So how do we proceed in light of this variation?

Results of Mediterranean trees (GOR, from central Anatolia) with a known age have been set against the C14 calibration curves.

Thanks to this, areas of positive or negative offset can be accurately defined.

On Graph B, A and C are negative offsets, B is a positive offset.

In other words, the C14 results are really older than measured for the steep parts of the curve (A and C), and are really younger than measured for the plateaus (B) for the examined areas.

So each period has its own, specific +/- offset variation.

Steep slopes of the calibration graph correspond with increased C14 production, and likely lower solar irradiance.

These are the periods that allow for the best precision in carbon dating - and that is of ultimate interest for early Qur'ānic manuscript dating!

These findings seem to be in line with experiments done on a tree from S. Jordan (Juniper).

pnas.org/content/pnas/1…

The authors conclude that offsets seem to apply on plateaus of the calibration curve.

Note of caution: the above articles focus on offset results obtained from 3350 Before Present, and might not apply to early Qur'ānic C14 results.

Coranica anticipated this objection by very accurately C14 dating a 710 CE papyrus of known age. See chart!

https://twitter.com/NaqadStudies/status/1242652020949073922?s=20

Being only students ourselves, Naqad relies on reading academic material and fairly representing their findings.

So what's our conclusion, having done this to the best of our abilities?

Coranica seems to stand on solid ground concerning the carbon dating of their samples.✅

Addendum:
Understand that C14 dating of early Islamic manuscripts is a controversial area of ongoing dispute.

You may expect this to be debated in ivy-lined halls - and on Twitter, by experts and hobbyists alike - for the foreseeable future!